Main Page | See live article | Alphabetical index

Junkers Jumo 004

The Junkers Jumo 004 was the world's first turbojet engine in production and operational use. Some 8,000 units were manufactured in Germany during late World War II and powered the Messerschmitt Me 262 and Arado Ar 234 aircraft. Variants of the engine were produced in Eastern Europe in the years following the war.

The practicality of jet propulsion had been demonstrated in Germany in early 1937 by Hans von Ohain working with the Heinkel company. Recognising the potential of the invention, the Reichsluftfahrtministerium (RLM - Reich Aviation Ministry) encouraged Germany's aero engine manufacturers to begin their own programmes of jet engine development. At the Junkers Motor Works in Dessau, Dr Franz Anselm, then in charge of Junkers' turbo- and supercharger development, was assigned to developing a working turbojet engine. The project was given the RLM designation 109-004 (the 109- prefix was common to all jet projects).

Anselm opted for a design that was at once conservative and revolutionary. His design differed from von Ohain's in that he utilised a new type of compressor which allowed a continuous, straight flow of air through the engine (an axial flow compressor), recently developed by the Aerodynamische Versuchsanstalt (AVA - Aerodynamic Research Institute) at Göttingen. On the other hand, he aimed to produce an engine that was far below the theoretical potential calculated for a turbojet, in the interests of expediting development and simplifying production. For the same reasons, he collaborated heavily on the development of the engine's turbine with Allgemeine Elektricitäts-Gesellschaft (AEG - General Electric Company) in Berlin, and instead of building development engines, opted to begin work immediately on the prototype of an engine that could be put straight into production. Anselm's conservative approach came under question from the RLM, but was vindicated when even given the developmental problems that it was to face, the 004 entered production and service well ahead of its more technologically advanced competitor, the BMW 003.

The first prototype 004A ran in late 1940, and in January the following year was brought up to full thrust. Problems with the compressor blades delayed flight tests until March 15 1942, when a 004A was carried aloft by a Messerschmitt Bf 110. On July 18, one of the prototype Messerschmitt Me 262s flew for the first time under jet power from its 004 engines and the 004 was ordered into production by the RLM.

The 004B production version was considerably lightened, and construction was modified to make lower use of scarce strategic materials. A series of turbine failures again delayed development at this point and it was not until nearly a year later, in mid 1943, that the first production examples were leaving the Junkers factory. These setbacks were the principal factor delaying the Luftwaffe's introduction of the Me 262 into squadron service.

Given the lower-quality steels used in the 004B, these engines typically only had a service life of some 10-25 hours (perhaps double this in the hands of a skilled pilot). Another shortcoming of the engine, common to all early turbojets, was its sluggish response to throttle. Nevertheless, it made jet power for combat aircraft a reality for the first time. A number of more advanced versions were in development at the end of the war, as well as a follow-on design, designated the Jumo 012.

Apart from the Me 262 and Ar 234, the engine was used to power the experimental Junkers Ju 287, and prototypes of the Gotha Go 229 and Heinkel He 280. There were plans to install it in the Heinkel He 162 as well as the Focke-Wulf Ta 183 and Henschel Hs 132 then under development.

Following World War II, Jumo 004s were built in small numbers by Malesice in Czechoslovakia, designated M-04 to power the Avia S-92, itself a copy of the Me 262. 004 copies were also built in the Soviet Union as the RD-10 engine, where they powered the Yakovlev Yak-15 as well as many prototype jet fighters.

In France, captured 004s powered the Sud-Ouest SO 6000 Triton and the Arsenal VG-70.