Gloster E.28/39

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IWM-CH14832A Gloster E28-39 205210674.jpg
The first E.28/39 prototype W4041/G
RoleExperimental prototype
National originUnited Kingdom
Manufacturer Gloster Aircraft Company
Designer George Carter
First flight15 May 1941 [1]
Primary user Royal Aircraft Establishment (RAE)
Number built2 prototypes [1]

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 and first flew in 1941. It was the third jet to fly after the German Heinkel He 178 (1939) and the Italian Caproni Campini N.1 motorjet (1940).

Jet aircraft aircraft propelled by jet engines

A jet aircraft is an aircraft propelled by jet engines.

Heinkel He 178 Experimental jet aircraft

The Heinkel He 178 was the world's first aircraft to fly under turbojet power, and the first practical jet aircraft. It was a private venture by the German Heinkel company in accordance with director Ernst Heinkel's emphasis on developing technology for high-speed flight. It first flew on 27 August 1939, piloted by Erich Warsitz. This flight had been preceded by a short hop three days earlier.

Caproni Campini N.1

The Caproni Campini N.1, also known as the C.C.2, was an experimental jet aircraft built in the 1930s by Italian aircraft manufacturer Caproni. The N.1 first flew in 1940 and was briefly regarded as the first successful jet-powered aircraft in history, before news emerged of the German Heinkel He 178's first flight a year earlier.


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 novel jet propulsion designs that Frank Whittle had been developing during the 1930s. Gloster and the company's chief designer, George Carter, worked with Whittle to develop an otherwise conventional aircraft fitted with a 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 to 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.

Air Ministry former department of the British Government

The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964. It was under the political authority of the Secretary of State for Air.

Frank Whittle British Royal Air Force engineer air officer

Air Commodore Sir Frank Whittle, was a British Royal Air Force air officer. He is credited with single-handedly inventing the turbojet engine. A patent was submitted by Maxime Guillaume in 1921 for a similar invention; however, this was technically unfeasible at the time. Whittle's jet engines were developed some years earlier than those of Germany's Hans von Ohain who was the designer of the first operational turbojet engine.

George Carter (engineer) British engineer

Wilfred George Carter CBE FRAeS was a British engineer, who was the chief designer at Glosters from 1937. He was awarded the C.B.E. in 1947 and was appointed Technical Director of Gloster Aircraft in 1948 remaining on the board of directors until 1954. He continued to serve Glosters for a number of years after his retirement in a consultancy role until 1958. He designed the first recognised jet aircraft.

The E.28/39 contributed valuable initial experience with the new type of propulsion and led to the development of the Gloster Meteor, the first operational jet fighter to enter service with the Allies. The first prototype 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; full-scale replicas have been created.

Gloster Meteor fighter aircraft family; Britains first jet fighter

The Gloster Meteor was the first British jet fighter and the Allies' only jet aircraft to achieve combat operations during the Second World War. The Meteor's development was heavily reliant on its ground-breaking turbojet engines, pioneered by Sir Frank Whittle and his company, Power Jets Ltd. Development of the aircraft began in 1940, although work on the engines had been under way since 1936. The Meteor first flew in 1943 and commenced operations on 27 July 1944 with No. 616 Squadron RAF. The Meteor was not a sophisticated aircraft in its aerodynamics, but proved to be a successful combat fighter. Gloster's 1946 civil Meteor F.4 demonstrator G-AIDC was the first civilian-registered jet aircraft in the world.

Science Museum, London science museum in London

The Science Museum is a major museum on Exhibition Road in South Kensington, London. It was founded in 1857 and today is one of the city's major tourist attractions, attracting 3.3 million visitors annually.

London Capital of the United Kingdom

London is the capital and largest city of both England and the United Kingdom. Standing on the River Thames in the south-east of England, at the head of its 50-mile (80 km) estuary leading to the North Sea, London has been a major settlement for two millennia. Londinium was founded by the Romans. The City of London, London's ancient core − an area of just 1.12 square miles (2.9 km2) and colloquially known as the Square Mile − retains boundaries that follow closely its medieval limits. The City of Westminster is also an Inner London borough holding city status. Greater London is governed by the Mayor of London and the London Assembly.



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. [2] 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. [3] Securing funding was a persistently worrying issue throughout the early development of the engine. [4] 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. [5]

Turbojet jet engine

The turbojet is an airbreathing jet engine, typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet, a compressor, a combustion chamber, and a turbine. The compressed air from the compressor is heated by the fuel in the combustion chamber and then allowed to expand through the turbine. The turbine exhaust is then expanded in the propelling nozzle where it is accelerated to high speed to provide thrust. Two engineers, Frank Whittle in the United Kingdom and Hans von Ohain in Germany, developed the concept independently into practical engines during the late 1930s.

Gloster Aircraft Company 1917-1963 aircraft manufacturer in England

The Gloster Aircraft Company was a British aircraft manufacturer from 1917 to 1963.

Power Jets

Power Jets was a British company set up by Frank Whittle for the purpose of designing and manufacturing jet engines. The company was nationalised in 1944, and evolved into the National Gas Turbine Establishment.

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. [6] 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. [7] Power Jets and Gloster quickly formed a mutual understanding around mid-1939. [8]

Power Jets W.1

The Power Jets W.1 was a British turbojet engine designed by Frank Whittle and Power Jets. The W.1 was built under contract by British Thomson-Houston (BTH) in the early 1940s. It is notable for being the first British jet engine to fly, as the "Whittle Supercharger Type W1", powering the Gloster E.28/39 on its maiden flight at RAF Cranwell on 15 May 1941. The W.1 was superseded by the Power Jets W.2.

World War II 1939–1945 global war

World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries. The major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China. It included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, and the only use of nuclear weapons in war.

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. [9] 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..." [10]

Design effort

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 selected. On 3 February 1940, a contract for two prototypes was signed by the Air Ministry. [11]

Manufacture of the E.28/39 commenced at Brockworth near Gloucester and then moved to Regent Motors in Regent Street, Cheltenham (now the site of Regent Arcade), which was considered safer from bombing. Whittle was dissatisfied with the speed at which production took place, probably caused by the Battle of Britain as the area around nearby Coventry was subject to high levels of German bomber activity. [12] In April 1941, the first of the E.28/39 prototypes was completed but a flight-worthy W.1A engine was not available and a non-flight capable W.1X unit was assembled and installed instead. [12]

While only a pair of prototypes had been ordered, the operational philosophy was that, once the prototypes had proved the capabilities of the design, a more substantial programme would begin; even before the first flight of the E.28/39, this 'production' combat aircraft had been envisioned as being a considerably more elaborate twin-engined design, with all of the equipment necessary to produce a fighter aircraft. [9] This aircraft, also produced by Gloster, became the Meteor, the first production jet-propelled aircraft to enter service with the Allies. [13]


The E.28/39 was a low-wing monoplane designed around the new jet engine. [9] 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. [9] It had a retractable undercarriage which was actuated via a hydraulic accumulator, with a manually-operated hand-pump to serve as a backup. An emergency compressed air arrangement was also present. [14] The flaps were also hydraulically-actuated, driven directly by the manual hand-pump. Unusually, the nose wheel was steerable by the rudder, which aided in ground manoeuvring. [9]

A replica E.28/39 on display at the Jet Age Museum Jet-Age-Museum-E28.jpg
A replica E.28/39 on display at the Jet Age Museum

The E.28/39 was powered by a Power Jets W.1 turbojet engine behind the pilot and the fuel tank. [9] The engine exhaust was directed through the centre of the fuselage, the jetpipe terminating about two feet behind the rudder. A nose air-intake led the air through bifurcated ducts around the cockpit. [9] A fuel tank, containing up to 82 Imp gal (372.8 liters), was behind the cockpit, 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 was hard to re-light during flight. [9]

The E.28/39 lacked features that would be considered key to a fighter, such as a radio. [9] The original engine was started by an Austin Seven car engine, connected by a flexible drive; this arrangement was replaced by an electronic starter system that used a ground booster battery instead. The cockpit, which was entered past a sliding canopy, lacked pressurisation or any form of climate control, such as heating. [9] Pilots were intended to wear electrically-heated flight suits but the lack of a generator and limited battery capacity, the latter being devoted to the automated sensors and recording devices that captured the results of each flight, meant this was not possible; pilots had to put up with the cold. [9]

John Grierson said:

"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." [15]


"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 ...." [16]


Statue in Coventry, England of Sir Frank Whittle observing the first British jet-powered flight Frank whittle statue 12u07.JPG
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 Plaque frank whittle statue.JPG
Plaque on base of the statue of Frank Whittle in Coventry, England

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. [11]

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. [17] [12] 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. [12]

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. [18] 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. [19] [18] Tests continued with increasingly refined versions of the engine. [20] [1] Small, auxiliary fins were added near the tips of the tailplanes to provide additional stability in high-speed flight. [21] 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. [22] 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. [23] [18] 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. [18] In April 1943, W4046 flew to Hatfield for a demonstration in front of the Prime Minister and members of the Air Staff. [12] 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 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". [21] The test pilot, Squadron Leader Douglas Davie, bailed out from 33,000 ft, suffering frostbite on the way down. [20]

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. [24] [25] 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". [1] [21] 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.

Surviving aircraft

Replica on Whittle Roundabout, junction of A426 and A4303, Lutterworth Replica Gloster Whittle.JPG
Replica on Whittle Roundabout, junction of A426 and A4303, Lutterworth

In 1946, the first prototype (W4041) was placed in the Science Museum in Central London, where it is exhibited today in the Flight Gallery. [25] 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.


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Specifications (Gloster E.28/39)

Gloster E.28-39.svg

Data from[ citation needed ]

General characteristics



See also

External video
Nuvola apps kaboodle.svg Period United News broadcast, officially revealing the existence of the E.28/39
Nuvola apps kaboodle.svg Compilation of footage, showing the fitting of the engine, rolling out and take-off of the aircraft along with several fly pasts
Nuvola apps kaboodle.svg Report by the Army Pictorial Service on the E.28/39

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  1. 1 2 3 4 Flight 11 May 1951, p. 553.
  2. Pavelec 2007, pp. 45–46.
  3. Pavelec 2007, pp. 43–44.
  4. Golley and Gunston 2010, pp. 92–94.
  5. Pavelec 2007, pp. 48–50.
  6. Golley and Gunston 2010, p. 139.
  7. Golley and Gunston 2010, pp. 156, 165.
  8. Golley and Gunston 2010, p. 127.
  9. 1 2 3 4 5 6 7 8 9 10 11 Flight International 13 May 1971, p. 677.
  10. Grierson, John. Jet Flight. London: Sampson Low, Marston and Co. Ltd, 1946.
  11. 1 2 Flanagan 2017, p. 35.
  12. 1 2 3 4 5 Flanagan 2017, p. 39.
  13. Jackson 2007, p. 119.
  14. Flight International 13 May 1971, pp. 677-678a.
  15. Flight International 13 May 1971, pp. 678–678a.
  16. Flight 27 October 1949, p. 557.
  17. Flight International 13 May 1971, pp. 677–678.
  18. 1 2 3 4 Flight International 13 May 1971, p. 678.
  19. T.N.A. AIR62/42/198
  20. 1 2 Flight International 13 May 1971, p. 678a.
  21. 1 2 3 Winchester 2005, p. 83.
  22. Flight International 13 May 1971, p. 679.
  23. Grierson, ibid.
  24. Flight 1949
  25. 1 2 Flight 11 May 1951, p. 554.


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