Gloster G.40 / E.28/39
In January 1930, Frank Whittle filed his first patent for the gas turbine engine. On April 12, 1937, the first Whittle engine, the Power Jets U.(1), ran on the test bench. In March 1938 the Air Ministry issued a contract for a single engine and on 3 February 1940 awarded Gloster a contract to produce the necessary airframe and further develop the aircraft under the specification E.28/39. Although the contract was seen as representing the operational requirements of a high-altitude interceptor, this aspect was not stressed, the main concern being to give special attention to the many new features associated with the installation of the turbojet engine.
The aircraft was designed by George Carter, Gloster's chief designer, and building of the aircaft began in great secrecy at Hucclecote but was soon moved to Regent Motors in Cheltenham as it was considered more secure. While the aircraft was being built its first engine the W1X was also under construction for use in the first taxi trials.
On the 7th April, 1941 W4041 the first E28/39 was moved to Hucclecote for taxi trials complete with a fake wooden propellor on the nose to disguise its uniqueness. The trials were successful with several hops being achieved of 100 - 200 yards even though the grass surface was not an ideal. Following these tests the aircraft was moved to RAF Cranwell for the fitting of the W1 flight engine, much lighter and constructed of higher quality materials to withstand prolonged operation.
The E.29/39 was a cantilever low-wing monoplane of all-metal construction with the single engine located in the fuselage aft of the pilot's cockpit. Air that passed through the nose orifice was channelled to pass each side of the cockpit to the engine.
The tricycle undercarriage built specially by Dowty was choosen by Carter to overcome potential problems raising the tail had the aircraft been fitted with a conventional undercarriage layout. They also decided to mount the engine in the middle of the aircraft behind the pilot with the jet pipe protruding from the back of the fuselage and fed from a bifurcated duct in the nose of the aircraft.
The first official flight took place with a 390-kg (860-lb) thrust W.1 engine from Cranwell on the evening of the 15th May 1941 as the weather earlier in the day was unsuitable. The pilot P.E.G Sayer took off after a ground run of about 600 yards after running the engine up to its maxium of 16,500 rpm. After he landed 17 minutes later he reported that he had found the aircraft to be incredibly quiet, vibration free and easy to control. Sayer flew the aircraft for a further 10 hours in the next 13 days at speeds of up to 370mph without any need to remove the engine covers including one flight of almost an hour with its maximum fuel load of 81 gallons and on another flight reached 25,000 feet. Subsequent development saw modifications made to the engine and airframe.
On 4 February 1942 the aircraft was flown with a 526-kg (1,160lb) thrust W.1A; on 30 July 1942, while flying with a 692-kg (1,526-1b) thrust Rover W.2B engine, the aircraft entered an inverted spin with jammed ailerons, forcing the RAE pilot to bale out.
In May 1943 W4041 was joined by W4046 fitted with the 771-kg (1,700-lb) thrust Power Jets W.2/500 turbojet, later boosted to 798kg (1,760-lb) thrust. This second aircraft though had a short life as it had to be abandoned in flight by Sqn Ldr Douglas Davie when the ailerons jammed at high altitude which gave him the distinction of being the first pilot to bail out of a jet aircraft in Britain, it crashed near Bramley in Surrey. W4041 remained at Farnborough and was involved in numerous tests culminating in the fitting of the Powerjets W500 engine which required stablizing fins to improve directional control. When W4041 was finally retired it was sent to the Science Museum in Kensington where it is displayed to this day.