Jendrassik Cs-1

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.