Category Archives: WW2

World War 2 saw the airplane rise to even greater importance than in the first World War. Air superiority became a crucial component of battlefield operations and air forces were massively expanded during the conflict.The Allied and Axis sides of the war developed enormous war machines, capable of developing and rolling out unprecedented numbers of advanced new military equipment in rapid response to changing conditions on the battlefield, as well keeping up with the technological advances of adversaries.

High altitude bombing raids and night fighting were hallmarks of the War for Europe, whilst aircraft carrier battles pitched the American and Japanese fleets against one another. The technology of the day was pushed to it’s limit with the use of superchargers in aircraft engines, the introduction of radar, and the rapid development of the jet engine by the war’s end.

The period ended as the Nuclear Age and subsequent Cold War were ushered in by the tremendous and tragic blows to Japan’s wearied people.

Heinkel He 162 Volksjäger

Nazi flag Nazi Germany (1944)
Jet Fighter – 116 ~ 270 Built

The Volksjäger Fighter colorized by Michael Jucan

The combined American, British and Soviet Air Forces began to take over the skies above Europe in the later part of the war. Germans were desperate to find a way to fight the combined Allied bomber raids that were slowly destroying German industry which was necessary for continuation of the war. A cheap and easy to build jet fighter was believed to be the solution to the Allied bombing raids. From these aspirations the Volksjäger, “The People’s Fighter,” project was born.

Emergence of the Volksjäger Concept

The men responsible for the creation of the Volksjäger idea and concept were civil engineers Hauptdienstleiter Dipl-Ing Karlo Otto Saur, who was also a member of the Nazi party, and Generaloberst Alfred Keller.

Otto Saur was quick to realize that by 1944 the Luftwaffe was a shadow of its former glory. This was most obvious for the fighter force, which was engaged in a desperate struggle with a more numerous and better equipped enemy. Otto Saur’s conclusion was that a cheap and easy to build jet fighter could tip the balance of power in Germany’s favor again. He was quick to present his idea to Hermann Göring, Reichsluftfahrtminister, the Reich’s Minister of Aviation, who immediately supported it.

Generaloberst Alfred Keller, who was in charge of the flying, training and sports association (Nationalsozialistisches Fliegerkorps – NSFK) also supported the Volksjäger idea. The NSFK organization was also involved in offering several courses, The Flying Hitler Youth (Flieger Hitlerjugend) on how to build model aircraft and glider flying training for schoolboys. In support of Otto Saur’s proposal, Alfred Keller came with his own proposal to use these young boys, with ages between 15 to 17, as pilots for the mass produced Volksjäger. In Keller’s opinion, all that was needed was some short training with gliders which would be supplemented with more training on the Volksjäger.

Many in the Luftwaffe command opposed this project and the idea of using young boys as fighter pilots against the numerous and well-equipped and trained Allied air forces. The greatest advocate against this project was Generalleutnant Adolf Galland, being supported by Willy Messerschmitt, chief designer of the famous Messerschmitt company, and Kurt Tank, the most well-known designer at Focke-Wulf. The most important reason behind this opposition was the fact that, towards the end of the war, Germany was lacking fuel, materials, pilots, production capacity and many other elements. They argued that all available resources should be directed to the development and production of the already existing Me 262 jet fighter.

In the years prior to the collapse of the Luftwaffe, such a concept would most likely never have gained any support from Luftwaffe officials. However, by 1944, the Germans were in a desperate need for a wonder weapon to turn the tides. As Hermann Göring was no longer in Hitler’s good graces, he was desperate to find a way to appease Hitler. The best way to do this was to somehow find a miraculous solution to salvage the Luftwaffe, stop the incessant Allied bombardment of Germany, and provide much-needed support to the beleaguered Wehrmacht. Through these psychological lens, Otto Saur’s and Alfred Keller’s proposals looked like an ideal solution. Despite the great opposition, Hermann Göring kept insisting that the Volksjäger development should begin as soon as possible. The Volksjäger would later be supported by Adolf Hitler and Albert Speer (the Minister of Armaments and War Production).

First Steps

In the search for a new low-altitude fighter, Oberst Siegfried Knemeyer was named responsible for the Volksjäger’s initial requirements. He was in charge of the Technical Equipment Office for flight development of the Ministry of Aviation (Reichsluftfahrtministerium, RLM). Siegfried Knemeyer was an experienced military pilot and engineer who participated in the test flights of many different experimental aircraft designs. From 1943 onward, he was part of Hermann Göring’s cabinet from where he actively supported the development of the new Me 262.

While the Me 262 jet fighter was superior to piston powered Allied planes, it was far from perfect. The most significant problem with the Me 262 was the poor performance at low altitude, where it was an easy prey for Allied fighters. This is also where Allied fighters and close support aircraft were very active and often attacked German airfields, supply trains and ground troops. The already existing Me 109 and Fw 190 were becoming outdated and insufficient by late 1944 standards. In order to effectively counter enemy planes at low altitude, a new design was needed according to Siegfried Knemeyer, who noted (Source: Robert F. He 162 Volksäger Units):

“… It became absolutely essential to develop a high-speed, single-seater fighter that had a sufficiently good performance which would enable it to take off when enemy aircraft were actually sighted. In addition, due to the bombing of our large airfields with long runways, these new fighters had to be able to take off in a very short distance and thus enable small landing grounds to be used. The mass production of such an aircraft had to be on such a scale as would enable the enemy to be engaged at any point and during the entire duration of their flight …… By limiting the endurance and the armament requirement for this new aircraft, the existing jet fighter (the Me 262) would have fulfilled the requirements. However, this aircraft had to be ruled out since it was not possible to produce the numbers that would have been required for combating these low-flying attacks and, in particular, because the provision of two power units per airframe was quite beyond the capacity of industry… “. Based on this, Siegfried Knemeyer gave a list of specifications which the new low-altitude fighter had to conform with:

  • This plane should be able to take off from runways less than 1970 ft (600 m) long.
  • It should be powered by a single jet engine, in order to lower the costs.
  • As the Jumo 004 engine could not be produced in sufficient numbers, another engine was needed. The new BMW 003 was recommended.
  • Maximum speed at sea level should be at least 465 mph (750 km/h).
  • The production process had to be as simple as possible without disturbing the production of the Me 262 and Ar 234.
  • The main building material should be wood. A larger number of furniture manufacturers and carpenters should be included in the production as they had the skill and experience in working with wood that would be needed.

Based on these requirements, the RLM placed an initial order for the new Volksjäger low-altitude jet fighter in July 1944. The first mockup needed to be ready by 1st October, 1944, and a fully operational prototype should have been ready by early December the same year. The main production was planned to begin in early 1945.

The Race for the Volksjäger

The first prototype, V1, built in late 1944. [worldwarphotos.net]
For some time, the Volksjäger seemed like it would remain only a paper proposal, as little progress was made until September 1944. On 7th September, a high priority teleprint message arrived at the Heinkel company. This message was sent by Dipl-ing Karl Frydag, Heinkel’s General Director at the Ministry, but also the leader of the Main Committee for Aircraft Construction and an acquaintance of Otto Saur. The high priority message was addressed to Prof. Ernst Heinkel and his main engineer team. This illicit message contained information including not-yet-published RLM tender requirements for the new Volksjäger jet fighter.

As the official tender request was to be issued by RLM in only a few days, Ernst Heinkel and his team moved quickly to use the small time advantage they had over other possible competitors. The first thing Ernst Heinkel did was to give instructions to reuse the P 1073 paper project that was intended for an RLM request from July. P 1073 was, according to the original plans, to be powered by two HeS 011 or Jumo 004C turbojet engines. One engine was to be mounted on top of the fuselage behind the cockpit and the second one below, right under the cockpit. The maximum speed using the HeS 011 engines was estimated to be around 630 mph (1010 km/h) at 19700 ft (6000 m). P 1073’s wing was swept back at 35° with a “V” shaped rear tailplane. The armament would include two 1.18 in (30 mm) MK 108 and two MG 151/20 0.78in (20 mm) cannons.

Later, due to the new specifications for the Volksjäger, P 1073 was modified to be powered by a single BMW 003 engine. Other changes, such as increasing the dimensions, a new straight wing design and adding new rear twin tail fins. The name was changed to P 1073-15. Further modifications were conducted at the Rostock-Marienehe plant. These included a high unswept wing design, the engine mounted above the fuselage, an armament of only two MG 151/20 0.78 in (20 mm) cannons, a tricycle undercarriage and a weight around 2.5 t. The maximum speed at ground level was 500 mph (810 km/h). It was possible to increase the offensive armament with bombs and 1.18 in/30 mm cannons. The name was again changed to P 1073-18.

By 9th (or 8th, depending on the source) September 1944, other German aircraft manufacturers received the RLM requirements for the new Volksjäger project. According to these, the Volksjäger fighter had to be able to take off in less than 1640 ft (500 m). It had to be powered by one BMW 003 jet engine and the total weight must not must not exceed 4410 lbs (2000 kg). The maximum speed at sea level had to be at least 460 mph (750 km/h). The flight endurance at full thrust had to be at least 30 min. The main armament had to consist of either two MK 108 (with 80 to 100 rounds per gun) or two MG 151/20 (with 200-250 rounds per gun) cannons.

The main construction material would be wood with a smaller amount of steel used. Protection for the pilot, fuel tanks and the main gun ammunition was to be provided. However, since great attention was dedicated to the short take off distance, the manufacturers were allowed to reduce the armor and ammunition load if needed. First proposals from all interested aircraft manufacturers were to be ready in only a few days, as a draconically unrealistic deadline was set for the 14th (or 20th depending on the source) September.

Despite being planned to be put into mass production, only limited numbers of the A-1 version were ever built. [worldwarphotos.net]
Besides Heinkel, which was “unofficially” familiar with the details of this tender a few days before its publication, others aircraft manufacturers participated and submitted their own proposal. The competitors included Arado (E 580), Blohm und Voss (P 211.02), Junkers (marked either as EF 123 or EF 124) and Focke-Wulf. Focke-Wulf actually presented two different proposals (Volksflitzer and Volksflugzeug). Others, like Fieseler and Siebel, lacked the manpower and production capacity to successfully participate in this tender. Messerschmitt did not participate in this competition as Willy Messerschmitt was against the Volksjäger concept from the beginning. He was a great opponent of this project, arguing that increasing the production rate of the Me 262 should have a greater priority and that the Volksjäger was a waste of time and materials which Germany was sorely lacking.

By the end of the competition period, all proposals were submitted to the RLM. After two days, a conference was held in Berlin with the representatives of all five companies, together with officials from the Luftwaffe and RLM. The Arado, Focke-Wulf and Junkers projects were immediately rejected. Even Heinkel’s original proposal came close to being rejected, as it would be complicated to build. It was judged that the best proposal was the Blohm und Voss P 221-02 project, as it was (at least on paper) easier to build and used a smaller quantity of duralumin. At this point, Heinkel representatives were trying to win the competition by arguing that, due to the cancelation of the He 177 and the He 219 programmes, they would have enough production capacity to manufacture the Volksjäger in great numbers. They also proposed to make the entire design far simpler for mass production.

In the following days, there were many difficult and exhausting discussions around the Heinkel and Blohm und Voss projects. There was a sharp debate between Heinkel Dipl-Ing. Francke and the RLM Generaldirektor Frydag which supported the Blohm und Voss project. These discussions caused some delays in making the final decision for the implementation of the Volksjäger project. At the same time, at the Heinkel factory at Schwechat near Vienna (EHAG – Ernst Heinkel AG), work began on calculations and drawings in preparation for the production of the first models of the Volksjäger, marked as the He 500.

The final discussion regarding the competition was held at Hitler residence in Rastenberg, in East Prussia. Hermann Göring enthusiastically and actively supported the He 500 without even considering the Blohm und Voss P 221-02 project. He also gained the support of Adolf Hitler and Albert Speer. Thus, in the end, the Heinkel project was chosen. This decision was also based on the experience that Heinkel had accumulated with the construction and development of jet technology (with the He 178 and He 280) but also due to the significant lobby that this company had.

Although Heinkel’s design won, there were requests for some alterations. For easier production and construction, the design of the tail, fuselage and the landing gear had to be simplified. As was originally planned, the first mockup was ready by 1st October 1944 and the first prototype was to be built by 10th December of the same year. The main production was to begin in January 1945 with 1000 planes per month, which would be increased to 2000 per month. These dates and numbers were, taking Germany’s economic and military situation into consideration, unrealistic and understandably never achieved.

According to Ernst Heinkel, the final designation for the new Volksjäger was meant to be He 500. However, the RLM officials, in the hope of somehow hiding its original purpose from Allied intelligence, gave it the designation “8-162”. In some sources, it is also called “Salamander”. This was actually a code name given for wooden component production companies. The He 162 is also sometimes called “Spatz” (Sparrow), but this name is, according to some sources, related to the He 162S training glider prototype.

Construction of the First Prototypes

The work on the final design was given to the engineers Siegfried Günter and Karl Schwärzler. A large design staff of some 370 men was at their disposal. The design work was carried out at the Heinkel workshop (at Schwechat Air Base) near Vienna. By 15th October, the first sketches and production tools were ready.

The Heinkel factory (in Vienna) was responsible for beginning the serial production of the He 162. In the hope of speeding up production, other factories were included along with many smaller companies. Each of these were to be responsible for producing certain parts and components of the He 162. When all necessary parts for the construction of the first prototype were built, they were to be transported to Vienna for the final assembly. Due to a lack of transport capability and insufficient quality of wooden parts (especially the wings), there were some delays.

Side view of the He 162. The cannon compartment’s wooden door is removed. [warbirdsresourcegroup.org]
Despite the fact that wood was easier to work with, there were huge issues with the quality of the delivered parts. Some of the problems encountered were that the production procedures were often not carried out according to regulations, the glue used was of poor quality, sometimes parts would not fit together. There were situations in which large numbers of wooden parts were returned to the suppliers simply because they could not be used. There were also problems with the first prototype’s engine as it was damaged during the transport and had to be repaired. All the necessary parts arrived by 24th November and the assembly of the first He 162 prototype could begin.

The He 162 V1 prototype (serial number Wk-Nr 200001) was ready for testing by 1st December, 1944. The first series of prototypes had the “V” (Versuchmuster) designation. Later, starting from V3 and V4, the designation was changed to “M” (Muster – model). If it is taken into account that, from the first drawing to the first operational prototype, no more than two months had passed, this was an impressive feat. The V1 prototype was to be tested at Heidfeld but, due to some stability problems with the undercarriage, only limited ground test trials were held.

These problems were addressed by 6th December, when the He 162 made its first test flight piloted by Heinkel’s main test pilot, Flugkapitän Dipl-ing Gotthold Peter. The flight lasted around 20 minutes at speeds of 186 mph (300 km/h). During this flight, probably due to the poor quality of production, one of the three landing gear doors simply broke free and the pilot was forced to land. Beside that, the whole flight was considered successful, there were no other problems and the engine performed excellently.

At the same time, three more prototypes (V2, M3 and M4) were under construction to be used for future tests. The second prototype was transported to Heidfeld (arrived 7th December). During the production of the first series of prototypes, a problem with the wing construction was noted. The main issue was the use of poor quality glue, but at that time this problem was largely ignored.

The moment when a V1 prototype was lost, when the right aileron failed. Unfortunately, the pilot did not survive. [worldwarphotos.info]
On 10th December, another flight was performed for the Luftwaffe military officials at Schwechat. Like in the previous flights, the pilot was Gotthold Peter. In the hope of impressing the gathered crowd, the pilot made a low pass (at 330 ft/100 m) at 456 mph (735 km/h). This flight was going well until the moment when a part of the wing and ailerons were torn off, which caused the pilot to lose control and crash to the ground. Despite having an onboard ejection seat, Peter failed to activate it (possibly due to high G-forces) and was killed in this accident.

The whole flight was captured on a film camera by one of the Luftwaffe officers. The film and the wreck were thoroughly examined by Heinkel engineers who immediately noticed a few things; the wing parts were joined by using low quality glue, the poor aerodynamics of the wing design and the instability of the prototype lateral axis led to the tear off of the wing parts. As a result of this accident, the wing design was strengthened and the maximum flight speed was restricted to only 310 mph (500 km/h). Also, the size of the horizontal stabilizer was increased, the main fuel tanks were reduced in size and the wings’ connection to the main fuselage was reinforced. This accident did not have any negative impact on the continued development on this project which proceeded without interruption.

After this accident, other pilots were reluctant to fly on the He 162. Due to this, Ernst Heinkel was forced to offer a sum of 80,000 Reichsmarks for any pilots who were willing to test fly the He 162. A pilot who agreed to fly was Dipl.-Ing. Carl Francke, who was the technical director of EHAG. He made the first test flight with V2 (serial number Wk-Nr 200002) on 22nd December, 1944. Later that day, a second pilot, Fliegerstabsingineur Paul Bader, made more test flights. Flight trials with the second prototype were carried out without much problems. The V2 prototype was used for testing different wing designs and different weapon installations (two 1.18 in/30 mm Mk 108 cannons). After this, V2 would be used mostly for ground examinations, conversions, equipment testing and for attempts to simplify the overall design in order to ease production.

The third prototype was ready by 20th December, when it was tested by Paul Bader at Heidfeld. While the flight went on without many problems, the pilot noted the poor front ground visibility and vibrations during takeoff and landing. In order to improve the He 162’s wing design, the experienced Dr Alexander Lippisch (who worked on the Me 163) was contacted and included in the project. His proposal for improving the He 162’s stability was to fit small “Ohren” (ears) to the wingtips. As these were later implemented on all produced He 162, they were generally known as the ‘Lippisch ears’.

The M3 and M4 prototypes were the first fighters to be equipped with these wingtips. These two models had strengthened and redesigned wing construction with thicker plywood covering, also to shift the centre of gravity, extra weight was added to the plane’s nose. These modifications improved the He 162’s overall performance and stability significantly. The M3 improved prototype was tested in late February 1945 when it managed to reach an incredible speed of 546 mph (880 km/h). The M4 prototype was ready by the end of 1944 but, due to some engine problems, the first flight was only possible at the beginning of 1945. The first flight tests were carried by Dipl-Ing Schuck on 16th January, 1945. As the M3 and M4 wing design and shape proved satisfactory, they were chosen to be used for the upcoming production of the first He 162A combat operational variant.

The M5 prototype was built but it was never used operationally nor did it ever fly. The M6 prototype, which was intended to be used as base for the He 162A-1 production model, made its first test flight on 23rd January, 1945. The M7 (the base for the He 162A-2) was used for vibration tests and trialing the braking parachute. The M8 was the first to be equipped with two MG 151/20 cannons (120 rounds of ammunition per gun). The M9 and M10 were intended as two seat trainer aircraft versions but none were built. The M11 and M12 were powered by the much stronger Jumo 004D Orkan turbojet engine. These were to be used as base for the He 162A-8. The M13 moniker was never assigned to any prototype due to the belief that this number was unlucky. The prototype models M14 to M17 were never built. The M18 and M19 were powered by the new BMW 003E-1 jet engine which was intended to be used for the He 162A-2 production model. The M20 was used for testing different and simpler undercarriage designs. The M21 and M22 were used for main weapon testing. The M23 and M24 were used for installation of new wing root filters and for handling flight tests.

These prototypes were extensively tested and examined in detail from 22nd January to 12th February. In this period, over 200 test flights were carried out. Not all test flights were successful and without accidents. On 24th February, M20 was damaged during landing due to undercarriage malfunction. The next day, while testing the M3, there was a malfunction that led the pilot losing control of the aircraft. He managed to get out but his parachute did not fully extend, leading to his demise. At the beginning of May, one more prototype was lost in an accident. In total, there were more than 30 prototypes built. It is interesting that, even before the testing of the prototypes was completed, preparations for production of the He 162 were already underway.

He 162 A-1 and A-2

Despite the original plans requiring the start of the production in early 1945, this was never achieved. Due to the chaos in Germany at that time, there were many delays with the arrival of the necessary parts. There were shortages of nose wheels, rudders, interior equipment, weapons parts, poor quality glue and many others. For example, at Rostock, there were more than 139 partly built fuselages which could not be completed due to a lack of parts. There was also a problem with the large number of wings and tails built that were defectuous and unusable. A generalized lack of fuel, transport vehicles and electricity, Allied bombing raids and the use of slave labour also negatively influenced the overall production. Around ten pre-series He 162A-0 (with different prototype numbers) were built and stationed at Schwechat to be used for more testing needed in order to eliminate more problems.

The Soviets flight tested some captured examples of the He 162, but their overall performance proved to be poor. [airpages.ru]
The production of the first series of operational aircraft was delayed and began only at the end of March 1945. The first production series were marked He 162 A-1 and A-2. There are few visual differences between these two models. The only major difference was the armament. The A-1 was equipped with two 1.18 in (30 mm) cannons and the A-2 with two 0.78 in (20 mm) cannons. As the production of 1.18 in (30 mm) cannons was halted due to Allied bombing and the Soviets capturing the production factories, the few remaining cannons were to be allocated to the Me 262. The production of the A-1 was stopped and the exact number of manufactured aircraft is unknown. Due the lack of 1.18 in (30 mm) cannons, the He 162 manufacturers were forced to use the lighter and weaker 0.78 in (20 mm) caliber weapons.

A number of serially produced A-2 aircraft were not used for troop trials, but were instead sent to test centres for future modifications and testing. A small number would eventually reach the German troops in April. While the production of the A-2 would go on until the war’s end, the total number of produced aircraft is unknown.

The He 162 Design

He 162 top view [warbirdsresourcegroup.org]
The He 162 was designed as a high-wing jet fighter with a simple fuselage with clean lines, tricycle retracting landing gear and built using mixed construction. The simple fuselage was built by using a cheap and light metal alloy (duralumin – a combination of aluminium and copper) with a plywood nose and (one-piece) wooden wings.

The fuselage was a semi-monocoque design covered with duralumin. The front part of the fuselage was egg-shaped and had good aerodynamic properties. The nose was made of plywood and was fixed to the fuselage by using bolts. The middle top part of the fuselage was flat and the engine was connected to it. The wood was also used for the undercarriage doors.

The wings were made out of wood and connected to the central fuselage by using four bolts. In order to ease production, the wings were built in one piece. The flaps and ailerons were built using a wood frame which was covered with plywood. The flaps were controlled by using a hydraulic system while the rods were controlled with wire. To help with the stability at the end of the wing, two wingtips (one on each side) were added. These were angled at 55° downwards and made of duralumin. The two-part rear tail was made of metal and was connected to the end cone of the fuselage. The tail rudders were controlled using wires and rods.

The He 162 used a tricycle landing gear design, with one wheel at the front and two more located in the centre of the fuselage. The landing gear was hydraulically lowered and raised. The dimensions of the front nose wheel were 500×145 mm and no brake system was provided for it. Interesting to note is that the front nose wheel, when retracting, partly reached into the lower part of the front cockpit. A small window was provided for the pilot so that he could see if it was fully operational. The two central landing wheels were larger, 600×200 mm. Both the front and the rear landing wheels retracted to the rear. To help with landings, hydro-pneumatic dampers were provided.

The plexi-glass cockpit was made of two parts, the front windshield and the rear hinging canopy which were screwed into the inner bar frame. In order to make the whole construction simple as possible the cockpit was not pressurized. For better ventilation on the left side a small round ventilation window was installed. The pilot cockpit was more or less a standard German design but much simpler. It provided the pilot with good all-around view of the surroundings, but there were some complaints by some pilots for poor front ground view.

The control panel was made of wood, on which the necessary instruments were placed. Only a few were provided for the pilot and these included the speed indicator, panel lights, turn and bank indicator, rate of climb, FK 38 magnetic compass, temperature indicator, AFN-2 display, oil and fuel pressure gauge, fuel level gauge, chronometer, ammunition counters and engine tachometer. The fighter controls were placed as standard in front of the pilot. On the pilot’s left-side, the fuel valve, flap controls, landing gear control, throttle lever and trimming control were located. On the opposite side was placed the radio system (FuG 25A). The pilot seat was of a simple design but equipped with Heinkel’s ejection system with a parachute. The He 162 was one of the first German aircraft to be equipped with an ejection seat as standard equipment. The cockpit was separated from the rest of the plane by a sloped metal plate. This plate was installed in order to provide the pilot some protection in case of emergency (like fuel tank fire etc.). Behind this plate were the oxygen supply tanks with a 3 l capacity.

The engine chosen for the He 162 A-2 was the BMW 003E-1/2 turbojet (in some sources the A version was used). The engine was fixed in a nacelle placed above the central fuselage. The engine consisted of a seven-stage axial compressor, injection nozzle, annular combustion chamber and one single-stage axial turbine equipped with sheet metal heat-resistant blades which were air-cooled. The exhaust nozzle was controlled by an adjustable needle which could be mechanically moved into four positions: Position A for idle, S for start, F for flying at altitudes lower than 26.200 ft (8.000 m) and M for flying at altitudes above 26.200 ft (8.000 m). The BMW 003E-1/2 turbojet could achieve maximum thrust of 1.800 lbs (800 kg).

One He 162 was put on display in London after the war. It still had German markings on it. [aviation-history.com]
When flying at a speed of 500 mph (800 km/h) at 36.100 ft (11.000 m), the maximum thrust would fall down to only 740 lbs/340 kg. To start the engine, a small Riedel piston engine (9.86 hp) was used. This engine could be started either by using an electric starter motor or manually with a ring-pull. The He 162 engine was 11 ft (3.6 m) long with a diameter of 2.3 ft (69 cm) and a weight of 1.375 lbs (624 kg). The estimated life cycle of the engine was only 50 hours. As the engine was positioned above the fuselage, in order to avoid any damage caused by exhaust gasses, a steel plate was placed under the jet nozzle. The position of the engine also means it was easier to mount and repair. It was also easier to replace it with a new one.

The fuel tank was positioned in the middle of the fuselage. In order to save weight and to ease the production, a rubber fuel tank was used. The main fuel tank had a capacity of 695 l and there were also two smaller 175 l tanks located in the wings. For takeoff, up to two smaller auxiliary Ri 502 rocket engines could be installed. They would be located in the lower rear part of the fuselage.

The He 162’s original weapon system consisted of two MK 108 cannons, but the most built version was equipped with weaker MG 151/20 cannons. The two cannons were placed in the lower front part of the fuselage. The main gun’s ammunition was stored behind the pilot, with 120 rounds for each gun. In order for the ground support crews to have access to the gun and ammunition, wooden door panels were provided. For the gunsight, the Revi 16G or 16B models were used. There was also a gyroscopic EZ 42 gunsight tested on one He 162, but this was never adopted for service.

Other Versions and Prototypes

Despite the improvements done to the main production versions, there were still room for enhancements and modifications of the He 162. Most efforts were devoted to the installation of stronger engines and various aerodynamic improvements in order to achieve the highest speed possible. There were also plans to make the He 162 much cheaper and easier to produce. Different armament loads were also tested or proposed. Most of these proposals remained on paper only, but some received limited testing.

The first in line of the intended improved He 162 was the A-3 version. This was meant to be armed with 1.18 in (30 mm) MK 103 or MK 108 cannons (depending on the source) located in a redesigned front nose, but it is unclear if any were ever built. Later, an identically armed version (A-6) with a redesigned and longer fuselage (30 ft/9.2 m) was proposed but, like the previous version, none were probably built.

In order to increase the He 162’s maximum speed, it was intended to install the Jumo 004D “Orkan” (2.866 lbs/1.050 kg of thrust) engine to replace the standard jet engine used. The new engines were to be transported to Schwechat and tested there on fully operational prototypes. The whole process was too slow, and only as late as March 1945 were the few prototypes almost finished, but due to the war’s end, none were ever fully completed or tested. This modification is known under the name He 162 A-8. The A-9 (in some sources marked as He 162E) was to be powered by one BMW 003R engine, supported by a second BMW 718 rocket engine for extra power. The engines were tested but they were never installed on any He 162. While Heinkel conceived up to 14 different proposals for the “A” version, beyond those mentioned above, almost nothing is known about the others.

Note that the following designations (B, C and D) were never found in any EHAG official documentation and are not known to have been used by the Germans. This article will use them for the sake of simplicity only. (Source: Miroslav B. and Bily B.)

Despite the fact that the He 162 was designed to be simple and easy to build, the engine was still relatively difficult to produce in great numbers. In hope to increase the number of engines being built, the Germans began testing the less demanding technology of pulse jet engines (used on the V-1 flying bomb). The first proposed pulse jet engine to be mounted on the He 162 (generally known as He 162B) was the Argus As 004 (with 1,102 lbs/500 kg of thrust). This was followed by a second proposal to mount two Argus As 014 (each with 739 lbs/335 kg of thrust) pulse jet engines. The single engine version is named, in some modern sources, as B-2 and the two engine version as B-1. None were ever built and tested, possibly because the pulse jet was considered inferior to jet engines.

Two different wing configurations proposed, often incorrectly marked as the “D” and ”C” versions. [airvectors.net]
There were many experiments with different wing designs and shapes in order to improve the flying performance and ease production. Two similar designs were based on all-metal swept wings. The first (today called the He 162C) had a back swept wing design with the second half of the wings bent down at a sharp angle. The second (often nowadays referred to as the He 162D) had an unusual forward swept wing design. Both of these models were to be powered by one Heinkel-Hirth 011A turbojet engine (2,866 lbs/1,300 kg of thrust). Both models also had different rear tail designs. The maximum estimated top speed with this engine was up to 620 mph (1000 km/h). There were also other proposed wing designs but, beside these two, none seem to have been tested. Only a few incomplete prototypes were built and they were captured by the advancing Allied forces by the end of the war.

In autumn of 1944, it was suggested to use the He 162 for the German “Mistel 5” weapon projects. This configuration would consisted on one unmanned Arado E 337a glide bomb that would be guided by an He 162 connected on top of it. As the Arado E 337a was never built, this project remain on paper only.

At the end of January, there was a proposal to modify a few He 162 to be used as “Behelfs-Aufklarer”, in essence improvised reconnaissance planes, but this was never implemented.

The Volksjäger Training Versions

As the Volksjäger project got a green light for its implementation and orders of planned production in the thousands, a solution on how to train such large numbers of new pilots was needed. One proposal was to begin training with gliders (including a glider version of the He 162) and, after a short period of time, the pilot (usually from the Hitler Youth) would learn to fly on the training versions of the He 162. The glider version was named He 162 S “Spatz” (Sparrow). According to other sources (M.Balous and M.Bily), the “S” stands for Segelflugzeug (glider).

These gliders had to be designed and built to emulate the He 162’s takeoff and landing properties as much as possible. In order to stay in the air, the gliders were to be connected to a 1 km long cable which was attached to a 150 hp motorized winch. The gliders were to have two seats, one for the future pilot and one for the instructor. One prototype was flight tested in late March 1945 by Ing Hasse. Even the famous German woman test pilot Hanna Reitsch made at least one flight in it. The He 162 S was very similar to the original He 162, with some modifications like larger wings and fixed landing gears. The choice for using gliders as replacement for training planes was based on the general lack of fuel. Around ten of these gliders were ordered and, if testing showed good results, some 200 were meant to be built. But, due to the bad economical situation in Germany at the time, only a few were ever built at Schönhage (Hannover).

The second training aircraft was a fully powered two seat trainer version. There is no official military marking or name for this version, but today it is often known as the He 162 Doppelsitzer (two seater). This version was to be powered by a BMW 003E-1 or E-2 engine. It was to have a second seat for the instructor placed behind the main cockpit. In order to make more room in the unmodified He 162 fuselage, the gun, ammunition and oxygen tanks had to be removed. The production of this version was planned to begin by the end of 1944 and was to be built by DLH (Deutsche Lufthansa) at Oranienburg. Only one incomplete prototype may have ever been constructed.

To help the training of new pilots at the Luftwaffe test center (Rechlin), a simulator model was built. It had the exact same cockpit like an operational He 162 with all instruments. Its primary purpose was to be used for combat and fire simulator training.

Main Armament Proposal

As already stated, the 0.78 in (20 mm) cannons were, by 1944/45 war standards, simply inadequate and the lack of stronger 1.18 in (30 mm) cannons forced the Germans to search for different (somewhat unconventional) weapons for the He 162.

To increase the offensive armament, the 2.2 in (55 mm) R4M air-to-air rocket was proposed to be installed under the He 162’s wings. Another proposal was to arm the He 162 with the SG 118 Rohrblocktrommel weapon system which consisted of three 1.18 in (30 mm) barrels (connected in a circle), each armed with 7 rounds. The last proposal was to use the 3.14 in (8 cm) Panzerblitz missiles. There were planned to use the EZ 42 gyroscopic gun sight on the He 162, but the single prototype was destroyed in an Allied bombing raid. If any of these proposals were ever been implemented or allocated a version name is unknown but very unlikely.

Production

The Germans were forced to relocate some production facilities deep underground. The Volksjäger was produced in one such underground production base at Hinterbrühl, Austria. Colorized by Michael Jucan [aviation-history.com]
It was hoped by the Luftwaffe military officials that the He 162 would be built in great numbers. They counted on the fact that, by using cheap materials (mostly wood) and by employing many smaller subcontractors (woodworkers and furniture manufactures), the overall costs and time necessary for the production would be reduced.

Several factories were responsible for the production of the He 162 at Heinkel-Nord in Rostock-Marienehe, Heinkel-Sud, Hinterbühl (underground factory), Vienna-Schwechat (prototype production) and Mittelwerke (Nordhausen). In order to increase the production, Heinkel and Junkers made an agreement to use the vast Junkers production capacities. Junkers would be responsible for the production of the majority of the new He 162 planes at Bernburg. Also, a large number of smaller subcontractors were to be included, like EHAG Walldwerk or Pütnitz. The main engine suppliers were Spandau and Zühlsdorf. The armament was to be provided by Deutsche Waffen und Munitionsfabrik at Posnan. The wooden elements would be made at Erfurt, Orla and Stuttgart-Esslingen (these were also building components for the Me 163 and Ta 154). Some 750 man-hours were needed for the He 162, together with 300 man-hours for the engine production. Due to slow production, Hitler gave an order on 27th March, 1945 for the SS to take over the whole Volksjäger project. However, this had only limited (if any) effect on the speed of production.

As it was only built during the last month of the war, when confusion and chaos were ever-present in almost all spheres of political or military life in Nazi Germany, exact information about how many aircraft of this type were built is impossible to find. Depending on the sources, the total production was in the range of 116 to more than 200. According to different Authors: C. Chan (240), D. Mondey (116), F. Crosby (200), A. Ludeke (270), D. Nešić (120). According to the German General Staff Department 6 (Generalstab Abteilung 6), the total number of He 162 built was 116 aircraft. After the war, around many airfields, some 100 He 162 in different conditions were found. Additional 800 aircraft were found in different stages of factory assembly, which also complicates determining the exact number of produced He 162.

On 7th April, 1945 Hitler gave orders to stop any further development and production of the He 162 in favor of the Me 262 and Arado 234. It is hard to say for sure, but as the He 162 was produced until the end of the war, this order seems to never have been fully implemented.

Operational Service

Lineup of Volksjäger captured by the British at Leck in May 1945 [worldwarphotos.info]
The delivery of He 162 fighters to Luftwaffe front units was limited due to many reasons, including slow production, lack of fuel and spare parts and the Allied advance, but eventually, a few units equipped with this aircraft would be formed.

The first operational unit to be equipped with the new He 162 was Erprobungskommando 162 located at Rechlin-Roggenthin. In April, due to the rapid Allied advance, the unit had to reposition near Munich. This was actually a test unit and, for this purpose, a number of the most experienced German pilots (some of them having experience in flying jet aircraft) were allocated to this unit. Once these pilots had gained enough experience flying the He 162, they were to be used as base for forming the first operational unit, 1./JG 80. Immediately after the start of production, a large training process at the NSFK gliding school began. As there was only one He 162 S glider aircraft available, other simpler gliders (like the DFS SG 38 Schulgleiter) had to be used as a temporary solution. The training process did not go the way the Luftwaffe Officials hoped it would go. It was too slow and, when the first group of new pilots was tested on the Arado Ar 96B (trainer version), the results were disappointing. At this point, the plan to use Hitlerjugend members as He 162 pilots was discarded, which was somewhat expected. The experiment with the young and inexperienced pilots proves that only the most experienced pilots could successfully fly the He 162. Beside pilot training, at the same time, the training of ground support staff was carried out at Fliegertechische-Schule 6 in Neumarkt and Wiedenberg.

In order to form the first operational combat unit with the He 162, an already-experienced unit would be needed. For this purpose, Jagdgeschwader 1 “Oseau” (JG 1) was chosen. It was commanded by Oberst Herbert Ihlefeld and it was equipped mostly with Fw 190 aircraft. On 8th February, 1945, the first orders were given by General der Jagdflieger (General of Fighters) Oberst Gordon Gollob to the 2nd and 3rd Staffels (first Gruppe JG 1) commanders to prepare their pilots to be moved to the Parchim Airbase near Rostock. Once there, the first flight training with the new He 162 was to be carried out. In late February, a group of 10 pilots (from 2nd Staffel) was moved to Vienna for more training. For pilot training, two prototype aircraft were used, as the production of operational “A” variant was slow. Despite being experienced pilots, there were some accidents caused either by pilot errors or due to some mechanical faults. The He 162 M8 was lost due to engine failure on 12th March, but the pilot survived. Only two days later, one pilot was killed when he made a mistake during landing. As there were no other He 162 aircraft available, this group was forced to return to Parchim Airfield. In late March 1945, around 10 pilots of the I./JG 1 (first Gruppe) were moved to the Marienehe factory (near Rostock). They were supplied with a number of He 162 that where previously used by the mechanics and test pilots of this factory. Once the handover was completed, the group with the He 162 returned to its original base of operation.

The RLM’s next plan was to begin re-equipping II./JG 1 with the He 162 as soon as possible. The unit was moved to Rostock at the end of March 1945, where the training should have begun. Other units were expected to be formed (I and II./JG 400, III./JG 1, JG 27 and JG 77), but nothing came of this. In May 1945, a Volksstume Jagdeschwader (in essence, an improvised militia unit) was to be formed at the Sagan-Küpper airfield by using mostly volunteer pilots. However, Allied occupation of this airfield prevented the implementation of this proposal. The only unit beside JG 1 to be supplied (in limited numbers) with He 162 was I.EJG 2 (Ergänzungsjagdgeschwader, auxiliary fighter training unit), but these were probably never used operationally.

By the end of March, JG 1 was supplied with around 58 operational He 162A-2 aircraft with some 25 more on the way. At the same time, I./JG1 was moved to Ludwigslust, where it was supposed to be supplied with new He 162 aircraft. Due to the rapid Allied advance, the unit was moved in April to the Schleswig-Holstein region (Leck airfield), near the Danish border. This unit had orders to defend Berlin from Allied bombers coming from over the North Sea. The I./JG1 was to be ready for operational service by 20th April. The first combat loss happened on 19th April, when one He 162 was shot down after a take-off by an American P-47 Thunderbolt. By the end of April, II./JG 1 was moved quickly to the Leck airfield to join the first Gruppe.

He 162 side view [worldwarphotos.info]
The first operational combat mission of I./JG1 was to attack an RAF front airfield on 20th April. While on their way, the He 162’s were intercepted by a group of Hawker Tempests (3 Sqn. RAF). In this engagement, only one He 162 was shot down and the pilot managed to survive without any injuries. At the same time, one P-51 Mustang scout pilot (12th Tactical Reconnaissance Squadron) reported to have shot down one He 162, but this was never officially confirmed.

The He 162’s first allegedly air victory (and possibly the only one) was achieved by Lt. Rudolf Schmitt from I./JG 1, when he shot down a British fighter. However, this fighter was later claimed to have been shot down by German ground AA fire. While Lt. Rudolf Schmitt may not have made the first air victory, he did successfully manage to use the ejection seat in a combat zone. Due to the Allied advance, on 5th May, 1945, JG 1 received orders to stop any further action and to destroy all operational aircraft. For some reason, the order was later recalled. The Leck airfield would be captured by British forces on the 8th, which ended the He 162’s short operational combat story.

Precise information on the He 162’s combat or deployment is hard to find mostly due the chaotic state in Germany at that time. According to some authors, like Francus G., none were ever used in combat.

Japan’s military attache, in early 1945, was interested in acquiring the license production of the He 162. After a short negotiation, the Germans gave permission for license production. But there was a problem of how to transport or send the necessary documents and sketches from Germany to distant Japan. The only solution was to use radio by converting the sketches into numerical code. Unsurprisingly, this did not work well and only limited information was send before the end of the war in Europe. Due to this reason, Japan never received the complete He 162 sketches.

In Allied Hands

As the British forces captured Leck airfield, they acquired a number of fully operational He 162s. Some 11 planes were selected by the British Technical Intelligence Team to be transported to the UK. Once there, all were sent to the Farnborough airfield, which was the headquarters of the Royal Aircraft Establishment (RAE). The He 162 aircraft were thoroughly examined and divided into groups either for part analysis or for flight testing. On 9th November, 1945, while flying an He 162 (AM61) at the Exhibition of German Aircraft at Farnborough, the pilot Robert A.M. lost his life in an accident.

One of the tested He 162 (marked AM 59 by the British) would be donated to the Canadian Museum in Ottawa together with another one received later that year. Later, two were given to British museums, one to the Imperial War Museum and the second to the RAF Hendon Museum. One would be given to France, possibly either AM 63 or AM 66.

The British also supplied the American with some He 162 captured at the Leck airfield. The Americans also managed to capture some abandoned He 162s across Germany. Some would be tested at the Wright and Freeman Field research centre. One He 162 was even kept in good flight condition up to 1946. This aircraft is today privately owned by the Planes of Fame Museum in California.

The French received or captured (it is not known precisely) five He 162, of which two were airworthy. These two were tested, but one was damaged during landing and the second was lost in May 1948 with the loss of the pilot’s life. One He 162 is preserved and can be seen at the Paris Aviation Museum.

During their advance through Germany, the Soviets managed to capture about seven planes, two of which were airworthy. These would be tested and and analyzed in great details. As the Soviets lacked any advanced jet technology at that time, adopting German captured technology looked like a logical step. Most interesting for the Soviets were the Jumo 004 and the BMW 003 jet engines that would be, in later years, copied and produced in some numbers. There were also some consideration from the Soviet military to copy and produce some of the German jet aircraft, including the He 162. One He 162, with the fuselage marking 02, was tested by the Soviet Flight Research Institute (near Moscow). The second, marked 01, was tested at the Central Aero-hydrodynamics Institute. He 162 02 would be flight tested on several flights in 1946. The results of these tests were disappointing for the Soviets and a decision was made not to further consider them for service, and they did not have any influence on the later Soviet aviation development.

Conclusion

The idea for the He 162 was born out of a mix of desperation, chaos and hope for some miraculous wonder weapons that could turn the air war’s tide to the German side again. It was designed to be cheap and built in great numbers. The impressive fact is that it was designed and built in only a few months, but, on the other hand, it was built in too small numbers, the engines used were often of poor quality and there was a lack of trained pilots, which, along with other problems, meant that the He 162 did not have any major impact on the war itself or on post war jet aircraft development. In the end, it was not the ‘Wunderwaffe’ that the designers hoped for, but it was still impressive, at least because of the speed with which it was designed and built.

Variants

As only a small number of He 162 were built, there were very few operational versions. Beside the prototype series, only the “A” version was built in some numbers.

Prototypes

  • He 162 V– Prototype series
  • He 162 A-0– Around 10 pre-production aircraft built used for testing

Main production version

  • He 162A-1 – Version equipped with two MK 108 cannons, a few were possibly built
  • He 162A-2 – The main production variant armed with two MG 151/20 cannons

Training versions

  • He 162S – Two seat glider trainer version, a few built
  • He 162 Doppelsitzer – Two seat powered trainer version, only one incomplete aircraft built

Experimental prototypes based on “A” versions

  • He 162A-3 – Proposed version armed with two MK 103 or 108 cannons
  • He 162A-6 – Proposed version with redesigned and longer fuselage armed with two MK 108 cannons
  • He 162A-8 – Version equipped with the Jumo 004D jet engine, only a few incomplete prototypes built
  • He 162A-9 – The A-9 was to be powered by one BMW 003R engine and supported by a second BMW 718 rocket engine. None built
  • He 162A Mistel 5 – Paper project, a combination of an He 162 and one Arado E 337 glide bomb.
  • He 162 “Behelfs-Aufklarer” – Proposed version to be built in limited numbers as reconnaissance planes. It was never implemented and remained a proposal only.

Note that the B, C and D designations were not official and are used in this article only for the sake of simplicity.

  • He 162B – Proposed version equipped with a pulsejet engine (similar to the V-1 flying bomb engine)
    • He 162B-1 – two engine version
    • He 162B-2 – single engine version
  • He 162C – Version with back swept wing, powered by Heinkel-Hirth 011A turbojet engine
  • He 162D – Version with forward swept wing designs powered by the same Heinkel-Hirth 011A turbojet engine

Operators

  • Nazi Germany – A few hundred built, but only small numbers were allocated to front units and saw limited combat action.
  • United Kingdom – Captured a number of operational He 162, 11 would be transported and tested in the UK.
  • United States – Received a small number of He 162 from the British but also captured some in Germany.
  • France – Received or captured at least five He 162 aircraft.
  • USSR – Captured seven completed He 162 which were tested after the war.
  • Japan – Military officials tried to acquire the license for production of the He 162 but the war’s end prevented this.

Specifications (Heinkel He 162 A-2)

Wingspan 23 ft 7 in / 7.2 m
Length 29 ft 8 in / 9.05 m
Height 8 ft 6 in / 2.6 m
Wing Area 38 ft² / 11.6 m²
Engine One BMW 003E-1 with 1,760 lbs/800 kg of thrust
Empty Weight 3,666 lbs / 1,663 kg
Maximum Takeoff Weight 5,324 lbs / 2,466 kg
Fuel Capacity 1,045 l
Maximum Speed at 6 km 560 mph / 840 km/h
Range 385 mi / 620 km
Maximum Service Ceiling 39,370 ft / 12,000 m
Climb speed 9.9 m/s
Crew One pilot
Armament Two 20 mm fixed forward firing cannons in the lower sides of the fuselage

Gallery

Illustrations by Ed Jackson artbyedo.com

Heinkel He 162 Volksjäger – 20222
Heinkel He 162 A-1 Volksjäger – 120235
Heinkel He 162 A-2 Volksjäger – 120077 “Nervenklau”
Heinkel He 162 A-2 Volksjäger – wearing Soviet colors as it undergoes testing after capture – Spring 1946

Credits

  • Duško N. (2008) Naoružanje Drugog Svetsko Rata-Nemačka, Tampopring S.C.G.
  • David M. (2006) The Hamlyn Concise Guide To Axis Aircraft Of World War II, Aerospace Publishing.
  • Alexander L. (2007). Waffentechnik Im Zweiten Weltkrieg, Parragon books
  • Francis C. (2006,2010) The Complete Guide To Fighters And Bombers Of The World, Anness Publishing
  • Richard S. and William C.(1967), The Heinkel He 162, George Falkner and Sons Ltd England,.
  • Balous M. and Bily M. (2004), Heinkel He 162 Spatz, MBI Bily.
  • Robert F.(2016) He 162 Volksjäger unit, Osprey Publishing.
  • Michael S. (2007) Attack and Interceptors Jets, Orange Books.

 

Boulton-Paul P.105 & P.107

UK Union Jack United Kingdom (1944)
Strike Fighter – None Built

Static model of the standard P.105. [British Secret Projects]
The Boulton-Paul P.105 is a little known single-engine aircraft meant to fill a variety of carrier-based roles. To do so, the P.105 would utilize a unique and innovative design that involved having interchangeable fuselage and cockpit modules that would pertain to a certain mission, and could be changed quickly to fill a needed role aboard carriers or other airbases. The design was not picked up for unknown reasons but its story doesn’t end there. The design would develop further into the P.107, a land-based escort version of the P.105. The P.107 would have a rear-facing turret and a twin boom tail design to allow greater traverse of the gun. This design wouldn’t be adopted either and the program would conclude before the war’s end.

History

Late in the Second World War, the Royal Naval Air Arm began seeking out an aircraft design that would be able to fill both the fighter and bomber roles. Having one aircraft perform multiple roles would eliminate the specialization of carrier-borne aircraft needed to fill the fighter, dive bomber, and torpedo bomber roles. No official requirement was ever put out to build such an aircraft, but several companies had begun developing aircraft that would fit this role, which had become known as the “Strike Fighter”. Westland, Blackburn, Fairey and Boulton-Paul would all develop designs that correspond to the strike fighter role. Boulton-Paul’s aircraft design would be known as the P.105.

Boulton-Paul is a lesser-known aircraft company which only had a single major type of aircraft enter mass production during the Second World War: the Defiant. The Defiant reflected a lot of their aircraft designs, which were all somewhat unorthodox. . In the Defiant’s case, it was a fighter with a rear turret. Boulton-Paul were much more successful in developing turrets for use on other aircraft, such as the Handley-Page Halifax, Blackburn Roc (which they co-developed alongside Blackburn), Lockheed Hudson and the late war Avro Lincoln. Despite having only one combat aircraft enter production, Boulton-Paul had a very active development section, although most of their designs would stay on the drawing board, with a few being lucky enough to receive prototypes. The designs came from an engineer named J. D. North, who was the main aircraft designer for Boulton-Paul. Before work started on their Strike Fighter design, North had been working on their P.103 and P.104 designs for the Naval Air Arm. The P.103 was an ultra-fast fighter design that utilized a contra-rotating propeller and a Griffon 61 or Centaurus engine. The P.103 wasn’t picked up for production, but North would use many aspects of the P.103 in the P.105. The contra-rotating propeller would once again be used, while the engine would start as a Griffon 61 but shift over to a Centaurus engine later.

3 way drawing of the P.105. Note the spotter’s lower window. [British Secret Projects]
The P.105 was meant to be a small, high-performing aircraft that could easily be converted to fill other roles, even carrier duties. To do so, it would use a unique idea. To fill the variety of carrier-borne roles, the P.105 would have modular cockpit and bomb bay sections. The interchangable modules included a torpedo-bomber (P.105A), reconnaissance aircraft (P.105B), fighter (P.105C) and dive-bomber (No designation given). Each section would have minor differences between them that fit their respective roles. With this system, more P.105 airframes could be stored in hangars and carriers, while the additional modules would take up less space than other aircraft specified for specific roles, thus increasing the combat capacity of the carrier the P.105 would be stationed on. Boulton Paul expected the aircraft to be very high performance and the P.105C version would be an excellent penetration fighter. Before any specifications were estimated, it was decided to switch from a Griffon 61 engine to the Centaurus inline engine. The brochure on the details of the aircraft was submitted to the RNAA, but no order for production came about. Exactly why it wasn’t adopted is unknown. The reasoning may come from the module system, as it could have been novel in concept, but complex in reality. Another reason could be that current aircraft at the time were deemed to have been performing adequately and didn’t need such a replacement.

3 way drawing of the P.107. Note the sliding aft canopy and smaller profile of the twin tail rudders. [British Secret Projects]
Although the P.105 wasn’t granted production, its story continues in the Boulton-Paul P.107. The P.107 is an intriguing design since very little information pertaining to its development history is available, but its design and specifications has been found. It can be assumed the P.107 began development during or shortly after the P.105 had been created. The P.107 wouldn’t be operated by the RNAA, but instead by the Royal Air Force as a long-range escort fighter. Major differences between the P.107 and P.105 include the lack of folding wings, the removal of the torpedo blister, the addition of a turret and the switch from a single rudder to a twin tail design to improve the firing angle of the turret. The P.107 could also be configured for different roles, but it is unknown if it used the same module system the P.105 used. The P.107 wasn’t selected for production either.

Design

The Boulton-Paul P.105 had a conventional fighter layout. In the front, it would utilize a contra-rotating propeller that had reversible pitch. Originally, the design would have mounted a Griffon 61 engine but was changed in favor of the Centaurus engine instead. The wings on the P.105 were inverted gull wings, much like those on the Vought F4U Corsair or Junkers Ju 87 Stuka. To conserve space in carriers, the wings would be able to fold. The fuselage had the most interesting aspect of the P.105 overall and that was its interchangeable cockpit and lower fuselage modules. Each variant of the P.105 would use different modules that would pertain to the intended role it served. The P.105A was a torpedo bomber and would use the torpedo blister present under the tail. The P.105B was a reconnaissance aircraft, and its cockpit would sit a pilot and observer. It would use a glass hull beneath the observer to assist in spotting. The P.105C was an escort fighter and would be a one-man aircraft. The last was a dive-bomber version, which only has very sparse details available. The dive bomber would carry two 1,000 lb (450 kg) bombs, most likely in an internal bomb bay module. The tail of the aircraft would be a conventional rudder and tailplane arrangement. The armament of the P.105 was a standard two to four 12.7mm machine-guns in the wings of the aircraft, with the only deviation being the P.105C, which would use four 20mm cannons instead.

Papercraft model of the P.107 [Kartonbau.de]
The P.107 borrowed many aspects of the P.105 design, but changed some details to better fit its role. The engine and frontal section would stay the same, keeping the contra-rotating propellers and Centaurus engine. Reference materials refer to the aircraft as being able to convert from an escort fighter to either a fighter-bomber or photo reconnaissance aircraft. However, whether it was conventional conversion or via the module system the P.105 used is unknown, the latter being most likely. The wing design would stay the same, with the inverted gull wing style. Given its land-based nature, the wings no longer folded to conserve space and the torpedo blister under the tail was removed. Behind the pilot, a gunner would sit and remotely control two 12.7mm machine guns. The machine-guns would be housed within the aircraft, with only the ends of the barrel protruding out. To give the gunner a better firing arc, the single tailfin was switched to a double tailfin. The turret and twin tail design are the most obvious differences between the P.107 and P.105. The aircraft’s fuel would be stored in a main tank and two smaller drop tanks. Fuel amount was expected to give the aircraft a 3,000 mi (4,827 km) range, with up to 30 minutes of combat. The drop tanks could be switched for 2,000 Ib (900 Kg) of bombs. For offensive armament, the P.107 would use four 20m cannons mounted in the wings.

Papercraft model of the P.107 [Kartonbau.de]

Variants

 

  • Boulton Paul P.105A– Torpedo bomber version of the P.105.
  • Boulton Paul P.105B– Reconnaissance version of the P.105. This version would have a glazed hull for the observer.
  • Boulton Paul P.105C– Fighter version of the P.105.
  • Boulton Paul P.105 Dive bomber– Dive bomber version of the P.105. No designation was given to this design.
  • Boulton Paul P.107– Land-based escort fighter derived from the P.105. The P.107 was near identical to the P.105 but had a twin boom tail to allow better vision and turn radius for a rear mounted turret. Photo reconnaissance and fighter bomber versions of the P.107 are also mentioned.

Operators

 

  • Great Britain – Had it been built, the P.105 would have been used by the Royal Fleet Air Arm. The P.107 would have been used by the RAF for escort duty had it been built.

Boulton-Paul P.105 Specifications

Wingspan 38 ft / 11.6 m
Length 34 ft 5 in / 10.5 m
Folded Width 15 ft 4 in / 4.67 m
Wing Area 250 ft² / 23.3 m²
Engine 3,000 hp ( 2,200 kW ) Centaurus CE.12.SM engine
Fuel Capacity 260 gal (1,180 lit)
Weights 12,285 Ib / 5,572 kg with torpedo

12,509 Ib / 5,674 kg with bombs

Climb Rate 3,660 ft/min / 1,110 m/min
Maximum Speed 469 mph / 755 km/h at 20,000 ft / 6,000 m
Cruising Speed 407 mph / 655 km/h
Range 1,300 mi / 2100 km – 3,320 mi / 5340 km
Crew Pilot

Other crew member (Depending on the variant)

Armament
  • 2-4 12.7mm machine guns (All versions)
  • 1x Torpedo (P.105A)
  • 2x 1,000 Ib (454 kg) bombs (Dive Bomber)
  • 4x 20mm cannons (P.105C)

Boulton-Paul P.107 Specifications

Wingspan 38 ft / 11.6 m
Length 34 ft 8 in / 10.6 m
Wing Area 250 ft² / 23.3 m²
Engine 3,000 hp ( 2,200 kW ) Centaurus CE.12.SM engine
Fuel Capacity Main: 495 gal (2,250 lit)

Drop Tanks: 140 gal (640 lit)

Weight 15,900 Ib / 7,200 kg
Max Speed 470 mph / 755 km/h at 22,000 ft / 6,700 m
Range With Drop Tanks: 3,000 mi / 4,800 km

Without: 2,200 mi / 3,540 km

Fighter-Bomber: 700 mi / 1,120 km

Crew 1 Pilot

1 Gunner

Armament
  • 4x 20 mm guns + 2x 12.7mm machine guns
  • 2,000 Ib (907 kg) of bombs

Gallery

Illustrations by Haryo Panji

Boulton-Paul P.107 Illustration by Haryo Panji
Boulton-Paul P.105 Reconnaissance Illustration by Haryo Panji

Credits

Yermolayev Yer-2ON

USSR flag USSR (1944)
VIP Transport – 3 Converted

A 1/4 view of the Yer-2ON. (AviaDejaVu)

The Yer-2ON was a VIP passenger transport aircraft designed in 1944 by Vladimir Grigoryevich Yermolayev and his Yermolayev OKB (design bureau). Based off of the firm’s preexisting Yer-2 bomber, the Yer-2ON was meant to fulfill the role of a government VIP transport aircraft which would carry government members to and from meetings in or out of the Soviet Union. Shortly after Vladimir Yermolayev died on December 31st of 1944 from a typhoid infection, the Yermolayev OKB firm was integrated into Pavel Sukhoi’s Sukhoi OKB firm where the project continued. Despite showing relatively promising performance, the Yer-2ON would eventually be cancelled due to the conclusion of the Second World War and the Sukhoi OKB’s need to concentrate resources on other projects. Thus, the three produced Yer-2ON would never be used for their intended purpose and were presumably scrapped some time post-war.

History

Diplomacy between the Allied countries during the Second World War was an essential step in defeating the Axis powers. With the increasing successes of the Allies during the war, meetings between representatives from the United States, Soviet Union and United Kingdom were held to discuss the future of Europe along with battle plans. In order to attend these meetings, the Soviet government became aware of the need for a long-range VIP passenger transport aircraft capable of carrying 10 to 12 people while maintaining comfort, reliability, cruising abilities at 13,000 ft to 16,400 ft (4,000 m to 5,000 m) and range of 2,500 mi to 3,100 mi (4,000 km to 5,000 km). After Joseph Stalin himself made a request for an aircraft meeting these requirements in January of 1944, a meeting was held between government and Soviet Air Force officials discussing the feasibility of converting existing bomber aircraft to meet this need. Not only would this save time, but also had the benefit of sharing the same airframe as aircraft already in production. In the end, the Yermolayev OKB’s liquid-cooled Charomskiy ACh-30B V-12 diesel engine powered Yer-2 bomber was chosen for conversion. Curiously enough, Yer-2 being used as a transport aircraft is quite ironic, as it reflects on Roberto L. Bartini’s 1937 Stal-7 transport aircraft, from which the Yer-2 bomber was originally developed from.

A frontal view of the passenger compartment. (AviaDejaVu)

Shortly after the NKAP (People’s Commissariat for Aviation Industry) approved Order 351 on May 23, 1944, the head designer of the Yermolayev OKB firm, Vladimir Grigoryevich Yermolayev, began work on converting the Yer-2 into a VIP passenger transport aircraft. In his address to the NKAP on that day, he promised that a completed example would be converted by Factory No.39 and be ready for tests by November 15th. This new variant would be designated Yer-2ON (Osoboye Naznachenie – Special Purpose). With most of the groundwork already completed, Yermolayev was able to complete the conversion blueprints by August. An inspection was conducted on the Yer-2ON’s plans on August 28th and was approved for production. The difference between the Yer-2ON and the standard bomber variant was the removal of all armament and replacement of the bomb bay with a passenger compartment. The passenger compartment would have been able to hold 9 passengers, as well as a flight attendant. All relevant technical drawings were sent to Factory No.39 in the Irkutsk Oblast. A total of four Yer-2 bombers were ordered for conversion, but standard Yer-2 production would run into difficulties as the diesel powered Charomskiy ACh-30B engines manufactured at Factory No.500 were found to have defects and needed to be addressed. As such, the project was put on hold for a considerable amount of time.

A rear view of the Yer-2ON. (Одноклассники)

On December 31st, Vladimir Grigoryevich Yermolayev passed away due to a typhoid infection. As a result, the Yermolayev OKB and its assets were integrated into Pavlov Sukhoi’s Sukhoi OKB firm. It would appear that N.V. Sinelnikov took over as head designer once the project was integrated into Sukhoi OKB. Once the issue with the engines was resolved, three Yer-2 bombers were set aside and were prepared to be converted into the Yer-2ON. Due to the relatively poor documentation of the Yer-2ON’s development, it is unknown when precisely the first Yer-2ON was completed, but most sources allege it was completed at the end of December. The manufacturer’s flight tests and maiden flight appeared to have taken place sometime in February of 1945. Through these tests it was revealed that the Yer-2ON was capable of covering a distance of 3,230 mi / 5,200 km while maintaining a flight ceiling of 19,700 ft / 6,000 m and a top speed of 270 mph / 435 kmh.

On April 16th, the first Yer-2ON made a record non-stop flight from the Irkutsk Aviation Plant’s airfield in Eastern Siberia to Moscow. This flight was accomplished by Heroes of the Soviet Union M. Alekseev and Korostylev over a flight time of 15 hours and 30 minutes and covered a distance of approximately 2,611 mi / 4,202 km. It would appear that a second flight would be conducted sometime near the end of April with the second converted aircraft once it was ready. The second flight had identical circumstances as the first flight (same pilots, destination, fuel load, etc). Interestingly enough, both flights concluded with enough fuel for four more hours of flight, attesting to the Yer-2’s long-range capabilities. A third Yer-2ON was converted at an unspecified time, but details of its tests (if it performed any at all) are unknown. Some internet sources claim that a fourth example was completed on May 10th of 1945, but this cannot be confirmed and disagrees with most publications.

One of the passenger seats of the Yer-2ON. (AviaDejaVu)

Despite the Yer-2ON performing relatively well and passing the manufacturer’s flight tests, the aircraft was never used for its intended role of government VIP passenger transportation. This was likely the result of the project being deemed as low priority within the Sukhoi OKB firm. At the time, Sukhoi was invested in other more pressing projects which led to the Yer-2ON being eventually canceled. Joseph Stalin himself was reputed to have aviophobia (a fear of flying) and the Yer-2ON not entering service did not appear to have consequences for the Sukhoi OKB. Nonetheless, the Yer-2ON project was dropped some time post-war and the three manufactured prototypes were likely scrapped as a result.

Design

A cutout drawing of the Yer-2ON’s interior. (AviaDejaVu)

The Yermolayev Yer-2ON was a two engine VIP passenger transport aircraft based on the Yermolayev Yer-2 bomber aircraft, powered by two liquid-cooled Charomskiy ACh-30B V-12 diesel engines capable of producing 1,500 hp each. The Yer-2ON was identical to the standard Yer-2 bomber in most respects, though armaments and turrets were removed and the bomb bay was converted to a passenger compartment with seats for 9 passengers and 1 flight attendant. The crew would have consisted of a commander pilot, a co-pilot, a navigator, a radio operator, and a flight attendant. In the passenger compartment, the left side (aircraft facing forward) had 5 seats while the right side had 4. The flight attendant’s seat was located behind the last seat on the right side, and was retractable. A luggage compartment was also provided. Another notable feature was the addition of a toilet compartment, as the aircraft’s long-distance travel routes required such a feature. Several windows were installed on the side of the fuselage for the passengers.

Operators

  • Soviet Union – The Yer-2ON was intended to be used as a passenger transport aircraft for government VIPs traveling in and out of the country to attend meetings.

Yermolayev Yer-2ON*

* – Statistics taken from “OKB Sukhoi: A History of the Design Bureau and its Aircraft” by Dmitriy Komissarov, Sergey Komissarov, and Yefim Gordon

Wingspan 75 ft 5.51 in / 23 m
Length 53 ft 7.31 in / 16.34 m
Height 15 ft 9.76 in / 4.82 m
Wing Area 850.35 ft² / 79 m²
Engine 2x liquid-cooled Charomskiy ACh-30B V-12 diesel engines
Engine Ratings 1,500 hp (1,120 kW) – Maximum at Sea Level

1,250 hp (930 kW) – Regular

Empty Weight 38,800 lb / 17,600 kg
Takeoff Gross Weight 41,890 lb / 19,000 kg
Maximum Speed 270 mph / 435 kmh at 19,680 ft / 6,000 m
Ranges 3,040 mi / 4,900 km – Standard

3,230 mi / 5,200 km – Maximum

Maximum Service Ceiling 19,700 ft / 6,000 m
Takeoff Run 3,445 ft / 1,050 m
Landing Run 3,346 ft / 1,020 m
Crew Pilot / Commander

Co-Pilot

Navigator

Radio Operator

Flight Attendant

Accomodation 9 Passengers

Gallery

Yermolayev Yer-2ON Side View Illustration
A side view of the Yer-2ON. (AviaDejaVu)
The entrance to the passenger section. (AviaDejaVu)
This photo shows what appears to be a retractable seat in the rear of the passenger compartment. This seat most certainly would be for the flight attendant. (AviaDejaVu)
Toilet compartment of the Yer-2ON. (AviaDejaVu)

Sources

 

Bolkhovitinov S-2M-103

USSR flag USSR (1936)
Experimental Light Bomber – One Prototype Built

Bolkhovitinov’s light bomber was a truly unusual design, with two engines mounted in the same fuselage.

Prior to the German invasion, the Soviet air industry was in the process of developing a series of new experimental ideas and concepts. While generally unknown around the world, some of these were interesting designs, such as the Bolkhovitinov “S” experimental twin-engine fast attack bomber. Due to the German advance and the need for immediately operational planes, the development of this model was terminated.

An Unusual Idea

The leader of the whole S-2M-103 project, aircraft engineer Viktor Federovich Bolkhovitinov.

The S-2M-103 was designed and developed by a Soviet aircraft engineer team led by Viktor Federovich Bolkhovitinov (Ви́ктор Фёдорович Болхови́тинов). Bolkhovitinov (February 1899 – 29 January 1970) was a Soviet professor at the Zhukovsky Air Force Academy in Moscow, and also an aircraft engineer. One of his best known designs was the four-engined Bolkhovitinov DB-A bomber that was intended to replace to aging TB-3 bomber.

During 1936, Bolkhovitinov and his team were looking for a solution for the lack of a high-speed light bomber in the Soviet Air Force. Their answer would be an unusual twin-engine aircraft with a peculiar wing configuration. Instead of a conventional wing placement, the wings were mounted very low on the fuselage, and the tail was a twin fin design.

When they began working on the first calculations and drawings, their greatest concern was how to reduce drag. Usual bomber designs with wing-mounted engines slowed down the plane due to excessive drag. Fighters, on the other hand, had much better aerodynamic properties as they were designed to achieve the highest possible speeds. Bolkhovitinov and his team decided that, for their purposes, they would reuse elements from other bombers (two engines, bomb-carrying capacities, defensive armament) and a one-part fuselage.

The problem was how to position the two engines in order to reduce the drag as much as possible. They quickly came up with the idea of putting them both on the same line (one behind the other) and in the same fighter-like fuselage. While this configuration would make the new plane longer, it could be designed with much better aerodynamic properties.

The development and design of the unusual twin-engine system began in 1936, while work on the aircraft design itself began the next year. By 1938, the design was completed and preparations for the construction of a fully operational prototype began in July that year. The prototype was completed in 1939 and flight tests were scheduled to begin in July 1939 (or in early 1940 according to some sources).

Designation

This was the single-engined version tested during the winter of 1940/41.

The aircraft’s original designation was simply “Bolkhovitinov S” or “Sparka/Cпаренный”, which means twin. Today it is generally known under the “S-2M-103” designation, where the “2” stands for twin-engine configuration and “M-103” is the name of the engine. There were other designations used for this plane, such as “BBS-1” (Ближний бомбардировщик скоростной, fast short-range bomber), “LB-S“ (легкий бомбардировщик спаренный, light twin-engined bomber) оr “BB“ (Болхови́тинов Бомбардировщик, Bolkhovitinov Bomber). As the plane is best known as the the S-2M-103, this article will use this designation.

Technical Characteristics

The S-2M-103 was designed as a low wing, all-metal construction, two-seater, two-engined fast attack bomber. The S-2M-103’s main fuselage had an elliptical cross-section. The fuselage consisted of four (bottom, top and left and right side) panels that were held in place by using four strong angled-section longerons. The S-2M-103’s structure was covered with a modern light alloy stressed-skin.

The wings were constructed using a structural box with flanged lightening holes (to save weight). The wings’ interior sheet ribs were covered on both sides (upper and lower) by metal skin and held in place by flush riveting.

The two three-bladed propellers turned in the opposite directions in order to provide better stability during flight.

The rear twin-finned tail was covered with duralumin skin. For better stability, the rudders were equipped with inset balanced hinges. For the tailplanes’ movement, an irreversible trimming motor was used. The elevator had trim tabs with a variable geared drive.

The S-2M-103 had a completely retractable landing gear that was operated electrically. The front wheels and the smaller rear tail wheel was able to retract backward 90 degrees. During the winter of 1940/41, the wheeled landing gear was replaced with fixed skis.

Drawing of the twin-engined configuration.

This aircraft had an unusual two tandem engine arrangement, placed in the same mounting in the fuselage. The rear-mounted engine’s shaft passed through the front engine’s cylinder blocks. Both engines were connected to the two propellers (with six blades in total) which, when powered, turned in opposite directions, which provided better stability during flight (at least in theory). The S-2M-103 was powered by two 960 hp (716 kW) Klimov M-103’s V-12 liquid cooled engines. This engine was based on the French Hispano-Suiza 12Y which was produced under license by the Soviet Union as the M-100.

The water radiators were placed under the fuselage and had controllable exit flaps. Two oil coolers were located on the ducts on both sides of the two engines. The fuel was stored in four fuel tanks that were placed in the wings (between the wing spars). Unfortunately, there is no information available about the capacity of these tanks.

The two crew members were positioned in an unusually large cockpit fully enclosed with a plexiglass canopy. The crew consisted of the pilot and the navigator. The navigator was also provided with a bombsight. The navigator’s position was covered with plexiglas on all sides, which provided him with an excellent all-around view, including under the plane. His additional role was to operate the rear-mounted machine gun.

The S-2M-103 lacked any forward-firing offensive armament. While it was planned to equip it with weapons mounted in the wings, this was never accomplished. For self-defense, one 0.3 in (7.62 mm) ShKAS machine gun was provided for the navigator/gunner. Due to its tail design, the rear machine gun had a wide firing arc. Later, it was planned to replace the single 7.62 mm rear gun with heavier twin 0.5 in (12.7 mm) UBT machine guns. There were also alleged plans to equip the S-2M-103 with a rear-mounted remotely controlled ShKAS machine gun. Whether this was ever implemented is unknown, as there no photographs or precise information are available. The bomb bay, which could carry 880 lb (400 kg) of bombs, was located under the pilot cockpit. The bomb bay opening doors were opened electrically.

Operational Tests

Side view of the S-2M-103.

The S-2M-103, piloted by D.N. Kudrin, made its first test flight in late 1939. More tests were carried out by the Army from March to July 1940, the plane being piloted by D.N. Kudrin and A.I. Kabanov. During these flight tests, the S-2M-103 proved to be able to achieve a maximum speed of 354 mph (570 km/h) at 15,400 ft (4,700 m). The tests also proved that the concept of installing two engines in the same fuselage had some advantages over the wing-mounted configuration. The most obvious was the reduced drag, which lead to increased speed and improved flight performance.

There were also some problems with the design. Immediately noticeable were the poor take-off and landing performance during these tests trials. Due to its high weight of 12,460 lb (5,650 kg), the S-2M-103 needed a 3,430 ft (1,045 m) long airfield. More tests were carried out by removing any extra weight. With the weight being reduced by some 1,100 lb (500 kg), the S-2M-103 now only needed a 2,800 ft (860 m) long airfield. During landing at speeds of 103 mph (165 km/h) the aircraft needed a 2,130 ft (650 m) long airfield. Some problems with the twin propellers were also noted. The rear-mounted propeller drive shaft was damaged due to strong vibrations. Unfortunately, there are no records of cruising speed, climbing speed, or maximum service ceiling.

The Single-Engine Version

For testing during the winter of 1940/41, instead of the standard landing gear, fixed skies were provided.

In the following months of 1940 and 1941, the S-2M-103 received a number of modifications in the hope of solving the issues observed during preliminary testing. The twin-engine configuration was replaced with a single M-105P engine with a power of 960 hp (or 1,050 hp depending on the source). The area where the second engine was previously located was filled in order to maintain the stability of the aircraft. Due to the removal the second engine, the second contra-rotating propeller was no longer needed. The new engine’s oil coolers were placed in the main radiator duct. The designers had a dilemma about what to do with the extra interior space left by the removal of the second engine, but this was never solved completely. With these modifications, the weight was reduced from 12,460 lb (5,650 kg) to 8,820 lb (4,000 kg).

The wing design was also changed to one done by Z.I. Iskovich by increasing its size and using a new aerofoil shape. The previous wing design had an area of 246.5 ft² (22.9 m²), while the new one had 252 ft² (23.4 m²). The last change was made to ease testing during winter, replacing the landing gear with fixed skis.

It appears that no official designation for this version existed but, using the same logic as for the two-engine version, it could be called S-M-105, but this is only speculation at best. According to some sources, the single-engined variant was marked as the S-1.

There were plans to improve the performance of the projected fighter version by mounting two M-107 engines. The new fighter was to be designated simply as the “I” or “I-1”. Due to the later cancellation of the S-2M-103 project, the I-1 was also abandoned.

The Fate of the S-2M-103 Project

More flight tests were carried out during the first half of 1941. While there is no precise information, the newly modified single-engined version of the S-2M-103 allegedly had poor performance. Despite the modifications, the new single-engined version managed to achieve a much lower top speed of 248 mph (400 km/h) at 14,440 ft (4,400 m). The poor performance, preparation for Pe-2 production at the factory where it was built, and the German Invasion of the Soviet Union led to the cancellation of the S-2M-103 project.

Operators

  • The Soviet Union – A single prototype was tested in 1940/41, but was not adopted for production.

Variants

  • S-2M-103 – Twin engine fast bomber
  • S-2M-103 (possibly S-M-105) – Single-engine version
  • I-1 – Improved fighter version equipped with two M-107 engines, due to cancelation of the S-2M-103 none were built.

Conclusion

The concept of installing two engines in the same fuselage had some advantages over the wing mounted configuration. It reduced drag, which lead to increased speed and flight performance. The S-2M-103 proved this by achieving speeds of up to 350 mph (570 km/h). However, its design had issues that were never resolved. Given enough time, those might have been solved. Alas, in 1941, the German Invasion and the need to increase production of already existing aircraft stopped all unimportant projects.

Bolkhovitinov S-2M-103 (original twin-engine configuration) specifications
Wingspan 37 ft 5 in / 11.4 m
Length 43 ft 4 in / 13.2 m
Wing Area 246.5 ft ² / 22.9 m²
Engine Two 960 hp (716 kW) Klimov M-103
Maximum Takeoff Weight 12,460 lb / 5,650 kg
Maximum Speed at 4.6 km 354 mph / 570 km/h
Range 435 mi / 700 km
Crew The pilot and the navigator
Armament
  • One 0.3 in (7.62 mm) ShKAS machine gun
  • Bomb load of 880 lb/400 kg

Gallery

Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

Drawing of the S-2M-103.
View of the engine compartment interior.
Rear view of the S-2M-103.

Credits

 

 

Fiat G.50 Freccia

Kingdom of Italy flag Kingdom of Italy (1935)
Fighter Plane – 774 to 791  Built

Freccia in Italian service. Colorization by Michael Jucan [monochrome-watches.com]
During the thirties, Fiat Aviazione was one of the most advanced aircraft manufacturers in Europe. With the advent of new technology at the time, it was obvious that the next stage in the development of the aircraft industry, especially in military aviation, would be centered around all-metal monoplanes. Fiat’s Chief Designer, Ing. C. Rosatelli, had been designing mixed-construction biplanes and even an all-metal bomber. As the demand for a modern, all-metal fighter plane was high, Fiat officials made a decision to hire a young aircraft engineer named Giuseppe Gabrielli, who would later design the Freccia, the first operational Italian all-metal fighter.

Giuseppe Gabrielli’s Work

The history of the Fiat G.50 began in 1931, when Fiat formed a new Aircraft Technical Bureau – Department 2 (Ufficio Tecnico Aviazione – Divisione II). The main purpose of this bureau was designing and building brand new types of modern all-metal planes. The same year, a young Italian engineer, Giuseppe Gabrielli, was hired by Fiat Chairman Senator Angelli to work for the Technical Bureau. Giuseppe Gabrielli had gained some experience in aircraft design while working for Piaggio. When he moved to Fiat, he immediately began working on several non-military aircraft projects. All of his projects were marked by the capital letter ‘G’, his initial. First was the G.2, an all-metal, three-engined plane, then the G.8 biplane trainer, and later the twin-engine passenger plane G.18.

During the thirties, the Italian Ministry of Aviation (Ministero dell Aeronautica) was interested in adopting a new, all-metal monoplane fighter and ground attack aircraft for the Italian Air Force. Some specifications for their request were: to use one radial engine, armed with at least two 0.5 in (12.7 mm) heavy machine guns with at least 300 rounds of ammunition and one 0.7 in (20 mm) gun or 1.45 in (37 mm) gun, and provisions for bombs on the ground attacker. A request was sent out to all domestic aircraft manufacturers. There were several proposals in response, but only the G.50 and the Macchi C.200 would be chosen for production. The others were either rejected (Ro.51 and A.U.T. 18) or built in limited numbers, like the Caproni F.5.

In order to solve the problem of the lack of an adequate fighter design, Fiat officials even considered the acquisition of a license to produce the American Seversky SEV-3, but nothing came of this. In April of 1935, Giuseppe Gabrielli began working on a new low-wing, all-metal plane named G.50. According to his first plans and drawings, it was to be armed with two machine guns, powered by a 550 hp radial engine (with a diameter of 39 in/1 m), weigh around 3,395 lbs (1,540 kg), and equipped with a retractable landing gear. At the same time, Fiat was testing a new FIAT A 74 RC 38 14-cylinder radial piston engine, so it was logical that Giuseppe Gabrielli decided to use it for his work. The A 74, in principle, was a direct copy of the American Pratt & Whitney R-1830 Twin Wasp which powered a large number of US planes, including the Douglas C-47, Consolidated PBY Catalina, Douglas TBD Devastator and Grumman F4F Wildcat. The expected speed of the G.50 with this new engine was around 285 mph (460 km/h) at 11,500 ft (3,500 m).

G.50 prototype (MM.334) during its first test flights. [airwar.ru]
On 28th September, 1935, Gabrielli submitted his project to the Ministry of Aviation. Military officials were impressed by the design, but ask for some modifications. These included a wingspan of 36 ft 1 in (11 m), a weight of 4,870 lbs (2,210 kg) and a maximum speed of 280 mph (452 km/h). The offensive armament was changed to two 0.5 in (12.7 mm) heavy machine guns located in the fuselage with an additional two 0.3 in (7.7 mm) machine guns placed in the wings. In addition, the G.50 was designed to carrying a bomb load of 220 lbs (100 kg) or, if needed, extra fuel tanks with 23.5 gal (90 l) capacity.

In January 1936, the Ministry of Aviation changed its original request, choosing instead to focus only on the fighter role. The Ministry of Aviation wanted to accelerate the development of the new fighter, and the proposed ground attack role was rejected. Because of this, the bomb load was deemed no longer necessary, and the main armament was reduced to only two 0.5 in (12.7 mm) machine guns with 150 rounds each. The most important requirement was that the new fighter should have the best possible flying performance.

Despite these changes, the Fiat officials decided to proceed with the G.50 project. As Fiat’s production capacities were overburdened, work on this new project was instead moved to the CMASA works at Marina di Pisa, part of Fiat since 1931. Giuseppe Gabrielli was finishing his last drawings and the list of needed materials and equipment in June 1936. In his final drawings, the armament was reduced to two heavy machine guns without the bomb load, and the plane would be powered by the new A 74 c/n engine.

The production of the first operational prototype was scheduled to begin in late summer of 1936. The prototype was finally ready at the beginning of 1937 and was transported to the city of Turin for further testing. This prototype, under registration number MM 334, made its first test flight on 26th February, 1937. The pilot was Giovanniego De Briganti, the CMASA test pilot. During initial testing, the pilot noted several faults and possible problems with the G.50. He especially pointed out the strong vibrations during flight and the aircraft’s tendency to spin.

On 22nd June, 1937, the G.50 prototype was moved to Marina di Pisa for more testing and modifications. After these modifications were completed, the prototype was sent to the Regia Aeronautica (Italian Air Force) experimental flight center near Rome. There, the G.50 prototype was tested by several army pilots. They noted that the controls were hard to work with at high speeds and a lack of climbing ability. Before the final order for mass production, Giuseppe Gabrielli was asked to solve these problems. For this reason, another prototype was made, designated MM 335.

The second prototype made its first flight on 20th October, 1937. After a series of successful flying tests, an accident occurred. On the 11th (or 8th, depending on the source) November, 1937, while flying the second prototype at high speed, the test pilot Briganti lost control of his aircraft and crashed to the ground. He did not survive the crash. His place was taken by the new chief test pilot, Enzio Guerra.

A G.50 from the 20th Group, front-side view. [wwiivehicles.com]
A combination of the accident and inferior performance that did not meet expectations, along with better overall performance of the Macchi C.200 threatened to shut down the G.50 project. But as the CMASA works were already in process of producing a series of 45 G.50’s, it was deemed a waste of resources to abandon or scrap the tooling equipment needed to produced the G.50 that had already been produced. A second reason for keeping the project running was the fact that it would take too much time for Fiat to prepare for the production of the Macchi C.200. The Air Ministry decided to go on with G.50 production, but insisted that the company correct the shortcomings of the plane by the time of production. Of the 45 ordered, the first 11 were used for many more trials. Two planes, MM 3357 and 335, the salvaged and rebuilt prototype, were sent to the experimental centre in Rome. Seven were stationed at the Pisa S.Giusto airfield and tested there. Two more ,MM 3570 and 3571, were tested by pilots Guerra, Rolandi and Cus. These trials were held in Turin and the main purpose was to investigate possible changes to the design of the G.50. The preliminary tests showed that the fully enclosed cockpit had to be changed before production, and a new design was necessary. This enclosed cockpit had several drawbacks which pilots often complained about. The closed cockpit was hard to open (especially in emergency situations), was made of poor quality plexiglass which was prone to cracking, offered poor visibility and sometimes exhaust fumes accumulated in the cockpit so the pilots were forced to fly with an open cockpit. After some testing and modifications, it was decided to used a partially enclosed cockpit. This solution was not perfect and was uncomfortable for pilots. Despite this, it was decided that all future planes would be built with an open cockpit only. More modification that were deemed necessary were the installation of a new start-up system, a better undercarriage locking system and adding a new oxygen mask for piloting at high altitude.

The G.50 was first showed to the public in October of 1937 at the International Aeronautical Show held in Milan. From 1937 to 1940, when the production was changed to the improved version, some 224 G.50 were built.

Technical Characteristics

A G.50 flying alongside a German Bf-110, possibly during the Battle of Britain [Wiki]
The G.50 Freccia, Italian for Arrow, was a single-seat, low-wing, all-metal fighter plane. The main fuselage was made from four angular shaped longerons with 17 metal frames. The wing construction consisted of a center section which was made of a steel tube connected to the lower fuselage and two metal spars connected with ribs. The four flaps were hydraulically actuated and at certain speeds they would automatically retract to their closed position. The fuselage, wing, and tail were covered with duralumin sheets. The only fabric-covered parts were the movable control surfaces in the wings and the tail.

This G.50 belonged to the 20th Group, transferred from Belgium to North Africa. [ea51.org]
The engine was placed in a tubular shaped mount made of chrome-molybdenum steel that was connected to the fuselage by four bolts. The engine and the cockpit were separated by a fireproof screen in order to protect the pilot from any possible fire outbreak, either due to engine malfunction or damage. The plane was powered by the 840 hp (626 kW) Fiat A 74 RC 38, 14 cylinder radial piston engine. With this engine, the G.50 could reach a maximum speed of 293 mph (470 km/h), with an effective range of 276 mi (445 km) and a service ceiling of 35,000 ft (10,700 m). An all-metal three-blade propeller produced by Fiat was used. One of major disadvantages of using a radial type of engine was the massive drag due to its large cross-section. In order for ground repair crews to have easy access to the engine and the fuselage interior, several access doors were added. The maximum fuel capacity was 83.5 gal (316 l.) There were two fuel tanks located in the wings 11.9 gal each (45 l) and two more in the fuselage, one larger with 26.4 gal (100 l) and a smaller one with 18 gal (68 l) with an additional auxiliary tank 13.75 gal (52 l) also located in the fuselage.

The first G.50 series had an enclosed cockpit design but as this created many issues, it was later changed to an open cockpit. Despite its disadvantages, the enclosed cockpit had an excellent rear view. Many different open cockpit designs were tested before the final design was chosen. The later version with the open cockpit had two smalls door installed to help entering or exiting the plane. The seat was adjustable, so it could be adapted to the pilot’s needs.

In front of the pilot, the dashboard was divided into three sections. On the upper section were the navigation instruments, reflector sight, fuel indicators and engine instruments. The middle section had the ammunition counter, warning lights, the position of the landing gear, compass and oxygen control panel. The lower section had the engine starter, cowling controls and compressed-air system indicator. The radio in the pilot’s cabin was the ARC 1, but the quality of the batteries was poor. A fire extinguisher system was also provided. There was also the possibility of installing one OMI FM62 camera gun.

The G.50 was equipped, like most modern aircraft of the time, with inward retracting landing gear, but the rear tail wheel was fixed. In the G.50 bis version, the rear tail wheel was changed to a retractable type. The landing gear could, if necessary, be manually operated. At first, it was of a Messier type, but it was later replaced with a Magnaghi design. The retracting landing gear was hydraulically operated, and pneumatically during lowering. In case both systems did not work for any reason, it could be manually operated. For easier and more pleasant landing, hydraulic shock absorbers were provided for both telescoping legs.

The main armament consisted of two forward-firing 0.5 in (12.7mm) Breda-SAFAT heavy machine guns, with some 150 rounds of ammunition for each machine gun. The guns were placed behind the engine top and both were synchronised in order not to damage the propeller. It is interesting to note that this gun used oil lubricant for faster firing and thus a lubricant tank was added on top of the engine. Some G.50 planes were armed with bomb racks and used in North Africa.

Modifications and Prototypes

As the war progressed, the Italians realized that they were lacking planes to fulfill the different necessary roles such as fast ground attack or training. In order to save time, the most obvious solution was to try to modify existing models instead of developing new ones. The G.50 would be modified in several ways, some of which demanded major changes to the plane’s design, while others were just minor variations, like the added sand filter for the G.50 S.A.

Trainer G.50 B

The Fiat G.50 B version with the longer cockpit design for the instructor and the student. [alieuomini.it]
As the G.50 was entering production and the first operational units were formed, a trainer was needed for new pilots. As most army pilots were accustomed to flying older biplanes, retraining them for flying the monoplanes was required. For this purpose, in late 1936 the Italian Air Ministry placed an order for Fiat to developed a two seat dual control plane based on the G.50. After the mock-up was built and inspected in March 1938, it was deemed sufficient for production. By April, an order for the first prototype was placed. But due to the constant changes to the design, the production of the first prototype was frequently delayed. It was not until June 1939 when the final design with an enclosed cockpit was chosen. The plane was named G.50 B. The capital ‘B’ stands for ‘bipost,’ the Italian word for two-seater. This version was recognizable by its long glazed canopy with the rear cockpit being open from the top. The first prototype, marked 3615, would be ready in late April 1940 when it was tested by Enzio Guerra.

After only a few test flights, it was deemed adequate and was put into production. The first ten were built in 1940, with the last one built in 1943. In total, some 108 (or 100, depending on the source) G.50 B trainers were built during the war. Production by years was: 10 in 1940, 82 in 1941, 11 in 1942 and 5 in 1943.

The first series of G.50 planes produced had an enclosed cockpit design, but this was later replaced with a semi-open design. [warbirdphotographs]
The G.50 B was, in essence, a modified single-seat version with a new cockpit and dual controls. The front part of the cockpit was fully enclosed in contrast with the rear which was open. The main armament was removed on the G.50 B. This version was very successful, as it was easy to build and offered almost the same flying performance as the single-seat version.

These were used mostly by the Regia Aeronautica Fighter Schools. Smaller numbers were operated as liaison planes or even in some front based fighter units. After the Italian capitulation, small numbers, possible 20 or more, were used by the National Republican Air Force. At least one was given to the Croatian puppet state in the Balkans. The last G.50 B were used by the Flying School in Lecce for a few years after the war, up to 1948.

The Improved G.50 bis

The final decision for the mass production of the G.50 fighter was not based on its performance, but instead on the fact that CMASA had already begun producing it. The performance of the G.50 was poor compared to the Macchi C.200. In order to justify the production, the Italian Air Force requested that Fiat to improve the G.50’s overall performance. The sought modifications were adding extra fuel tanks, increasing capacity from 83.5 gal (316 l) to around 108.3 gal (410 l), redesigning the rear fuselage and the vertical tail surfaces, better glazing of the cockpit to protect the pilot from air turbulence, the addition of armor plates behind the pilot seat, and the tailwheel to be made retractable. The original ARC 1 radio, with its poor quality batteries, was only changed in October 1941 with the R.B.30.

The new improved version was designated the G.50 bis. According to Italian original plans, the first planes should have been ready by late 1938, but this was never achieved. The whole process was slow and the first aircraft was tested on 13th (or 9th) of September 1940 at Turin. As the main engine was not changed, despite the other modifications, the general flying performance was almost the same. The only improvements were easier maintenance and increased operational range. As these tests were completed, an order for production was given. From 1940 to 1943, around 439 of these versions were built by CMASA and Fiat.

G.50 S.A Ground Attacker

A G.50 somewhere in Africa, where it saw extensive combat action, in many cases as a improvised ground attack plane. [asisbiz]
A certain number of planes that were serving in North Africa were modified by adding sand filters and a bomb rack. The landing gear was also modified for easier landing.

G.50 A Ground Attacker

The G.50 A was designed to be used as a fighter-bomber on the “Aquila” aircraft-carrier which was under construction. For this modification, the G.50 B two seater version was reused. The main offensive armament was to be increased to four 0.5 in (12.7 mm) machine guns. The problem was that the wing design did not allow the installation of the new weapons directly in the wings. The solution was to increase a part of the central section of the wings in order to accommodate these guns. Additional bomb racks were also to be added. One prototype, serial number MM 8595, was built and tested in October 1942. The whole concept proved to be problematic and the project was abandoned. The prototype would be used up to 1943 in testing new wing designs. In some sources, this model is designated as G.50 A/N.

G.50 bis “Tuffo” Dive Bomber

This was a dive bomber version designed in 1941 and 42, possibly inspired by the famous German Ju-87 “Stuka.” A bomb load of up to 990 lbs (450 kg) was planned, with two 200 lbs (100 kg) bombs placed under the wings and one 550 lbs (250 kg) under the main fuselage. For this modification, the addition of dive brakes were necessary. There is no information about prototype construction, but there is a great chance that it was never made.

G.50 B Naval Observer

One plane (MM 6548) was rebuilt for a naval observation role in 1943. It had a larger tail, different wing sections, a camera and an arrestor hook for use on an aircraft carrier. It was also equipped with a B 30T transmitter, B.G.42 direction finder and a A.R.18 receiver. Only one was built, possibly because of the impending Italian capitulation.

G.50 O/R

This version was based on the G.50 bis and the only difference was the installation of a arrestor hook for aircraft carrier use. Around 16 planes were modified for this role and were in use by the 155th Group Autonomo, mostly for training, in 1943.

Other Projects

Beside these, there were some minor projects that were proposed, but the majority if not all of them were not implemented. On the base of the G.50 B some project were proposed like the: night fighter, land reconnaissance or even a floatplane fighter (G.50 Idro).

Prototypes based on the G.50

During the war, in order to improve the flying performance of the G.50, many new designs and weapon loads and engines were tested.

G.50 ter

This was a further development of the canceled G.52 project. The new project, designated the ‘G.50 ter,’ was to be equipped with the same 1000 hp (746 kW) Fiat A 76 engine as the G.52. Even before production of a prototype, the new engine was found to have a number of flaws. The first prototype powered by the new engine was ready by late July 1941. First flying tests were carried out at the Aeritalia airfield, with the plane being piloted by Agostini. During these flight tests, the engine proved to be mechanically unreliable and it could not reach expected performance. More test were held in November 1941, but in the end the project was canceled and only one plane was built.

G.50 V

The G.50 V prototype, powered by a new German engine. Even though this design solved the aerodynamic problems, it was never put into production. [Pinterest]
In late 1939, the Italian Ministry of Aviation made a decision to begin negotiations with the German Daimler-Benz company for a production license of the newest liquid cooled DB 601A engine (1035 hp). It had a much lower frontal area and had much better aerodynamics than the larger Italian radial engines. The license was eventually obtained and Alfa Romeo was put in charge of the production of this engine, but it was never built in any great numbers.

In early 1940, the Italian Ministry of Aviation asked Fiat to build a modified version of the G.50 using this new engine. Two prototypes were to be built by CMASA, and these were marked as G.50 V (the ‘V’ stand for Veloce, which means fast). The first prototype, serial number MM 479, was built and tested in late August 1941 by the test pilot Ezio Guerra. Immediately, the new design proved to have some issues, such as an inefficient engine cooling system and the controls being difficult to operate. By the end of 1941, most these problems were solved and a new series of tests was scheduled.

In December 1941, more extensive flight tests were carried out by test pilot Valentino Cus in order to determine the precise flight performance, in particular the maximum speeds at various heights and the climbing rate. Maximum speed achieved was some 360 mph (580 km/h), and a maximum altitude of 16,400 ft (5,000 m) was reached in 5 minutes and 30 seconds. Mostly due to the introduction of the new FIAT G.55 and the lack of DB 601 engines, the G.50 V project abandoned.

G.51

In 1940, it was proposed to equip one G.50 with the new A 75 R engine. Nothing came of this project.

G.52

Information about this version differs significantly depending on the source.

According to Piero Vergnano, Fiat worked on improving the performance of the A 74 engine used on the G.50 for quite some time. This lead to the development of the new 1000 hp (746 kW) Fiat A 76 engine. In 1938, Fiat suggested the installation of this engine in the G.50 to the Air Ministry. At first, the request was accepted and an order for two prototypes was placed. By late 1939, the project was canceled due to the acquisition of new German DB 601A engines, and no prototypes were ever built. According to Gianni Cattaneo, the G.52 was in fact just a further development of the G.50 V. Due to the appearance of the new G.55 fighter, this project was abandoned.

G.53

This proposal was a combination of the G.50 B powered by the DB 601A engine. It was developed in 1941. It was intended to be used as a fast reconnaissance plane, but the Air Ministry never showed any interest in this proposal and nothing came of it.

First Operational Units

As CMASA began producing the first G.50 planes in late 1938, an experimental military fighter unit was formed for further testing and training. This unit was located at the Ciampino airfield near Rome. The unit was named Gruppo Sperimentale da Caccia (Experimental Fighter Unit/Group). Command of this new unit was given to Major Mario Bonzano, at that time a famous pilot ace from the Spanish Civil War (flying the CR.32 biplane). Pilot training on this new plane lasted until January 1939, when the Italian Air Force High Command decided to send a unit of 12 planes to Spain for real combat testing.

In Spain

A group of 12 new G.50 fighters arrived in January 1939 in Spain, having been transported by sea. This unit was based at Escalona Airport, some 43.5 mi (70 km) from the capital of Madrid. Starting in March, this unit carried out flight patrols and fighter cover missions for bombers at altitudes between 24,600 to 26,240 ft (7,500 to 8,000 m). By that time, the opposing air force had been almost destroyed and air to air combat was rare. The only combat action that was recorded happened when a lone Soviet-built I-16, possibly flown by a Canadian pilot by the name of Dickinson, was intercepted by a G.50. The Italian aircraft was damaged and the pilot was forced to land. None of the 12 G.50 that were sent were lost in combat during the Spanish Civil War. At the end of this war, 11 operational G.50 fighters were given to the new Spanish fascist regime. These planes were used by the 27 Gruppo Caza (Fighter Group). After 1943, they were sent to Spanish Morocco, to be used by the 2. Regimento Mixto (mixed regiment) together with several German supplied He-112B.

A small number of G.50 fighters were used in the Spanish Civil War. Their combat operations were minimal and all were gifted to the new Spanish state. [Wiki]
After his return to Italy, Major Bonzano made his report of the effectiveness of the G.50. According to him, the G.50 had good maneuverability, effective armament and was easy to operate at altitude. On the other hand, he pointed out that the visibility was poor and the landing gear construction was weak and prone to malfunctioning. His conclusion about the effectiveness of the main armament would prove to have a great negative impact for the G.50 in the future.

In Finnish Service

Finnish G.50 on the airfield. [ww2aircraft.net]
Because of the likelihood of a Soviet attack in 1939, the Finnish government and Army wanted to equip their forces with modern equipment and weapons. As a result, a Finnish military delegation visited Turin in 1939, where the new G.50 fighters were being tested. The delegation was impressed with the aircraft’s performance, so they placed an order for 35 brand new G.50. Most of the planes sold were of the first series produced by CMASA, with serial numbers 3599 to 3614. These were supplemented by planes from the second productions series (serial numbers 4722 to 4750).

A very interesting fact is the maximum speed achieved by Finnish pilot Tapani Harmaja. As he was testing the flying performance of the G.50 at an airfield near Latina, he managed to reach a speed of 515 mph (830 km/h). He achieved this by diving from a high altitude of 11,480 ft (3,500 m) down to 1,310 ft (400 m). This was the fastest speed reached by any aircraft in Italy at that time.

Due to the outbreak of the Second World War in Europe, the transportation of the purchased aircraft was slow and complicated. The planes were disassembled and then transported by train through Italy to the north of Germany and then by ship to Sweden, and from there to Finland. As they were transported in parts, the assembly was done at Gothenburg. When they were completed, the pilots were instructed to fly them to their new stations. The first 14 G.50’s were received in February 1940 and the last in June 1940. While flying en route to their designated airfields, two planes were lost in accidents in February 1940.

The G.50 arrived too late to have any large impact on the Winter War (30 Nov. 1939 to 13 Mar. 1940) but they saw some combat during this period. The first G.50 planes were equipped with the 26th Fighter Wing (Lentolaivue 26 or just simply LeLv or HLeLv) located at Haukkajarvi. They were used to replace the older Gloster Gladiators used by this unit. By 13 March, the Finnish pilots flying the G.50 claimed to have shot down 11 Soviet planes. There is some disagreement between the sources, authors Gianni C. and David M. states that this unit did not participate in the Winter War.

Finland operated 35 G.50s during the war. Most saw extensive service during the Continuation War when, despite their obsolescence, they proved to be effective in the hands of Finnish pilots. [Wiki]
Until the German and Finnish attack on the Soviet Union in June 1941, known in Finland as The Continuation War, Finnish technicians and engineers tried to improve the performance of the G.50 fighters. Most Finnish G.50s were from the first series, equipped with the enclosed cockpit. This design was not popular with the Finnish pilots and was replaced with an open cockpit. The vertical stabilizer and rudders were replaced with improved ones. Also, the Finnish tested snow skis taken from Fokker D.XXI’s, for the G.50 allowing them to better land on on frozen airstrips.

At the start of the German invasion of the Soviet Union in 1941, Finland joined the war with a much larger air force than it had in the previous conflict. LeLv 26 was stationed at an airfield near Utti, and was charged with the protection of the area around Lake Ladoga where they saw most of the action they were involved in. The G.50 proved to be an effective fighter in the hands of Finnish pilots. On 25th June 1941, six Finnish G.50 fighters managed to shoot down 10 Soviet bombers with no losses. Later in August, pilots from LeLv 26 managed to shoot down nine Soviet fighters. The most famous Finnish pilot was Oiva Tuominen, who had a total of 23 (33 or 43 according to different sources) air victories, with around 15 while flying the G.50. For his service, he was awarded the Mannerheim Cross, the highest Finnish military medal at the time. By the war’s end, LeLv 26 had around 88 air victories with the loss of 11 G.50s. Only two were shot down by Soviet planes, one was lost to AA fire, and eight more were lost either to accidents or mechanical failures. The Finnish G.50s remained in use up to June 1944, when they were moved to the rear for second-line duties. By the end of the war, there were still some 22 (the exact numbers are not known) operational G.50 fighters and they were used up to 1947.

In Italian Service

Fiat G-50 “1-3” of the 1 Experimental Group in Escalona, in March 1939

According to the Italian military program codenamed “R” (Programme R), the Italian Air Force was to be heavily reinforced with many new units and more modern aircraft designs. With the existing G.50 fighter, it was planned to form and equip one Stormo (Stormo-regiment) and one Fighter Wing/Group (Gruppo).

The first unit to receive the new G.50s was 51° Stormo located at the Ciampino airport near Rome, in November 1939. This regiment consisted of the 20th Group, with 351st, 352nd and 353rd Squadrons, and the 21st Group, with 354th, 355th and 356th Squadrons. Almost all of the squadrons were equipped with the newer G.50 with the open cockpit, and only the 351st Squadron was equipped with the first series with the enclosed cockpits. To more effectively train both experienced and new pilots, military war game exercises were often held by the Italian Army. During one of these games the 51° Stormo would earn its military emblem, a black cat with a green mouse. During one exercises, a group of different fighter planes were tasked with intercepting a group of S.M.79 bombers, marked with the green mouse emblem. The older CR.32 biplane could not fulfill this task, but the new G.50 from the 352nd Squadron accomplished this without any problem. From that point on, the pilots from 51° Stormo began painting the emblem on their planes.

Quite soon, the order was given to form a second unit, 52° Stormo. It consisted of the 22nd Group (357th, 358th and 359th Squadrons) and the 24th Group (360th, 361st and 362nd Squadrons). The 24th Group was equipped with older FIAT CR.32 planes that were soon to be replaced with G.50’s. 52° Stormo operated from two airports, Pontendera and Sarzana. Both of these groups had around 100 brand new G.50s.

Western Front

By the time Italy entered the War in the West, there were some 118 G.50 planes on hand, with 97 operational, and some 21 were ready for delivery to designated units. In an attempt to profit from the fast Allied defeat in Western Europe, Italy declared war on France on the 10th of June 1940. Most G.50s saw some limited action, mostly covering SM.79 bombers during their attack on Corsica on 15th and 16th June. Subsequent attacks followed on 17th and 19th June. The center of operations then moved to the north, in the French Alps on 21st June. Due to a lack of proper training, the G.50 pilots had problems adapting to this type of aircraft, as most of them had flown only on the older biplanes. The G.50 proved to have good flying performance at low speeds, but was hard to control at high altitudes and higher speeds.

Battle for Britain

In order to support the German air raids on Great Britain, a special unit (Corpo Aereo Italiano C.A.I) was formed in late 1940 and was sent to Belgium. For this operation, the 20th Group, with 45-48 G.50’s, was selected under the command of Col. Bonzano. Despite the original planes being planned to reach their base of operations in Belgium by September 1940, this was delayed until October 1940. This delay occurred mostly due to bad weather. During the transfer from Italy to Belgium, two G.50’s were lost to accidents. The first combat actions were carried out in late October 1940, and were mostly bomber support missions. Similar missions were planned for 11th November against Great Yarmount, but they were canceled due to bad weather. From November 1940 to January 1941, the G.50 flew on many surveillance missions but there was no contact with enemy planes. By the end of January 1941, most Italian Air Force units returned home, with the exception of the 20th Group.

The C.A.I had great technical problems during this operation. The G.50 was designed for the Mediterranean rather than the cold climate of the North, and there were problems with freezing and defective instruments, unreliable batteries and fuel problems.

By April 1941, the remaining units were ordered to return to Italy. Missions conducted against Britain were unsuccessful and they did not go well for the Italian pilots, as they did not win any air victories. Italy had lost more than six aircraft with two dead pilots. This operation was a strategic failure for the Italian Air Force, mostly due to poor planning, adverse weather conditions and inefficiency of the planes used.

In the Balkans

Mussolini ordered an invasion of Greece in October 1940. For that purpose, fewer than 80 G.50 fighters based in Southern Italy (33) and occupied Albania (43) were used. Initially, because of the lack Greek air resistance, the G.50 were used as ground attack planes. But, after the arrival of the British forces in November, the first air battles started. Due to the fact that the Italian pilots had some experience during the Spanish Civil War, they managed to achieve some successes against the British. The G.50’s main opponent was the Gloster Gladiator, which had poorer flying performance in comparison. Later, however, more modern Hurricanes appeared, which were much more advanced than the G.50.

During the war in Greece, there were a number of engagements between the British and the Italian Air Forces. During one dogfight on 20th February 1941, some 10, possibly even 12, British planes were shot down in a single engagement by a group of 22 G.50s. The Italians only lost one plane. However, during the same day, British Hurricanes managed to shoot down four G.50s in a different engagement. On the 28th of February 1941, some 12 British planes were shot down at the loss of 27 Italian aircraft. In one unusual case, a collision took place between a G.50 and a Gladiator. Because of the heavy damage, the Gladiator crashed to the ground, while the pilot of the G.50, despite the damage received, managed to fly about 123 mi (200 km) back to his home base and safely land. Due to significant disagreements among sources, there is no accurate data on the losses of both sides. As the G.50 proved to be inferior to the Hurricane, they were gradually replaced with the more advanced Macchi C.200 planes.

During the attack on Yugoslavia, the so-called “April War” in April 1941, the G.50 were used in escort missions. There were very few air battles and, by 17th April, the war was over.

In the Mediterranean and North Africa

During the North African campaign, the first G.50s were stationed near Tripoli by the end of 1940 and early 1941. The first units to operate in Africa were the 151st, 152nd and 358th Squadrons with around 76 to 80 planes. Even before these units saw any action, there were great problems with the maintenance of these planes due to sand. Taking into account that North Africa is dominated by the Sahara desert, it is very strange that the Italian military leaders did not take into account the fact that the desert sand could affect the plane’s engine. Since a certain number of planes were taken out of action by this, the demand for special sand filters was high. There were also problems with the sand getting into the landing gear which caused issues. To solve these problems, the Air Ministry urged CMASA and Aeritalia to provide adequate sand filters and modify the landing gear. The G.50 planes modified in such a way were marked as G.50 A.S (A.S standing for Africa Sahariana).

The G.50 saw heavy fighting in North Africa. Depending on the combat situation, it was used in a standard fighter role, for ground attack, defence missions, or for bomber escort. As the war progressed, the G.50 was mostly used in a ground attack role by equipping them with a 220 lbs (100 kg) bomb load to increase its offensive armament. For this purpose, 50° Stormo was formed. 50° Stormo mostly operated around the Sidi Barrani sector, where it attained some success against the British P-40 and Hurricanes. The pilot Bovoli (from 50° Stormo) shot down six British Blenheim bombers in July 1941.

During 1941 and early 1942, despite reinforcements, G.50 losses were increasing. At the beginning of 1941 there were only 20 planes operational, but with reinforcements the number increased to 80 in October and then fell down to 35 in December 1941. Most planes were lost not in air combat but instead during enemy ground and air attacks on airfields, as well as accidents. For example, the 20th group suffered heavy losses when 18 G.50 were destroyed as British armored forces attacked the airfield at Martubi on 19th November 1941. By the end of 1941, the only unit operating the G.50 was the 12th Group stationed at Tripoli. By 1942, most G.50 fighters were either lost or replaced with more modern Macchi C.200 and C.202. The surviving G.50s were relocated to second line airfields in Sardinia (24th Group), Greece (151 Group) and in the Aegean (154th Group). By the time of the Axis defeat in Africa (1943), only the 358th Squadron was still using the G.50.

Despite having poorer flying performance than its main opponents, the P-40 and the Hurricane, the G.50 proved to be a formidable plane in the right hands. The G.50 also proved capable in its new role as a ground attack plane, in which it destroyed a large number of enemy planes on the ground.

The Last Stand

The 20th Group’s emblem, a black cat hunting green mice. [ea51.org]
After late 1942, the remaining G.50 fighters that were stationed in Italy serving as trainers and for second line operations. After the defeat in Northern Africa, the Italian army was in disarray and the rapid Allied landing in Sicily in July of 1943 worsened the situation. Many surviving G.50s were used to equip the 158th and 159th Groups. These two groups suffered heavy losses attacking strong Allied positions in Sicily. In a period of only a few days, the two groups ceased to exist.

After Sicily, the Allies landed on the Italian mainland and, on 8th September 1943, Italy capitulated. By that time, there were only around 40 to 48 G.50 airplanes still in service, of which only 17 were operational. A small number of G.50 were used by the new National Republican Air Force (Aeronautica Nazionale Repubblicana/ANR) in Northern Italy until the end of WW2 as second line and training planes. A few were even used by the Italian Co-Belligerent Air Force (Aviazione Cobelligerante Italiana, or ACI) in the southern part of Italy, which had switched over to the Allied side.

In NDH Service

In the middle of 1942, in exchange for raw resources and materials, Italy delivered 10 G.50 (9 single seat and one two-seat trainer) airplanes to the NDH, the independent state of Croatia Air Force (reg. number 3501-3510). These were not newly produced planes, but instead G.50s that returned from the front and were repaired. The planes that were supplied were used alongside French-built MS.406 fighters supplied by the Germans. In 1944, six more airplanes were obtained from Italy, now under German control (reg. number 5686, 5965 and 06186, the rest are unknown) bringing the total number used to around 16 planes, possibly more as the exact numbers are not known. According to Tihomir T. and Darko Č. NDH forces acquired three G.50, after the withdrawal of Italian forces in 1943.

Their participation in the war was negligible and they saw little if any action. On 15th September 1944, only 7 were reported, with none fully operational for service. There were several cases of desertion among Croatian pilots while flying the G.50. On 2nd September 1944, pilot Andrija Arapović escaped to the island of Vis, under the control of the Yugoslav communist Partisans. A second pilot flying a G.50 fled to the Allies stationed in Italy.

Partisan forces put the captured G.50 to use during the war and it would remain in service up to 1946. An interesting fact about Andrija Arapović’s G.50 aircraft (reg. number 3505) is that it still exists today and can be seen in the Belgrade Military Aviation museum near the airport “Nikola Tesla” in Serbia. This is the only surviving example of a G.50 in the whole world, but it is in very bad condition and has been under restoration for years. By the end of the war, the Yugoslav Partisans had captured almost all of the surviving G.50s in Croatian service, but their use was limited due to a lack of spare parts.

G.50 production attempts in China

Italians were for some time trying to negotiate with Chinese authorities about opening an aviation production factory in China. After initial negotiations in June 1934, the Chinese signed a contract with the Aeronautico Italiano per la China (Aerocina). This company was owned by the Italian Government in conjunction with Caproni, Breda, Fiat and SIAI. According to this contract, the Italians were to build the SINAW (Sino-Italian National Aircraft Works) factory in Nanchang. With this agreement, the Italians were to provide tools and machines necessary for the factory to work. The head of the soon-to-be factory was the Italian Luigi Acampora and the Director was General Chu Lin. The production of the first operational aircraft was to begin from July 1937 on and all Italian personnel were to return to Italy after five years of cooperation.

The SINAW officially started production in November 1936 with six Savoia-Marchetti SM.81B bombers. Future plans included production of 30 Breda Ba.65s and 50 Fiat G.50s. The factory was slightly damaged during the Japanese bombing of Nanchang on the 20th October 1937. By November the Italian Government made a decision to discontinue any further cooperation and stopped all future deliveries of equipment and materials. This was done mostly due to Japanese military actions and the poor cooperation of the Chinese. By early December 1937, all Italian personnel returned home, and the deal with the Chinese was abandoned without a single G.50 being built.

Production and Variants

Besides the few prototype planes, a total of 791 (source Piero V.) G.50 and its variants were built during the war. Other authors give different numbers, according to Chris B. some 774 were produced and author Gianni C. quotes the figure of 778 planes. Author Duško N. give a figure of 788 planes.

The production of the G.50 fighter began in 1937 and ended in 1940, with a total 244 planes. The production totals by years were: two prototypes in 1937, 14 planes in 1938, 75 in 1939 and 153 in 1940. The improved G.50 bis was produced from 1940 to 1943 with a total of 439 planes built (421 according to some sources). 71 planes were built in 1940, some 253 in 1941, 113 in 1942 and the last 2 were built in 1943. If we compare these production numbers with other modern fighters of the time, the G.50 was built in relatively small numbers. The G.50 and its modifications and prototypes were produced by CMASA and Fiat during the war.

Conclusion

The Fiat G.50 was the first Italian all-metal fighter plane to enter operational service in significant numbers. In the early stages of the war, it proved to be an effective fighter, but as the war progressed, it became obvious that it was outdated in comparison with other modern fighters like the Hurricane. The G.50 was easy to control at lower speeds and had good maneuverability. The negative side was the lack of engine power and the overall design of the radial engine which affected the aerodynamics of the G.50. There were problems with cockpit visibility, but the most notorious issue was the lack of effective offensive armament, which consisted of only two heavy machine guns. Despite all this, with a good pilot the G.50 proved that it could be an effective fighter and it was responsible of downing of a significant number of Allied planes during the war.

  • G.50 prototype – Two prototypes built, the second was lost in an accident.
  • G.50 – Production aircraft.
  • G.50 bis – Improved version.
  • G.50 A.S – A number of G.50 planes that were used in North Africa were modified with sand filters and improved landing gear.
  • G.50 A – One plane was modified with an increased offensive armament of four 12.7 mm machine guns in October 1942. Only one was constructed and used up to 1943 for testing different wing designs.
  • G.50 B – Two-seat trainer version, around 100 to 108 built.
  • G.50 bis “Tuffo”– Dive bomber version, none built.
  • G.50 B naval observation – One G.50 was modified to be used by the Italian Navy in 1943.
  • G.50 O/R – Based on the G.50 bis, some 16 were built and used for training in 1943.

Prototypes:

  • G.50 ter – Equipped with a stronger 1000 hp (746 kW) FIAT A.76 engine, only one built.
  • G.51– In 1940, it was proposed to equip one G.50 with the new A 75 R.C.53 engine, none built.
  • G.52 – Proposed project, none built.
  • G.50 V– Equipped with a German Daimler-Benz DB 601 engine, one built.
  • G.53 – Proposed project based on the G.50 B and powered by the DB 601, none built.

Operators

  • Kingdom of Italy – Operated around 720 G.50 aircraft, starting from the Spanish Civil War until the Italian Armistice.
  • Croatia (NDH) – Used at least 16 G.50 aircraft during the war (supplied by the Italians and Germans).
  • Finland – Operated 35 G.50’s during the Winter War and the Continuation War.
  • Fascist Spain – Used some aircraft given to them by the Italians at the end of the Spanish Civil War and after.
  • SFR Yugoslavia – Captured some G.50 fighters from NDH during the war. Their use was very limited.
  • National Republican Air Force (Aeronautica Nazionale Repubblicana/ANR) – Operated a small number of G.50s, mostly as trainers.
  • Co-Belligerent Air Force (Aviazione Cobelligerante Italiana, or ACI) – Operated limited numbers.
  • Nazi Germany – A few were captured and saw limited use with the Luftwaffe.
  • China – There were plans to produce 50 G.50 aircraft in China but nothing came of this.
G.50 Freccia Specifications
Wingspan 35 ft 11 in / 10.9 m
Length 26 ft 3 in / 8 m
Height 10 ft 7 in / 3.28 m
Wing Area 196.5 ft² / 18.25 m²
Engine One 840 hp (626 kW) Fiat A.74 RC.38, 14 cylinder radial piston
Empty Weight 4,353 lbs / 1,975 kg
Maximum Takeoff Weight 5,324 lbs / 2,415 kg
Fuel Capacity 316 l
Maximum Speed 292 mph / 470 km/h
Range 267 mi / 445 km
Maximum Service Ceiling 35,100 ft (10,700 m)
Climb speed Climb to 19,700 ft (6,000 m) in 7 minutes and 30 seconds
Crew One pilot
Armament
  • Two 12.7 mm Breda-SAFAT heavy machine guns

Gallery

Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

Fiat G.50 Prototype
Fiat G.50 “1-1” belonging to Mario Bonzano in Spain
G.50 MM4743 in Finnish Service
G.50 bis in Croatian Service circa 1941
G.50 B MM6137 in Luftwaffe Service

A G.50 from the 351st squadron in flight somewhere in Italy in January of 1941. [alieuomini.it]
Freccia in Italian service [monochrome-watches.com]
Side view of two G.50s, probably in Africa. [warbirdphotographs]

The Germans managed to capture a small numbers of surviving G.50s, but their use was limited. [warbirdphotographs]
The NDH received around 16 G.50 (with one G.50 B) planes during the war, but their use was very limited. [Asisbiz]

Credits

Messerschmitt Me 163S Habicht

Nazi flag Nazi Germany (1945)
Rocket Interceptor Trainer – 1 Built

A rear 3/4 view of the Soviet captured “White 94” Me 163S. Colorization by Michael Jucan [Yefim Gordon]
The Messerschmitt Me 163S (Schulflugzeug / Training Aircraft) Habicht (Hawk) was an unarmed two-seat training glider based off of the famous Messerschmitt Me 163 Komet. Originally designed for the purpose of training novice pilots for landing, the Habicht ultimately never saw active service with the Germans and only a single example was produced through the conversion of a serial Me 163B-1. With the sole example captured by the Russians after the war, the Habicht underwent extensive testing by the Soviet Air Force which helped them understand the flying characteristics of the Komet and prepared Soviet pilots for flying the powered Komets. The Habicht undoubtedly played a part in helping Soviet engineers understand the Komet and thus played a part in the future development of Soviet rocket aircraft.

History

A closeup view of the Me 163S showing the right wing. [Yefim Gordon]
The Messerschmitt Me 163 Komet was one of Nazi Germany’s most famous aircraft produced during the Second World War. Although bearing the title of the world’s first mass-produced rocket-powered interceptor, the Komet did have its fair share of flaws, such as the volatile and sometimes dangerous Walter HWK 109-509 rocket engine, which prevented it from becoming an effective weapon against the Allies.

As the Komet was designed to have a limited amount of fuel to engage Allied bombers, pilots were expected to glide the Komet back to friendly airfields once they disengaged from combat. With gliding landings as a potential problem for the less experienced pilots, one of the ideas proposed by Messerschmitt designers in 1944 was to introduce a dedicated trainer variant of the Komet which would have a student pilot accompanied by an instructor pilot. Designated as the Messerschmitt Me 163S (Schulflugzeug / Training Aircraft) Habicht, the trainer glider differed from the production model with the addition of an instructor’s cockpit behind the forward cockpit. This addition was accompanied by the removal of the Walter HWK 109-509 rocket engine and the Habicht would have to be towed by another aircraft in order to get airborne. Another interesting addition to the Habicht was a second liquid tank behind the instructor’s cockpit for counterbalancing. All the liquid tanks would be filled with water for weight simulation and ballast. A total of twelve examples were planned for production, but only one was produced due to wartime production constraints.

The sole example of the Habicht was built by converting an earlier Me 163B-1 production model. Due to the scarcity of information regarding the Me 163S, it is unknown exactly when the Habicht was produced and what sort of testing it may have undergone during German possession. However, it is known that the Soviet Union was able to capture the only example during the final stages of the World War II’s Eastern Front. The sole Habicht was sent to the Soviet Union along with three Me 163B Komets during the Summer of 1945 for thorough inspection and testing. In historian Yefim Gordon’s book “Soviet Rocket Fighters – Red Star Volume 30”, he claims that in addition to the three Komets, seven Habicht trainer models were also captured. This, however, remains quite dubious as there is no evidence that more than one Habicht existed, and all current photographic material, research materials, and books all suggest that only a single example was produced.

The Me 163S in simulated flight configuration aided by struts. [Yefim Gordon]
As the Soviets were particularly interested in rocket propulsion aircraft, the State Defence Committee issued a resolution which called for the thorough examination of the Walter 109-509 jet engine and the Me 163 Komet along with captured German documents on rocket propulsion. The three Me 163B Komets, of which only one was airworthy, and the Me 163S Habicht were sent to the Flight Research Institute (LII), the Valeriy P. Chkalov Soviet Air Force State Research Institute (GK NII VSS), and the Central Aerohydrodynamic Institute (TsAGI). The Habicht and Komets saw extensive testing in Soviet hands, undergoing several structural, static and wind tunnel tests. During the initial flight testing period, the Komet only flew as a glider as Soviet pilots and engineers were unsure of whether or not the Walter rocket engine was ready for use since bench tests were not completed. Securing the T-Stoff and C-Stoff propellants for the rocket engine was also a problem. In order to understand the handling characteristics of the Komet, the Habicht was flown numerous times at different altitudes, as was the unpowered Komet. A Tupolev Tu-2 bomber was responsible for towing the Habicht to these altitudes. Under Soviet ownership, the Habicht was given the nickname of “Карась” (Karas / Crucian Carp) due to the glider’s distinct silhouette. The test pilot responsible for flying the Habicht was Mark Lazarevich Gallaj. In general, the Habicht was considered relatively easy to handle by the Soviet test pilots. It is unknown how many test flights the Habicht underwent, but the aircraft certainly aided Soviet pilots in understanding the handling characteristics of the Komet. The Habicht’s service came to an end once the Soviet state trials of the Komet concluded. The sole example was scrapped sometime in 1946, along with seemingly all the other Komets.

If the Me 163S was able to be mass produced and flown with the Luftwaffe, the aircraft would have been a valuable tool to train German pilots. Landing the Komet was a problem for some pilots and in some cases resulted in fatalities but, with the use of the Habicht, the number of accidents would have certainly decreased.

Design

The Me 163S hung upside down in an unspecified TsAGI workshop for static testing. [Yefim Gordon]
The Messerschmitt Me 163S Habicht was a semi-monocoque aluminum based two-seat training glider developed off the standard tailless Messerschmitt Me 163B-1 Komet. The sole example was converted from a production Komet, which meant dramatic modifications had to be made to the aircraft. The Walther HWK 109-509 rocket engine was removed and in its place was a cockpit for an instructor. The fuel tanks in the airframe were all filled with water to simulate fuel weight while another water tank was added behind the instructor’s cockpit for ballast purposes. There was no armament fitted to the glider. There was a small transparent section between the student pilot’s cockpit and the instructor pilot’s cockpit, presumably for the purpose of communication. As there are no known German documents on the Habicht and Russian documents are scarce, not much is known on the other differences the Habicht may have had. Detailed specifications of the Habicht are unknown, but theoretically it should have been identical to the standard Me 163B-1 Komet except for possibly weight, air drag and center of gravity.

Operators

  • Nazi Germany – The intended operator and producer of the Me 163S Habicht.
  • Soviet Union – The main operator of the Me 163S Habicht. A single Habicht was captured and tested by the Soviets after the war. The Habicht was scrapped in 1946.

*Editor’s note: As noted above, the exact specifications of the Me 163S Habicht are unknown. However they are presumed to be similar to that of the Me 163B-1 Komet.

Gallery

Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

Me 163S Habicht “White 94” in Russian Service [Haryo Panji]
Me 163S Habicht in German Service [Haryo Panji]
 

 

Now known as the “White 94”, the Me 163S sits idly by. [Yefim Gordon]
A closeup view of the Me 163S showing the transparent section between the two cockpits. [Yefim Gordon]
The Me 163S in simulated flight configuration aided by struts. [Yefim Gordon]
A top down view of the “White 94” Me 163S. [Yefim Gordon]
A photo of the “White 94” Me 163S in flight being towed by a presumed Tupolev Tu-2. The pilot in the photo is likely Mark L. Gallaj. [Yefim Gordon]
The Me 163S inside TsAGI’s T-101 wind tunnel for testing. The struts support the Habicht and simulate its flight configuration. [Yefim Gordon]
An alternate closeup view of the Me 163S during static tests. [Yefim Gordon]

Yet another inverted static test, but this time the tail wheel strut and tire were removed from the Me 163S. [Yefim Gordon]

Sources

Akaflieg Berlin B9

Nazi flag Nazi Germany (1942)
Experimental Aircraft – 1 Prototype Built

Three-quarters view of the B9, note the large glazed cockpit. Colorized by Michael Jucan [airwar.ru]
The Akaflieg Berlin B9 was a German experimental twin engine aircraft designed with the pilot placed in the prone position.  It was designed to withstand extremely high g-forces. One prototype was built and tested by a glider production workshop in 1943 but it would not be adopted for mass production. The author would like to especially thank Carsten Karge from the Archiv Akaflieg Berlin for providing information on this generally unknown aircraft.

Why prone position?

During sharp up and down turns while flying an aircraft, strong g-forces appear that act on the pilot, potentially leading to loss of consciousness. Under normal flying conditions, the g-forces that appear are relatively harmless. The first effect of the g-force which the pilot notices is the difficulty of moving his body normally, as normal movements feel much heavier. Another effect of strong g-forces, which is much more dangerous, is the loss of oxygen flow to the brain. In some cases, the flow of oxygen and blood to the human brain can be greatly diminished, which can lead to the pilot losing consciousness momentarily. This effect lasts a short time, but it is enough for the pilot to lose control of the plane with a potentially fatal outcome.

While today, devices such as advanced anti-g suits help the pilot withstand strong g-forces, during the World War Two, other solutions had to be found. The Germans had noticed that, especially during sharp dive bombing actions, the pilots often lost consciousness. One way to tackle this was to put the pilot into a prone position, which in essence means to fly the plane while lying on the belly. In this position, the pilot has both his heart and his brain at the same level, which means that blood is no longer stopped from travelling to the brain during high-g maneuvers. Thus, this flying position allows the pilot to endure much greater g-forces than he would normally be able to if he would be in an ordinary sitting position. Other advantages of the prone position are the reduced aircraft size, smaller fuselage, less drag due to the smaller cockpit, and it would be easier for the pilot to operate the plane when conducting bomb sighting and ground attack, among other advantages.

During the war, the Germans would test several such aircraft designs, sush as the Henschel Hs 132 or B9, mostly for the ground attack role. Beside a few prototypes built, none were ever used operationally.

History

The SF 17 prone glider was the forerunner of the B9 powered aircraft [Akaflieg Stuttgart]
In order to test the idea of an aircraft with the pilot in the prone-position, the Aero-Technical Group (Flugtechnische Fachgruppe/FFG) of Stuttgart designed and later built the FS 17 all-wood test glider. It was especially designed to withstand forces up to 14 G. It made its first test flight on 21st March, 1938. In the spring of 1939, FFG Stuttgart made the first design drawings and calculations for a prone-piloted aircraft. This aircraft was to be powered by two Hirth HM 50 engines with an estimated speed of 250 mph (400 km/h).

FFG Stuttgart never completed this project as it was forced, for unknown but likely politicaly reasons, to hand over the project to Akaflieg (Akademische Fliegergruppe/Academic Aviator Group) Berlin. It is possible the order came from the German Experimental Department for Aerospace (Deutsche Versuchanstalt für Luftfahrt e.V. Berlin-Aldershof) DVL or even from the Ministry of Aviation (RLM – Reichsluftfahrtministerium), but precise information is lacking. Akaflieg Berlin, founded in 1920, was one of the oldest gliding clubs in Germany and it still exists today.

The RLM designation for this aircraft was “8-341” but Akaflieg used the simpler B9 designation. The technical characteristics that the new plane was supposed to have were a good field-of-view for the pilot in the prone position, a high degree of safety for the pilot, a high speed during diving, good general flying characteristics and being able to withstand forces of up to 25 G, or 22 G depending on the sources.

Akaflieg Berlin had a small number of engineers and workers and an adequately equipped workshop to complete the task given. For this purpose, a design team was formed with Theodor Goedicke, Leo Schmidt and Martin G. Winter, which was responsible for the creation of this new aircraft design. The first prototype was to be ready by August 1942 but this was never achieved, and the prototype was only completed in early 1943. It made its first test flight on the 10th April, 1943 at the Schönefeld airfield, near Berlin.

The Design

Front view of the B9 [airwar]
The B9 was a single-seat, low wing, mixed construction aircraft with the pilot in prone position. It consisted of a metal airframe, made of steel ribs, covered with wood and canvas. The main fuselage’s cross-section was trapezoidal shaped. As the B9 was specifically designed to withstand forces of up to 25 G, it had to have a strong fuselage.

The wings were made of wood covered with duralumin sheets. In order for the wooden wings to withstand the strong torsional forces which occur during high acceleration maneuvers, the spaces between the spars were heavily reinforced. The middle part of the wings viewed from above have a square shape and then narrow towards the wing tips. The wings were held in place by four bolts on each side. The rear tail design was a simple one, with standard rudder and elevators.

The B9 had a standard retractable landing gear copied from the Me-108, which consisted of two larger wheels and one smaller non-retractable wheel at the back. The landing gear was lowered and raised manually. The front wheels retracted into the engine nacelles, but they were not fully enclosed.

The B9 had a large 4.9 ft (1.5 m) long glazed cockpit with good all-around view. But, as the pilot was in a prone position, the above and the rear views were limited by the human body’s inability to turn the head in these directions. The glazed cockpit was made of two parts, the front windshield and the rear larger canopy that opened to the right side. The cockpit interior had to be especially designed for a pilot lying in the prone position. The usual flight controls were almost useless in this situation and, thus, certain changes were necessary. It was important to divide the controls on both sides of the cockpit, in order to avoid the pilot crossing hands, which could lead to complications in flight. On the right side were the controls for ailerons and elevation. The pilot would use his right hand to gain access to the harness and the canopy release mechanism. For controlling the rudders and brakes, the pilot would use his feet. Using his left hand, he would operate the remaining instruments, the throttles, flaps, ignition switches, emergency pump, fire warning, undercarriage control and others. Additional engine and flight instruments were located behind the pilot. These included, among others, the distance indicator, climb indicator, compass, oil and fuel pressure gauges and airspeed indicator. For the pilot to be able to see them, a small mirror was provided. There were also inclined and horizontal line markers on the inner windshield to help the pilot with orientation. For flying at high altitude, an oxygen supply system with a mask was provided to the pilot.

The aircraft was powered by two Hirt HM 500 air-cooled engines, with 105 hp each. The maximum speed was around 140 mph (225 km/h) but, according to some sources, it was as high as 155 mph (250 km/h). The four fuel tanks, with a total capacity of 25 gallons (95 l), were located between the spars on both engine sides. The B9’s effective operational range was 250 mi (400 km). Originally, the B9 was meant to be equipped with two variable-pitch propellers, but it was instead fitted with ordinary wooden fixed pitch propellers made by the Schäfer company.

As the B9 could be used as a ground attack aircraft, a bomb rack was meant to be installed, but it is not clear if this was ever implemented.

Operational Testing

The B9 in flight [airwar]
The operational prototype was ready by the summer of 1943. The first test flights were carried out by Ing. L. Schmidt and Dipl.-lng. E. G. Friedrichs. On one flight, L. Schmidt had an accident, the details of which are not known, but the plane probably suffered only minor damage.

The B9 was meant to make a series of test flights in order to ascertain if the prone position design had any merit and to test the general flying and overall structural performance. If these proved to be successful, the B9 would serve as base for future development and be put into active service. The B9 aircraft received the ”D-ECAY” marking, which was painted on both sides of the fuselage.

The tests were carried out from July to October 1943, during which time around thirty pilots had the opportunity to fly it. The test flights were conducted without any major problems and only one accident was recorded. This accident was caused not by any mechanical problems, but by a pilot mistake during takeoff. The B9 was damaged, but it was repaired and put back into service in only a few weeks.

The pilots did not have many objections to flying in the new prone position. They described it as comfortable and that it was relatively easy to adapt to the new commands. There were some issues, like fatigue and tiredness of the neck and shoulder muscles because of the constant moving of the upper arms. There were also some complaints about the chin supporter, which was deemed as unpleasant during flight but it was essential during high g-force maneuvers. During these test flights, the control panel and the controls did receive some changes in design. The large and fully glazed cockpit provided the pilot with good front and below fields of view, while the rear and upward view was somewhat problematic due to the prone position.

These tests showed that this type of aircraft was well suited for bomber, ground attack, high speed reconnaissance and possibly even in a high-speed fighter role. But it was also noticed that, due to the somewhat restricted view, the use of low speed prone pilot aircraft without air support was not recommended. Despite being designed to withstand forces of up to 25 G, the maximum achieved was only 8.5 G. One of the reasons for this was the use of low rotational speed propellers.

For 1944 and 1945 unfortunately, there is no information about the B9’s operational use. The B9 was found abandoned at the Johannisthal airfield near Berlin after the war. In what condition it was by the time of capture is not known. What is unusual is that the B9 was captured by the Americans and not the Soviets (according to author Hans J.W.). What the Americans did with the plane is unknown to this day, but it was most likely scrapped.

Only one B9 plane prototype was ever built. By 1943 and 44, a large amount of resources were invested in the production of fighters for the defense of the Reich and there were neither the time nor the resources needed to develop and test such an aircraft.

Akaflieg Berlin B9 Specifications

Wingspan 30 ft 10 in / 9.4 m
Length 19 ft 8 in / 6 m
Height 7 ft 7 in / 2.3 m
Wing Area 128 sq ft / 11.9 m²
Engine Two Hirt HM 500 engines, with 105 hp each
Empty Weight 2,207 lbs / 940 kg
Maximum Takeoff Weight 2,458 lbs / 1,115 kg
Fuel Capacity 95 l
Maximum Speed 140 mph / 225 km/h
Range 250 mi / 400 km
Maximum Service Ceiling 13,000 ft / 4.000 m
Climb to 13,125 ft / 4,000 m 4 minutes and 12 seconds
Crew One pilot
Armament None

Gallery

Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

 

Akaflieg Berlin B9 – Prototype [Haryo Panji]
B9 drawings [airwar]

Sources

Ikarus MM-2

Yugoslavia flag Yugoslavia (1939)
Prototype Advanced Trainer – 1 Built

The MM-2 prototype had an unusual color scheme with a combination of red and polished aluminum.

With the emergence of new fighter planes in the years leading up to the Second World War, it became necessary to replace the older biplane trainer aircraft, which were too slow, in order to efficiently train new pilots to fly the newest fighters. Thus, it was logical that more modern advanced trainer aircraft would be needed. The MM-2 was an experimental Yugoslavian solution to this problem.

First Steps

At the end of the thirties, the Yugoslav Air Force was equipped with modern planes, such as the German Me-109, the indigenous IK-3, and the British Hurricane, highlighting the need for an updated trainer. There were several older aircraft in use for the role, like the FP-2 and the Rogožarski PVT, with a maximum speed of around 140 mph (230 km/h) but there was a need for a much faster and modern aircraft trainer.

The designer of the MM-2 trainer, Captain Dragutin Milošević.

To fill this gap, Air Force engineer and pilot Captain 1st Class Dragutin Milošević, on his own initiative, began to work on a new advanced trainer in 1936. The first aerodynamic calculations, choice of engine, structure, and the design were done by 1937. This new plane was conceived as a two-seater with seats one behind the other, with an enclosed cockpit and dual controls. It had a low wing, mixed construction, with a single engine and retractable landing gear. The engine would have been the Renault 6Q-02, giving 162 kW (220 hp). Milošević never gave a designation for this plane, but was later simply named the M-1.

Captain Dragutin Milošević submitted this project to the Yugoslav Department of Aviation in 1937. The Department analyzed this proposal and, while on paper it would have had great flying performance, a decision was made to reject it because the parts necessary for its construction had to be imported from abroad.

This decision did not discourage Captain Milošević, and he made attempts to improve his design. He proposed replacing the Renault with the license-built Gnome-Rhone K-7 309 kW (420 hp) air-cooled 7-cylinder engine. By adding this engine, the length of the plane would be reduced from 23 ft 7 in to 20 ft 4 in (7.2 m to 6.7 m) but the total weight increased to 2,160 lbs (980 kg). To improve the landing characteristics of the aircraft, it would have been necessary to increase the distance between two front landing wheels from 6 ft 2 in to 7 ft 10 in (1.9 m to 2.39 m). All aerodynamic and statistical calculations were finished by 1939. The second version was named M-2 and it was, in essence, the basis of the future MM-2 aircraft.

One wooden model (1:10 scale) was built by the Albatros factory in Sremska Mitrovica. This model would be used to test the aerodynamic properties and accuracy of earlier calculations. Aerodynamic properties were tested in the Paris wind tunnels on the 17th and 18th of July 1939. After these trials, the fuselage length reverted to the original 23 ft 7 in (7.2 m).

Later, Captain Milošević did new calculations that showed that certain changes to the design of the aircraft were necessary. Adding weapons and increasing fuel capacity would lead to an increase of the mass of the M-2 by 242 lbs (110 kg), some 60 lbs (30 kg) in fuel and 176 lbs (80 kg) in armament. After all the other modifications, the total mass reached 2,782 lbs (1,262 kg) compared to the initial 2,160 lb (980 kg). The wing area had to be increased from 129 to 146 sq ft (12 to 13.6 m²) and the wingspan from 27 ft 10 in to 30 ft 3 in (8.5 to 9,23 m).

Adoption of a Prototype

Captain Milošević submitted a letter, together with documents, plans and calculations, to the supreme headquarters of the Yugoslavian Air Force, notifying them of the test results of the proposed M-2 aircraft. Since he did not receive any kind of response, he asked Major Đorđe Manojlović, also an aviation engineer, for help. Although Đorđe Manojlović did not have a direct impact on the design of the M-2, his great influence and connections in the Supreme Air Force Command lead to the continuation of the project. The cooperation of these two men lead to the final approval for construction of the M-2 aircraft project.

The only MM-2 prototype during its construction by Ikarus.

When the Air Force Headquarters of the Army of the Kingdom of Yugoslavia accepted the M-2, construction of this project was given to the Ikarus factory. The contract was signed on the 25th March 1940. It was planned to build one prototype aircraft for testing in order to ascertain if the M-2 was fit to be accepted for serial production. The project was monitored by a team composed of engineer Sava Petrović, Air Force Major Vojislav Popović and the technician Stefan Lazić. The prototype was ready by the first half of November 1940.

Origin of the Name

In the Kingdom of Yugoslavia, there was a custom of using the initials of the names of the designers as the official designation for most of new types of aircraft in service (like the IK-2/3), and MM-2 was no exception. MM comes from the initials of the surnames of Captain Dragutin Milošević and the constructor and engineer Major Đorđe Manojlović. There is sometimes confusion about the exact name of this aircraft. It is sometimes also called MiMa-2. In some documents found after the war, it is also called M.M. 2. In this article, the MM-2 name will be used, as it is the most common.

Technical Characteristics

Captain Dragutin Milošević’s first drawing of the MM-2. Note that the engine nose design appears to be for an inline engine, different from the actual prototype.

The MM-2 was designed as an advanced two-seater trainer, with seats one behind the other, with dual controls and a fully enclosed cockpit. It was a low wing, mixed construction, a combination of wood and metal, single engine aircraft with retractable landing gear.

The wings had a trapezoidal shape with a rounded top. They were constructed by using two racks which were made of steel tubes welded together. The racks were welded to the plane’s hull and the wooden ribs were connected to them by rivets. The wings were covered with canvas, except for the central parts, which were made of aluminum sheet. This was done so that the technicians and repair crews could have easy access to the inside of the wing. The ends of the wings were made of wood that were held in place by steel fittings. The flaps were covered in canvas and operated either manually or hydraulically.

The MM-2 hull was of mixed construction. The main body was made by using welded pipes. The front part was covered with aluminum sheet and the rear with canvas. The tail was made mostly of wood and covered with canvas.

The main engine was the Gnome-Rhone K-7, which supplied 310 kW (420 hp). It was domestically built under license from Franch aircraft manufacturer Rakovica. It was hoped to use a two-bladed metal propeller but, due to the lack of resources, wood was used. The maximum estimated speed (never achieved) was around 250 mph (400 km/h), with an effective range of 475 mi (764 km) with some 40 gallons (150 l) of fuel capacity. Climbing to 6,500 ft (2,000 m) could be achieved in 3 minutes and 9 seconds, but the maximum service ceiling was never adequately tested.

The landing gear was supposed to be of the ‘Nardi’ type imported from Italy, but it was planned to domestically build the landing gears for the production version, to avoid being dependent on foreign countries. On the prototype, no radio was installed but it was hoped to equip all future production aircraft with the FuG VII radios.

The main armament consisted of two wing-mounted 7.7 mm Darn-type machine guns with 175 rounds of ammunition for each gun. The total bomb load consisted of four 10 kg bombs carried under the wings. It must be noted that the armament was never installed on the prototype, as testing was interrupted by the beginning of the war.

First Test Flights

MM-2 Side View

The first test flights were made by the beginning of the 1941 at the Zemun airport. The pilot for these flights was Vasilije Stojanović, the test pilot of the Ikarus factory. By the end of March 1941, some 45 flights had been made with a total of 20 flying hours. The pilot assessed the flying performance of this plane as excellent. The results of these tests indicated that this aircraft had good flight performance. The controls were adequate, both instructor and the students cockpits had enough room with a good field of view and, during flights, the aircraft did not present any tendencies for sudden unpredictable movements. Due to its good air brakes and flaps, take-offs and landings were quite easy. There were no major objections from the test pilot about the MM-2.

The MM-2 could very easily reach speeds of up to 217 mph (350 km/h). The design maximum speed was never tested, but calculations suggested that it could be as high as 250 mph (400 km/h). This was never confirmed due to the outbreak of the war. The MM-2 prototype had an unusual color scheme with a combination of red on most of the rear fuselage and wings, and polished aluminum on the majority of the fuselage and the engine section, with a small Yugoslav flag painted on both sides of the tail.

On the 25th of March 1941, a contract was signed between Ikarus and the Air Force. According to this contract, Ikarus was to prepare for production of MM-2 trainer planes in the near future. Before the production would begin, a last series of tests was to be conducted by a test group at an airfield near city of Kraljevo. An order was given to Stojanović to fly the MM-2 from Zemun to the Kraljevo airfield. Once there, it was planned to do some more flight performance trials in order to examine the limit of the flying characteristics of the MM-2 aircraft. Stojanović completed the flight on the 4th April. Final production was never achieved due to the German invasion of Yugoslavia that started only a few days later.

Operational Service

The MM-2 did not see any active service in the Royal Yugoslav Army because of the beginning of the April war, the German attack on Yugoslavia in April 1941. After the defeat of the Yugoslav army, the Independent State of Croatia, or NDH, was created. In order to form the new NDH military air force, it was necessary to find and obtain planes to equip these new units. Like many other former Yugoslav planes, the MM-2 was also pressed into NDH service in a very limited role.

It seems that the MM-2 had some engine problems (possibly sabotaged) when it was captured by the Germans at airfield near Kraljevo. It is possible that it was in a bad condition since the Germans did not even bother to repair it and put it into operational use.

The MM-2, together with other Yugoslav captured aircraft, was collected and handed over to the NDH. After a while, the MM-2 was repaired under code name No. 6301, and returned to active service. Additional flight tests were conducted by Georgije Jankovski, a test pilot for Dornier-Werke. In September 1941, the plane was transferred to the Zemun airport and handed over to Croatian Major Ivan Pupis for future use. Major Pupis was the leader of the group responsible for the repair, reception and later transfer of all Yugoslavian aircraft captured during the April war. When the MM-2 was repaired and ready for active service, Pupis to keep it for his personal use rather than handing it over to the military.

On the May 13 1942 pilot Vid Saić, he lost control of the aircraft and crashed due to inexperience. The MM-2 was deemed too complicated and expensive to repair.

The MM-2 was ‘owned’ by Pupis until March 23rd, 1942, when he received a direct order from the Croatian Aviation Command to transfer the MM-2 to the ‘Rajlovac’ airfield near the city of Sarajevo in Bosnia. The aircraft arrived at the beginning of April 1942. The MM-2 was given to the 17th Squadron (Jato) which was part of the 6th group (Skupina) under the Command of the Major Romeo Adum. The MM-2 was used mostly for limited test flights. On May 13, 1942 while piloted by Vid Saić (from the 18th Squadron), the plane crashed. The pilot survived the crash with no injuries. A commission was formed to investigate the causes of the crash and found several irregularities: The pilot did not ask for permission and had no orders to fly on the MM-2 that day, and he also did not know anything about the flying characteristics or the condition of the plane. The conclusion was that the pilot was guilty for the accident and, as punishment, Vid Saić lost his Pilot rank. The damage to the MM-2 was estimated to be around 90%. There was no point to try to rebuild it from scratch and the remaining parts were destroyed. There is no information whether it was equipped with any armament in Croatian military service.

Production

Due to the outbreak of war on April 6th, 1941, except for the prototype, no other specimen of this aircraft was ever built. In some documents and letters found after the Second World War, it was discovered that the Ministry of Aviation planned to order around 50 copies of the MM-2 aircraft. Along with this, the Yugoslav military negotiated with Germany for the purchase of Arado Ar 96 training planes, but nothing came of this.

After the war, the new communist Ministry of Aviation and the Ikarus factory representatives were also interested in restarting the production of this aircraft but, as the chief designer had died in one of the many German prison camps and the necessary machines and tools were lost during the war, this was too difficult and was abandoned.

Operators

  • Kingdom of Yugoslavia – Built and tested the single prototype.
  • Independent State of Croatia NDH – Used the MM-2 captured during the April war, but it was lost in an accident.

MM-2 Specifications

Wingspan 30 ft 6 in / 9.23 m
Length 23 ft 7 in / 7.20 m
Height 9 ft 6 in / 2.89 m
Wing Area 14.6 ft² / 13.60 m²
Engine One Gnome-Rhone K-7, 309 kW (420 hp) air-cooled 7-cylinder engine
Empty Weight 1,071 lbs / 894 kg
Maximum Takeoff Weight 2,290 lbs / 1,330 kg
Fuel Capacity 150-160 l
Maximum Speed 250 mph / 400 km/h
Cruising Speed 390 mph / 630 km/h
Range 475 mi / 764 km
Maximum (estimated) Service Ceiling 6,600 ft / 2,000 m
Climb speed Climb to 2,000 m in 3 minutes and 9 seconds
Crew Two, instructor and student pilot
Armament
  • Two Darn M30 7.7 mm machine guns in wings
  • Total bomb load around 40 kg.

Gallery

Illustration by Haryo Panji https://www.deviantart.com/haryopanji

Ikarus MM-2 Side View [Haryo Panji]
MM-2 Front View
MM-2 Rear View

Sources

Hütter Hü 136 Stubo

Nazi flag Nazi Germany (1938)
Armored Ground Attack Aircraft – 1 Replica Built

Stubo I Replica [aviationmuseum.eu]
The Hütter 136 was an interesting concept for a ground attack aircraft that employed numerous experimentations in its design. The cockpit was fully armored, the landing gear was replaced by a skid, and the entire propeller would be jettisoned off during landings. The aircraft came in two forms: the Stubo I, a short design with the ability to carry an external 500 kg bomb, and the Stubo II, a lengthened version that could carry two internal 500 kg bombs. The program never progressed as far as production and work stopped on the project shortly after the Henschel Hs 129 was ordered for production.

History

Artist’s Impression of the Stubo I [Heinz Rodes]
During the years leading up to the Second World War, Nazi Germany found itself needing a competent air force to rival those it would soon face. Restrictions set by the Treaty of Versailles severely hindered the German military both in size and equipment in order to ensure that German power would not threaten the continent again, as it did during the First World War. History notes that the Germans broke this treaty, at first covertly and then overtly, with the Allies showing no response or protestation to the blatant violations. Germany began amassing a massive military force in preparation for war. New programs and requirements were laid down in preparation for the inevitable war. These projects included many newly tested concepts, such as dive-bombing. The Junkers Ju-87 Stuka proved the effectiveness of dive bombing in the Spanish-Civil War, with a famous example being the Bombing of Guernica, but a newer attacker was eventually needed to complement it. An order in 1938 was put out by the Reichsluftfahrtministerium (Aviation Ministry, “RLM”) to develop a new armored ground-attacker. One of the companies that would participate in this requirement would be Hütter.

2-way and cutaway of the Stubo II

The designs of Ulrich and Wolfgang Hütter are relatively unheard of when it comes to aircraft. They began their aviation career designing glider aircraft in the 1930s, such as the popular Hü 17, some of which were used post-war. The Hütter brothers built a career in designing aircraft for the Luftwaffe (German Air Force) between 1938 and 1944 under the codename of Ostmark. The two began working on the project mentioned before for an RLM request for a new ground-attacker in 1938. The requirement laid down very specific guidelines to be followed. The new aircraft needed to have good flight performance and an armored airframe for extra protection, as well as enough speed to evade fighters. In preparation for the new designs, the RLM notified designated factories that would begin to produce these airframes upon adoption into service. The Hütter brother’s response would be the Hü 136. Other competitors included the Henschel Hs 129 and the Focke-Wulf Fw 189V-1b, an armored ground attack version of their reconnaissance plane. Not all projects for a new attacker were armored at this time. Other new designs included the Junkers Ju 187 and Henschel Hs P 87.

The Hütter Hü 136 was nicknamed the Stubo, a shortened version of the name Sturzbomber (Dive Bomber). The aircraft itself would be a single-engine design. Two versions of this aircraft existed. The first, Stubo I, was meant to fill the need for a heavily armored attacker and would be used in ground-attack and dive-bombing tactics. The second was the Stubo II, a two-seater which was essentially a longer version of the Stubo I and carried twice the bomb load internally. The flight performance of the Stubo II was estimated to be the same as that of the Stubo I although, given the design characteristics, that estimation is highly doubtful. The two designs did not meet the requirements for bomb load and range. To make the aircraft more efficient, the brothers took an interesting design change. Taking a note from their glider designs, they removed the conventional landing gear and replaced it with an extendable landing skid, which made the aircraft lighter and freed more space for fuel. This, however, posed serious designs problems. The Hü 136 now had to take off using a detachable landing gear dolly, similar to how the Messerschmitt Me 163B rocket plane would take off a couple years later. Due to this, the propeller would not have enough clearing and would hit the ground during landings. To fix this, the two brothers made the propeller detachable. During landings, the aircraft would eject the propeller, which would gently parachute to the ground above an airfield for recovery and reuse. To assist in landings, a new surface brake was also added to the aircraft.

2-way and cutaway of the Stubo I

The far more conventional Henschel Hs 129 would be designated the winner of the competition. Subsequently, no construction was ever started on either the Stubo I or II. The Stubo proved to be an interesting but flawed concept. The limited visibility from the armored cockpit would negatively affect the aircraft in all operations. Dogfighting, bombing and even flying in general would be affected by the cockpit’s design. The change in landing gear design may have extended the range and lowered weight, but pilots now had to learn how to land using a skid. The fact the entire propellor evacuated the aircraft was a huge issue in itself. Once ejected, the landing could not be aborted, and if the landing attempt failed, there was no chance to loop around and try again.

This, however, would not be the last project designed by the Hütter brothers for the Luftwaffe. Wolfgang would begin working on a long-range reconnaissance version of the Heinkel He 219 called the Hütter Hü 211. Another project is the rather unknown Hütter Fernzerstörer (Far Destroyer), a long-range turboprop attacker meant to be used on the Eastern Front. With the war ending, no further Hütter aircraft were designed. One would think the story of the Stubo ends with its cancellation, but the story continued rather surprisingly recently. The Military Aviation Museum in Virginia Beach, VA, acquired a full-scale replica of the Stubo I in 2017 and it is currently on display in their German Experimentals section, along with full-scale replicas of other “Luft 46” designs.

Design

The Stubo I was a single-engine armored ground attacker. In the front, it mounted a detachable propeller and a Daimler-Benz DB 601 inline engine. In the fuselage, a large gap was present between the engine and cockpit. This was most likely the fuel tank where the fuel tank was placed. Beneath the aircraft, a single 1010 Ibs bomb (500 kg) was mounted on an external hardpoint. This hardpoint most likely would be in the way of the landing skid, implying the payload had to be dropped before making an attempt at landing. For takeoff, a dolly would have to be mounted beneath the aircraft. This would be jettisoned shortly after the Stubo would be airborne. For landing, the aircraft would use an extendable skid. The wings of the aircraft had slight dihedral, which meant the wings were angled upward from the body. The Stubo I had an armored steel cockpit that was completely enclosed. For visibility, a small sight in the front and two side portholes were given. Had the aircraft been produced, peripheral vision would have been nonexistent and dogfighting would have been near impossible if it needed to defend itself. Normal operations, such as navigation and landing would have also been hindered, while combat operations such as target acquisition and attack run planning would have been exceedingly difficult. A tailfin was mounted directly behind the cockpit and not in a conventional tail design. Sources also mention the Stubo I would have mounted machine-guns, but the plans do not show exactly where or of what type these would have been.

Artist’s Impression of the Stubo II [Heinz Rodes]
The Stubo II was virtually identical to the Stubo I, aside from its extended fuselage. This lengthened design would allow the Stubo II to carry two 1010 Ibs (500 kg) bombs in a bomb bay, compared to the single bomb carried on a hardpoint by the Stubo I. Among smaller differences, the Stubo II’s wings had no dihedral compared to the angled dihedral of the Stubo I. With the lengthened fuselage, the landing skid was also extended to accommodate the longer airframe. It most likely also carried over the machine guns used on the Stubo I. The Stubo II uses nearly identical sized wings to the Stubo I, which gives the Stubo II a rather odd design, having the body lengthened but the wing size remaining the same. This would have definitely affected performance and possibly would have made the aircraft more unstable in maneuvering with the extra weight.

Variants

 

  • Stubo I – Armored ground-attacker that would carry a single external 500 kg bomb. Sources also mention machine guns, but documents don’t show where exactly they would have been located.
  • Stubo II – A lengthened version of the Stubo I, the Stubo II had an internal bomb load of two 500 kg bombs.

 

Operators

 

  • Nazi Germany – If the Hütter 136 would have entered production, Nazi Germany would have been the main operator of the craft.

Hütter 136 “Stubo I” Specifications

Wingspan 21 ft 4 in / 6.5 m
Length 23 ft 7 in / 7.2 m
Height (estimate) 5 ft 3 in / 1.6 m
Engine 1x 1,200 hp (894 kW) DB 601 Inline Engine
Loaded Weight 8,160 lbs / 3,700 kg
Maximum Speed 348 mph / 560 km/h
Range 1,240 mi / 2,000 km
Maximum Service Ceiling 31,170 ft / 9,500 m
Crew 1 pilot
Armament
  • 1x 1010 lbs (500 kg) bomb
  • At least 2 machine guns of unknown type (Most likely MG 15 or MG 17)

Gallery

Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

Stubo I Side View [Haryo Panji]
Stubo II Side View [Haryo Panji]

Sources

Martin-Baker Tankbuster

UK Union Jack United Kingdom (1942)
Anti-Tank Aircraft Design – None Built

3D artist impression of the Tankbuster in flight [candymountain.jp]
The Martin-Baker Tankbuster was a concept British anti-tank aircraft that was designed according to an order in 1942 for a specialized ground attacker. The aircraft had a twin-boom, pusher design and was only armed with a 6-pounder (57mm) cannon, most likely a Molins M-Class Gun. Compared to its competitors, the Tankbuster was strictly limited to exactly what it was named for; busting tanks, and would find itself having trouble against other ground targets or even defending itself. With the program being canceled in early 1943 and Martin-Baker working on more important projects, all work stopped on developing the Tankbuster any further.

History

Drawing of the Martin-Baker Tankbuster [British Secret Projects]
In early 1942, the Royal Air Force began seeking a new ground-attack aircraft that would replace the 40mm-armed Hawker Hurricane Mk.IID. An order was officially placed on March 7th for a specialized ground attacker that would be used against a multitude of targets including ground units, enemy aircraft, transports/shipping, and a main focus on destroying tanks. To accomplish the destruction of the aforementioned targets, the aircraft was meant to use more heavier guns than the Hurricane Mk.IID. Alternative weapon arrangements included: three 40mm Vickers S cannons, four 20mm Hispano Mk.V cannons, a combination of two 20mm with two 40mm cannons, six unguided rocket (RP) racks with two 20mm cannons or one 47mm Vickers gun with two 20mm cannons. Two 500Ibs bombs could also be added. The expected speed for the design had to reach at least 280mph (450 km/h) at 3,000ft (900 m). Visibility was also a necessity and forward view had to be unobstructed and clear. Full production was to be expected by 1944. The programs would be overseen by the Air Staff.

Over 10 different designs by several aircraft companies were subsequently created for this program. A majority of them were of unorthodox design. Armstrong-Whitworth (AW.49) and Boulton-Paul (P.99) both created twin boom designs. Boulton-Paul also submitted a canard design labelled P.100 and a biplane design labelled P.101, the latter being seen as a safe alternative to the radical canard and twin boom designs prevalent through the program. Perhaps the most interesting of the designs was the submission by Martin-Baker.

3D artist impression of the Tankbuster [candymountain.jp]
At the time of its submission, Martin Baker had been working steadily on their MB.5 project, which would eventually become one of the best performing piston aircraft built by Britain, but this wouldn’t be completed until 1944. Their design for the ground attacker was submitted several months after the order was given by the Air Staff and was only named the “Tankbuster”. Martin Baker’s concept was for a twin boom design that deviated extensively from the given requirements. The aircraft was armed with a single 6-pounder (57mm) cannon, and the aircraft would be completely encased in 1/2-inch armor. The armor itself weighed 4,900Ibs (2,200kg).

The project wasn’t very impressive nor reasonable in the eyes of the Air Staff, especially compared to the other designs in the program. Its single large-caliber gun extremely limited its target range and it would only have been able to attack one of six predicted target types the program requested. The aircraft lacked any other offensive or defensive armament and would rely on its armor alone to protect itself, a gambit that other designs in the program resolved by following the armaments listed by the Air Staff. Attempts to add more ordnance such as additional guns, rockets or bombs to the wings would have added too much stress on the airframe. The main feature of the aircraft was the root of its problems, its gun. The gun itself couldn’t be removed from the airframe and an aircraft going into battle with a single weapon would be inefficient for resources. The Tankbuster didn’t meet the armament expectations and fell under the expected speed by 10mph (16 km a h). On April 15th, 1943, Air Marshall F J Linnell (who was a good friend of James Martin, a founder of the company) advised Martin-Baker to drop development of the Tankbuster in favor of continuing work on the more successful MB.5 project going on at the same time.

Near the later days of April 1943, the Air Staff brought the program the Tankbuster was designed for to an end. They concluded that, at the time, developing and producing an entirely new ground attack aircraft would impede the current war programs and that the submissions were too specialized in design compared to modifying aircraft already being produced for ground attack duties. One such aircraft they pointed to was the Hawker Hurricane Mk IV, a ground attacker version of the famous fighter which was performing successfully in the role and had started production in March of 1943. Later additions to the ground attack role would be the Hawker Typhoon, which became a scourge to German ground troops. Even if the program had continued towards production, it was significantly unlikely the Tankbuster would have been chosen for the role. The aircraft was way too specialized and disliked by the Air Staff, and Martin Baker was working on an aircraft that would yield much better results. Although the Tankbuster may have been the runt of a doomed program, it still proves to be an interesting, albeit flawed solution in the name of destroying enemy armor.

Design

The Martin-Baker Tankbuster was a twin-boom single-engine design. The aircraft would have been constructed entirely of metal. The airframe itself would be covered in an additional 1/2-inch (12.7mm) armor. This armor would weigh 4,900Ibs (2,223kg) on its own. The armor covered the entire body and also the engine cowling. What’s interesting to note is that the aircraft had two engine intakes, one facing forward and one facing the rear. The radiator and oil tank were mounted in the frontal fuselage. The radiator itself was armored by offset plates that would prevent bullets from ricocheting inside. The cockpit area had clear forward visibility, and would seat a single pilot. The canopy would most likely have had bulletproof glass to complement the rest of the armored body. For it’s engine, the Tankbuster would have mounted a Griffon II engine in pusher configuration. This is relevant to Martin-Baker’s other project, the MB.5, as this aircraft also used the Griffon. The reason the aircraft utilized a pusher configuration was it gave the pilot clear visibility in the front and the gun could be placed directly forward. The pusher configuration isn’t common because of the fact that it leaves the engine open to enemies that are chasing the aircraft. This would have been especially deadly for the Tankbuster, given it has no defensive armament. The tail section and wings would also be constructed of metal. The wings were wide to improve low level flight. There was an attempt to diversify the targets by adding additional weapons to the wings, but this would only overload them. The Tankbuster had a fixed tricycle landing gear. This decision was made to conserve interior space but would have slowed the aircraft considerably. The only armament the aircraft would have been armed with would be a 6-pounder cannon (57mm) that would be frontally mounted, supplied with 30 rounds of ammunition. The aircraft would only be allowed to target heavily armored targets. To assist in aiming, the gun was placed towards on horizontal axis. This would prevent the aircraft from pitching when the gun was fired.

Role

The Tankbuster’s design might seem odd by conventional aircraft standards, but every single feature the aircraft had was to assist in it’s role of attacking enemy armor. Long, flat wings would give the aircraft an edge in low-level flight. The pusher engine would give the aircraft a clear view and nothing to obstruct the cannon. The entire airframe being heavily armored would protect against AA fire and enemy aircraft. Going into battle, the Tankbuster would need escort fighters to protect against opposing interceptors. Once in the combat zone, the Tankbuster would begin its assault on enemy tanks. The De Havilland Mosquito also mounted the 6-pounder Molins gun and was also used in the ground-attack role, but only for a short time before switching to an anti-shipping role. It is likely the Tankbuster would have also undergone this change had it entered production.

Variants

  • Martin-Baker “Tankbuster” – The only version of the Tankbuster drawn was the original design with a single cannon.

Operators

  • United Kingdom – This aircraft would have been operated by the Royal Air Force had it been produced.

Martin-Baker Tankbuster Specifications

Wingspan 47 ft 10.8 in / 14.6 m
Length 41 ft / 12.5 m
Wing Area 471.5 ft² / 43.8 m²
Engine 1x 1,730 hp ( 1,290 kW ) Griffon II Inline-Engine
Weights 12,000 Ibs / 5,440 kg
Climb Rate 2,250 feet/min / 686 meters/min
Maximum Speed 270 mph / 434 km/h
Minimum Speed 75 mph / 122 km/h
Crew 1 pilot
Armament
  • 1x 6-pounder (57mm) Molins M-Class cannon

Gallery

Illustration by Haryo Panji https://www.deviantart.com/haryopanji

Scale model of the Tankbuster [modelingmadness.com]

Sources