Evolution of Small Turboshaft Engines

There is an ever increasing interest in the small, under 1000 hp, turboshaft engine for use as aircraft propulsion powerplants. This paper discusses the historical evolution of these powerplants, their current state-of-the-art, and their future potential. The effect of a continually advancing technology on the performance, weight, and cost of these engines is discussed. The level of technology in the small gas turbine engine is compared to that of larger engines, pointing out some of the technical differences resulting from engine size effects. The interaction of engine performance, cost, weight, reliability, and maintainability is discussed; and some of the potential tradeoffs between these areas are presented.