Tag Archives: Jet

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.

 

North American XP-86 Sabre

USA flag old United States of America (1945)
Prototype Fighter – 3 Built

The first XP-86 Prototype 45-59598, flown by George Welch

The North American F-86 Sabre is one of the most well-known fighter aircraft of all time, marking the transition from the propeller to the jet turbine. It first entered service with the newly formed U.S. Air Force in 1949, and was instrumental in denying air superiority to Communist forces during the Korean War. After the war ended, many Sabres entered service with dozens of foreign air arms, becoming the primary fighter equipment of many Allied nations. It was built under license in Canada, Japan, Italy, and Australia. Its service was so long-lived that the last operational F-86 was not withdrawn from service until 1993.

History

The F-86 Sabre began its life as North American Aviation’s company project NA-134, which was originally intended for the US Navy. As the war in the Pacific edged toward its climax, the Navy was making plans to acquire jet-powered carrier-based aircraft, which it was could be pressed into service in time for Operation Olympic-Coronet, the invasion of Japan planned for May 1946. The Navy had planned to acquire four jet fighters, the Vought XF6U-1 Pirate, the McDonnell XFD-1 Phantom, the McDonnell XF2D-1 Banshee, and the North American XFJ-1 Fury.

Work on the NA-134 project began in the late autumn of 1944. The NA-134 had a straight, thin-section wing set low on a round fuselage. It featured a straight through flow of air from the nose intake to the jet exhaust that exited the aircraft under a straight tailplane. The wing was borrowed directly from the P-51D, and had a laminar-flow airfoil. It was to be powered by a single General Electric TG-180 gas turbine which was a license-built version of the de Havilland Goblin. The TG-180 was designated J35 by the military and was an 11-stage axial-flow turbojet which offered 4000 lb.s.t. at sea level. The Navy ordered three prototypes of the NA-134 under the designation XFJ-1 on January 1, 1945. On May 28, 1945, the Navy approved a contract for 100 production FJ-1s (NA-141).

At the same time that North American was beginning to design the Navy’s XFJ-1, the U.S. Army Air Force (USAAF) issued a requirement for a medium-range day fighter which could also be used as an escort fighter and a dive bomber. Specifications called for a speed of at least 600 mph, since the Republic XP-84 Thunderjet already under construction promised 587 mph. On Nov 22, 1944, the company’s RD-1265 design study proposed a version of the XFJ-1 for the Air Force to meet this requirement. This design was known in company records as NA-140. The USAAF was sufficiently impressed that they issued a letter contract on May 18, 1945 which authorized the acquisition of three NA-140 aircraft under the designation XP-86.

The Navy’s XFJ-1 design had to incorporate some performance compromises in order to support low-speed carrier operations, but the land-based USAAF XP-86 was not so constrained and had a somewhat thinner wing and a slimmer fuselage with a high fineness ratio. However, the XP-86 retained the tail surfaces of the XFJ-1.

The XP-86 incorporated several features not previously used on fighter aircraft, including a fully-pressurized cockpit and hydraulically-boosted ailerons and elevators. Armament was the standard USAAF equipment of the era–six 0.50-inch Browning M3 machine guns that fired at 1100 rounds per minute, with 267 rounds per gun. The aircraft was to use the Sperry type A-1B gun/bomb/rocket sight, working in conjunction with an AN/APG-5 ranging radar. Rocket launchers could be added underneath the wings to carry up to 8 5-inch HVARs. Self-sealing fuel tanks were to be fitted, and the pilot was to be provided with some armor plating around the cockpit area.

In the XP-86, a ten percent ratio of wing thickness to chord was used to extend the critical Mach number to 0.9. Wingspan was to be 38 feet 2.5 inches, length was 35 feet 6 inches, and height was 13 feet 2.5 inches. Four speed brakes were to be attached above and below the wings. At a gross weight of 11,500 pounds, the XP-86 was estimated to be capable of achieving a top speed of 574 mph at sea level and 582 mph at 10,000 feet, still below the USAAF requirement. Initial climb rate was to be 5,850 feet per minute and service ceiling was to be 46,000 feet. Combat radius was 297 miles with 410 gallons of internal fuel, but could be increased to 750 miles by adding a 170 gallon drop tank to each wingtip. As it would turn out, these performance figures were greatly exaggerated.

A mock-up of the XP-86 was built and approved on June 20, 1945. However, early wind tunnel tests indicated that the airframe of the XP-86 would not be able to reach the desired speed of 600 mph. It is highly likely that the XP-86 project would have been cancelled at this time were it not for some unusual developments.

Saved by the Germans

After the surrender of Germany in May of 1945, the USAAF, along with a lot of other air forces, was keenly interested in obtaining information about the latest German jet fighters and in learning as much as they could about secret German wartime research on jet propulsion, rocket power, and ballistic missiles. American teams were selected from industry and research institutions and sent into occupied Germany to investigate captured weapons research data, microfilm it, and ship it back to the US.

The First XP-86 Prototype in Flight Testing [San Diego Air & Space Museum]
By the summer of 1945, a great deal of German data was pouring in, much of it as yet untranslated into English. As it turned out, German aeronautical engineers had wind-tunnel tested just about every aerodynamic shape that the human mind could conceive of, even some ideas even only remotely promising. A particular German paper dated 1940 reported that wind tunnel tests showed that there were some significant advantages offered by swept wings at speeds of about Mach 0.9. A straight-winged aircraft was severely affected by compressibility effects as sonic speed was approached, but the use of a swept wing delayed the effects of shock waves and permitted better control at these higher speeds. Unfortunately, German research also indicated that the use of wing sweep introduced some undesirable wing tip stall and low-speed stability effects. American researchers had also encountered a similar problem with the swept-wing Curtiss XP-55 Ascender, which was so unstable that it flipped over on its back and stalled on one of its test flights.

In 1940, these German studies were of only theoretical interest, since no powerplants were available even remotely capable of reaching such speeds. However, such studies caught the attention of North American engineers trying to develop ways to improve the performance of their XP-86.

Going Supersonic

The first XP-86 prototype in what would be a temporary white paint scheme

The optimal design for an aircraft capable of high speeds produces a design that stalls easily at low speeds. The cure for the low-speed stability problem that was worked out by North American engineers was to attach automatic slats to the wing leading edges. The wing slats were entirely automatic, and opened and closed in response to aerodynamic forces. When the slats opened, the changed airflow over the upper wing surface increased the lift and produced lower stalling speeds. At high speeds, the slats automatically closed to minimize drag.

In August of 1945, project aerodynamicist L. P. Greene proposed to Raymond Rice that a swept-wing configuration for the P-86 be adopted. Wind tunnel tests carried out in September of 1945 confirmed the reduction in drag at high subsonic speeds as well as the beneficial effect of the slats on low speed stability. The limiting Mach number was raised to 0.875.

Based on these wind-tunnel studies, a new design for a swept-wing P-86 was submitted in the fall of 1945. The USAAF was impressed, and on November 1, 1945 it readily approved the proposal. This was one of the most important decisions ever made by the USAAF. Had they not agreed to this change, the history of the next forty years would undoubtedly have been quite different.

North American’s next step was to choose the aspect ratio of the swept wing. A larger aspect ratio would give better range, a narrower one better stability, and the correct choice would have to be a tradeoff between the two. Further tests carried out between late October and mid November indicated that a wing aspect ratio of 6 would be satisfactory, and such an aspect ratio had been planned for in the proposal accepted on November 1. However, early in 1946 additional wind tunnel tests indicated that stability with such a narrow wing would be too great a problem, and in March the design reverted to a shorter wingform. An aspect ratio of 4.79, a sweep-back of 35 degrees, and a thickness/chord ratio of 11% at the root and 10% at the tip was finally chosen.

All of these changes lengthened the time scale of the P-86 development in comparison to that of the Navy’s XFJ-1. The XFJ-1 took to the air for the first time on November 27, 1946, but the XP-86 still had almost another year of work ahead before it was ready for its first flight.

The first XP-86 prototype in flight during testing [North American Aviation]
On February 28, 1946, the mockup of the swept-winged XP-86 was inspected and approved. In August of 1946, the basic engineering drawings were made available to the manufacturing shop of North American, and the first metal was cut. The USAAF was so confident of the future performance of the XP-86, that on December 20, 1946 another letter contract for 33 production P-86As was approved. No service test aircraft were ordered. Although the 4000 lb.s.t. J35 would power the three XP-86 prototypes, production P-86As would be powered by the General Electric TG-190 (J47) turbojet offering 5000 lb.s.t.

The first of three prototypes, 45-59597, was rolled out of the Inglewood factory on August 8, 1947. It was powered by a Chevrolet-built J35-C-3 turbojet rated at 4000 pounds of static thrust. The aircraft was unarmed. After a few ground taxiing and braking tests, it was disassembled and trucked out to Muroc Dry Lake Army Air Base, where it was reassembled.

Test pilot George “Wheaties” Welch took the XP-86 up into the air for the first time on October 1, 1947. The flight went well until it came time to lower the landing gear and come in for a landing. Welch found that the nosewheel wouldn’t come down all the way. After spending forty minutes in fruitless attempts to shake the nosewheel down into place, Welch finally brought the plane in for a nose-high landing. Fortunately, the impact of the main wheels jolted the nosewheel into place, and the aircraft rolled safely to a stop. The swept-wing XP-86 had made its first flight.

On October 16, 1947, the USAF gave final approval to the fixed price contract for 33 P-86As, with the additional authorization for 190 P-86Bs. The P-86B was to be a strengthened P-86A for rough-field operations.

XP-86 number 45-59597 was officially delivered to the USAF on November 30, 1948. By that time, its designation had been changed to XF-86. Phase II flight tests, those flown by USAF pilots, began in early December of 1947. An Allison-built J35-A-5 rated at 4000 lbs of static thrust was installed for USAF tests. The second and third XP-86 prototypes, 45-59598 and 45-59599 respectively, joined the test program in early 1948. These were different from the first prototype as well as being different from each other in several respects. Numbers 1 and 2 had different fuel gauges, a stall warning system built into the control stick, a bypass for emergency operation of the hydraulic boost system, and hydraulically-actuated leading-edge slat locks. The number 3 prototype was the only one of the three to have fully-automatic leading-edge slats that opened at 135 mph. Numbers 2 and 3 had SCR-695-B IFF beacons and carried the AN/ARN-6 radio compass set.

The original XP-86 prototype was used for evaluating the effects of nuclear blasts on military hardware at Frenchman Flats. It was later scrapped. [This Day in Aviation]
In June of 1948, the new US Air Force redesignated all Pursuit aircraft as Fighter aircraft, changing the prefix from P to F. Thus the XP-86 became the XF-86. XP-86 number one was officially delivered to the USAF on November 30, 1948. The three prototypes remained in various test and evaluation roles well into the 1950s, and were unofficially referred to as YP-86s. All three prototypes were sold for scrap after being used in nuclear tests at Frenchman Flats in Nevada

Design

The three XP-86 prototypes flying in formation together in 1948 [National Archives]
Evolving from the NA-134 project with wings borrowed from a P-51, the XP-86 would eventually end up with a low swept wing mounted to a tubular fuselage, with a large jet intake opening at the nose. The plexiglass bubble canopy gave the pilot great visibility, and afforded the pilot a pressurized cockpit. The tail featured a swept back rudder with tailplanes angled upwards, marking a departure from the largely perpendicular angles seen on most of the Sabre’s propeller driven predecessors. The landing gear was a tricycle configuration, which helped balance the weight of the jet engine at the rear.

The wing of the XP-86 was to be constructed of a double-skin structure with hat sections between layers extending from the center section to the outboard edges of the outer panel fuel tanks. This structure replaced the conventional rib and stringer construction in that area. This new construction method provided additional strength and allowed enough space in the wing for fuel tanks.

The wing-mounted speed brakes originally contemplated for the XP-86 were considered unsuitable for the wing design, so they were replaced by a hydraulic door-type brake mounted on each side of the rear fuselage and one brake mounted on the bottom of the fuselage in a dorsal position. The speed brakes opened frontwards, and had the advantage that they could be opened at any attitude and speed, including speeds above Mach One.

The maximum speed of the XP-86 was over 650 mph, 75 mph faster than anything else in service at the time. The noise and vibration levels were considerably lower than other jet-powered aircraft. However, the J35 engine did not produce enough thrust, and the XP-86 could only climb at 4,000 feet per minute. However, this was not considered an issue, since the production P-86As were to be powered by the 5000 lb.s.t. General Electric J47.

The XP-86 could go supersonic in a dive with only a moderate and manageable tendency to nose-up, although below 25,000 feet there was a tendency to roll which made it unwise to stay supersonic for very long. Production Sabres were limited to Mach 0.95 below 25,000 feet for safety reasons because of this roll tendency.

For the second and third prototypes, the ventral brake was eliminated, and the two rear-opening side fuselage brakes were replaced by brakes which had hinges at the front and opened out and down. These air brakes were adopted for production aircraft.

Prototype number 3 was the only one to be fitted with armament. The armament of six 0.50-inch M3 machine guns were mounted in blocks of three on either side of the cockpit. Ammunition bays were installed in the bottom of the fuselage underneath the gun bay, with as many as 300 rounds per gun. The guns were aimed by a Mk 18 gyroscopic gunsight with manual ranging.

Possibly the First Supersonic Aircraft

George Welch Circa 1947 – [San Diego Air & Space Museum]
There is actually a possibility that the XP-86 rather than the Bell XS-1 might have been the first aircraft to achieve supersonic flight. During some of his early flight tests, George Welch reported that he had encountered some rather unusual fluctuations in his airspeed and altitude indicators during high speed dives, which might have meant that he had exceeded the speed of sound. However, at that time, North American had no way of calibrating airspeed indicators into the transonic range above Mach 1, so it is uncertain just how fast Welch had gone. On October 14, 1947, Chuck Yeager exceeded Mach 1 in the XS-1. Although the event was kept secret from the general public, North American test crews heard about this feat through rumors and persuaded NACA to use its equipment to track the XP-86 in a high-speed dive to see if there was a possibility that the XP-86 could also go supersonic. This test was done on October 19, five days after Yeager’s flight, in which George Welch was tracked at Mach 1.02. The tests were flown again on October 21 with the same results. Since Welch had been performing the very same flight patterns in tests before October 14, there is the possibility that he, not Chuck Yeager, might have been first to exceed the speed of sound.

In any case, the fact that the XP-86 had exceeded the speed of sound was immediately classified, and remained so for several months afterward. In May of 1948, the world was informed that George Welch had exceeded Mach 1.0 in the XP-86, becoming the first “aircraft” to do so, with an aircraft being defined as a vehicle that takes off and lands under its own power. The date was set as April 26, 1948. This flight did actually take place, but George Welch was not the pilot. In fact, it was a British pilot who was evaluating the XP-86 who inadvertently broadcasted that he had exceeded Mach 1 over an open radio channel. However, the facts soon became common knowledge throughout the aviation community. The June 14, 1948 issue of Aviation Week published an article revealing that the XP-86 had gone supersonic.

Variants

  • XP-86 45-59597 – The first prototype Sabre produced, was reconfigured many times with various test configurations. May have been the first aircraft to have gone supersonic in October 1947 with George Welch at the controls.
  • XP-86 45-59598 – The second prototype, had different production model speedbrake and flap configuration, various sensors and equipment installed for testing purposes.
  • XP-86 45-59599 – The third prototype, and the only Sabre prototype to have been armed, fitted with the standard six M3 Browning guns

Operators

  • United States – The prototypes were extensively tested by North American Aviation before being handed over to the U.S. Air Force in 1948.

North American XP-86 Specifications

Wingspan 37 ft 1.5 in / 11.32 m
Length 37 ft 6.5 in / 11.44 m
Height 14 ft 9 in / 4.5 m
Wing Area 299 ft² / 27.8 m²
Engine 1x Chevrolet J35-C-3 Turbojet Engine

4000 lbst

Fuel Capacity 410 US Gal / 1,552 L

750 US Gal / 2,839 L with wingtip drop tanks

Weights
Empty 9,730 lb / 4,413 kg
Gross 13,395 lb / 6,076 kg
Maximum Take Off 16,438 lb / 7,456 kg
Climb Rate
Rate of Climb at Sea Level 4000 ft / 1219 m per minute
Time to 20,000 ft / 6,096 m 6.4 minutes
Time to 30,000 ft / 9,144 m 12.1 minutes
Maximum Speed
Sea Level 599 mph / 964 kmh
14,000 ft / 4267 m 618 mph / 995 kmh
35,000 ft / 10,668 m 575 mph / 925 kmh
Takeoff Run 3,030 ft / 924 m
Range 297 mi / 478 km
Maximum Service Ceiling 41,300 ft / 12,588 m
Crew 1 pilot
Armament
  • 6x Browning M3 machine guns, 267 rounds per gun
  • Sperry type A-1B gun/bomb/rocket sight
  • AN/APG-5C ranging radar
  • Underwing Rocket Launchers, up to 8x 5-inch HVAR

Gallery

Illustrations by Ed Jackson

XP-86 – 1st Prototype 45-59597 circa 1947 note it bears the P for “Pursuit”
XP-86 – 1st Prototype 45-59597 circa June 1948 in white paint scheme, note the wingtip pitot probes
XP-86 – 1st Prototype 45-59597 circa 1948, note the additional test equipment behind the pilot’s seat
XP-86 – 2nd Prototype 45-59598 circa 1948
XP-86 – 3rd Prototype 45-59599 circa 1948

Credits

He 178

Heinkel He 178

nazi flag Nazi Germany (1939)
Experimental Jet Plane – 2 Built

On the 27th of August 1939, test pilot Erich Warsitz made the first test flight above the Rostock-Marienehe factory airfield with the new Heinkel He 178. With this flight, the He 178 went in to history as the world’s first fully operational jet-powered aircraft.

History

In March 1936 Dr Hans Pabs von Ohain, a pioneer of the gas-turbine engine, and Max Hahn were hired by aircraft designer and manufacturer Ernst Heinkel, founder of Heinkel Flugzeugwerke. Their objective at Heinkel was to design and build a working turbojet engine. The concept of a jet turbine engine was not something new at the time, but no one had applied it efficiently or used its potential for the development of the future of aviation.

Other German firms also showed interest in the radical and revolutionary idea of new jet engine technology, especially Junkers Flugzeugwerke. Junkers engineers would eventually develop the first operational combat jet fighter in the world, the Me-262. Heinkel hoped to achieve building the first operational and functional jet engine before all other firms, as quickly as possible.

In September of 1937, the first prototype of the new turbo-jet engine, named HeS 1 was demonstrated. It could achieve a thrust of 551 lbf (250 kgf). The next version, the HeS 2, was deemed a complete failure, with only some 198 lbf (90 kgf) of thrust and subsequent work on this design was abandoned.

The next developmental model, the HeS 3 was ready and tested in 1938. The HeS 3 reached 970 lbf (440 kgf) of thrust, weighing 793 lbs (360 kg) and had a diameter of 3 ft 11 in (1.2 m). Heinkel used one modified He 118 plane and equipped it with this test jet engine slung under its fuselage. This was however not the first operational jet aircraft, as the testbed took off and landed under its own piston engine’s power. This flight is generally considered to be a success.

A new upgraded HeS 3b, upgraded from the earlier 3a version, with some 1,100 lbf (500 kgf) of thrust, was ready to be tested in 1939 in a specially designed aircraft, the He 178 which had been completed earlier that year.

The He 178 was a shoulder wing aircraft, made mostly of wood with a semi-monocoque metal fuselage.  The He 178 was equipped with retractable landing gear. The pilot’s cabin was located well forward of the wing’s leading edge. The jet engine drew in air from the front nose inlet, with the jet exhaust emerging from a long narrow pipe at the rear of the aircraft, in the tail. Later a new HeS 6 engine was installed, with 1,300 lbf (590 kgf) of thrust.

The characteristics of the He 178 were as such: maximum speed with the HeS 3b was 580 km/h (360mph). The theoretical estimated maximum speed was much higher, up to 700 km/h (435 mph), but the question of whether it could have been successfully achieved lingers. Service ceiling was 7000m and the effective range was some 200 km.

Operational Service

On its first test flight the engine ingested a bird which caused some minor internal engine damage, but the pilot managed to safely land the plane. Despite this incident this first test flight was considered a success. After several more test flights were accomplished, the first He 178 (V1) was placed in the air museum in Berlin, where it would eventually be destroyed in a 1943 bombing raid. Soon after, the assembly and production of the second plane was ready with some modifications, most importantly larger wings. The second  prototype (V2) never flew, and it is not known if it was ever completely built. It’s fate is unknown.

Luftwaffe officials showed little interest in jet aircraft with fuselage mounted engines, due to the increased complications involved in their design and maintenance. Fuselage mounted engines required more rigorous technical inspections, presented production complications, and were overall seen as less efficient designs. Officials instead preferred fighter aircraft with wing mounted turbojet engines, such as the later Me 262 and He 280.  In the end the He 178 project as a fighter aircraft was abandoned.

Versions

The first airframe was designated V1, with the second unfinished airframe with larger wings designated the V2.

  • He 178 V1 – Experimental jet-aircraft
  • He 178 V2 – Second prototype jet-aircraft

 

Heinkel He 178 Specifications

 

Wingspan 23 ft 7 in / 7.2 m
Length 24 ft 6 in / 7.48 m
Height 6 ft 10 in / 2.1 m
Wing Area 86.04 ft² / 7.9 m²
Engine One HeS 3b centrifugal-flow turbojet
Empty Weight 3,572 lb / 1,620 kg
Maximum Takeoff Weight 4,405 lb / 1,998 kg
Maximum Speed 360 mph / 580 kmh

Estimated (theoretical) maximum possible speed up to  435 mph / 700 km/h

Range 124 mi / 200 km
Maximum Service Ceiling 22,965 ft / 7,000 m
Crew 1 pilot
Armament
  • None

Gallery

He 178 V1 Profile View
He 178 V2 Profile View

Source:

Nešić, D. (2007). Nemačka : ratno vazduhoplovstvo. Beograd: Tampoprint Vojnoizdavački zavod, Direkcija za izdavačku i bibliotečko-informacionu delatnost., Bishop, C. (2002). The encyclopedia of weapons of World War II. New York: MetroBooks., Kuipers, L. (2010). No. 9919. Heinkel He 178 V1., Heinkel He 178 in Luftwaffe Resource Center. Sharpe, M. (1999). Attack and interceptor jets. New York: Barnes & Noble., He.178 in Airwar.ru Images: Side Profile Views by Escodrion – https://escodrion.deviantart.com