Airco DH.5

The Airco DH.5 was a British First World War single-seat fighter aircraft designed specifically to replace the obsolete Airco DH.2. It was one of the first British fighter designs to include the improved Constantinesco gun synchronizer, which allowed a forward-firing machine gun to fire through the propeller faster and more reliably than the older mechanical gears. It was also one of the earliest biplanes to feature a marked "back-stagger" of its wings.

The DH.5 was inferior to other fighters already in production, and proved unpopular and unsatisfactory in service. It was replaced as soon as supplies of the S.E.5a permitted.

Design and development

Captain Geoffrey de Havilland designed the Airco DH.5 to combine the superior performance of a tractor biplane with the excellent forward visibility of a "pusher" type. The construction was that of a conventional tractor biplane of the time, but the main planes were given 27 inches of backward stagger, so that the lower wing was positioned forward of the upper wing. In the prototype armament installation, the forward-firing .303 in (7.7 mm) Vickers machine gun was either fixed to fire upward at an angle or possibly mounted so that its elevation could be adjusted in flight; in the production installation the gun was given a more conventional fixed mounting on top of the cowl, offset to the left, to fire in the line of flight. As the pilot was seated forward of the centre of gravity, the main fuel tank was necessarily behind the cockpit, below the oil tank. An auxiliary gravity fuel tank was fitted over the top main plane, offset to the right.