Cierva Air Horse–Forgotten helicopter

Cierva Gyrodyne

My paper on the Cierva (later Fairey) Gyrodyne is also available for those interested. This appeared in a 2008 edition of Vertiflite.

Email me at [email]jph@wt.net[/email] for a copy.

Two Flight Test Pilots and a Flight Test Observer was certainly standard crewing, sad as it was that it happened.

From what I have read the Airhorse seemed an ill concieved and ungainly device that even given a huge budget and development would never have made it into a viable machine.
The saddest bit is that three people were killed when it crashed, did it really need that many to operate it.

Richard

… hints at doubt on Spraying Mantis

Excellent!:D

The Cierva W.11 strikes me as one of those aircraft that appeared ahead of its time but probably wasn’t in reality.
A turboshaft engined version would have been far superior, and may have been more desireable back then if it was available, but smaller and far less complex designs were about only a few years later which could carry not far of the same weights.
As Ken suggests the CAOR.3/46 requirement, on behalf of the the MoCA and Colonial Office, seems to be another justification for the E.19/46 eperimental military project, which was brave attempt by a small company.
VZ724s crash in June 1950 sadly killed the test-pilots Sqn Ldr ‘Jeep’ Cable and Alan Marsh, aswel as FTO H.J.Unsworth.
WA555 lingered on for more flight tests and was later stored at MoS Chelford before scrapping by Staravia in Feb 1958.

The aforementioned W.9, now that was ahead of its time, a true forerunner of todays NOTAR helicopters, except that it was Gipsy Six piston powered and needed a driven fan and exhaust gas mixing system (thus added weight/complexity) to produce the anti-torque eflux.

(When I offer a contrarian position I have either/both fact, or synthesis logically from fact. No conspiracies. But here I do surmise, though ISTR MRH.Uttley, Westland & the Br. Helicopter Industry,1945-60, Cass, 2001 hints at doubt on Spraying Mantis.)

RN for ASW trials and RAF for radar calibration shared 51 Lend/Lease Sikorsky R-4B Gadfly/Hoverfly I; 40/RAF, 2/FAA R-6A Hoverfly II were assembled by General A/c. RN sent to Br.Air Commission, DC, a Requisition for 250 R-5A (HO2S-1). That was withdrawn end-1944, but the DG, Sir Richard Fairey cottoned on to a civil prospect and caused his firm to hire Weir/Cierva’s Chief Engineer, Dr.Bennett, his team, and his patented C.41 Gyrodyne.

Peace. Bristol enters rotors, hiring Raoul Hafner. G&J Weir Ltd’s Cierva Autogiro Co.Ltd. in 1945 flew W.9 (torque-offset by engine efflux). RN still saw rotor roles, especially ASW, but landlubber PM Maj.Attlee‘s position was: “there is no-one to fight at sea”. The Army had accepted the demise of assault gliders, looked forward to RAF Valettas, adding to RAF Dakotas, for rough strip/para delivery upclose, and could see a place for rotary insertion behind the lines, and for hot Casevac if payload could be whirled. But 1947 Defence Budget was for Empire garrison/pacification. No lines, so no case to o’erleap them.

MoS extracted funds for a modest rotary demonstrator programme, funding Hafner’s T.171 (9/45), Bennett’s (now) FB-1 (9/47) as concept vehicles, Bristol T.173 (4/47, 2xT.171 shunted as one) as “transport”, and W.11 (7/46) as “ambulance” and as “crop sprayer” for the Tanganyika groundnuts scheme. That fast became an eco-scam even dwarfing today’s wind farm wheeze. Think about how you would spread pesticide over vast tracts of flatland, hot and high. You would take Scottish Aviation’s Storch-inspired Pioneer, off dusty strips accessible to trucks. You have no need for a no-payload complex device jumping up where no bowser, no hopper could get at it.

The Pest Control Ltd “Requirement” was a faddish ticket to Colonial Office Aid. Twaddle. “Civil” rotors: economically illiterate. The purpose of T.173 was to insert a slick of soldiers/Marines; the purpose of W.11 was for ASW, AEW, off carriers. T.173 became T.192 Belvedere, and W.11’s RN roles were met by (T.191, rapidly cancelled for {S.58}) Wessex, after Korea proved combat rotors, restored funding for carriers, and stimulated turboshafts for rotors.

Somewhere (!) I have files,reports and photos ,as well as the test pilot’s log book ..all due to go to The Helicopter Museum archive in due course.They already have a large model on display and film of it flying but need more volunteers to log in material and documentation in an orderly way.Until then it remains in storage at home.

I have researched the Air Horse extensively and have obtained a large number of documents on the aircraft from the UK National Archives (that place is a gold mine of aviation history).

A few facts:

There was persistent heavy vibration in the front rotor that was only partially ameliorated.

Top speed never exceeded about 70 mph because of vibration.

Control was a problem since opposite rigging was required for powered flight vs. autorotative flight. The demonstration flights at the 1949 Farnborough Air Show included mainly right turns because of poor control authority when making left turns. Vibration when flying to and from Farnborough was also a serious concern.

The Air Ministry imposed a fixed-price development contract on the project which left the Cierva Autogiro Company chronically short of funds with too much effort spent in requesting further finances. On the bright side, the AIr Ministry praised the Cierva Autogiro Company for efficient management of resources during the course of the contract.

The crash was caused by fai;ure of the swashplate driving link in the front rotor – poor machining was involved as in the Fairey Gyrodyne accident – which caused the collective pitch to increase to maximum value and resulting in the reported pitch up followed by the dive into the ground.

Thanks for the input. The cooling radiators were located at the bottom of an internal cooling air tunnel in front of the Rolls Royce Merlin 24 engine. Air was drawn in through grills on top of the fuselage and passed through a variable pitch fan which was ejected downwards to cool the radiators and transmission oil coolers. The crash of the Air horse was attributed to a fatigue fracture of the drive link to the front rotor.
For it’s time this was an incredible machine . Although limited in payload3,755lb it had an absolute ceiling of 28,000 feet and an endurance of 4.3 hours. Had one of the prototypes not crashed I wonder if it would have had a future in the commercial field as well as the military.
As NewForest states it was intended for crop-spraying, presumably by Fisons-Airwork for cotton spraying in Sudan. It would have been too unwielding to control amongst the English landscape ?

Have read somewhere that cooling was a problem and the entrance door was always left open in flight to help, would think noise might be a issue with that Merlin blatting away inside the cabin, where were the radiators fitted?

Richard

Interesting that the design was adapted for possible use as a crop sprayer!

http://en.wikipedia.org/wiki/Cierva_Air_Horse

VX724, ff 8 December 1948, crashed 13 June 1950
http://www.vicflintham.co.uk/post-war-research-aircraft-and-prototypes/Helicopters.html
WA555
:confused: