De Havilland Hawk Moth

de Havilland

Industry	Aerospace
Founded	May 20, 1920 (1920-05-20)
Headquarters	London , United Kingdom

The de Havilland DH.75 Hawk Moth was a British four-seat cabin monoplane from the 1920s, constructed by de Havilland at the Stag Lane Aerodrome located in Edgware, London.

Design and development

The DH.75 Hawk Moth represented the inaugural model in a series of high-wing monoplane Moths, created primarily as a light transport or air-taxi intended for export markets. Its fuselage was built from steel tubing covered with fabric, while the wings were crafted from wood. The aircraft's maiden flight occurred on 7 December 1928 at Stag Lane Aerodrome. Initially, it was powered by a 200 hp (149 kW) de Havilland Ghost engine—essentially two de Havilland Gipsy engines combined within a single crankcase to form an air-cooled V-8 configuration. However, this powerplant proved insufficient, leading to the installation of a 310 hp (230 kW) Armstrong Siddeley Cheetah seven-cylinder radial engine in all but one of the completed units. Structural modifications accompanied this engine upgrade, including an increase in both wingspan and chord, resulting in the aircraft being reclassified as the DH.75A.

In December 1929, the prototype was showcased in Canada equipped with both wheel and ski landing gear. After conducting floatplane trials with the second unit, the Canadian government placed an order for three civil-use aircraft. The initial Canadian example (which was actually the original Hawk Moth) lacked port-side doors, preventing its operation as a floatplane; consequently, it was assigned to the Controller of Civil Aircraft. Further evaluations by de Havilland Canada during 1930 cleared the second and third aircraft for float operations. Due to payload limitations when fitted with floats, these Canadian models were primarily operated on skis or wheels. To rival American competitors, the eighth Hawk Moth was developed as the DH.75B, featuring a more powerful 300 hp (224 kW) Wright Whirlwind engine. Production ceased thereafter, leaving two airframes unfinished.

Operational service

Out of the five aircraft produced, three remained in Canada while the other two were shipped to Australia. One Australian example, VH-UNW (formerly G-AAFX), gained prominence when Amy Johnson used it in 1930 to travel from Brisbane to Sydney after her De Havilland Moth Jason was grounded due to damage. Major De Havilland subsequently piloted Miss Johnson from Sydney to Perth aboard this plane, from where she embarked on a sea voyage back to Britain. VH-UNW was eventually acquired by Hart Aircraft Service in Melbourne, primarily utilized for sightseeing flights.

In February 1934, the aircraft changed hands to Tasmanian Airways, receiving the name City of Hobart and operating routes between Brighton, Tasmania and Launceston, Tasmania. On 10 January 1935, a piston-rod failure forced an emergency landing at Brighton, rendering the engine irreparable. By mid-1936, the airframe, now without an engine, was sold to G. H. "Harry" Purvis who installed a Wright Whirlwind engine and resumed joy flight operations in New South Wales. Its final operator was Connellan Airways based in Alice Springs, with the aircraft being retired from active service in 1949.

Variants

DH.75

Initial prototype powered by a de Havilland Ghost V8 engine; only one built and later re-engined.

DH.75A

Main production model featuring an Armstrong Siddeley Lynx VIA radial piston engine; six units constructed.

DH.75B

Last production variant equipped with a 300 hp (224 kW) Wright R-975 Whirlwind radial engine; single example built. The DH.75A VH-UNW was upgraded to this specification in 1936.

Operators

Template:AUS

• Royal Australian Air Force

Canada

• Royal Canadian Air Force

Template:UK

• Royal Air Force

Specifications (D.H.75A (Landplane))

File:DH.75 Hawk Moth 3-view drawing NACA Aircraft Circular No.91.jpg

Three-view illustration of the De Havilland DH.75 from NACA Aircraft Circular No.91

See also

• List of de Havilland aircraft

References

• http://www.australianflying.com.au/news/the-de-havilland-dh-75-hawk-moth-in-australia