NotesThe "Harkness Hornet" aero engine was designed, initially as air-cooled, by Don Harkness and built at his Sydney engineering works, Harkness & Hillier Ltd, Parramatta Road, Five Dock, New South Wales, in 1929. For its 'type' certificate test and aircraft use Harkness converted it to water-cooling by using the cylinder bank from a French-built Hispano-Suiza aero engine of 1914. This was a water-cooled V8 engine used in a number of allied aircraft during the First World War. To this cylinder bank he attached a crank case of his own design.
Donald (Don) James Harkness (1890-1972) was a well known Australian racing car driver and engineer. He was born in the inner-western Sydney suburb of Leichhardt and began his engineering career as a teenager repairing the Gnome aero engine fitted to the Bristol Boxkite of the early Australian aviator, William Ewart Hart. Just before WWI Harkness joined J. C. Hillier, a motor engineer, in Sydney and by 1921 was a full partner in Harkness & Hillier Ltd. For the next 40 years, this firm built a variety of stationary and marine engines, timber jinkers, gas producers and automotive components. The firm also made parts for the Australian Six automobile and in 1924 took over that enterprise.
The "Harkness Hornet" engine was to be used in the Genairco aircraft, a locally-built biplane made by the General Aircraft Co. who established a factory at Mascot Aerodrome, New South Wales in 1929. In all nine aircraft were built by the company between 1929 and their liquidation in 1933. The "Harkness Hornet" was used to test one of the early Genaircos VH-UOG, which was registered on 20 November 1930 and test flown by Captain E.W. Leggatt. (This aircraft is also in the Museum's collection, object number 2007/143/1). However, while the Hornet engine was considered to be good; its performance was comparable to readily available English engines, the fact that it was water-cooled complicated its installation in the Genairco relative to the ease of installation of an air-cooled engine and the English Cirrus and Gipsy engines were generally used in the production run instead. The Genaircos were significant because the General Aircraft Co. was the first to serial-build aircraft in Australia, made to an Australian design, rather than one-off models or aircraft made to an overseas design.
A "Harkness Hornet" was also fitted to the "Wonga" aircraft, designed by the Australian aeronautical engineer Leslie John Roberts Jones (1886-1970). After serving in the Australian Flying Corps during World War I, Jones worked for the aircraft manufacturer, A.V. Roe, in England before returning to Australia in 1921 and working with several early aviation companies. In 1927 he was commissioned to build an aircraft for the Australian market and an all-steel welded framework plane, named the "Wonga", was the result. It was successfully flown in test flights with a Curtiss OX-5 engine, but after storm damage in August 1930, it was rebuilt with a "Harkness Hornet" engine. A contemporary account of the design and construction of the aircraft appears in "The Australian Engineer", published on 6 December 1930 entitled, "An all steel aeroplane". It was read by Jones himself before the Institute of Engineers, Australia. (This paper is in the Museum's collection, object number P 2581). Unfortunately the "Wonga" crashed on 16 June 1932 killing both occupants, thus bringing the project to an end.
In 1933 Jones and T.D.J. Leech designed an aircraft to compete in the 1934 MacRobertson London to Sydney air race (MacRobertson International Air Races). The aircraft was to be powered by two high compression "Harkness Hornet" engines, each producing 150 hp. It was hoped that the project could be completed through public donations and the construction was begun in the sporting department of Grace Brothers department store in Sydney to ensure public awareness but insufficient public donations caused the end of the project.
MadeHarkness and Hillier Limited 1929
DesignedHarkness, Donald James null