Country of origin:

Australia

Description:

Single-seat homebuilt monoplane

Power Plant:

One 20 kw (27 hp) Henderson four-cylinder air-cooled converted motor cycle engine

Specifications:

History:

The Gray Monoplane was designed by William Herbert Gray of Parramatta, NSW, a self taught engineer who, in 1928, designed and commenced construction of his own monoplane. To this end he obtained two patents in Australia and a number in other countries for his designs. Work proceeded for some years on construction but was delayed during World War II due to lack of necessary material, and the aircraft was placed in storage. In 1962 work re-commenced, but ceased again in 1964 due to the death of the designer/builder.

A scale model was constructed by the designer to prove his theories and at about the same time he prepared a set of drawings of a single-seat cantilever monoplane which would incorporate his theories and the ideas he had patented. Aircraft quality Sitka spruce and birch plywood were obtained in Sydney, NSW for the aircraft and some parts were built from high-grade steel. The fuselage was completed first and tyres and tubes were obtained from Goodyear Tyre Company for the spoked wheels. A screw-jack system for the variable wing incidence was designed and built. The construction of the wing was tapered box spars of spruce and plywood with two boxed centre-section ribs onto which were mounted the screw-jack variable incidence fittings.

Mr Gray commenced pilot training at Adastra Flying School at Mascot, NSW in 1931 but eventually stopped lessons and did not obtain a pilot’s licence.

Features of the design which were patented included: (1) a hand operated variable wing incidence control which could vary the angle of attack up to thirty degrees whilst in flight and reduce wing drag to a minimum; and (2) a pair of vertical rudders which operated normally and, when opened out into a “V” shape by pushing both pedals forward simultaneously, acted as an airbrake. Mr Gray considered that the features of his design would allow a steeper landing approach at a reduced speed of 42 km/h (26 mph) in still air; and also permit short take-off and landing runs.

The engine to be installed in the aircraft was never finalised, and a Szekely radial engine was considered but Mr Gray thought it did not provide enough power. He was also running tests on a 20 kw (27 hp) Henderson four-cylinder converted motor-cycle engine at one stage to increase its power output and this was expected to be installed.

In 1936 the Henderson engine was sold for installation in an aircraft Mr Darcy Shipman was building at Glenreagh, NSW and at this time the Gray aircraft was placed into storage. In 1962 he re-commenced work on the aircraft and redrafted his original drawings. In October 1963 he moved to Grafton, NSW and at this time was considering the installation of a converted Volkswagen engine. He died in 1964 before the aircraft was completed.

In November 1964 the aircraft was sold to Keith Campbell of Baulkham Hills, NSW who intended to complete the aircraft. This did not happen and eventually Dr Tony Fisher of Taren Point, NSW bought the aircraft and donated it to the Camden Museum of Aviation in 1968 where it was put on display.