De Havilland DH.88 - Design and Development

Design and Development

Despite previous British air racing successes, culminating in 1931 in the outright winning of the Schneider Trophy, there was no British aeroplane capable of putting up a challenge over the MacRobertson course with its long overland stages. The de Havilland company stepped into the breach by offering to produce a limited run of 200 mph (322 km/h) racers if three were ordered by February 1934. The sale price of £5,000 each would by no means cover the development costs. In 1935, de Havilland suggested a high-speed bomber version of the DH.88 to the RAF, but the suggestion was rejected. (Later, de Havilland developed the de Havilland Mosquito along similar lines as the DH.88 for the high-speed bomber role.)

Three orders were indeed received, and de Havilland set to work. The airframe consisted of a wooden skeleton clad with spruce plywood, with a final fabric covering on the wings. A long streamlined nose held the main fuel tanks, with the low-set central two-seat cockpit forming an unbroken line to the tail. The engines were essentially the standard Gipsy Six used on the Express and Dragon Rapide passenger aircraft, tuned for best performance with a higher compression ratio. The propellers were two-position variable pitch, manually set to fine before takeoff using a bicycle pump and changed automatically to coarse by a pressure sensor. The main undercarriage retracted upwards and backwards into the engine nacelles. The DH.88 could maintain altitude up to 4,000 ft (1,200 m) on one engine.

With de Havilland managing to meet the challenging production schedule, testing of the DH.88 began six weeks before the start date of the race. On the day of the race, the three distinctively-coloured aircraft took their places among 17 other entrants ranging from a new Douglas DC-2 airliner to two converted Fairey Fox bombers.