Category Archives: German Empire

Junkers D.I

German Empire flag German Empire (1918)
Monoplane Fighter – 40 built

The first Junkers D.I prototype J.9/I [Nhungdoicanh]
The German Air Force was responsible for several great revolutions in the development of aviation during both World Wars. While the development of jet technology in the Second World War is probably the best known, during the First World War, one of the most important such evolutions was the development of the first all-metal planes. The man responsible for this was the famous Hugo Junkers. The corrugated metalwork first seen on the D.I would become a hallmark of later Junkers aircraft.

The first all-metal projects

Aviation technology before the First World War revolved around wood as the main building material. Wood was used as it was easy to process and was easily available in great quantities and simple carpenters could be put to work on airplane construction.

One of the first persons who ever experimented with the idea of building an all-metal plane was the well-known German aviation designer and inventor Hugo Junkers (1859-1935). While working as a professor of thermodynamics at the Technische Hochschule (Technical University) in Aachen in 1907, he met a colleague, Professor Hans J. Reissner. Professor Reissner was involved in experiments with many novel ideas, such as aerodynamics in aviation. This moment would have a big impact on Hugo Junkers, as he would develop a great interest in aviation.

One of the few produced J 2 prototype which lead to the D.I [Wikimedia]
Hugo Junkers’ initial efforts were focused on solving the problem of poor aerodynamics of already existing aircraft. In 1912, his preliminary research showed that planes had better aerodynamics properties if they were designed to have an airfoil structure. In essence, this means that the whole plane, wing, body, and control surfaces had to have curved surfaces specially designed to give the best possible ratio of lift to drag. In order to perform even more experiments in aerodynamics, Junkers financed the construction of a wind tunnel at the Frankenberg laboratory. In the following years he continued his research, and by 1914 he had performed around 4,000 different tests and built 400 test models.

In 1914, Junkers had the first indications that an all-metal monoplane with thick wings was a feasible idea. While metals, like iron, were available in large quantities, lighter metals, like duralumin, an aluminum alloy, were more desirable for this purpose. The negative aspect of duralumin was the fact that it was difficult to work with. The techniques and technology of the day were inadequate, and the process of forming duralumin was slow and crude. As this could delay his work for years, Hugo Junkers decided to use the iron plates as a replacement, as they were much easier to work with.

After having constructed one all-metal wing prototype with a 9.18 ft (2.8 m) wingspan, Hugo Junkers made a request on the 2nd of February, 1915 to the German War Ministry for funds so he could build an all-metal prototype plane. This request was rejected, but it did not discourage Junkers from continuing his research. His second request was accepted in July 1915. With these funds, Hugo Junkers was able to construct a working prototype by December 1915.

The base of the prototype was made of iron ribs which were covered with iron sheets which were only 0.1 to 0.2 mm thick, held in place by electric welding. A second layer of sheet metal was added to reinforce the whole construction. The first prototype, designated the Junkers J 1, was ready by the end of 1915. It was powered by a Mercedes D.II 125 hp engine. After some ground testing, the new plane was shipped to Döberitz, the main German aviation training and test site in December 1915. Once there, the first test flight took place on 18 January, 1916. This was the first flight of a plane with an all-metal frame. The Idflieg (Inspektion der Fliegertruppen – Inspectorate of Flying Troops) was impressed with this prototype and ordered six more all-metal planes for future testing as a fighter plane. The J 1 design was not without problems, as there were some issues with the wing connection to the fuselage. During one test landing, one of the wings separated entirely.

Hugo Junkers began working on a second improved prototype named J 2. The problem with the wing-fuselage connection was solved by changing the internal design. The wings were divided into a couple of parts. The main section was connected directly to the fuselage and the others were affixed by screws. In only a few months, the first Junkers J 2 was ready to be tested. The J 2 was powered by a single Mercedes D.II 120 hp engine which was later changed to a stronger Mercedes D.III 160 hp. It made its first flight on 11 June, 1916. However, unlike the first prototype, the flying performance of the Junkers J 2 was poor. The speed was good, but the plane was simply too heavy at 2,480 lbs (1,160 kg) and thus useless as a fighter. Some six were ordered and built for future testing but the Idflieg lost any interest in it. Despite being rejected for operational service, it was still deemed important for testing construction methods and acquiring additional research.

After Hugo Junkers and his team analysed the Junkers J 2, they concluded that the plane could be vastly improved if lighter materials were used. Their solution was to undertake a study of how to make duralumin easier to work with. In time, specialized tooling and machines were developed and designed in the hope of producing adequate duralumin parts that could be used for aircraft construction. Despite the use of the duralumin in Zeppelin construction, the Junkers team made many improvements to these processes.

Thanks to these developments with aluminum processing, Junkers tried to build a fully operational all-metal monoplane. This was a private venture marked as the Junkers J 3. It was short lived, as the Idflieg refused to finance its development and only a single incomplete airframe was built. The Idflieg was more interested in all-metal ground attack biplanes.

The improved J 7 prototype

Side view of the J 7 prototype. [Wikimedia]
Hugo Junkers and his team continued to develop their own all-metal plane project. The J 4 served as a prototype for the J.I biplane and J 5 was never completed. Next in line was the Junkers J 7 as a single seat fighter and the J 8 two-seat close ground-support version. The J 8 prototype would eventually lead to the J 10 and the CL I. As the the J 7 and J 8 were developed, tests done in the wind tunnels showed that the low wing design provided good performance. One extra benefit of this design was the fact that the low wing would provide some extra protection for the pilot during a harsh landing. However, the weakest point in the design was the fuselage. Hugo and his team had significant problems designing a structure that would be strong enough to support all the necessary equipment, engine, and fuel tanks while still being light enough to maintain fighter maneuverability. They eventually reached a achieved a design that met most of the requirements.

The Junkers J 7 was constructed by using steel bars to form the structures of the plane and these were then covered in duralumin sheets. This method was copied from the J 4, with the only difference was that parts of the surface of J 4 were covered with fabric, while J 7 was all-metal. The J 7, piloted by Feldwebel Arved Schmidt, made its first test flight on 17 September, 1917. As the tests continued, Schmidt was generally pleased with how the plane behaved. In his report he said that the plane “.. made a good impression and possessed no serious fouls but the unique rotating wingtip ailerons were somewhat overbalanced…”. The J 7, despite its large front mounted radiator to accommodate the Mercedes D III 160 hp engine, managed to reach a speed of 77 mph (124 km/h). Many further trial flights were conducted, and in early October 1917 Schmidt managed to reach an altitude of 16,400 ft (5,000 m) in 17 minutes. This was a great result especially considering that the J 7 had a weight of 1,572 lbs (713 kg) and with added military equipment, the same altitude could be reached within 24 minutes.

For the next series of test flights, the J 7’s wings were equipped with conventional ailerons. These trials were held in late October 1917. The pilots were Leutnant Gotthard Sachsenberg and Theo Osterkamp. This time, the J 7 was pitted against the Albatros D.III. The J 7 proved to be a better fighter but the problems with the ailerons persisted. Both pilots gave a “green light” for the J 7 to go into production.

On 20th October, 1917 Idflieg made a decision to establish a new cooperation between Hugo Junkers and Anthony Fokker. Junkers-Fokker Werke AG was thus founded. It was hoped that the lack of production capacity of Junkers’ team would be supplemented by Fokker’s. This meant that there were two companies working on the J 7 project, Junkers (Jco) and Junkers-Fokker (Jfa). Despite the Idflieg’s hopes for good cooperation, this was never achieved as both sides sought control of the project.

Pilot and his assistant are starting the D.I. in front of the ‘Zeppelin’ hangars at Wainoden. [flyingmachines.ru]
In December, new modified ailerons were tested and the large nose radiator was also changed. While flying the J 7, the pilot, Tonny Fokker, had an accident upon landing. The plane was damaged but quickly repaired in time for the inspection made by Hauptmann Schwarzenberger from the Idflieg. He gave positive reviews of this plane and suggested that it should be used in the First Fighter Competition held in Germany. For this purpose, it was equipped with a new Mercedes engine and received new aerodynamically-balanced ailerons.

This competition was held from January to February 1918. Many front line pilots flew the J 7, including the famous Red Baron. He had positive comments for the J 7, in his report the plane being rated as having better climb rate and speed than other fighters in field use. However, he also noted the presence of some oscillation in the wings during sharp turns.

In January, Fokker once again had an accident during landing, but the damage was minimal. The plane was damaged again during its flight to Dessaou for wing modifications, but was repaired and ready for further testing by early February. These accidents also proved that its construction was much more robust than that of ordinary wooden planes. In March 1918, the last tests took place, with Leutnant Krohn as the pilot. His report read “.. On take-off the aircraft accelerates quickly and leaves the ground in a short time. It reacts instantaneously to the control. After ten degrees of control-stick movement, which suffices for an 80-degree bank, the control becomes very heavy. In a spiral, the aircraft reacts quickly to the controls. On the whole, the aircraft is at least as manoeuvrable as the new Albatros D.III or D.VI when diving at 155 mph (250 km/h) airspeed without any vibration in the wings..”

The ailerons were modified for the last time, which solved all previously mentioned problems with the controls. The J 7 prototype plane was used by a Fligertruppe in late March 1918. The J 7 was also used in the Second Fighter Competition held in July 1918. Despite proving to be an adequate fighter, the J 7 would never be accepted for service.

The J 9 and the D.I

The J 9/II rear view. [Militär Wissen]
At the same time as the J 7 was developed, Junkers began work on an improved model named J 9. Two prototypes were built, simply marked as J 9/I and J 9/II, the first of which was ready by April 1918. The J 9 was similar in construction to the J 7, but it was better suited for possible mass-production. By March 1918, Idflieg was negotiating with Junkers about the possible production of six planes for more testing. Hugo Junkers was disappointed with this, as he expected the signing of a major production contract. He thought it was a waste of precious time and that the plane did not need further testing. By early May, he managed to convince military officials to put the J 9 into production. A contract was signed for the production of 100 all-metal planes, including other Junkers models CL.I and the J.I, with around 20 copies of the J 9, now officially designated as the D.I. The first group was to be built by late July, with 6 in June and 14 by July.

This is the J 9/II prototype that was powered with the Benz Bz. IIIbo V-8 195 hp engine . Due to some mechanical problem with this engine prevent it from participating in the Second Fighter Competition. [Militär Wissen]
The D.I (J 9/I) prototype made its first flight on 12 May, 1918 (Some sources incorrectly state April), piloted by test pilot Leutnant Krohn. The D.I prototype was ready to participate in the Second Fighter Competition. For this, it was equipped with the Mercedes D. IIIaü engine. During this competition, the D.I prototype presented itself well. The second D.I prototype (J 9/II) was equipped with the Benz Bz. IIIbo V-8 195 hp engine. Due to problems with this engine, it was not used in this competition. During these tests, the J 9/I was equipped with two Spandau machine guns located above the engine compartment, with one on each side. At the end of the Second Fighter Competition, several front fighter pilots were asked to test these new models. As most pilots, such as Oberleutnant Goering, thought that biplanes were the future, they marked the D.I as a complete failure.

A second commission rejected the notion that it was a complete failure, referencing its demonstrated performance. One demerit marked by this commission was the lack of downward visibility from the cockpit. This was based on the German air fighting tactics which had been adopted due to Allied air superiority. This tactic involved attacking Allied planes using high speed dives from above, and thus downward vision was deemed critical. The D.I lacked this due the to the large low-placed wings, but it compensated with the metal construction that made it more resilient to low caliber rounds.

On the 21st August 1918, Idflieg place an order for 100 more Junkers all-metal planes, including the CL.I and the J.I, of which around 20 were D.I fighters. At the beginning of August 1918, three D.Is were ready for static machine gun testing. Three more were almost completed with five more to be constructed by early September 1918. For more firing tests, two were sent to Adlershof. Due to the installation of the offensive armament, some small modifications were needed.

Despite entering production, there were still some modification that were needed. The first D.I produced had a longer fuselage and larger wings. As it was tested, there were problems with vibrations of the fuselage and maneuverability. As this could endanger the entire production, a series of quick modifications were done to the remaining four, possibly five, produced aircraft. These were built with modified, shortened fuselages and smaller wingspans. In total, around nine operational fighters and two prototypes were ready by the war’s end.

Construction

The first four D.I planes still under construction. The plane on the right is the J.7 prototype. [Nhundoicahn]
The D.I was designed as a single seat, all-metal low-wing fighter plane. It consisted of a metal airframe of steel ribs covered with corrugated duralumin sheets. Duralumin is a trade name for one of the earliest types of aluminum alloy. The corrugated surface of the duralumin offered increased strength, rigidity, and projectile resistance without a significant weight penalty. This method of aircraft skin construction would later be used in larger Junkers bombers in World War II becoming an iconic hallmark of the company, going on to inspire the look of the Citroen H van of the late 1940s. Aluminum construction low wing monoplane designs in would later come into widespread adoption, becoming the standard by World War II. In this way, the C.I’s design was truly ahead of its time.

The airframe was designed by Hugo Junkers, but it said that even he was never completely satisfied with its design. It nevertheless did its job and was robust, durable, and easier to maintain and repair. It offered the pilot a greater chance of survival during a forced landing than a wooden airframe. The D.I’s metal airframe provide good protection from most weather conditions in comparison to standard wooden built planes. The D.I could be left out in the elements and exposed to strong rain and wind without fear of damaging the plane. Due to use of lighter metals, the D.I’s total weight was 1,835 lbs (843 kg).

The main engine chosen for this plane was the BMW III water-cooled 6-cylinder inline, supplying 185 hp (138 kW). With this engine, the maximum speed that could be achieved was 118 mph (185 km/h).

The pilot was located behind the engine and had a good visibility of the to the front, sides, above, and rear, but the downwards visibility was somewhat limited due to the plane’s large and low wings. The wing’s design was similar to previous prototypes, as it was divided into a few parts. The central part of the wings was directly connected to the fuselage and the remaining were connected by fasteners. Under the pilot there were two fuel tanks. The total fuel capacity is not precisely known.

The landing gear was fixed, like on all planes of the era. The landing wheels were mounted on an axle that was connected to the plane by triangular-shaped steel bars. The main armament consisted of two Spandau (7.92 mm) machine guns mounted above the engine compartment.

Production

Around 40 aircraft were ordered by Idflieg to be built by Junkers, 20 in May and a second group of 20 in August. Junkers completed around 27 planes before production was stopped in February of 1919.

The Junkers-Fokker joint company was also involved in the planned production of the D.I. The exact production details are not known. The Junkers-Fokker company was given an order to produce 20 more D.I, but it only produced 13. During the production run from June 1918 to February 1919, around 40 D.I fighters were built in total by both companies in addition with two prototypes..

What is interesting is the lesser known fact that Idflieg wanted to give a contract for the production of 50 D.I planes to Hansa-Brandenburg but, as the war ended in November 1918, this never took place.

In combat

This D.I was captured on the Western Front, note the two color stripe behind the pilot cockpit, suggest that it was used in combat. [Pinterest]
The war ended before more could be produced, and thus only limited numbers were sent to the front. These were given to front line units, possibly in the Flanders sector in October 1918. Later, in early 1919, during the Entente advance after the Armistice, five D.I fighters were captured. Four were found at Hombeek in Belgium. Of these four, only one was in flying condition, two were badly damaged, and the condition of the fourth is unknown. One more was found(missing half of its parts at an airfield near Brussels. There is little information about their use in combat.

However, there is evidence that gives some indication of the D.I seeing some combat. On the plane captured at Hombeek in Belgium, there were markings behind the pilot’s cockpit that may have been kill markings, but this is at best just speculation. The aircraft captured near Brussels had machine gun bullet holes, but the origin of these is unknown.

At the war’s end, the US Air Service, after analyzing the collected data and field reports, made a report “.. no one was found who had ever seen one of these airplanes in flight …. Some of the RAF pilots, however were sure that it had been used in service..”

The Junkers D.I did see combat action after the war against Soviet Bolshevik forces in the Baltic countries. The D.I was used by Kampfgeschwader Sachsenberg (under the command of Leutnant Gotthard Sachsenberg), being mostly used in the air support role, covering the German Freikorps units that remained there after the war.

Leutnant Gotthard Sachsenberg was very impressed with the D.I’s overall performance. His report reads: ”.. The Junkers aircraft have proven themselves beyond all expectations. The weather resistance of the aircraft is so great that it was possible to allow the aircraft to stand for weeks on end in the open during snow, rain, and thaw of the March season. A tarpaulin cover over the propeller and the engine sufficed to provide protection. Since neither tents nor hangars were available, no other aircraft except the Junkers would have been able to serve in Russia at that time.. the advantage of the weather resistance, the exceptional speed and the invulnerability of the aircraft outweighed the small disadvantages. In crashes and emergency landings relatively little occurred …. the Junkers aircraft, with improvement, will without doubt, take first place as a combat type…”.

Today, only a single D.I has survived the War and can been seen at the Musée de l’Air et de l’Espace near Paris.

Junkers D.I Specifications:
Wingspan 28 ft 6 in / 9 m
Length 23 ft in / 7.25 m
Height 7 ft 4 in / 2..25 m
Wing Area 159 ft² / 14.8 m²
Engine One BMW III water-cooled 6-cylinder, 138 kW (185 hp)
Empty Weight 1.440 lbs / 654 kg
Maximum Takeoff Weight 1.835 lbs / 834 kg
Climbing speed 3.280 ft / 1 km in 2 to 3 minutes
Maximum Speed 118 mph / 185 km/h
Range 185 mi / 300 km
Maximum Service Ceiling 19.700 ft / 6,000 m
Crew 1 pilot
Armament Two 7.92 mm machine guns

Gallery

Side profiles by Ed Jackson – www.artbyedo.com

Junkers D.I 5029/18
Junkers D.I in Brown
Junkers D.I 5999/18
Junkers D.I 5185/18
Junkers D.I Camouflage Livery w/ Brass Radiator & Panels

This is one of the four Junkers D.I captured by the Allies in Belgium after the war. Due to the marking on the wheels, it can be ascertained that this one was built by the Junkers company. [Nhungdoicanh]
This D.I was powered by a 185 hp engine and was used in the Third Fighter Competition held in October 1918. [Wikimedia]
Sources

 

The Red Baron's Fokker Dr.1 475/17 - March 1917

Fokker Dr.I

German Empire Flag German Empire (1917)
Fighter Plane – 320 Built

The Fokker Dr.I was a triplane built by Fokker-Flugzeugwerke during the First World War. The design, based off of Britain’s Sopwith Triplane, is well known thanks to the Red Baron, Manfred von Richthofen, for being the plane in which he scored his final kills.

A Borrowed Idea

In the early part of 1917 the Sopwith Triplane of the Allies began appearing on the battlefield, quickly trouncing German Albatros D.III fighters with its superior maneuverability and climbing ability. The Idfleig, the German bureau overseeing aircraft design immediately ordered development of a triplane, known as dreidecker (3 winged) in German.

Nearly all of the German aircraft manufacturers followed suit. Fokker set about to develop its own triplane by modifying an unfinished prototype biplane. This initial prototype, like Sopwith’s design, utilized a rotary engine and steel tube fuselage. However the initial prototype, the V.4 did not have external interwing bracing. The next prototype, the V.5 introduced bracing between the wings to minimize flexing on the upper wing. The prototypes were met with much excitement for their exceptional maneuverability and climb rate over anything else the Germans had previously produced. The Red Baron himself, Manfred von Richthofen was believed the Dr.I held much promise for the fortunes of German air power and demanded his superiors to commence production immediately, as well as promising his men that they would soon be able to “move like devils and climb like monkeys.”

Construction

Replica Dr.1 in a Black and White Striped Livery
Replica Dr.1 in a Black and White Striped Livery

The appearance of the Dr.1 is characterized by its three-wing design – therefore dubbed a ‘triplane.’ The design also featured small sustentation surface of an aerofoil shape mounted between the wheels of the landing gear. The tail was also completely mobile with unbalanced ailerons possessing more surface area than the ailerons of the upper wing. The wings had deep section hollow box-spars that provided lightweight strength to the wings. The lack of interplane struts on the initial prototype resulted in excessive wing vibration during flight, so interplane struts were added. The ribs were of plywood, as well as the leading-edges covers at the spar, with the leading-edges made of wire. The middle wings had some cut-outs to improve downward visibility of the pilot. The fuselage was constructed using welded steel-tubing bracing with diagonal wires to create the rigid box-shaped structure, being a fabric-covered with triangular plywood fillets, except the undercarriage and center-section, which were made of steel streamlined tubing.

The tail-plane had a triangular shape, being framed in steel tubing the same way as the balanced rudder and elevators. The wheels featured an elastic shock cord, while a steel-tipped tailskid was installed at the rear.

Evaluation

The first prototype Dr.1 flew in July of 1917. Production of the Dr.I commenced on August 11th of 1917. In preproduction the triplane carried the designation F.I. Two were made and issued to Richthofen and Leutenant Werner Voss. These two aces promptly used these planes on the battlefield, scoring kills within the first few days of flying in early September. Voss took to the skies on August 28th and by September 11th had scored 8 kills.

The result of this evaluation period led Voss and Richthofen to recommend the Dr.I for production as soon as possible, declaring it superior to the Sopwith Triplane. Orders were placed for 300 Dr.I’s.

On September 14th the commander of Jasta 11, OberLeutnant Kurt Wolff was shot down whilst flying Richthofen’s F.I by a new Sopwith Camel of Britain’s Naval 10 squadron. Voss, whilst flying on September 23rd, scored his 48th victory just before being shot down in an epic dogfight wherein he managed to damage all 7 of his opponent’s SE-5a’s in the skirmish.

The Fokker Dr.I in Use

Replica Dr.1 in Flight
Replica Dr.1 in Flight

The Dr.I, upon its arrival to the battlefield in October was well regarded for its climbing ability and light controls. The ailerons were not very effective, however the tailplane elevator and rudder controls were very yielding. Rapid turns to the right were very quick thanks to the directional instability afforded by the rotation of the rotary engine, a characteristic that was taken advantage of by pilots.

Although not a particularly fast plane, it balanced this shortcoming with great maneuverability thanks to its light weight, while also having good upward visibility. It also had a decent climb rate, characteristics that all seemingly made the Dr.I a formidable adversary to its Allied opponent, the Sopwith Camel. This made of the Dr.1 a good aircraft for dogfights, yet structural and construction problems in the wings would hamper the aircraft’s promising initial assessment.

The Dr.I was armed with twin 7.92 Spandau machine guns, which could fire simultaneously or independently in synchronization with the propeller.

The Dr.I, for all its improvements over previous German aircraft, had numerous  shortcomings. Among them was its tendency to ground looping upon landing. This occurs when the aircraft tilts on landing such that one wing makes contact with the ground. For this reason skids were attached to the wingtips of the lower wing on the production version. Also while the Dr.I had excellent climbing ability, its dive and level flight speed were less than desirable, leaving it vulnerable to faster Allied planes in many situations.

Wing Problems

Following the proper introduction of the production model Dr.I in October, by the end of the month two consecutive top wing failure accidents promptly caused all triplanes to be grounded. The wing structure of the Dr.I was thoroughly investigated and numerous problems were discovered, the first of which was weak attachment of wingtips, ailerons, and ribs. Further, the doping of the fabric and wood varnishing was found to be of poor and inconsistent quality, leading to water absorption and premature rot in crucial wing spars.

Fokker’s corrective action was to improve quality control on the production line, as well as modifying and repairing existing models. The problem was believed to have been solved, and the Dr.I continued to see use well into 1918, but later the wing failures returned.

Much later in 1929, research at NACA revealed that a triplane configuration like the Dr.I’s exerted as much as 2.5 times more lift coefficient on the upper wing. The extreme difference in this force no doubt contributed to many of the wing failures seen in the Dr.I over its operational lifespan. Examples such as this show the importance of research and competence in advanced aerodynamics during the design phase of an aircraft.

Legacy

As had been seen in September 1917, the Dr.I was inferior to the capabilities of the British Sopwith Camel by the time production had commenced. Despite this, German production went on for the initial 300 ordered.

Fokker D.VII would eventually replace the Dr.1 on the battlefield, with surviving dreideckers relegated to training and home defence units, re-powered with a Goebel Goe II 100 hp engine. By the time of the armistice was signed, the Dr.1 was tested by Allied pilots at fighter flying schools in Nivelles (Belgium) and Valenciennes (France), being deemed as an aircraft with impressive performance.

Variants

  • V.4 – The initial prototype
  • V.5 – First production prototype
  • V.6 – Enlarged prototype powered with a Mercedes D.II engine
  • V.7 – Prototype with Siemens-Halske Sh.III engine

Dr.1 Specifications

Top Wingspan 7.12 m / 23 ft 4 in
Mid Wingspan 6.23 m / 20 ft 5 in
Lower Wingspan 5.7 m / 18 ft 8 in
Length 5.77 m / 18 ft 11 in
Height 2.95 m / 9 ft 8 in
Wing Area 18.66 m² / 200.85 ft²
Engine 1  9-cylinder rotary Oberursel UR II engine (110 HP), or a LeRhône Type 9Ja (110 HP)
Maximum Take-Off Weight 586 Kg / 1,291 lb
Empty Weight 406 kg / 895 lb
Loaded Weight 586 kg / 1,291 lb
Climb Rate 5.7 m/s (1,122 ft/min) or 1000 meters in 2’45’’
Maximum Speed 185 km/h / 115 mph at sea level; 165 km/h / 102,5 mph at 4000 m
Range 300 Km / 186 miles
Maximum Service Ceiling 6100 m /20,000 ft
Crew 1 (pilot)
Armament 2 X 7.92 mm Spandau 08/15 with 500 rounds each

Gallery

The Red Baron's Fokker Dr.1 475/17 - March 1917
The Red Baron’s Fokker Dr.1 475/17 – March 1917
Fokker Dr.1 217/17 - March 1917
Fokker Dr.1 217/17 – March 1917
Fokker Dr.1 152/17 - March 1917
Fokker Dr.1 152/17 – March 1917
Replica Dr.1 in a Black and White Striped Livery
Replica Dr.1 in a Black and White Striped Livery
Replica Dr.1 Ready for Takeoff
Replica Dr.1 Ready for Takeoff
Closeup of Replica Dr.1's Cockpit
Closeup of Replica Dr.1’s Cockpit
Fokker Dr.1 9 Cylinder Rotary Engine
Fokker Dr.1 9 Cylinder Rotary Engine
Replica Dr.1 in Flight
Replica Dr.1 in Flight

Sources

Guttman, R. (2011). The Triplane Fighter Craze of 1917. HistoryNet., Berger, R (Ed.). Aviones [Flugzeuge, Vicenç Prat, trans.]. Colonia, Alemania: Naumann & Göbel Verlagsgessellschaft mbH., Donald. D. (2009). Aviones Militares, Guia Visual [Military Aircraft. Visual Guide, Seconsat, trans.]. Madrid, Spain: Editorial Libsa.Dwyer, L. (2013). Fokker Dr.I Triplane. The Aviation History Online Museum.Leivchentritt, L. (2013). Fokker Dr.I Specifications. Fokker Dr.I.com., Old Rhinebeck Aerodrome (2016). Fokker Dr.1 Triplane. Cole Palen’s Old Rhinebeck Aerodrome.The Aerodrome (2016). Fokker Dr.I. The Aerodrome.Fokker Dr.I. (2016, June 19). In Wikipedia, The Free Encyclopedia. [Images] Dr1 Black-White Livery by Neal Wellons / CC BY-NC-ND 2.0Dr1 Dark Red by Geoff Collins / CC BY-NC-ND 2.0, Dr1 Cockpit by Phil Norton / CC BY-NC-ND 2.0, Dr1 Flight by Ian / CC BY 2.0, Dr1 Engine by Erik Wessel-Berg / CC BY-NC-ND 2.0Plane Profile Views by Ed Jackson

Spandau LMG08/15 1918 - Side Profile View

Spandau LMG 08

German Empire Flag German Empire (1915)
Machine Gun – 23,000 built

The Spandau LMG 08 was the air cooled aircraft version of the German Army’s MG 08 machine gun. The infantry version of the MG 08, like the Vickers Machine Gun, was water cooled and based on the design of Hiram Maxim’s famed Maxim Gun.

Design

After the success of the MG 08 in infantry use, Spandau set about lightening the weapon and adding large slots to the water jacket for aircraft use.  The first letter in lMG 08 is actually a lowercase L which stands for luftgekühlt meaning air cooled. From the beginning the lMG was designed to fire in a fixed position from an aircraft.

Early Spandau LMG 08 Triple Mount
Early “Overlightened” LMG 08

Early designs had so many cooling slots that the weapon was considered “over-lightened” and the rigidity of the cooling jacket was considered “fragile.” Various slot patterns were experimented with until the final design of the LMG 08/15, a refined version of the weapon with many improvements as well as a lighter weight. The final weight for the refined lMG 08/15 came out to 26 lbs compared with 57 lbs for the original iteration of the MG 08. The various versions of the lMG were all designed to be interchangeable so aircraft could be easily upgraded to newer versions. Like the Vickers, the closed bolt design lent itself to easy synchronization with the propellers, with most German fighters appearing with twin LMGs by late 1916 with the introduction of the Albatros D.I and D.II.

The ammunition belt of the lMG 08 utilized the design of the Parabellum MG14 for its light weight, rather than that of the infantry version of the MG 08. After a cartridge was fired the belt was fed into a side chute on the side of the breech block. The chute would guide the empty belt into a storage compartment to prevent the empty belts from interfering with any aircraft mechanisms.  Empty cartridge cases however were expended out of a round hole on the receiver just under the barrel on all version of the MG 08. In most aircraft the empty cases were guided out of the aircraft.

Use of the Spandau lMG 08

The lMG 08 was used on almost all German fighter aircraft of the WWI period. After its introduction in 1915, synchronization technology was rapidly being developed. On the Fokker E.I the introduction of the synchronizer system with a single mounted lMG 08 led to a period of German air superiority over the Western Front known as the Fokker Scourge. Later aircraft almost universally used a twin synchronized setup, including Germany’s most famous ace, Baron von Richthofen ‘The Red Baron.’

Twin Synchronized lMG 08s on a replica Fokker DR.I
Twin Synchronized lMG 08s on a replica Fokker DR.I

There were various styles of cocking handles in use, seemingly dependent upon pilot preference. Safety interlocks were also introduced to ensure the safety of the ground crew who at times could be in the line of fire. Another modification seen in aircraft use was a countdown style rounds counter.

Spandau lMG 08 Gun Specifications

Weight 12 kg / 27 lb
Length 1.45 m / 4 ft 9 in
Barrel Length 720 mm / 28 in
Cartridge 7.92mm x 57
Action recoil with gas boost
Rate of Fire 400 to 500 rounds/min
Muzzle Velocity  860 m/s  /  2,821 ft/s
Effective Firing Range 2,000 m / 2,200 yd
Maximum Firing Range 3.500 m / 3,800 yd (indirect fire)
Feed System 250 round fabric belt

Gallery

Spandau LMG08/15 1918 - Side Profile View
Spandau lMG 08/15 – 1918

Sources

Fokker E.I. (2016, April 21). In Wikipedia, The Free Encyclopedia.Synchronization gear. (2016, May 15). In Wikipedia, The Free Encyclopedia.MG 08. (2016, March 22). In Wikipedia, The Free Encyclopedia.The Vintage Aviator (n.d.), The Spandau LMG 08/15, Images: Fokker DR.I Spandau Guns – 2013 by Julian Herzog / CC BY 4.0

Albatros D.III

German Empire Flag German Empire (1916)
Fighter Plane – 1,866 Built
The Albatros D.III was a bi-plane fighter manufactured by Albatros Flugzeugwerke Company in the Aldershof district of Berlin, Germany. The plane helped secure German air superiority and several top German aces flew the D.III, including Manfred von Richthofen – The Red Baron.  It was armed with 2 7.92mm LMG 08/16 machine guns which were an air cooled and synchronized version of Germany’s MG08.

Design of the D.III

Designed by Robert Thelen, the D.III was based off of the D.I and D.II that preceded it, utilizing the same basic fuselage.   This fuselage design was semi-monocoque, meaning that the skin of the aircraft, which was plywood, could bear some weight and add structural rigidity.

Albatros D.III - The Red BaronAfter seeing the success of the French Nieuport 11 and 17, the Idflieg which was the bureau overseeing German aviation development at the time requested that the new D.III adopt a sesquiplane layout similar to the Nieuports. A sesquiplane configuration consists of a modified biplane design with shorter and and narrower lower wings with the advantage being less drag at speed. As a result, the top wing was lengthened, and the lower wing’s chord was shortened, meaning the wing measured less from leading edge to trailing edge. The bracing, between the top and bottom wings was reconfigured to a “V” shape leading owing to the single spar used in the lower wings. Because of this the British coined their own nickname for the D.III: “The V-strutter.”

Water Cooled Mercedes Power

The D.III utilized a water-cooled Mercedes inline 6 cylinder 4 stroke engine appropriately designated as the D.IIIa. The water cooling and overhead camshaft yielded more horsepower than the radial engines that were more common, with the D.IIIa pumping out 170 hp. In the interest of weight savings the crankcase was aluminum, whilst the separate cylinders were steel and bolted onto the crankcase. Unlike previous designs each cylinder had a separate water jacket.

Flaws Emerge

Several problems were discovered during the D.III’s introduction. The first of which was the placement of the aerofoil shaped radiator above the cockpit. Although it was well placed to avoid battle damage, it tended to scald the pilot if there was a leak or puncture in the radiator for any reason. The design was changed to relocate the radiator right of the cockpit.

Albatros D.III - Wrecked at FlandersAnother issue had to do with several lower wing failures. Even The Red Baron himself, Manfred von Richthofen experienced this with a crack appearing on his new D.III and was forced to make an emergency landing.  Initially this puzzled engineers and was attributed to poor workmanship during manufacturing, but in reality the lower wing was experiencing excessive flexing under aerodynamic load. The eventual cause was determined to be the wing’s spar which was located too far aft. As a result of the changeover to the sesquiplane layout, only a single spar was used in the lower wing. Modifications were made to the design and existing aircraft to strengthen the wing. In spite of the modification pilots were advised to avoid steep or prolonged dive maneuvers.

Performance

The D.III was well regarded among pilots from its introduction despite having heavier controls. It offered improved stability, maneuverability, and climbing ability over the preceding D.II. Downward visibility was also much improved thanks to the narrower lower wing.

Bloody April

Albatros DIII - Climbing

The Albatros D.III was the most dominant fighter in the air during April 1917. The British forces attacking at Arras, France pushed for strong air support in the battle, but were their pilots were not nearly as well trained as the German pilots. To make matter worse, the British planes in use such as the Sopwith Pup, Nieuport 17, and Airco DH.2 were vastly inferior to the D series aircraft in use by the Germans. The British would go on to lose 275 aircraft. By contrast the Germans only lost 66 aircraft during the conflict.

Albatros D.III Specifications

Wingspan  9 m / 29 ft 6 in
Length  7.33 m / 24 ft 1 in
Height  2.9 m / 9 ft 6 in
Wing Area 23.6 m² / 254 ft²
Engine 1 water cooled inline Mercedes D.IIIa engine
Maximum Take-Off Weight 886 kg / 1,949 lb
Empty Weight 659 kg / 1,532 lb
Maximum Speed 175 km/h / 109 mph
Range 480 km / 300 mi
Maximum Service Ceiling 5,500 m / 18,000 ft
Crew 1 (pilot)
Armament 2 x 7.92 mm LMG 08/15 machine guns

Gallery

Sources

Albatros D.III. (2016, March 1). In Wikipedia, The Free Encyclopedia., Avistar.org (n.d.) Albatros D.III Images: Albatros D.III – Flying by DeciBit, Albatros D.III – Side View by Serge Desmet / CC BY-SA 1.0