The Gyrodyne was a high‐performance rotorcraft concept developed by the Fairey Aviation Company in the 1940's. The aircraft achieved the world helicopter speed record of 129 mph in the G class in 1948. It was, and is, unique in that it featured a propeller offset from the centerline
of the aircraft, thereby fulfilling the dual role of anti‐torque device and auxiliary propulsion. This paper examines the flight mechanics and performance aspects of a configuration that appears not to have found favor in subsequent compound helicopter concepts. Design compromises in
the implementation of a propeller or rotor for combined anti‐torque and propulsion requirements are discussed qualitatively. A contemporary rotorcraft flight mechanics simulation model is then used to quantitatively examine the trim, stability, control response and performance differences
between a conventional medium single main and tail rotor helicopter, and a potential gyrodyne equivalent. The results suggest that the gyrodyne can achieve a maximum speed, limited by retreating blade stall, that is 30% higher than the equivalent helicopter. However, power requirements
at hover and low speed are some 10% greater, and lateral/directional stability and response characteristics are poorer. Notwithstanding this it is concluded that the gyrodyne concept offers an elegant and efficacious design solution to the high performance helicopter problem.
Department of Aerospace Engineering, University of Glasgow, Glasgow, UK
Publication date: October 1, 2007
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