The De Havilland Aircraft Company DH29 'Doncaster' had its origins in the unbuilt DH26 as a long range transport aircraft. It was a single engine monoplane, with a thick section cantilevered high wing, the first such design in the United Kingdom.
The type was ordered on 7th March 1921 by the Air Ministry for experimental long range trials. Although structurally successful, the aircraft was dogged by low-speed handling problems, combined with buffeting and vibration. It featured unswept wings (wooden structures covered with fabric) and a box section wooden fuselage with a single fin. The pilot and navigator sat in a high-up open cockpit positioned ahead of the wing with an enclosed passenger cabin.
The first prototype (J6849) flew on 5th July 1921, the first flight ending in a large diameter ground loop due to loss of low speed directional control.
Early in the types test career, the cockpit was raised to reduce the buffeting experienced by the flight crew. The engine was also raised in an attempt to improve directional control.
The resulting reduction in ‘head’ from the fuel tanks in the wing leading edge meant that a streamlined fuel header tank was required. This was added on the wing centreline, with a pair of wind-driven pumps to ensure continuity of fuel supply to the engine.
The prototype aircraft was modified prior to being despatched to Martlesham Heath for testing from September 1921.
The second aircraft (G-EAYO) was built as a ten-seat commercial aircraft in September 1921, although sadly it attracted very little interest from the airlines of the day so further production and development was abandoned. The aircraft was transferred to Martlesham Heath for trials from 9th November 1922. A military variant was proposed but this remained unbuilt.
In its final form, the DH29 was known as the De Havilland Doncaster and featured circular portholes rather than rectangular cabin windows and a rear gunner’s position.
|Powerplant||One 450 hp Napier Lion IB engine|
|Span||54 ft 0 in|
|Maximum Weight||7,500 lb|
|Capacity||Pilot and seats for ten passengers (civil).|
|Maximum Speed||116 mph at 10,000 ft|
|Cruising Speed||100 mph|
|Number built||Two aircraft only: J8649, J8650 / G-EAYO|