What does an aircraft company do when military contracts dry up? Just as some companies are asking themselves that question in today’s post­Cold War economy, the Fairey Aviation Company, Ltd., asked itself the question at the end of World War II after having been a major producer of British carrier-based aircraft since World War I. Fairey’s answer was to reinvent the helicopter and revolutionize the short-haul airline industry. After 15 years of effort, its unique project, the Rotodyne, came within an inch of achieving that goal.

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Long before powered flight was actually achieved, inventors and aircraft designers had attempted to combine the speed of horizontal flight with the ability to take off and land vertically. The development of rotary-wing aircraft was the first practical solution to that problem. The first successful rotary-wing craft was the autogiro, first developed in Spain by Juan de la Cierva in 1923. Unlike the later helicopter, the autogiro did not have a powered rotor. Propulsion came from a propeller in the conventional manner, and the rotor was utilized solely for lift in autorotation. Control was achieved by means of elevators, a rudder and usually ailerons, although a degree of roll control could also be maintained by varying the angle of the rotor head. The autogiro achieved an impressive STOL (short takeoff and landing) performance, but it could neither take off vertically nor hover.

The more familiar helicopter, as perfected by Igor Sikorsky in 1939, took the concept one step further by utilizing the powered rotor for forward propulsion as well as for lift. By the end of World War II, the helicopter showed considerable development potential, while the autogiro had become a dead end.

The helicopter concept itself was far from perfect, however. Not the least of its intrinsic drawbacks was its limited maximum speed. That was partly because the portion of the rotor that moved opposite to the direction of flight, referred to as the ‘retreating blade,’ had a tendency to stall as airspeed increased, resulting in excessive vibration. The helicopter also built up a disproportionate amount of drag as its speed increased because of the forward tilt of the rotor, which was necessary since it provided the aircraft’s forward thrust.

Fairey Aviation initiated development of a new type of rotary-wing aircraft in 1946. It was intended to combine the advantages of the autogiro, helicopter and airplane. The company was well-equipped for such an ambitious project. Doctor J.A.J. Bennett, who led the development team, had formerly been a research engineer at the Cierva Autogiro Company. During World War II, Dr. Bennett had also studied rotary wing aircraft development in the United States as principal technical officer to the British Air Commission in Washington, D.C. The Fairey design team also included Squadron Leader B. Arkell and Wing Commander R.A.C. Brie, both of whom were among the first British pilots to qualify in rotary-wing aircraft.

The idea behind the ‘compound helicopter,’ as Fairey called its concept, was essentially simple. The aircraft would take off and land vertically with a power-driven rotor, like a helicopter, using a controllable-pitch propeller for yaw control. Once airborne, all propulsive power would be transferred to the propeller, with lift being generated by the then- autorotating rotor and a pair of small, conventional wings. The combination of lift from the wings and the reduced drag of the autorotating rotor would, theoretically, produce an aircraft far more efficient than a conventional helicopter.

The flight controls of the compound helicopter were arranged in such a way that the rotor’s collective pitch, which controlled lift in the helicopter mode, would change automatically as the throttle was opened or closed. Roll and pitch were controlled by tilting the rotor head. A single tractor propeller in the starboard wingtip was used to control yaw, as well as to provide forward thrust in the autogiro mode. A conventional tail with an elevator and twin rudders was installed to maintain the aircraft’s trim in horizontal flight and to control the aircraft in the event of engine failure.

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