The development of the Do 31 was motivated principally by heavy interest expressed by the German Air Force in the acquisition of short take-off and vertical landing aircraft (STOVL)-capable aircraft. Such ambitions received a further boost from the issuing of NATO specification NBMR-4, which called for a VTOL-capable tactical support aircraft that would be operated in conjunction with the EWR VJ 101, a West German VTOL strike aircraft designed under the NATO contract of BMR-3. A total of three aircraft, two flight-capable and one static airframe, were constructed and used for testing. On 10 February 1967, the Do 31 performed its maiden flight; the first hovering flight of the type took place during July 1967.
During the late 1950s and 1960s, the German Air Force became increasingly concerned that, in the event of a major conflict with the Eastern Bloc, its airfields would be highly vulnerable to attack, quickly preventing the use of conventional aircraft in any such conflict. Seeking to counter this threat, the service actively researched the possibility of dispersed operations; one of the options was the use of the nation’s Autobahnens, which necessitated such aircraft to possess short take-off and vertical landing aircraft (STOVL) capabilities. Due to this interest, a series of trials were conducted, which involved the modification of several German Air Force Lockheed F-104 Starfighters so that they could be rocket-launched from stationary ramps; these trials became known as the zero length launch (ZELL) programme. The Starfighters were to be recovered to short strips using aircraft carrier-type arresting gear; similarly, the later Do 31 was intended to use these same austere air strips as forward operating bases.[
You are definitely intrigued to discoverDornier Do-31 VTOL-transport "1967"
Both flying prototypes have been preserved in Germany, but the fate and current location of the non-flying testbed (E2) is not known.
Capacity: 36 troops and 3,500 kg (7,715 lb)
Length: 20.53 m (67 ft 4 in)
Wingspan: 18 m (59 ft 3 in)
Height: 8.53 m (28 ft 0 in)
Max takeoff weight: 27,422 kg (60,500 lb)
Powerplant: 8 × Rolls-Royce RB162-4D Vertically mounted turbojet lift
Maximum speed: 730 km/h (452 mph, 393 kn)
Cruise speed: 650 km/h (404 mph, 351 kn)
Range: 1,800 km (1,120 mi, 970 nmi) with maximum payload
Service ceiling: 10,700 m (35,100 ft)
Rate of climb: 19.2 m/s (3,780 ft/min) -using Pegasus engines only
The Do 31 was the first, and so far only, vertical takeoff jet transport ever built. During April 1970, it was announced that the project had been terminated, although the Do 31 performed its final public flight on 4 May 1970 during the Internationale Luft- und Raumfahrtausstellung (ILA) in Hannover