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__NOTOC__ The Dunne D.5 was a British experimental aircraft built in 1910. A tailless swept-wing
biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...
, it was designed by
J. W. Dunne John William Dunne (2 December 1875 – 24 August 1949) was a British soldier, aeronautical engineer and philosopher. As a young man he fought in the Second Boer War, before becoming a pioneering aeroplane designer in the early years of the 20th ...
and built by
Short Brothers Short Brothers plc, usually referred to as Shorts or Short, is an aerospace company based in Belfast, Northern Ireland. Shorts was founded in 1908 in London, and was the first company in the world to make production aeroplanes. It was particu ...
at Leysdown for his company, the Blair Atholl Aeroplane Syndicate Ltd. Like its military predecessors it was driven by twin
pusher propeller In an aircraft with a pusher configuration (as opposed to a tractor configuration), the propeller(s) are mounted behind their respective engine(s). Since a pusher propeller is mounted behind the engine, the drive shaft is in compression in nor ...
s, but it had a considerably more powerful
engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...
. The D.5 first flew in the summer of 1910, thus becoming his first powered aeroplane to fly. Dunne had long ago literally dreamed of this flight. The D.5 was later certified as the first fixed-wing aircraft ever to achieve natural stability in flight, with one of the official witnesses being Orville Wright.


Design and development

On leaving the
Army Balloon Factory The Royal Aircraft Establishment (RAE) was a British research establishment, known by several different names during its history, that eventually came under the aegis of the Ministry of Defence (United Kingdom), UK Ministry of Defence (MoD), bef ...
at Farnborough in 1909,
J. W. Dunne John William Dunne (2 December 1875 – 24 August 1949) was a British soldier, aeronautical engineer and philosopher. As a young man he fought in the Second Boer War, before becoming a pioneering aeroplane designer in the early years of the 20th ...
set up the Blair Atholl Aeroplane Syndicate Ltd., to continue developing his unusual tailless swept-wing aircraft, none of which had yet flown under power. The D.5 was his first design for them and it followed the general layout of the earlier D.4 Army machine in having a tailless, swept biplane wing with pronounced wash-out and endplates, and driven by twin pusher propellers. However it differed in having a streamlined central nacelle or fuselage housing the pilot and engine. The control surfaces were, like the wing, similar to the D.4.
Elevon Elevons or tailerons are aircraft control surfaces that combine the functions of the elevator (used for pitch control) and the aileron (used for roll control), hence the name. They are frequently used on tailless aircraft such as flying wings. ...
s on the upper wing tips were the only movable surfaces. However on the D.5 they were operated independently by two levers on either side of the cockpit. There was no rudder, with turning being coordinated by the aerodynamic design of the swept and washed-out wings. Unlike most aircraft, they were arranged such that raising an elevon both reduced lift and increased drag, while lowering it had the opposite effects. Thus, the wing being lowered would be dragged back (a phenomenon known as proverse yaw), automatically coordinating a banking turn. Endplate fins were fitted to the wings to improve efficiency, with square cutouts to avoid fouling the elevons. Construction of the main airframe was contracted to
Short Brothers Short Brothers plc, usually referred to as Shorts or Short, is an aerospace company based in Belfast, Northern Ireland. Shorts was founded in 1908 in London, and was the first company in the world to make production aeroplanes. It was particu ...
, who occupied sheds alongside the Syndicate's at the
Aero Club of Great Britain The Royal Aero Club (RAeC) is the national co-ordinating body for air sport in the United Kingdom. It was founded in 1901 as the Aero Club of Great Britain, being granted the title of the "Royal Aero Club" in 1910. History The Aero Club was fou ...
's new flying ground at Shellbeach on the
Isle of Sheppey The Isle of Sheppey is an island off the northern coast of Kent, England, neighbouring the Thames Estuary, centred from central London. It has an area of . The island forms part of the local government district of Swale. ''Sheppey'' is derived ...
. The engine was a Green C.4 35 hp water-cooled, four-cylinder inline type, significantly more powerful than those the Army had allowed. Twin radiators were fitted on either side, standing up and aligned with the airflow in order to minimise drag. The mid-mounted engine chain-drove twin pusher propellers, mounted on outriggers behind the wing. As before, the propellers rotated in opposite directions to cancel out their torque. Following construction at Leysdown, the D.5 was taken to Eastchurch, the new site of the (now Royal) Aero Club and the Syndicate located a short distance away on Sheppey. Early trials were not encouraging, with the machine in its original form proving too heavy. Dunne undertook extensive lightening to Short's construction.


Operational history

The D.5 first flew in the summer of 1910. Dunne taxied it to the top of a rise in the ground which lay downwind, turned the machine and took off downhill into the wind. He later recalled in his book ''
An Experiment with Time ''An Experiment with Time'' is a book by the British soldier, aeronautical engineer and philosopher J. W. Dunne about his precognitive dreams and a theory of time which he later called "Serialism". First published in March 1927, the book was ...
'' that, as a child, he had experienced exactly this flight in a dream.Constance Babington Smith; ''Testing Time'', Pages 11-17. The D.5 proved to be aerodynamically stable in flight. Two demonstration flights were made for the
Royal Aero Club The Royal Aero Club (RAeC) is the national co-ordinating body for air sport in the United Kingdom. It was founded in 1901 as the Aero Club of Great Britain, being granted the title of the "Royal Aero Club" in 1910. History The Aero Club was foun ...
in December 1910, officially witnessed by the visiting Orville Wright and by
Griffith Brewer Griffith Brewer (23 July 1867–1 March 1948)Penrose 1967, p.575 was an English balloonist, aviator and patent agent. He was also a founding member of the Royal Aero Club. He became a friend of the Wright Brothers, and was one of their mai ...
. During the second flight, Dunne took his hands off the controls for an extended period, while he wrote a note on a piece of paper provided for him by Brewer. This note was the first ever documentary evidence of an aircraft's performance written in flight by the pilot himself. The D.5 was subsequently certified as the first fixed-wing aircraft ever to achieve stable flight. That December, the D.5 was crashed by another pilot, and parts of it would be re-used to build the first D.8.


Specifications


References

;Notes ;Bibliography * * {{Dunne aircraft 1910s British experimental aircraft Dunne aircraft Tailless aircraft Biplanes Single-engined twin-prop pusher aircraft Aircraft with counter-rotating propellers Aircraft first flown in 1910