Major Frank Halford's radical concept of mating two Gipsy I engines into a common crankcase produced a 198 hp V-8 engine known nowadays as the DH Ghost.
Once this was achieved the DH75 prototype (G-EBVV) was then designed around this new engine and it flew from Stag Lane for the first time on 7th December 1928.
Better known as the Hawk Moth, the DH75 was a strut-braced, high-wing monoplane with a welded steel fuselage and a somewhat ungainly undercarriage arrangement, reminiscent of that adopted by a number of similar American aircraft of the same period. The wing planform was very similar to that adopted for the later DH80 Puss Moth.
However, it was immediately apparent that the type was underpowered, so it was redesigned as the DH75A which featured an increased wing span and chord, powered by the 240 hp Armstrong Siddeley Lynx engine.
In December 1929 the aircraft was demonstrated in Canada, fitted with both wheel and ski undercarriages.
Later, it was demonstrated with floats which resulted in the Canadian Government ordering 3 aircraft. The first aircraft (actually the first Hawk Moth) did not have portside doors so it could not be fitted with floats and so it was utilised by the Canadian Controller of Aircraft.
Whilst the second and third aircraft were cleared for use with floats, the restrictions on their payload made them unsuitable and so they were fitted with either wheels or skis.
Two aircraft were built and exported to Australia and Amy Johnson used one of these to fly from Brisbane to Sydney in 1930 after her DH60 Gipsy Moth 'Jason' sustained damage on landing in Darwin.
One DH75A was entered in the 1930 King’s Cup Air race, being placed seventh at an average speed of 126.2 mph.
In an attempt to compete with U.S. built aircraft, a DH75B was produced in May 1930 with a 300 hp Wright Whirlwind engine although production never commenced leaving 2 incomplete airframes.
In total, only eight aircraft were completed, comprising the prototype DH75, six DH75A and the single DH75B.
Variants & Numbers built
|DH75||One only G-EBYY with 198hp DH Ghost engine|
|DH75A||Six aircraft, 240hp Armstrong Siddeley Lynx engine|
|DH75B||One unregistered prototype, 300hp Wright Whirlwind engine|
|DH75A Hawk Moth|
|Powerplant||One 240 hp Armstrong Siddeley Lynx VIA seven cylinder radial engine|
|Span||47 ft 0 in|
|Maximum Weight||3,650 lb|
|Capacity||Pilot and three passengers.|
|Maximum Speed||127 mph|
|Cruising Speed||105 mph|