Turboshaft

A turboshaft engine is a form of gas turbine that is optimized to produce shaft horsepower rather than jet thrust.

In concept, turboshaft engines are very similar to turbojets, with additional turbine expansion to extract heat energy from the exhaust and convert it into output shaft power.

[3] The first gas turbine engine considered for an armoured fighting vehicle, the GT 101 which was based on the BMW 003 turbojet, was tested in a Panther tank in mid-1944.

Originally conceived as an auxiliary power unit, it was soon adapted to aircraft propulsion, and found a niche as a powerplant for turboshaft-driven helicopters in the 1950s.

[5] This was following the experimental installation of a Boeing T50 turboshaft in an example of the Kaman K-225 synchropter on December 11, 1951, as the world's first-ever turboshaft-powered helicopter of any type to fly.