The De Havilland DH81 Swallow Moth was designed as a small, light-weight and low-power private aircraft which was intended as an affordable machine for the private owner. It was a plywood covered fueselage with a closely coweled engine bay to provide a very sleek appearance.
The DH81 sat pilot and passenger in open cockpits and featured a tapered low-set wing whilst power was provided by an 80 hp Gipsy IV inverted engine. It sat on a basic fixed undercarriage beneath the fuselage with a tailskid fitted at the rear.
Geoffery de Havilland flew the unregistered first prototype on 24th August 1931 and the test flying that followed demonstrated a maximum achievable speed of 117 mph. A series of significant modifications were introduced to the prototype, which was re-designated DH81A. The most apparent change was the introduction of a one-piece side-hinged canopy to enclose both occupants.
The wing centre section was increased in thickness and there were also changes to the fin and rudder geometry and these modifications helped increase the maximum speed to 129 mph. The DH81A subsequently flew with the class B markings E-7.
With valuable material resources needed for the production of standard moths, the project was set aside and no production was ever undertaken by the company.
The DH81 is regarded as being influential in the subsequent design of the DH94 Moth Minor (also a low wing monoplane of modest power).
|Powerplant||One 80 hp DH Gipsy IV inverted inline air cooled engine|
|Span||35 ft 6 in|
|Maximum Weight||1,330 lb|
|Capacity||Pilot and passenger|
|Maximum Speed||DH81 117 mph; DH81A 129 mph|
|Cruising Speed||100 mph|
Single unregistered prototype flown as DH81, modified with enclosed cockpit canopy as DH81A E-7.
Via email: Heritage@baesystems.com