Dunne D.8
| D.8 | |
|---|---|
 |
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| Dunne D.8 at Farnborough, 11 March 1914 | |
| Role | Experimental aircraft |
| National origin | United Kingdom |
| Manufacturer | Blair-Atholl Syndicate Ltd, London |
| Designer | J. W. Dunne |
| First flight | June 1912 |
| Primary users |
Royal Flying Corps US Signal Corps United States Navy Canadian Aviation Corps |
| Number built | 5 |
| Developed from | Dunne D.5 |
The Dunne D.8 of 1912 was one of a series of tailless swept wing biplanes, designed by J. W. Dunne to have inherent stability. One of the few built was the only Dunne aircraft to fly, albeit very briefly at RAE Farnborough, under Government ownership. Others were used by the US Signal Corps and United States Navy and the short-lived Canadian Aviation Corps. It was the latter's first and only warplane.
J. W. Dunne's first swept biplane wing aircraft, designed to have automatic stability, dated from his employment at the Balloon (later) Aircraft Factory at Farnborough during 1906–09. To preserve military secrecy testing was done at Blair Atholl in Scotland. After leaving Farnborough, Dunne set up a private company, the Blair-Atholl Syndicate Ltd. Its first aircraft was the Dunne D.5. When this crashed in 1911 it was rebuilt as the D.8. The two models shared very similar wings and the same engine, but the D.8 had a single pusher propeller instead of the chain-driven pair of the D.5. Their fuselages and undercarriages were also different.
The D.8 was a tailless four bay unstaggered biplane with its wings swept at 32°. Its constant chord wings were built up around two spruce spars, the forward one forming the leading edge. To help achieve stability the incidence and interplane gap decreased outboard, the former becoming negative. This washout on tips well behind the centre of gravity provided longitudinal stability in the same way as a conventional tailplane, set at lower incidence than the wings. Camber increased outwards. Simple, near parallel, pairs of interplane struts joined the spars. The outer interplane struts were enclosed with fabric, forming fixed side curtains that provided directional (yaw) stability. Wing tip elevons were used for control, operated by a pair of levers, one either side of the pilot. The D.8 initially used just a pair of these, mounted on the upper wing, a rectangular cutout in the side curtains allowing for their movement as on the D.5. Large parts of the aircraft were built by Short Brothers.
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