Unique film of Britain's first Proto-Jet Aircraft, Whittle E28, 7th April 1941. Archive film 34011

Testing the new Whittle jet aircraft the E28 on an airfield during World War Two. Taxiing up and down. In flight. The E.28/39 was delivered to Brockworth for ground tests beginning on 7 April 1941, using a non-flightworthy version of the Power Jets W.1 engine. Some short 'hops' of about 6 ft in height from the grass airfield were made. The prototype was incapable of high-speed taxi runs because the jet engine was highly inefficient when moving at slow speeds. Raising the engine's governor from 12,000 rpm to 16,000 rpm more than tripled the ground speed that the prototype could attain. Following the completion of these ground tests, the aircraft was fitted with a flightworthy engine rated for 10 hours use, and then transferred to Cranwell which had a long runway. On 15 May 1941, Gloster's Chief Test Pilot, Flight-Lieutenant Gerry Sayer flew the aircraft under jet power for the first time from RAF Cranwell, near Sleaford in Lincolnshire, in a flight lasting 17 minutes. In this first series of test flights, a maximum true speed of 350 m.p.h. was attained, in level flight at 25,000 ft. and 17,000 turbine revolutions per minute. Tests continued with increasingly refined versions of the engine. Small, auxiliary fins were added near the tips of the tail-planes to provide additional stability in high-speed flight. John Grierson, in 1971, called these "end-plates" and wrote that their purpose was to increase the fin area due to the problem of rudder blanking in a side-slip. On 21 October 1942, Sayer disappeared during an acceptance test flight in a Hawker Typhoon, presumed killed in a collision and his assistant Michael Daunt took over testing of the E.28/39. The oil system had been changed before he flew; after it was proven, the aircraft was handed over to the RAE for testing by service pilots. The second prototype E.28/39 (W4046) - initially powered by a rover W2B engine - joined the test programme on 1 March 1943. Flying of W4046 was by Gloster test pilots John Grierson and John Crosby Warren, because Michael Daunt was then involved with the F.9/40 (later known as the Gloster Meteor) testing revealed problems with engine oil and lubricants. In April 1943, W4046 flew to Hatfield for a demonstration in front of the Prime Minister and members of the air Staff. It was taken to Farnborough and fitted with a 1,500 lbf (6.7 kN) W2.B and achieved 466 mph. On 30 July 1943, while on a high-altitude test flight, the second prototype was destroyed in a crash resulting from an failure. The accident was attributed to the use of the wrong type of grease in the aileron controls; one aileron had 'stuck in position, sending the aircraft out of control'. The test pilot, Squadron Leader Douglas Davie, bailed out from 33,000 ft, suffering on the way down. The first prototype was fitted with the 1,700 lbf (7.6 kN) thrust W2/500 and was flown to 42,000 ft, but level speed at altitude was not attempted due to fuel shortage. The pilot commented in his report on a need for cockpit heating and a larger fuel tank. The aircraft continued flight tests until 1944. By that time, more advanced turbojet-powered aircraft were available. The Gloster E.28/39 was later able to achieve high speeds, highest being 505 mph at 30,000 feet with a W.2/700 engine and it proved to be a capable experimental platform and exhibited a 'good climb rate and ceiling'. Experience with the E.28/39 paved the way for Britain's first operational jet, the Gloster Meteor. The Meteor was powered by the Rolls-Royce Welland engine, which was the next stage in development