Secret Projects of the Luftwaffe - Vol 1 - Jet Fighters 1939 -1945

Dan Sharp

• Publisher: Tempest
• Year: 2020
• ISBN:
  9781911658801
• Topic: History
• Subtopic: World War II
• Index: History

Germany’s air ministry was quick to grasp the potential of the jet engine as early as 1938 and by 1939 several German aircraft manufacturers were already working on fighter designs that would utilize this new form of propulsion. Rocket engines too were seen as the way of the future and companies were commissioned to design fighters around them. As the Second World War began, the urgent need to bring these advanced new types into production saw a host of innovative aircraft designs being produced which would eventually result in Messerschmitt’s Me 262 jet fighter and the Me 163 rocket-propelled interceptor. And as the war progressed, efforts were increasingly made to find better ways of utilizing jet, rocket and latterly ramjet engines in fighter aircraft. Aviation companies from across Germany set their finest minds to the task and produced some of the most radical aircraft designs the world had ever seen. They proposed rotating wing ramjet fighters, arrowhead-shaped rammers, rocket-firing bat-winged gun platforms, sleek speed machines, tailless flying wings, tiny mini fighters and a host of others ranging from deadly looking advanced fighters to downright dangerous vertical launch interceptors. Secret Projects of the Luftwaffe Volume 1: Jet Fighters 1939-1945 by Dan Sharp, based on original research using German wartime documents, offers the most complete and authoritative account yet of these fascinating designs through previously unseen photographs, illustrations and period documentation from archives around the world.

Chapter 1

Early developments

Jet and rocket fighters to 1940

When the victorious Allies shattered Germany’s aircraft industry after the First World War, they inadvertently encouraged a new wave of innovation in aviation – leading to the design and manufacture of the world’s first jet- and rocketpropelled fighters.

A flight of low-wing rocket-propelled fighters drawn by Alexander Lippisch to illustrate a talk he gave to Hauptmann Oskar Dinort at Döberlitz airfield in December 1934 on the military potential of tailless aircraft. IOWA STATE UNIVERSITY LIBRARY SPECIAL COLLECTIONS AND UNIVERSITY ARCHIVE

After his tailless Ente aircraft was used as a testbed for Fritz von Opel’s solid-fuel rockets in 1928, Lippisch went on to design this rocket-propelled aircraft for him in 1929.

RRG AND DFS, 1924–1935

A passion for gliders took hold in Germany soon after the war and can be directly attributed to the imposition of the onerous Treaty of Versailles signed in June 1919. Among its many terms and conditions was a ban on the manufacture and importation of all aircraft and aircraft parts for six months. All German “military and naval aeronautical material” had to be handed over to the Allies – effectively crippling the German aviation industry and leaving thousands of military aviators without aircraft to fly. And the next generation, brought up on tales of German pilots’ wartime heroics, had no way of following in their footsteps.

The ban was lifted on building small powered aircraft in 1922 and on larger aircraft in 1926 but Germany’s dire economic situation meant large established manufacturers such as Junkers and Albatros struggled to remain afloat. Fokker had left Germany and been re-established in the Netherlands while Gothaer Waggonfabrik and Bayerische Flugzeugwerke both abandoned aviation for several years. A handful of new companies were formed – including Arado in 1921, Heinkel and Rohrbach in 1922 and Focke-Wulf in 1923 – but they remained relatively small.

With powered aircraft in short supply, ex-military aviators and young men eager to fly for the first time turned to gliders instead. Individual enthusiasts and clubs were able to construct their own gliders using widely published plans and a new organisation, the Rhön-Rossitten-Gesellschaft (RRG), was set up in 1924 to regulate and promote the burgeoning glider community. The RRG, led by Professor Walter Georgii, also worked to develop new gliders and to improve existing designs – conducting research on everything from aerodynamics, lightweight materials and control systems to cockpit design, pilot training and the effects of flight on the human body.

At the same time there was growing interest in the possibilities of rocket propulsion. First World War veteran and rocket enthusiast Max Valier discussed the idea of using powder rockets to propel an aircraft in correspondence with his friend and fellow enthusiast Hermann Oberth in July 1924. This idea later received widespread publicity in lectures and books, with Junkers becoming interested.

The Delta I, built in 1931, was powered by a 30hp Bristol Cherub engine which came from Theo Croneiss, a director of Bayerische Flugzeugwerke. It was the beginning of an association between Lippisch and the company that would come to fruition eight years later.

Lippisch built the twin-engine push-pull Delta IV in 1932 for Gerhard Fieseler, who called it the Fieseler F 3 Wespe. He found it almost uncontrollable in flight, however, and handed it back to the RRG without paying.

A meeting was held between Valier and Junkers personnel on September 7, 1925, but the company would not consider the viability of rockets for aircraft without a working prototype of the motor Valier had in mind and the idea stalled.

Just over two years later, Valier signed a deal with manufacturer Opel to build a rocket-powered car. Tests of the rocket motor in a standard Opel car commenced in January 1928 and on March 12 it managed to reach 75km/h. The following day, Valier and Fritz von Opel, grandson of the company’s founder, visited the RRG and explained to the head of the organisation’s technical department, Alexander Lippisch, that they wanted to commission a glider with a canard or ‘tail-first’ layout. Although the pair were initially rather cagey about exactly why this configuration was necessary, Lippisch soon established that they wanted to fit solid-fuel rockets to the aircraft. The unusual layout would ensure that there would be no tail structure behind the rockets when they were firing.

Plan views of the Delta IVa and the aircraft as it was rebuilt after a crash in December 1935 – the Delta IVb.

Lippisch duly designed and had built the straight-winged Ente or ‘Duck’, which was test flown under rocket power on June 11, 1928,1 by Fritz Stamer – manager of the RRG’s training section and Lippisch’s brother-in-law. It was the first rocket-powered manned flight in history but would prove to be the last for some time. Stamer had a lucky escape when one of the rockets blew up and the glider caught fire, von Opel lost interest soon after and Valier was killed in May 1930 when one of his alcohol-fuelled rocket motors exploded.

Lippisch continued to design gliders for the RRG and towards the end of 1929 was commissioned to build a new tailless aircraft for aviation pioneer Hauptmann Hermann Köhl. The result was a high-winged experimental glider with swept leading edges and an entirely straight trailing edge, a wing shape like the triangular Greek letter ‘delta’. Unsurprisingly, Lippisch called it the Delta and it was completed in mid-1930.2

Testing of the Delta convinced Lippisch that the powered version, which was what Köhl wanted, would perform better with a low wing and work therefore began on another new aircraft, the Delta I, incorporating a Bristol Cherub engine donated by Theodor Croneiss, a director of the Bayerische Flugzeugwerke (BFW).3 This would be the first in a series of controversial powered Delta designs – controversial because although they offered high manoeuvrability they were reportedly very difficult to control in flight.

In February 1932, First World War fighter ace and stunt pilot Gerhard Fieseler commissioned the RRG to build him three examples of a new tandem-seat delta aircraft, to be powered by a pair of British Pobjoy R engines with one pushing and one pulling, which the RRG knew as the Delta IV but Fieseler himself called the F 3 Wespe. Work on it commenced in April and the first machine was completed in June but Fieseler was deeply disappointed in it – finding it almost uncontrollable.4

The Fieseler company itself made numerous alterations to the aircraft, under Lippisch’s direction and at its own expense, in an attempt to resolve its problems but eventually Fieseler managed to get out of his contract with the RRG without having to actually buy the aircraft thanks to a technicality. The single completed Delta IV was left with the RRG. Later that year, Ernst Heinkel of the Heinkel company invited Lippisch to a meeting to discuss the potential further development of his delta aircraft but then pulled out of the project.

Following the seismic political shift that occurred when Adolf Hitler became the German chancellor on January 30, 1933, the RRG was reorganised into two separate companies – the Deutschen Luftsportverband (DLV) or ‘German Airsport Association’ and the Deutsche Forschungsanstalt für Segelflug (DFS) or ‘German Research Institute for Gliding’. With fresh funding for aviation research now available from the government, Lippisch was made head of his own department at the latter. Stamer and Hans Jacobs – Lippisch’s assistant and soon to be Germany’s premier conventional-layout glider designer – also became part of the DFS under Georgii’s continued leadership.5

The Delta IV stripped to its bare frame after being converted from the IVb into the IVc.

Lippisch planned to rebuild the DFS 39 again with more sharply swept wings as the Delta IVd but this design would remain on the drawing board.

The Delta IV had changed beyond all recognition by the time it became the IVc – subsequently redesignated DFS 39 and seen here in flight.

In December 1934, Lippisch presented a lecture to Hauptmann Oskar Dinort and his men at Döberitz airfield on the military potential of tailless aircraft, illustrating the presentation with a drawing of futuristiclooking rocket-powered fighters.6 Just over a year later Dinort would become the commanding officer of another flying wing pioneer – Walter Horten. In 1935 the technical department of the DFS was split in two, with Jacobs taking control of everything to do with conventional gliders and Lippisch being given a separate experimental delta and allwing division.7

With the much-altered Delta IV airframe now under his control, and with the DFS’s expanded research budget available, Lippisch had it rebuilt without its pusher engine as the Delta IVa. This was found to have significantly improved handling characteristics.

Towards the end of the year the Delta IVa was damaged in a crash and a technical commission was formed from representatives of the Deutsche Versuchsanstalt für Luftfahrt (DVL) or ‘German Institute for Aeronautical Research’ and the technical office of the RLM to review the p...