GYRO HISTORY

History of the gyroplane: a short article of how this innovative concept began

The Fairey Rotodyne

This excerpt comes from a study produced by Dr Frank Anders in 1988, and reproduced in part here, relates how the problem of gridlock at major hubs was evaluated, attacked and solved in 1957.

The Fairey Rotodyne originated from an idea for a large compound helicopter by Dr J. A. J. Bennett and Capt. A. G. Forsyth of Fairey Aviation, whose original study dates back to 1947. Their concept evolved into the ‘Eland’ Rotodyne prototype, which successfully completed its maiden flight in November 1957.

Its four-bladed rotor was powered in helicopter mode by tip jets, driven by compressed air. This compressed air was lit with fuel at tip jet combustion chambers to drive the rotor, removing the necessity for an anti-torque tail rotor. The tip jets were extinguished at about 60mph after a normal helicopter take-off, converting the aircraft to an autogyro. In autogyro mode the collective pitch of the rotor blades, and hence rotor lift, was reduced with up to about half the weight taken by the wings. This allowed much higher speeds than had previously been possible. When approaching land the tips were relit, thus converting the aircraft back to helicopter mode for a normal helicopter hover and landing.

In 1958, the Rotodyne prototype achieved economic cruise speeds of 150 knots. A world record speed of 190.9mph was set on 5 January 1959 for the 100-km closed circuit. The craft had the remarkable safety feature of being able to convert from autogiro mode to helicopter mode and hover with one engine shut down and its prop feathered. Additionally, it demonstrated safe landings in full autogiro mode.

The greatest criticism of the Rotodyne, in spite of its performance as a VTOL craft, was of the noise generated by the tip jets. The noise attenuation program at the time of cancellation had produced reductions down to the then-desired 96dB at 600ft distance. Noise critics failed to appreciate that the full power tips-lit time in service was only about one minute during take-off and climb and one minute at landing. In fact, to prove a point, test pilot Ron Gelattly made two flights over downtown London and several take-offs and landings at Battersea Heliport on a dead calm morning with no complaints raised. At the time of the project's cancellation, the continuing development of silencers had further reduced the noise level by another 16dB. Instrument flying of the aircraft was very stable and Gelattly often demonstrated transitions from helicopter to autogyro and back again, in Instrument meteorological conditions (IMC), at less than 500ft above the ground!

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The Rotodyne's tip drive and unloaded rotor made a tremendous breakthrough in performance and handling compared to pure helicopters and other forms of convert-a-planes. The aircraft was flown at 175 knots and pulled into a steep climbing high G- turn with no adverse handling characteristics. It was demonstrated at the Farnbourgh and Paris airshows each year from 1958 to 1962 and always amazed onlookers. From any point of view the Rotodyne was an aircraft ahead of its time.

Throughout Europe and Britain, city-centre to city-centre transport was being touted as taking very little flying time. Kaman Helicopters in the U.S. was proposing a licensure for civil and military production. Interest was shown from Okanagan Helicopters Ltd. of Vancouver B.C., New York Airways, Chicago Helicopter Airways and Japan Airlines, who considered the aircraft for its Osaka–Tokyo route.

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Nearly 1000 passengers, including a fair portion of the world's airline chiefs, service chiefs and British ministers of parliament, were flown as a demonstration of the enhanced safety of the prototype in order to emphasise faith in the design.

By January of 1959, British European Airways (BEA) announced that it would write a letter of intent for six developed Rotodynes, with the hope of a requirement for up to 20 aircraft for operation on shorter routes. This was in addition to an RAF ‘order’ for 12 military transport version. In March of 1959, New York Airways planned to purchase five Rotodynes costing about 10 million dollars, with an option for an additional 15 at a later date. The U.S. Army showed considerable interest with a rumoured buy of 200 machines. None of this occurred.

Why then, was the project cancelled and the concept not pursued? Why has there not been a logical progression of existing technology dating back 40 years instead of a radical departure from that technology?

In 1959, the British Government, determined to reduce its participation in the aviation industry, reduced the number of helicopter firms. Under the direction of Minister of Aviation Duncan Sandys, the consolidation process was begun. It was done by cutting government funding. Sandys wanted one consolidated helicopter manufacturer centred on Westland aircraft. This meant that Fairey, the helicopter division of Bristol, would have to be taken over by the Westland firm.

In February 1962, the final axe fell, first with withdrawal by BEA, then the withdrawal of the military order. The world's first vertical take-off military/civil transport died.

The Rotodyne demonstrated that a large economical VTOL airliner was a practical proposition in 1959!

All of this occurred almost 40 years ago. Had the Rotodyne persevered, accentuated with modern low fuel consumption engines and modern electronics for the hydraulic control system, commercial aviation would now have a transport of great potential competing with both fixed and rotary wing machines.

One would think such a remarkable aircraft would be retired to a prestigious position in an elite British museum. In fact, the aircraft was dismantled and destroyed, and all tooling which was used to create the Rotodyne was destroyed. Even in a search of London's aviation museums and memorabilia, there is no evidence other than the few articles about the craft written in European and British aviation publications. A few components have been found and brought together at the International Helicopter Museum at Weston-super-Mare.

Present-day problems with air transport are much the same as they were 40 years ago, just more intense. An interesting comment was made in 1989 by Mr Michael Heatly, author of the Illustrated History of Helicopters, referring to the Rotodyne, ‘in many ways the Rotodyne was a project decades ahead of its time. Many subsequent projects from the drawing boards of the worlds' rotorcraft manufacturers bore so little relation to this futuristic craft that it would seem more at home in the 80s skies than those of the 50s. The possibility of a similarly configured VTOL feeder liner achieving success in future decades cannot be ruled out.’


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