Airco DH.9

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De Havilland DH.9 preserved at the Musee de l'Air et de l'Espace, Paris Le Bourget
Photo from  Wikimedia Commons

Airco DH.9 was a British bomber ( with two-seater) derived from Airco DH.4
Designed to succeed the Airdo DH.4 the underpowered Airco DH.9 proved very disappointing. The device was then modified to allow a Liberty 12 engine, becoming Airco DH.9A. The Airco DH.9A was an essential instrument of British colonial policy in the 1920s.

The Airco  DH.4 just came on when Geoffrey de Havilland began development of its successor. As sometimes reproached DH.4 the position of the fuel tank located between the pilot and the gunner, which did not facilitate communication between two men, the fuselage was redesigned DH.4: The cockpit was postponed behind the cabin, before the reservoir. To improve forward visibility, which does not really taking advantage of the decline of the pilot, the radiator was mounted under the fuselage and the engine hood refined, with a engine partly outdoors. And this engine was none other than the B.H.P Galloway Adriatic, which should equip the DH.4. Developed by Beardmore-Halford-Pullinger, this engine was to develop in its standard version and 300 hp two-seater to ensure comfortable performance to compete with the German fighters. For the rest the DH.9 retained the wing and tail of its predecessor. So it was a classic biplane entoilée wooden structure and armament was identical to that of DH.4.

In early 1917, the German bombing of London led to the decision to double the size of the RFC, in particular to create a large fleet of bombers. The DH.9 having on paper excellent performance, with a cell similar to that of Airco DH.4, which facilitated the transfer of production to another, 4630 DH.9 were put in order, production was be distributed between ten manufacturers. The prototype, a modified DH.4, first flew at Hendon in July 1917. Unfortunately the BHP engine was a big disappointment. Very temperamental, it was necessary to limit the power to 230 hp continuous regime, which had very negative effects on the bomber performance, especially at altitude. The Airco DH.9 was slower than DH.4 he had to replace and it was not uncommon for the number of formations crossing the forehead significantly reduced simply because the engine power did not allow the aircraft keep training.

Repowering Attempts were therefore made: A lighter and more powerful version (on paper) of BHP Puma Armstrong-Siddeley engine of 230 hp also, but more reliable and a Fiat A12 engine and finally a Napier Lion 430 hp which posed problems of supply. None of these solutions will bring a satisfactory solution, it was necessary to resolve to redraw the tandem around a more reliable and powerful engine. Yet the mass production of DH.9 was continued until 1919, and the aircraft was not removed from the service by the RAF in 1920.

Information :

Country origin : British
Desihner : Geoffrey de Havilland
Introduction : in 1917
First flight ; in July 1917
Length :  9.27 m
Height ; 3.44 m
Wingspan : 12,92 m
Wing area : 40,32 m²
Powerplant: 1 × Siddeley Puma piston engine,172 kW
Top speed 178 km / h
Rise time to about 1980 m altitude : 10 min. 20 sec.
Ceiling : 4725 m
full tank ; about 700 km
Empty weight : 1012 kg
Max. Off mass : 1508 kg
Crew : 2 (a pilot / a bombardier)
Armament : 1 rigid forward-firing 7.7-mm-Vickers-MG, one or two 7.7 mm Lewis machine guns on the swivel head, 209 kg bombs

Countries of Militay Operators :

Greek AircoDH.9
 Kingdom of Hejaz
 New Zealand
Turkish Airco DH9 
Spain Kingdom of Spain
South Africa
Soviet Union
United Kingdom
United States

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