Wiki Junkers Jumo 004
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The Jumo 004 was the world's first turbojet engine in production and operational use. Some 8,000 units were manufactured by Junkers 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. Contents [hide]
* 1 History * 2 Design * 3 Variants * 4 Specifications (Jumo 004B) * 5 Trivia * 6 See also
[edit] History
The practicality of jet propulsion had been demonstrated in Germany in early 1937 by Hans von Ohain working with the Heinkel company. Most of the RLM remained uninterested, but Helmut Schelp and Hans Mauch saw the potential of the concept and encouraged Germany's aero engine manufacturers to begin their own programmes of jet engine development. Eventually in 1939 Otto Mader, head of Junkers Motoren (Jumo), stated that even if the concept was useful, he had no one to work on it. Schelp responded by stating that Dr Anselm Franz, then in charge of Junkers' turbo- and supercharger development, would be perfect for the job. Franz started his development team later that year, and the project was given the RLM designation 109-004 (the 109- prefix was common to all jet projects).
Franz 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 compressor), recently developed by the Aerodynamische Versuchsanstalt (AVA - Aerodynamic Research Institute) at Göttingen. The axial-flow compressor not only had excellent performance, about 78% efficient in "real world" conditions, but it also had a smaller cross-section, important for a high-speed aircraft design.
On the other hand, he aimed to produce an engine that was far below its theoretical potential, in the interests of expediting development and simplifying production. One major decision was to opt for a simple combustion area using six "flame cans", instead of the more efficient single annular can. 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. Franz'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.
[edit] Design
The first prototype 004A ran in spring 1940, and in January the following year was brought up to full thrust, 946 lbf (4.2 kN). Vibration problems with the compressor blades delayed the program at this point, until a new stator design by Max Bentele solved the problem. With the new stators in place the engine developed 1,320 lbf (5.9 kN) in August, and passed a 10-hour endurance run at 2,200 lbf (9.8 kN) in December. The first flight test took place on 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 to the extent of 80 engines.
The 004A was strictly a test-bed, unsuitable for mass production due to its solid, and thus heavy, construction and considerable use of expensive high-temperature metals in the "hot section". For production, the 004B turned to air cooling instead, using hollow turbine blades made of inexpensive steel, cooled by compressed air "bled" from the compressor. The first production versions weighed 220 lb (100 kg) less than the 004A's, and in 1943 had passed several 100 hour tests.
Later in 1943 a series of engines suffered vibration problems, and solutions dragged on. Eventually, in December, Max Bentele was once again brought in during a meeting at the RLM headquarters, where he suggested several seemingly small changes to change the natural frequencies of the turbine blades, and a slight reduction in operational rpm from 9,000 to 8,700. This cured the problem, but it was not until early 1944 that full production could finally begin. These setbacks were the principal factor delaying the Luftwaffe's
The Jumo 004 was the world's first turbojet engine in production and operational use. Some 8,000 units were manufactured by Junkers 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. Contents [hide]
* 1 History * 2 Design * 3 Variants * 4 Specifications (Jumo 004B) * 5 Trivia * 6 See also
[edit] History
The practicality of jet propulsion had been demonstrated in Germany in early 1937 by Hans von Ohain working with the Heinkel company. Most of the RLM remained uninterested, but Helmut Schelp and Hans Mauch saw the potential of the concept and encouraged Germany's aero engine manufacturers to begin their own programmes of jet engine development. Eventually in 1939 Otto Mader, head of Junkers Motoren (Jumo), stated that even if the concept was useful, he had no one to work on it. Schelp responded by stating that Dr Anselm Franz, then in charge of Junkers' turbo- and supercharger development, would be perfect for the job. Franz started his development team later that year, and the project was given the RLM designation 109-004 (the 109- prefix was common to all jet projects).
Franz 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 compressor), recently developed by the Aerodynamische Versuchsanstalt (AVA - Aerodynamic Research Institute) at Göttingen. The axial-flow compressor not only had excellent performance, about 78% efficient in "real world" conditions, but it also had a smaller cross-section, important for a high-speed aircraft design.
On the other hand, he aimed to produce an engine that was far below its theoretical potential, in the interests of expediting development and simplifying production. One major decision was to opt for a simple combustion area using six "flame cans", instead of the more efficient single annular can. 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. Franz'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.
[edit] Design
The first prototype 004A ran in spring 1940, and in January the following year was brought up to full thrust, 946 lbf (4.2 kN). Vibration problems with the compressor blades delayed the program at this point, until a new stator design by Max Bentele solved the problem. With the new stators in place the engine developed 1,320 lbf (5.9 kN) in August, and passed a 10-hour endurance run at 2,200 lbf (9.8 kN) in December. The first flight test took place on 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 to the extent of 80 engines.
The 004A was strictly a test-bed, unsuitable for mass production due to its solid, and thus heavy, construction and considerable use of expensive high-temperature metals in the "hot section". For production, the 004B turned to air cooling instead, using hollow turbine blades made of inexpensive steel, cooled by compressed air "bled" from the compressor. The first production versions weighed 220 lb (100 kg) less than the 004A's, and in 1943 had passed several 100 hour tests.
Later in 1943 a series of engines suffered vibration problems, and solutions dragged on. Eventually, in December, Max Bentele was once again brought in during a meeting at the RLM headquarters, where he suggested several seemingly small changes to change the natural frequencies of the turbine blades, and a slight reduction in operational rpm from 9,000 to 8,700. This cured the problem, but it was not until early 1944 that full production could finally begin. These setbacks were the principal factor delaying the Luftwaffe's
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