Le Bell ATV était un projet expérimental d'avion à décollage vertical utilisant deux turboréacteurs à la fois pour le vol vertical et le vol horizontal.
Il s'agissait de 2 Fairchild J44, chacun d'eux ayant une puissance de 454 kg de poussée. Ils étaient montés de part et d'autre, le long du fuselage, et pouvaient pivoter de 90°, depuis la position vertical jusquà l'horiozontal.
This VTOL was a private-venture test vehicule (Bell Chief Aircraft Engineer, Stan Smith, obtained $100,000 of Bell funds Apr 53 to develop ATV) which had been built up from a number of readily available components :
- Schweizer 1-23 sailplane fuselage and empennage,
- Cessna 170 wing,
- Bell 47 landing gear,
- French Turbomeca Palouste turbocompressor for vertical flight reaction thrust via ducts and nozzles in wing tips and tail.
- Fairchild J44 turbojet engines supplied by Air Force ( 6 with 5-hr service life for $1 each).
First flights of N1105V culminated Jun 54 with compressor failure on right engine which severed fuel line and destroyed tail while Joe Cannon was testing it.
Repaired, was successfully flown by Dave Howe 16 Nov 1954 and partial transitions to horizontal flight performed with engines left in vertical position.
Apr 55, conventional Cessna landing gear installed, and vertical and horizontal flights were made by Howe.
In May, Howe unsuccessfully attempted horizontal to vertical transitions at 5,000 feet; when engines rotated, pitch-up occurred, and as stick was pushed forward to compensate, aerodynamic and reaction control pressures were sufficient to deform aft fuselage.
Since major test aims were complete and last J44s had 4.5 hours on them, project was terminated in favor of X-14.
ATV weighed about 2,000 pounds and accelerated from 0-100 mph in 100 ft.
Was only able to fly well in cold weather (relatively high air density) when engine thrust was about equal to aircraft weight.
6 key test results:
- successful turbojet VTOL flight with a 1:1 power/ weight ratio;
- proof that a person could control such an aircraft;
- simple, workable reaction control system;
- jet engines operating in sustained vertical and horizontal positions;
- transitional flight that was more stable than hovering flight;
- proof that jets could be operated vertically over concrete surfaces without damaging them.