15th. May 1942 British Jet Engine plane

The Gloster E.28/39, (also referred to as the "Gloster Whittle", "Gloster Pioneer", or "Gloster G.40") was the first British jet-engined aircraft to fly. It was designed to test the Whittle jet engine in flight, leading to the development of the Gloster Meteor.

Design and development

In September 1939, the Air Ministry issued a specification to Gloster for an aircraft to test one of Frank Whittle's turbojet designs in flight. The E.28/39 name comes from the aircraft having been built to the 28th "Experimental" specification issued by the Air Ministry in 1939. The E.28/39 specification required the aircraft to carry two .303 Browning machine guns in each wing, but these were never fitted.

Gloster's chief designer George Carter worked closely with Whittle, and laid out a small low-wing aircraft of conventional configuration. The jet intake was in the nose, and the single tail-fin and elevators were mounted above the jet-pipe, although due to uncertainty about the spinning characteristics of a jet aircraft, at in an earlier design stage twin fins and rudders were considered. Two jet pipe/rear fuselage arrangements were also originally considered due to the potential loss of thrust through the jet pipe itself, a 'short jet' with a cutaway rear fuselage and short exhaust, and a 'long jet' with a fully enclosed jet pipe, however the 'long jet' was subsequently selected. A contract for two prototypes was signed by the Air Ministry on 3 February 1940, and the first of these was completed by April 1941. Manufacturing started at Brockworth near Gloucester, but was later moved to Regent Motors in Cheltenham High St (now the Regent Arcade) which was considered a location safer from bombing.

Testing the initial flight tests were relatively early in the Second World War, the German Heinkel He 178 had been first test-flown on 27 August 1939, at Rostock-Marienehe on the Baltic Coast, days before the outbreak of the war.

Statue in Coventry, England of Sir Frank Whittle observing the first British jet-powered flight

Plaque on base of the statue of Frank Whittle in Coventry, England

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. These included some short "hops" of about 6 ft in height from the grass airfield. With these initial tests satisfactorily completed, 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 r.p.m. turbine revolutions.^[1]

Over the following months, tests continued with increasingly refined versions of the engine. Later in the test program small, auxiliary fins were added near the tips of the tailplanes to provide additional stability in high-speed flight.^[2] 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.^[3]