Bell XV-3
| Bell XV-3 | |
|---|---|
 Bell XV-3 over NASA premises |
|
| Type: | VTOL - experimental aircraft |
| Design country: | |
| Manufacturer: | |
| First flight: |
August 1955 |
| Commissioning: |
- |
| Production time: |
- |
| Number of pieces: |
2 |
The Bell XV-3 (factory designation Model 200) is one of the tilt rotor - VTOL - convertible aircraft . These planes take off vertically with their rotors pointing upwards like a helicopter . To take up horizontal flight, the rotors are then swiveled forward by 90 °. The transition from hovering to level flight is called transition. The XV-3 uses a radial engine that is located between the wings in the fuselage and drives the propellers via long-distance shafts .
history
The XV-3 was jointly developed by Bell and the United States Army . On August 23, 1955, the first of two prototypes made its maiden flight; but still as a helicopter with a three-blade rotor. In the later tests, the transition from hovering to level flight should be tested. On October 25, 1956, test pilot Dick Stansbury swiveled the rotors forward 17 °, causing the machine to vibrate so strong that he passed out and lost control. Stansbury was slightly injured in the crash landing and the XV-3 was destroyed.
With the second test model, the world's first transition was carried out on December 18, 1958, and almost 200 km / h was achieved in the subsequent level flight. A two-bladed rotor on stiffened wings was used, but the engineers never got the instability under control. The second prototype completed 125 flight hours and 110 complete transitions on more than 250 flights, until both rotors tore off due to vibrations and technical defects in a wind tunnel test in November 1968. The XV-3 program was then discontinued.
successor
Building on the experience with the XV-3, Bell built a new test aircraft with the designation "Model 300" at the end of the sixties and, together with NASA, the "Model 301", which completed its first hover on May 3, 1977. Due to the interest of the US Army, the model was named XV-15 . With an automatic flight control and stabilization system, stability problems that the XV-3 still had in level flight during the attempts at that time could be solved. In 1989, the direct result of the "XV-15" tests premiered: Together with Boeing, Bell developed the V-22 "Osprey" , which is now in service with the United States Marine Corps.
Technical specifications
| Parameter | Data |
|---|---|
| crew | 1 |
| length | 9.23 m |
| span | 9.54 m |
| height | 4.11 m |
| Rotor circle diameter | 10.06 m |
| Preparation mass | 1634 kg |
| Max. Takeoff mass | 2179 kg |
| Top speed | 291 km / h |
| Service ceiling | 3660 m |
| Hover altitude | 2256 m (with ground effect ) |
| Range | 410 km |
| Engines | Pratt & Whitney R-985 AN3 radial engine with 336 kW |
