The Cierva W.9 was a British 1940s experimental helicopter with a three-blade tilting-hub controlled main rotor, and torque compensation achieved using a jet of air discharged from the rear port side of the fuselage.
Development
In 1943, primary investor
G & J Weir Ltd. revived the moribund
Cierva Autogiro Company
The Cierva Autogiro Company was a British firm established in 1926 to develop the autogyro.
The company was set up to further the designs of Juan de la Cierva, a Spanish engineer and pilot, with the financial backing of James George Weir, a Scotti ...
to develop an experimental helicopter to
Air Ministry Specification E.16/43. The W.9 was to investigate
James G. Weir's contention that a powered tilting hub-controlled
rotor with automatic
collective pitch control, and torque reaction control using jet efflux, was both safer and more efficient than the
Sikorsky R-4 helicopter fitted with manually controlled main rotor cyclic and collective pitch and the anti-torque tail rotor system. The W.9 was completed late in
1944
Events
Below, the events of World War II have the "WWII" prefix.
January
* January 2 – WWII:
** Free French General Jean de Lattre de Tassigny is appointed to command French Army B, part of the Sixth United States Army Group in Nor ...
and assigned
serial ''PX203''. It was damaged during ground-running due to incorrect control phasing arising from a high order of pitch-flap coupling, and did not start test flying until
1945
1945 marked the end of World War II and the fall of Nazi Germany and the Empire of Japan. It is also the only year in which nuclear weapons have been used in combat.
Events
Below, the events of World War II have the "WWII" prefix.
Januar ...
.
The most visible characteristic of the W.9 was torque compensation and directional control by using blown air rather than a tail rotor. A variable pitch fan cooled the engine; the heated air and engine exhaust passed through the long hollow tailboom and exhausted to port. Foot pedals controlled the fan pitch. Of more importance, however, was the shaft-driven hydraulically-actuated rotor hub with rotational speed variation to give automatic collective pitch control. Development of the rotor system resulted in a tilting hub combined with cyclic pitch control of each blade to minimize control forces. Manual control of collective pitch was added to the automatic collective pitch change system to provide precise vertical control in hover and the ability to cushion a landing from an autorotative descent.
The W.9 was first publicly demonstrated during an air display in Southampton on 22 June 1946. It was displayed at the Seventh
SBAC Airshow at Radlett in 1946
The helicopter was destroyed in an accident in
1946
Events January
* January 6 - The 1946 North Vietnamese parliamentary election, first general election ever in Vietnam is held.
* January 7 – The Allies recognize the Austrian republic with its 1937 borders, and divide the country into f ...
and the project was abandoned. Parts of the W.9 rotor hub were used in the
W.14 Skeeter prototype.
Specifications (W.9)
Operators
;
*
Air Ministry
See also
*
NOTAR
References
{{Cierva aircraft
1940s British experimental aircraft
1940s British helicopters
W.9
NOTAR helicopters
Single-engined piston helicopters
Aircraft first flown in 1945