|The first E.28/39 prototype W4041/G|
|National origin||United Kingdom|
|Manufacturer||Gloster Aircraft Company|
|First flight||15 May 1941|
|Primary user||Royal Aircraft Establishment (RAE)|
|Number built||2 prototypes|
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, in 1941. It was the third successful jet to fly after the German Heinkel He 178 (1939) and the Italian Caproni Campini N.1 (1940).
The E.28/39 was the product of a specification which had been issued by the Air Ministry for a suitable aircraft to test the innovative jet propulsion designs that Frank Whittle had been developing during the 1930s. Gloster, and the company's chief designer, George Carter, worked in close cooperation with Whittle to develop an otherwise conventional aircraft outfitted with a single Power Jets W.1 turbojet engine. Flying for the first time on 15 May 1941, a pair of E.28/39 aircraft were produced for the flight test programme. Following initial satisfactory reports, these aircraft continued for be flown to test increasingly refined engine designs and new aerodynamic features. Despite the loss of the second prototype, due to improper maintenance causing a critical aileron failure, the E.28/39 was considered to be a success.
The E.28/39 contributed valuable initial experiences with the new field of propulsion, and would directly lead to the development of the Gloster Meteor, the first operational combat-capable jet fighter to enter service with the Allies. The first prototype itself continued test flying until 1944, after which it was withdrawn from service; in 1946, it was transferred to the Science Museum in London, where it has been on static display ever since. In addition, multiple full-scale replicas have also been created.
The development of the turbojet-powered E.28/39 was the product of a collaboration between the Gloster Aircraft Company and Sir Frank Whittle's firm, Power Jets Ltd. Whittle formed Power Jets Ltd in March 1936 to develop his ideas of jet propulsion, Whittle himself serving as the company's chief engineer. For several years, attracting financial backers and aviation firms prepared to take on Whittle's radical ideas was difficult; in 1931, Armstrong-Siddeley had evaluated and rejected Whittle's proposal, finding it to be technically sound but at the limits of engineering capability. Securing funding was a persistently worrying issue throughout the early development of the engine. The first Whittle prototype jet engine, the Power Jets WU, began running trials in early 1937; shortly afterwards, both Sir Henry Tizard, chairman of the Aeronautical Research Committee, and the Air Ministry gave the project their support.
On 28 April 1939, Whittle made a visit to the premises of the Gloster Aircraft Company, where he met several key figures, such as George Carter, Gloster's chief designer. Carter took a keen interest in Whittle's project, particularly when he saw the operational Power Jets W.1 engine; Carter quickly made several rough proposals of various aircraft designs powered by the engine. Independently, Whittle had also been producing several proposals for a high-altitude jet-powered bomber; following the start of the Second World War and the Battle for France, a greater national emphasis on fighter aircraft arose. Power Jets and Gloster quickly formed a mutual understanding around mid-1939.
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 designation originates from the aircraft having been developed in conformance with the 28th "Experimental" specification issued by the Air Ministry in 1939. The E.28/39 specification required the aircraft to carry a pair of 0.303 in (7.62 mm) Browning machine guns in each wing, along with 2,000 rounds of ammunition, but these were never fitted. The second paragraph of the contract for the first aeroplane stated: "The primary object of this aeroplane will be to flight test the engine installation, but the design shall be based on requirements for a fixed gun interceptor fighter as far as the limitations of size and weight imposed by the power unit permit. The armament equipment called for in this specification will not be required for initial trials but the contractor will be required to make provision in the design for the weight and space occupied by these items..."
Early on, 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 located in the nose, while 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 an earlier design stage an alternative arrangement using twin fins and rudders was considered. A pair of 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, necessitating the tailplane to be carried on booms, and a 'long jet' with a fully enclosed jet pipe; the 'long jet' was subsequently selected. On 3 February 1940, a contract for two prototypes was signed by the Air Ministry.
Manufacturing work on the E.28/39 commenced at Brockworth near Gloucester, activity was later relocated to Regent Motors in Regent Street, Cheltenham (now the site of Regent Arcade), which was considered a location safer from bombing. Whittle was dissatisfied with the speed at which production took place, which was likely impacted by the ongoing Battle of Britain as the area around nearby Coventry was subject to high levels of German bomber activity. In April 1941, the first of the E.28/39 prototypes was completed; however, at this time, a flight-worthy W.1A engine was not available for the aircraft to be fitted with, thus a non-flight capable W.1X unit was assembled and installed instead.
While only a pair of prototypes had been ordered, from the onset, the operational philosophy was that, once the prototypes had proved the capabilities of the design in successful flight testing, a more substantial programme would then be cleared to proceed with; even prior to the E.28/39's first flight being conducted, this 'production' combat aircraft had been envisioned as being a considerably more elaborate twin-engined design that would incorporate all of the equipment necessary to produce a viable fighter-calibre combat aircraft. This aircraft, also produced by Gloster, would ultimately emerge as the Meteor, the first production jet-propelled aircraft to enter service with the Allies.
The E.28/39 was a low-wing monoplane, specifically developed to harness and trial the newly developed jet engine. It was described as possessing a slightly tubby appearance as a result of a round fuselage. Due to the elimination of any risk that would have been posed by conventional propeller tips striking the ground, the E.28/39 could be outfitted with an unusually short undercarriage for the era. It was outfitted with a retractable undercarriage, which was actuated via a hydraulic accumulator, which had a manually-operated hand-pump to serve as a backup. An emergency compressed air arrangement was also present. The flaps were also hydraulically-actuated, driven direct by the manual hand-pump. Unusually, the nosewheel was steerable by the rudder, which aided in ground maneuvering.
The E.28/39 was powered by a single Power Jets W.1 turbojet engine, which was installed behind the pilot and the fuel tank. The engine's exhaust was directed through the centre of the fuselage, the jetpipe terminated about two feet behind the rudder. A nose air-intake led the air through bifurcated ducts around the cockpit. A single fuel tank, containing up to 82 Imp gal, was located directly behind the pilot's position; this location has been alleged to have been adopted as a countermeasure against the impact of negative g, which posed the risk of causing the engine to flame out, which in turn suffered from re-lighting difficulties during flight.
The E.28/39 lacked features that would be considered key to an active combat fighter, such as the lack of radio sets. The original engine was started by an Austin Seven car engine, which was connected by a flexible drive; later on, this arrangement was replaced by an electronic starter system that used a ground booster battery instead. The cockpit, which was accessed by a sliding canopy, lacked pressurisation or any form of climate control, such as heating systems. While pilots were intended to wear electrically-heated flight suits, the lack of an onboard generator and limited battery capacity, the latter being prioritised towards the automated sensors and recording devices that captured the results of each flight, this was not possible and pilots had to put up with the cold conditions throughout a given flight.
One of the pilots of the E.28/39, John Grierson, stated of his experiences of flying the aircraft: "The main impressions of my first jet-propelled flight were first of the simplicity of operation. The throttle was the only engine control; there were no mixture or propeller levers, supercharger or cooling-gill controls and the fuel system had simply one low-pressure valve between the tank and the engine pump, and one high-pressure valve between the pump and the engine. There was no electric booster pump. Secondly the absence of vibration or the sensation of effort being transmitted to the pilot's seat was outstanding." He also stated his opinion of the type: "The very favourable impressions of jet propulsion obtained ... have all been endorsed by subsequent flights ... The E.28 is a most pleasant little aeroplane to handle, particularly on account of the excellent field of vision from the pilot's seat ... "
Although 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.
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. Initial taxiing performance was unsatisfactory, being incapable of performing high speed taxi runs; this was a product of the jet engine being highly inefficient when moving at slow speeds. The issue was rapidly rectified by raising the engine's governor from 12,000 rpm to 16,000 rpm, which had the effect of more than tripling the ground speed that the prototype could attain.
Following the successful 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.
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. 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. Testing had revealed problems with engine oil and lubricants. 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). 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. It 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 aileron 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, successfully bailed out from 33,000 ft, suffering frostbite on the way down.
The first prototype was fitted with the 1,700 lbf (7.6 kN) thrust W2/500. It was flown successfully 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. It 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 fighter aircraft, the Gloster Meteor. The Meteor was powered by the Rolls-Royce Welland engine, which was the next stage in development from the Power Jets W.1.
In 1946, the first prototype (W4041) was placed in the Science Museum in Central London, where it is exhibited today in the Flight Gallery. A full-size replica has been placed on an obelisk on a roundabout near the northern perimeter of Farnborough Airfield in Hampshire, as a memorial to Sir Frank Whittle. A similar full-size model is on display in the middle of a roundabout at Lutterworth in Leicestershire, where the aircraft's engine was produced.
A full-scale model taken from the same moulds, with authentic paint scheme and detailing, has been built by members of the Jet Age Museum in Gloucestershire. It has recently been on display in Brockworth, Gloucester, Kemble (at both the Kemble Air Day and the MVT Show), and formed part of the display for the Sir Frank Whittle Centenary commemorations at RAF Cranwell in June 2007.
Specifications (Gloster E.28/39)
Data from
- Crew: One
- Length: 25 ft 4 in (7.74 m)
- Wingspan: 29 ft 0 in (8.84 m)
- Height: 8 ft 10 in (2.70 m)
- Wing area: 146 ft² (13.6 m²)
- Airfoil: G.W.2-section
- Empty weight: 2,886 lb (1,309 kg)
- Loaded weight: 3,748 lb (1,700 kg)
- Fuel capacity: 81 gallons
- Powerplant: 1 × Power Jets W.1 turbojet, 860 lbf (3.8 kN)
- Maximum speed: 338 mph (544 km/h) at 10,000 ft (3,050 m)
- Range: 410 mi (656 km)
- Endurance: 56 minutes
- Service ceiling: 32,000 ft (9,755 m)
- Rate of climb: 1,063 ft/min (5.9 m/s)
- Thrust/weight: 0.21
- Guns: None fitted but provision for four 0.303 in (7.7 mm) Browning machine guns
- Bell P-59A – first US jet fighter design
- Gloster E.1/44 – Gloster's third jet design to fly
- Gloster Meteor – first British jet fighter to see combat in the Second World War.
- Heinkel He 178 – world's first flying turbojet aircraft.
- Heinkel He 280 – first turbojet-powered fighter design
- Lockheed P-80 Shooting Star – first US operational jet-fighter aircraft.
- Messerschmitt Me 262 – world's first operational jet fighter.
- Related lists
- Flight 11 May 1951, p. 553.
- Pavelec 2007, pp. 45–46.
- Pavelec 2007, pp. 43–44.
- Golley and Gunston 2010, pp. 92–94.
- Pavelec 2007, pp. 48–50.
- Golley and Gunston 2010, p. 139.
- Golley and Gunston 2010, pp. 156, 165.
- Golley and Gunston 2010, p. 127.
- Flight International 13 May 1971, p. 677.
- Grierson, John. Jet Flight. London: Sampson Low, Marston and Co. Ltd, 1946.
- Flanagan 2017, p. 35.
- Flanagan 2017, p. 39.
- Jackson 2007, p. 119.
- Flight International 13 May 1971, pp. 677-678a.
- Flight International 13 May 1971, pp. 678-678a.
- Flight 27 October 1949, p. 557.
- Flight International 13 May 1971, pp. 677–678.
- Flight International 13 May 1971, p. 678.
- T.N.A. AIR62/42/198
- Flight International 13 May 1971, p. 678a.
- Winchester 2005, p. 83.
- Flight International 13 May 1971, p. 679.
- Grierson, ibid.
- Flight 1949
- Flight 11 May 1951, p. 554.
- Blackburn, Robert J. "No Airscrew Necessary..." Flight, 27 October 1949. pp. 553–558.
- "Britain's Turbine Aircraft." Flight, 11 May 1951. pp. 553–554.
- Flanagan, William A. Aviation Records in the Jet Age: The Planes and Technologies Behind the Breakthroughs. Specialty Press, 2017. ISBN 1-58007-230-5.
- Golly, John and Bill Gunston. Jet. Eloy Gutierrez, 2010. ISBN 1-907472-00-2.
- Grierson, John. "Britain's First Jet Aeroplane." Flight International, 13 May 1971. pp. 677–679.
- Jackson, Robert. Britain's Greatest Aircraft. Pen and Sword, 2007. ISBN 1-84415-600-1.
- James, Derek N. Gloster Aircraft since 1917. London: Putnam, 1987. ISBN 0-85177-807-0.
- Mondey, David. The Hamlyn Concise Guide to British Aircraft of World War II. London: Chancellor Press, 1994. ISBN 1-85152-668-4.
- Morgan, Eric B. "A New Concept of Flight." Twentyfirst Profile, Vol. 1, No. 8. New Milton, Hantfordshire, UK: 21st Profile Ltd. ISSN 0961-8120.
- Pavelec, Sterling Michael. The Jet Race and the Second World War. Westport, Connecticut: Greenwood Publishing, 2007. ISBN 0-275-99355-8.
- Swanborough, Gordon. British Aircraft at War, 1939–1945. East Sussex, UK: HPC Publishing, 1997. ISBN 0-9531421-0-8.
- Winchester, Jim. X-Planes and Prototypes. London: Amber Books Ltd., 2005. ISBN 1-904687-40-7.
|Wikimedia Commons has media related to Gloster E.28/39.|
- Meteor Flight
- Model replica
- "E.28/39 Fin Arrangement and Spinning Characteristics" a 2012 JAH paper on the E.28/39