The first true turboshaft engine for helicopters was built by the French engine firm Turbomeca, led by the founder, Joseph Szydlowski.
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An unusual example of the turboshaft principle is the Pratt & Whitney F135-PW-600 engine for the STOVL F-35B - in conventional mode it operates as a turbofan, but when powering the LiftFan, it switches partially to turboshaft mode to send power forward through a shaft (like a turboprop) and partially to turbojet mode to continue to send thrust to the rear nozzle.
It was essentially a Bell 47J-3 with an unclad, tubular tail boom, and powered by a Turboméca Astazou II turboshaft engine.
Boeing C-127, a designation for a proposed, large, turboshaft -driven transport aircraft to have been built in the early 1950s by the United States
Soloviev D-25, a 1960 Soviet gas-turbine turboshaft helicopter engine
The 7,500 lb AAI vehicle was proposed to be equipped with a 1,200 shp Honeywell HTS900 turboshaft engine to power four electric wheel motors or the 56-inch ducted fan, and spin up the 50-foot rotor.
Other differences compared with the MD 520N include a new six blade main rotor (the MD 520N has a five blade unit) and a more powerful Allison (now Rolls-Royce) Model 250 turboshaft.
A turboshaft Eland is on display at the The Helicopter Museum, Weston-super-Mare.
General Electric T58, 1955 United States turboshaft engine developed for helicopters
LHTEC T800, a turboshaft engine for rotary wing applications