The Gloster E.28/39 was the first British aircraft to be powered by a jet engine, making its maiden flight in 1941. As such it represented a momentous breakthrough for British aviation, and would eventually lead to the development of the Gloster Meteor, the first operational British jet aircraft.
The Gloster E.28/39 was built around Sir Frank Whittle’s experimental W.1 jet engine. Whittle had been working on the gas turbine jet engine since 1930, but had failed to gain official support. In 1936 he had finally raised enough capital to found Power Jets Ltd, where work began on the U-type engine. This featured a centrifugal compressor and a single large combustion chamber, and made its first test run in April 1937, in what was the first ever running of an aircraft turbine engine.
In 1939, with war approaching, Whittle finally got official approval (and funding) to develop a jet engine for flight. This led to the W.1 engine, which featured a centrifugal compressor and ten small combustion chambers. Test versions of this engine were already up and running by September 1939, when the Gloster chief designer George Carter visited Power Jets. He was not impressed by this early engine, which produced around 400lb of thrust, made a horrific noise and ran so hot that some parts of the metal glowed red. Over the next year Whittle and his team would refine this early engine, with the final W.1 producing 860lb of thrust for take off during the official first flights in May 1941.
Carter was visiting Power Jets because Gloster had been chosen to produce the aircraft to go around the engine. One of his most recent designs had been the twin-boomed F.18/37, designed as a possible replacement for the Spitfire and Hurricane. That particular contract went to Hawker, where it produced the Typhoon, but Carter’s design was similar to one of Whittle’s ideas for a possible jet aircraft. Frank Whittle visited the Gloster works on 29 April 1939, where he examined the F.18/37, where he began to establish a good working relationship with Carter. In September 1939 the Air Ministry officially asked Gloster if they would be willing to design a jet-propelled aeroplane, and work began on the new jet.
The twin boom design was soon abandoned. The main problem with it was that the exhaust jet would pass directly over the tail surfaces, with unknown effects. Carter then suggested a canard layout, with the wings at the back and the “tail” at the front, a layout used on a number of modern high performance aircraft, amongst them the Eurofighter Typhoon. Power Jets rejected this design as too radical.
The final design adopted for the E.28/39 was much more conventional. The aircraft was a mid-winged monoplane, with the pilot in front of the wing spar and the engine behind it. The air intake was in the nose, with the cold air passing by the sides of the cockpit on its way to the compressor. The jet pipe was built into the fuselage, emerging just behind the conventional tail assembly. The only unusual feature of the aircraft design was the use of a tricycle undercarriage, with the third wheel in the nose rather than in the tail. The E.28/39 was the first British single seat aircraft to use this form of undercarriage. Carter and his team were still faced with some tricky problems, caused by the new engine. The intense heat created by the jet engine meant that the rear fuselage was likely to expand far more than normal. The control surfaces needed to be larger than on a propeller driven engine.
The first formal specification for the aircraft, E.28/39, was issued to Gloster on 13 February 1940. This called for an aircraft capable of reaching 380mph at sea level, and of carrying four Browning machine guns. During 1940 this specification was modified twice, by Corrigendum No.1 of 7 June 1940, and Issue II of 27 December 1940. These saw the guns deleted and a radio added, and were prompted by a realisation that the Whittle W.1 engine was unlikely to provide enough power to carry a useful military load.
The new aircraft were given a number of different names. Officially it was the Gloster E.28.39, often shortened to the E.28. It was also known as the Gloster Whittle, or the GW for short, the Pioneer, the Squirt and the Weaver. Two aircraft were to be built, with serial numbers W4041 and W4046. These aircraft would be given the codenames Tourist 1 and Tourist 2 during trials at Edge Hill.
Work on the fuselage frames was completed by 8 July 1940. Work then began on the metal covering, while work on the wings was well underway. The threat of German bombing then forced the British aircraft industry to disperse. Gloster moved the two E.28s from their main plant at Brockworth to Regent Motors, Cheltenham, where work on the fuselage continued. Finally, in early 1941 they were ready to be moved back to Brockworth.
Work on the engines was also progressing well. In November 1940 Power Jets put together a loosely built version of the engine, the W.1X, which was used to help assemble the airframe. They also began work on a second W.1X that would be suitable for the airframe chassis trails and taxi tests and the W.1 flight engine itself.
The first E.28, W4041, was ready for chassis trials in March 1941. The taxi test W.1X engine was installed, and on Sunday 6 April the first engine run was carried out in the hanger at Brockworth, with the jet pipe sticking out of the hanger doors. On this occasion the engine ran for ten minutes in its first run and eleven in its second.
On the following day, Monday 7 April, the E.28 made its first short taxi tests. The engine was restricted to 13,000rpm. The aircraft began to move when the engine reached 10,000rpm. It demonstrated poor acceleration but good steering, before it the aircraft was moved back to the hanger to prepare for longer tests on the following day.
On the morning of 8 April 1941 the second taxi test were performed. This time the engine was restricted to 15,000rpm, and the aircraft moved more freely. During these taxi tests Frank Whittle had a short spell at the controls, which was captured on film.
On the afternoon of 8 April the engine power was increased again, this time to 16,000rpm. Jerry Sayer, Gloster’s chief test pilot, took the controls, making three runs. On all three runs the E.28/39 left the ground, reaching a height of six feet above the ground, and flying for 100-200 yards. The E.28/39 had made its first flight.
The first official flight came on 15 May 1941, at Cranwell. The aircraft had been transported to Cranwell on 4 May. By this time the W.1X engine had been replaced by the W.1 flight engine, and the over-sensitive throttle corrected. On 14 May the E.28 made its first taxi test with the new engine.
On 15 May 1941 the E.28 made its first proper flight. The aircraft took off at 19.40 and landed at 19.57, after a flight of 17 minutes, again with Jerry Sayer at the controls. Between 15 and 28 May, the E.28/39 made seventeen flights, logging 10 hours 28 minutes of flying time, including an official demonstration on 21 May in front of the Secretary of State for Air.
By the time the E.28 made its first flights, work had already begun on its successor, the Gloster Meteor. It had been realised that the early Whittle engines did not offer enough power for military aircraft, and so a twin engined design was adopted for the new aircraft. Once again George Carter would lead the early design team.
This did not end the useful life of the E.28/39. Having proved that it was indeed possible to build a jet powered aircraft, the two E.29s were then used as test beds for further development. Tragically Jerry Sayer was killed on 21 October 1942, while flying a Hawker Typhoon. He was followed as test pilot by his former deputy, Michael Daunt, and by Group Captain H.J. Wilson, the chief test pilot at the Royal Aircraft Establishment, Farnborough. A dedicated airfield was created at Edge Hill, where W4041 was used to test new versions of the W.1 engine, as well as testing the W.2/500/3 engine in 1942. It was also used to familiarise new pilots with jet aircraft and made its last flight on 20 February 1945. It is now on display in the Science Museum in South Kensington.
The second W.28, W4046, had a much shorter life. It did not make its first flight until 1 March 1943, nearly two years after the W4041, powered by a W.2B/110 engine. On 17 April 1943 the W4046 made the first cross country jet flight, from Edge Hill to Hatfield, where on 19 April it was demonstrated to Winston Churchill, before returning to Edge Hill on 20 April.
From 3 May until 30 July 1943 W4046 was operated by the RAE at Farnborough, making a total of 111 flights in that time. It actually made more flights in five months than the W4041 did in four years. On 30 July, while being flown by Squadron Leader Douglas Davie, the commanding officer of the RAE’s turbine flight, the ailerons jammed at 37,000ft during a turn to the right. The aircraft flipped over, and the jet engine flamed out. The canopy broke open and Davie was thrown clear of the aircraft. He had to free-fall for the first 20,000 feet before he reached a height were he could open his parachute, suffering from frostbite during the fall. The aircraft itself was destroyed in the crash.