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|Jendrassik Cs-1 displayed in the Museum of Technology in Budapest|
The Jendrassik Cs-1 was the world's first working turboprop engine. It was designed by Hungarian engineer György Jendrassik in 1937, and was intended to power a Hungarian twin-engine heavy fighter, the RMI-1.
Design and development
Following the running of an experimental gas turbine engine of 100 bhp output, in 1937 György Jendrassik began work on a turboprop engine, which would be produced and tested in the Ganz works in Budapest.
Of axial-flow design with 15-stage compressor and 7-stage turbine, it incorporated many modern features. These included a rigid compressor-turbine rotor assembly carried on front and rear bearings. There was a single annular combustion chamber, of reverse-flow configuration to shorten the engine, air cooling of the turbine discs and turbine blades with extended roots to reduce heat transfer to the disc. The annular air intake surrounded a reduction gear for propeller drive takeoff, and the exhaust duct was also annular.
With predicted output of 1,000 bhp at 13,500 rpm the Cs-1 stirred interest in the Hungarian aircraft industry with its potential to power a modern generation of high-performance aircraft, and construction was begun of a twin-engined fighter-bomber, the Varga RMI-1 X/H, to be powered by it.
The first bench run took place in 1940, becoming the world's first turboprop engine to run. However, although the design was inherently sound, combustion problems were experienced which limited the output to around 400 bhp. There was nothing inherently wrong with the design, however, and continued work on the flame cans should have allowed it to develop to full power.
Work on the engine stopped in 1941 when the Hungarian Air Force selected the Messerschmitt Me 210 for the heavy fighter role, and the engine factory converted over to the Daimler-Benz DB 605 to power it. The prototype RMI-1 was later fitted with these engines in 1944.
- Green, W. and Swanborough, G.; "Plane Facts", Air Enthusiast Vol. 1 No. 1 (1971), Page 53.
- Gunston World, p. 111
- Gunston, Bill (2006). The Development of Jet and Turbine Aero Engines, 4th Edition. Sparkford, Somerset, England, UK: Patrick Stephens, Haynes Publishing. ISBN 0-7509-4477-3.
- Gunston, Bill (2006). World Encyclopedia of Aero Engines, 5th Edition. Phoenix Mill, Gloucestershire, England, UK: Sutton Publishing Limited. ISBN 0-7509-4479-X.