An innovative VTOL design is set to take flight in Utah over 40 years after it became an unfortunate casualty of rationalisation in the British aircraft industry.
At the end of WW2 Fairey Aviation, then noted for their naval aircraft, began investigating compound helicopters where the rotor is unloaded in forward flight by a small wing. This type of aircraft still offers improved performance over conventional helicopters. Fairey began with a small piston powered craft called the Gyrodyne, this looked something like a small helicopter of the time but with small stub wings. The anti-torque rotor was moved from the tail to the tip of the right hand wing; so that as well as counteracting the main rotor it could provide forward thrust when the rotor was free-wheeling in cruising flight. After a successful test programme, including a world speed record, Fairey took the design a step further, using jet thrust at the rotor tips, allowing reaction-less vertical take off and hovering, combined with twin pusher props on the wing tips. The success of this design led to the construction of the Fairey Rotodyne.
The Rotodyne was a compound helicopter of unprecedented size, a fully operational prototype for a point to point airliner, with a 90 foot rotor blade mounted 20 feet above a passenger cabin capable of carrying 48 passengers. To top it all it could travel at over 200mph, not far short of the current helicopter world speed record. The Prototype made over 350 flights, including 200 vertical to horizontal transitions, BEA, New York Airways and the RAF all placed orders while Kaman helicopters took out a licence to manufacture Rotodynes in the US. It is easy to see why Fairey thought they had a winner on their hands. In 1959 the Minister for transport even said so in the House of Commons, yet three years later this extraordinary aircraft was abandoned.
Key orders, from state owned BEA and the RAF failed to materialise and the rationalisation in the UK aircraft industry swallowed up Fairey, making the project no longer viable. All UK helicopter activity was condensed into Westland Aviation, including a twin rotor project from Bristol called Belvedere. Securely funded by a government contract Westland chose to pursue the Belvedere, despite its inferior performance and prospects, rather than the capable but unconfirmed Rotodyne.
The projects failure is often attributed to the noise from the tip jets but this was more of an excuse, noise levels had already been reduced to the level of a London Underground train prior to cancellation. Indeed in the airliner role, the only case where this could have been a problem, the tip jets where only lit for a few short minutes at the start and end of the flight. Test pilot Ron Gellatley even made several landings and departures from a city centre heliport without a complaint being raised. Unfortunately this extraordinary aircraft was broken up after cancellation with only small sections surviving at the Helicopter museum in Weston-super-Mare.
The Rotodyne's prescience has now been testified to by the recent DARPA contract awarded to a group led by Groen Brothers Aviation of Salt Lake City. Groen Brothers have long advocated the continuing advantages of gyrodynes, the original Fairey design has now given its name to the class of aircraft, and have succeeded in securing a DARPA contract to demonstrate technology for a combat search and rescue gyrodyne. Working in collaboration with Adam aircraft, Georgia Tech and Williams international, phase 1 will involve sub-scale testing on a converted Adam A700 in the near future with further phases leading to the design of a new SAR gyrodyne.
Westland Aviation are now part of Agusta and still hold the helicopter speed record with a Westland Lynx. Groen Brothers manufacture a range of modern autogiros and have a number of concepts for gyrodyne airliners and heavy lifters they hope to realise in future.