<div class="htmlview paragraph">Written from the point of view of the helicopter constructor, this paper attempts a comprehensive review of the experience accumulated by airframe, engine, and control systems designers in the United Kingdom in the course of developing a wide variety of first generation turbine engined helicopters.</div> <div class="htmlview paragraph">Some experimental results are examined to illustrate and define the requirements for future engine control systems, and to show that the handling characteristics of free power turbine engines can be improved to equal the best characteristics previously experienced with fixed shaft turbines.</div>