Tag Archives: Turbojet Engine

12 April 1937

“Whittle’s first experimental jet engine (W.U.) in his Power Jets workshop at Lutterworth.” Painting by Roderick John Lovesey (1944–2002).

12 April 1937: At his laboratory at the British Thompson-Houston Works in Rugby, Warwickshire, England, Royal Air Force Flight Lieutenant Frank Whittle prepares the first test of his prototype aircraft engine, the Power Jet W.U. (“Whittle Unit”), which he calls a “supercharger.”

Using an electric motor, Whittle spins the engine up to 1,000 r.p.m. He switches on the pilot jet, which sprays atomized diesel fuel into the engine’s combustion chamber. A hand-cranked magneto supplies electricity to fire a spark plug to ignite the fuel. Whittle continues to spin the engine to 3,000 r.p.m., at which speed the combustion cycle is self-sustaining. The Whittle Unit continues to accelerate uncontrolled to about 8,500 r.p.m.

This was the very first successful test of a turbojet engine.¹

Whittle’s first patent for a turbojet engine, filed 16 January 1930. (frankwhittle.co.uk)

With the exception of the uncontrolled acceleration, the test was successful. It would later be found that the acceleration was caused by liquid fuel pooling in the combustion chamber. The Whittle Unit was based on Whittle’s own patent, No. 347,206, which was filed 16 January 1930. The patent was published in 1931. (Following World War II, copies of these patent documents were found at several laboratories in Germany.) In 1935, Whittle was unable to afford the £5 required to renew his patent, and it entered the public domain.

The Power Jet W.U. was a single-shaft turbojet engine with a single-stage, centrifugal-flow compressor, a single combustion chamber, and a single-stage, axial-flow turbine. The engine had two air intakes, one for each side of the compressor impeller. The impeller was double-sided with a diameter of 19 inches (48.26 centimeters). It had 30 blades and was constructed of Hiduminium R.R. 56, a high strength, high-temperature, aluminum alloy produced by High Duty Alloys, Ltd., at Slough, Berkshire, England. The compressor blade tips had a width of 2 inches (5.08 centimeters). The inner diameter of the compressor scroll was 31 inches (78.74 centimeters). The turbine was 14 inches (35.56 centimeters) in diameter with 66 individual blades. Each blade was 2.4 inches (6.096 centimeters) long, with a chord of 0.8 inches (2.032 centimeters). The turbine was constructed of Firth-Vickers Stayblade, a chrome-nickel stainless steel alloy produced by Firth Brown Steels of Sheffield, South Yorkshire, England. The turbine bearing housing was water-cooled.²

Frank Whittle’s first experimental turbojet engine.

Air entered the compressor where it was heated and pressurized by the spinning impeller to about 4 times normal atmospheric pressure. This caused the air temperature to increase substantially. The pressurized air was passed on to the combustion chamber where the fuel spray was ignited by the spark plug. Burning gas passed through the turbine blades, causing them to spin at very high speeds. The turbine turned a shaft which lead forward to turn the compressor impeller. Exhaust expelled through the tailpipe provides thrust.

Rotor assembly of the first experimental engine. The turbine is at left, and the compressor impeller is at center. (University of Cambridge)

Testing of the Whittle Unit continued until 23 August 1937. For reasons of safety, British Thompson-Houston would not allow Whittle to test the engine above 12,000 r.p.m., and recommended that he move his laboratory to a BTH-owned foundry at the Ladywood Works, Lutterworth, Leicestershire, England.

After analyzing test data, Whittle concluded that the Power Jet W.U. had poor compressor efficiency; that there was excessive preheating of air entering the rear intake because of combustion chamber heat; the combustion of the air/fuel mixture was unsatisfactory; and there was excessive frictional loss in the turbine.

The W.U. eventually reached 17,750 r.p.m and produced approximately 1,390 pounds of thrust (6.18 kilonewtons). Whittle continued testing a series of improved W.U. turbojets until 1941, when he built the Whittle W.1X engine.

Whittle W.1

On 15 May 1941, a Whittle W.1 powered the Gloster E.28/39 prototype jet fighter on its first flight. (In October 1941, General Henry Harley (“Hap”) Arnold, U.S. Army Air Forces, arranged to have the W.1X flown to the United States so that the U.S. could develop its own jet engine, the General Electric Type I.)

The Gloster-Whittle E.28/39 in its original configuration. The horizontal paint stripe was used as an indication of heating by the turbojet engine. (BAE Systems)

* * * * * * *

Air Commodore Frank Whittle, RAF, in his office at Lutterworth, Leicestershire, England, circa 1945, with scale models of the Gloster-Whittle E.28/39, and Whittle Supercharger Type W.1 engine. (Imperial War Museum, TR 3737)
Frank Whittle, age 4.

Air Commodore Sir Frank Whittle, O.M., K.B.E., C.B., F.R.S., F.R.Ae.S., Royal Air Force, was born 1 June 1907 at 72 Newcombe Road, Earlsdon, Coventry, England. He was the older of two sons of Moses Whittle, a foreman in a machine tool factory, and Sara Alice Garlick Whittle. He attended Earlsdon Council School, just around the corner from his home. In 1916, the Whittle family moved to 9 Victoria Street, Royal Leamington Spa, in Warwickshire, where he was educated at the Milverton Primary School. After about two years, he earned a scholarship to what would later be called the Leamington College for Boys.

In 1923, Frank Whittle left school to join the Royal Air Force. He was initially turned down because he was just 5 feet tall (1.52 meters) and very underweight. Six months later, he had grown another 3 inches (7.6 centimeters) and increased his weight and strength. Whittle was accepted under an assumed first name (he soon reverted to his real name) to a three-year course as an aircraft mechanic. A superior officer recommended him for officer and pilot pilot training at the Royal Air Force College, Cranwell, in Lincolnshire.

Prize winners, RAF Cadet College, Cranwell, July 1928. Frank Whittle is standing at the center of the image. (Gale & Polden Ltd., Aldershot via RAF College Cranwell)
Pilot Officer Frank Whittle, RAF.

Frank Whittle graduated from RAF Cranwell and on 21 August 1928 was granted a permanent commission as a Pilot Officer, Royal Air Force, with seniority from 28 July. He was considered to be an exceptional pilot, and had scored second in his class in academics. At his graduation ceremony, Whittle, flying an Armstrong Whitworth Siskin at 1,500 feet (457 meters), performed an aerobatic maneuver called an “English bunt,” the first RAF officer to do so.³

Pilot Officer Whittle served as a pilot and flight instructor, and was promoted to the rank of Flying Officer, 28 January 1930.

Flying Officer Whittle married Miss Dorothy Mary Lee at Coventry, 24 May 1930. Mrs. Whittle was three years his senior. They would have two sons, David and Ian.

David Whittle, Dorothy Mary Lee Whittle, Group Commander Frank Whittle, and Ian Whittle.

In 1931, Whittle was assigned as a test pilot at the Marine Aircraft Experimental Establishment, Felixstowe, Suffolk. He flew more than 20 aircraft types.

Flying Officer Frank Whittle in a life raft, circa 1932. A Royal Navy Fairey Seal, S1325, is sinking in the background. (frankwhittle.co.uk)

In 1932, he attended the Officers School of Engineering at RAF Henlow, in Bedfordshire. Flying Officer Whittle was promoted to the rank of Flight Lieutenant, 1 February 1934. Whittle had scored so high in his studies at Henlow that the RAF sent him to the RAF E Course at the Peterhouse College of the University of Cambridge. He graduated in 1936 with Bachelor of Arts degree and a First in Mechanical Sciences Tripos.

Photograph of Whittle’s student record card, Department of Engineering, University of Cambridge.
Dorothy and Frank Whittle outside the Senate House after the degree ceremony. (University of Cambridge)

While at Cambridge, Flight Lieutenant Whittle entered into a partnership to form Power Jets Ltd., and began work on his design for the Power Jets W.U. The engine would be built by the British Thompson-Houston Works.

On 1 December 1937, Flight Lieutenant Whittle was promoted to the rank of Squadron Leader. The RAF assigned him to the Special Duty List, allowing him to continue post-graduate work at Cambridge and to work on the turbojet engine.

Squadron Leader Whittle was promoted to Wing Commander (temporary), 1 June 1940.

Wing Commander Whittle developed the Whittle W.2, which powered the Gloster Meteor on its first flight, 5 March 1943. He was promoted to Group Captain (temporary), 1 July 1943.

Fifth of eight F9/40 prototypes, Gloster Meteor DD206/G was the first to fly, 5 March 1943.

Group Captain Whittle was appointed Commander of the Military Division of the Most Excellent Order of the British Empire (CBE), 1 January 1944. He was promoted to Acting Air Commodore.

King George V, on 5 November 1946, granted unrestricted permission to Air Commodore Whittle, CBE, to wear the Legion of Merit in the degree of Officer, a military decoration conferred by the President of the United States for exceptionally meritorious conduct in the performance of outstanding services and achievements.

Air Commodore Sir Frank Whittle, CB, photographed 1 July 1947, by Walter Stoneman. (National Portrait Gallery NPG x188861)

In the King’s New Year’s Honours List, 1 January 1947, Air Commodore Whittle, CBE, was appointed a Companion of the Most Honourable Order of the Bath (CB). In May 1948, for his work on jet engines, Whittle was awarded £100,000 ⁴ by Royal Commission on Awards. King Edward VIII appointed Air Commodore Whittle an Ordinary Knight Commander of the Most Excellent Order of the British Empire (KBE), 10 June 1948.

Group Captain Sir Frank Whittle, KBE, CB, was retired from the Royal Air Force, 26 August 1948, due to medical unfitness for Air Force service. He retained the rank of Air Commodore.

Sir Frank Whittle, circa 1951. (Baron/Hulton Archive/Getty Images)
Air Commodore Frank Whittle, RAF. (Edwin Irvine Halliday, 1960)

After retiring from the RAF, Whittle joined the British Overseas Airways Corporation as a technical adviser. He left BOAC in 1952. On 1 January 1953, Frederick Mueller Ltd. published his autobiography, Jet: The Story of a Pioneer. Later that year, he joined Shell, one of the world’s largest petroleum companies, as a Mechanical Engineering Specialist. He invented a turbine-powered oil well drill. In 1957, he went to work for Bristol Aero Engines.

In 1960, the Norwegian Institute of Technology, Trondheim, Norway, awarded Whittle an honorary degree, Doctor Technices honoris causa. In 1967, the University of Bath, in Somerset, England, awarded him the honorary degree of Doctor of Science.

From 1967 to 1976, Sir Frank and Lady Dorothy resided at Walland Hill, a 4,130 square foot (383.6 square meters) house on 5 acres, built in 1865, and overlooking the Teign Valley and Dartmoor. The house is situated about ¾-mile (1.2 kilometers) from Chagford, Devon.

Walland Hill, near Chagford, Devon, England.

Following his divorce from Dorothy, Lady Whittle, Sir Frank Whittle married the former Mrs. Virgil Lee Hall (née Hazel Ardyce Steenberg) on 5 November 1976, at Fort Leslie J. McNair, at a United States Army base located in Washington, D.C. He emigrated to the United States in 1977 and became a research professor at the United States Naval Academy at Annapolis, Maryland.

Whittle was the author of a textbook, Gas Turbine Aero-Thermodynamics With Special Reference to Aircraft Propulsion, published by Pergamon Press, Oxford, in 1981.

On 14 February 1986, Queen Elizabeth II appointed Whittle to the Order of Merit (OM), dated 11 February 1986.

Loughborough University, Leicestershire, awarded Whittle the honorary degree of Doctor of Technology in 1987.

In February 1996, Whittle was diagnosed with lung cancer. 24 days after the death of his first wife, Lady Dorothy, at 10:40 p.m., 8 August 1996,⁵ Air Commodore Sir Frank Whittle, O.M., K.B.E., C.B., F.R.S., F.R.Ae.S., Royal Air Force (Retired), died at his home at 10001 Windstream Drive, , Columbia, Maryland. He was 89 years old. His remains were cremated, then interred at St. Michael’s and All Angels’ Church, RAF Cranwell.

Sir Frank Whittle, photographed by Elliot & Fry, 30 November 1950. (National Portrait Gallery NPG x99798)

A memorial was held at Westminister Abbey, 15 November 1996. Air Chief Marshall Sir Michael James Graydon, GCB, CBE, FRAeS, said of him, “It is given to few people, and even fewer in their own lifetime, to open up new horizons for their fellow human beings. That is what Frank Whittle did by paving the way for popular air travel on a scale that few people thought possible at the time. This practical realization of a soaring vision is surely the very essence of genius.”

The Daily Telegraph called him “the greatest aero engineer of the century.” Prime Minister Margaret Thatcher said, “Sir Frank helped to change both the way we live and the world we live in.”

A very interesting documentary about Whittle, including interviews with the Air Commodore, can be seen on YouTube:

¹ Hans-Joachim Pabst von Ohain’s turbojet engine, the Heinkel HeS 1, burning gaseous hydrogen, was first run in September 1937, about six months after Whittle’s Power Jets W.U.

Schematic of von Ohain’s Heinkel HeS 1 turbojet engine.

² “The Whittle Jet Propulsion Gas Turbine,” by Air Commodore Frank Whittle, C.B.E., R.A.F., M.A., Hon. M.I. Mech.E., The Engineer, 12 October 1945, Pages 288–290.

³ The English bunt begins in straight and level flight. The pilot performs an outside half loop, ending in inverted level flight.

⁴ Equivalent to £4,651,934/$5,771,654 in 2023.

⁵ 02:40, 9 August, UTC.

© 2023, Bryan R. Swopes

17–22 November 1946

Avro Lancastrian C.1 VH742 after installation of Rolls-Royce RB.41 Nene Mk.I gas turbine engines. The inboard Merlin engines have been shut down and their propellers feathered. (Royal Air Force)

17 November 1946: A modified Avro 691 Lancastrian C.1, VH742, under the command of Rolls-Royce’s chief test pilot, Captain Ronald Thomas Shepherd, O.B.E., flew from London Heathrow Airport (LHR) to Aéroport de Paris – Le Bourget (LBG) for 17th Salon de Aviation (Paris Air Show) with two Rolls-Royce RB.41 Nene Mk.I turbojet engines for propulsion. The airplane’s two Rolls-Royce Merlin V-12 piston engines were shut down, except for takeoff and landing, and their three-bladed propellers were feathered to reduce drag. It was the first-jet-powered passenger transport to fly from one country to another.

A contemporary aviation industry news article described the event:

The Nene-Lanc, Flies to Paris

THE flight of the Nene Lancaster from London to Paris last Monday, to play its part in connection with the exhibition, may be said to have marked a historic part in British aircraft development, for it constituted the first time that any jet-powered airliner had flown from one country to another. Moreover, since this particular aircraft has been flying fairly regularly since round about the time of the Radlett exhibition, the flight to Paris was no special performance, but merely one more public demonstration of its inherent reliability.

In the hands of Capt. R. T. Shepherd, chief test pilot for Rolls-Royce, the “Nene-Lanc” landed at Le Bourget at 10.58 a.m., G.M.T., after a 50-minute flight from London Airport, giving an average speed of 247.5 m.p.h. [398.3 kilometers per hour] Two passengers were carried in addition to the crew; they were Mr. Roy Chadwick, the Avro designer, and Mr. R. B. William Thompson, Chief Information Officer of the Ministry of Supply.

Capt. Shepherd said that he was very pleased with the aircraft’s performance and added that, but for having to circle Le Bourget Airport Twice before landing, the flight would have been completed in 43 minutes.

FLIGHT and AIRCRAFT ENGINEER, No. 1978. Vol. L., Thursday, November 21st, 1946 at Page 561, Column 2.

Five days later, VH742 flew back to England:

Return Trip

THE return of the Nene Lancastrian on Nov. 22nd, direct from Le Bourget to Heathrow, was made in only 49 min, including landing, actual flying time from point to point being 41 min—an average speed of 322 mp.h. [518.2 kilometers per hour] This remarkable performance was in spite a beam wind and the dead weight and drag of the two inboard Merlins, which are only used for takeoff and landing.

Passengers of the return trip included Mr. Roy Chadwick, chief designer and a director of A. V. Roe and Co., Air Comdre. Kirk and Air Comdre. Pike.

FLIGHT and AIRCRAFT ENGINEER, No. 1979., Vol. L., Thursday, November 28th, 1946 at Page 588, Column 1.

Avro Lancastrian (nene engine test bed). © IWM (ATP 14764B)
Avro Lancastrian C.1 VH742 with Rolls-Royce Nene engines. © IWM (ATP 14764B)

The Rolls-Royce RB.41 Nene engine first been run in October 1944. It  installed in a Lockheed YP-80A Shooting Star, 44-83027, and the engine was first flown 18 July 1945 with Rolls-Royce test pilot Wing Commander John Harvey Heyworth, A.F.C., in the cockpit. The Nene-powered P-80 had made approximately 30 test flights when it was damaged beyond repair at RAF Syerston, 6 December 1945. With test pilot Andy McDowall flying, a fractured fuel pipe caused the engine to flame out from fuel starvation. McDowall tried to glide to a landing but another airplane was on the runway. He touched down on the grass but the landing gears were pushed up through the Shooting Star’s wings.

The jet fighter had been too small to allow for adequate test equipment. A larger aircraft was needed. The R.A.F. assigned VH742 the role of test aircraft.

The new Lancastrian arrived at the Rolls-Royce Flight Test Establishment at Hucknall Aerodrome, Nottinghamshire, 30 October 1945. The modification was engineered and the airplane was modified. The Lanc’s two outboard Rolls-Royce Merlin V-12 engines were removed and two Nene Mk.I engines were installed in underslung nacelles. The wing flaps were shortened by 3 feet, 4 inches (1.016 meters) and the ailerons by 10 inches (0.254 meters) to provide clearance from the jet engines’ exhaust. Sheet steel was installed on the lower surfaces of the wings as protect against the heat.

Three fuel tanks were installed in each of the Lancastrian’s wings. The center tank contained gasoline for the Merlin engines, while the inner and outer tanks, plus two auxiliary tanks in the fuselage, carried kerosene for the jet engines. Fuel capacity was 760 gallons (2,877 liters) of gasoline and 2,420 gallons (9,161 liters) of kerosene.

In the Lancastrian’s cockpit, additional instruments were installed for the turbojets: tachometers reading from 0–20,000 r.p.m.; oil pressure gauges, 0–80 p.s.i.; exhaust gas temperature, 400˚–750 ˚C., and exhaust gas pressure.

The first flight of the modified VH742 took place 14 August 1946, with Ronnie Shepherd in the cockpit. Running on the jet engines alone, the airplane was extraordinarily quiet and vibration free. Like all early turbojets, the Nenes were slow to accelerate from low r.p.m. Test pilots had to use caution. Jim and Harvey Heyworth also flew VH742 during the last half of August.

RB.41 Nene. (Rolls-Royce)
RB.41 Nene. (Rolls-Royce)

The Rolls-Royce RB.41 Nene Mk.I was developed from the earlier RB.40 Derwent.¹ It was considerably larger and produced nearly double the thrust. It was a single-stage centrifugal-flow compressor/single-stage axial-flow turbine, rated at 5,000 pounds of thrust (22.24 kilonewtons) at 12,400 r.p.m. for takeoff.

A second Nene-powered Lancastrian was added to the test fleet at Hucknall the following year. Last Nene flight took place in August 1949.

VH742 had been ordered by the Royal Air Force during World War II as an Avro Type 683 Lancaster B. Mk.III, a very long range heavy bomber, and assigned identity markings PD194. With the end of World War II in Europe, orders for hundreds of Lancaster bombers were cancelled. The partially completed PD194 was modified on the assembly line as a Lancastrian C. Mk.I passenger transport and renumbered as VH742.

The Avro Type 691 Lancastrian was a four-engine civil transport based on the World War II very long range heavy bomber, the Avro Lancaster. The airliner was operated by a flight crew of four and carried one flight attendant. It could carry up to thirteen passengers. The Lancastrian was 76 feet, 10 inches (23.419 meters) long with a wingspan of 102 feet (31.090 meters) and overall height of 19 feet, 6 inches (5.944 meters). The empty weight was 30,220 pounds (13,707.6 kilograms) and gross weight was 65,000 pounds (29,483.5 kilograms).

The Lancastrian Mk.III was powered by four 1,648.9-cubic-inch-displacement (27.04 liter) liquid-cooled, supercharged, Rolls-Royce Merlin T24/2 single overhead camshaft (SOHC) 60° V-12 engines producing 1,650 horsepower and turning three bladed propellers.

The airplane a cruise speed of 245 miles per hour (394.3 kilometers per hour) and a maximum speed of 315 miles per hour (506.9 kilometers per hour). The service ceiling was 25,500 feet (7,772 meters) and the range was 4,150 miles (6,679 kilometers).

Rolls-Royce test pilots (left to right) Wing Commander John Harvey Heyworth, AFC; Squadron Leader Alexander James Heyworth, DFC and Bar, FRAeS; Captain Ronald Thomas Shepherd, OBE; Wing Commander Andrew McDowall, DSO, AFC, DFM; and Herbert Clifford Rogers, OBE, DFC; with Merlin 632/ Avon-powered Avro Lancastrian C.2 VL970, circa 1949. Each one of these men served as Chief Test Pilot for Rolls-Royce. (Rolls-Royce)
Rolls-Royce test pilots (left to right) Wing Commander John Harvey Heyworth, A.F.C.; Squadron Leader Alexander James Heyworth, D.F.C. and Bar, FRAeS; Captain Ronald Thomas Shepherd, O.B.E.; Wing Commander Andrew McDowall, D.S.O., A.F.C., D.F.M.; and Herbert Clifford Rogers, O.B.E., D.F.C.; with Merlin 632/ Avon-powered Avro Lancastrian C.2 VL970, circa 1949. Each one of these men served as Chief Test Pilot for Rolls-Royce. (Rolls-Royce)

91 Avro Lancastrians were built, including modified Lancaster bombers. The transport variant first flew in 1943. In addition to the Royal Air Force, commercial Lancastrians were operated by British European Airways, British Overseas Airways Corporation and British South American Airways. The last one was retired in 1960.

Rolls-Royce built more than 1,100 RB.41 Nene engines. It was licensed for production by Pratt & Whitney as the J42. Forty Nenes were sold to the Soviet Union under the condition that they would not be used for military purposes. These were reverse-engineered and produced as the Klimov RD-45 which powered the Mikoyan-Gurevich MiG-15 fighter.

¹ While Rolls-Royce named its piston-driven aircraft engines after birds of prey, the turbojet engines were named for rivers.

© 2018, Bryan R. Swopes

1 October 1942

Bell XP-59A Airacomet 42-108784, first flight at Muroc Dry Lake, 1 October 1942. (U.S. Air Force)

1 October 1942: At Muroc Dry Lake, in the high desert north of Los Angeles, California, Bell Aircraft Corporation’s Chief Test Pilot, Robert Morris Stanley, made the first flight of the top secret prototype turbojet-powered fighter, the Bell XP-59A Airacomet, serial number 42-108784. Weather was “C.A.V.U.” (Ceiling and Visibility Unrestricted) and wind was from the west at 20 miles per hour (9 meters per second).

Bell Aircraft Corporation Chief Test Pilot Robert M. Stanley in the cockpit of an XP-59A Airacomet. (National Museum of the United States Air Force)

In his report, Stanley wrote:

4.     All take-offs were made using 15,000 r.p.m. on both engines with flaps fully up and with the airplane pulled off the ground at about 80 to 90 m.p.h. Throttle was applied promptly and acceleration during take-off appeared quite satisfactory. The run was estimated to be in the vicinity of 2,000 feet, possibly more. The first flight reached an altitude of approximately 25 feet, and landing was made using partial power without flaps. This take-off had the wind approximately 60° on the right bow and must be considered a cross-wind take-off.

5.     Aileron and elevator action appear satisfactory, although the rudder force appears undesirably light causing the airplane to yaw somewhat for very light pedal pressures. Left rudder was needed for take-off due to cross wind.

—Bell Aircraft Corp. Pilot’s Report 27-923-001, at Page 1-12, by Robert M. Stanley, 1 October 1942

Bell XP-59A Airacomet 42-108784 disguised with a false propeller. (U.S. Air Force)
One of the three Bell XP-59A prototypes, circa 1942. (U.S. Air Force)
Bell Aircraft Corporation XP-59A Airacomet 42-108784. (U.S. Air Force photo)
Bell Aircraft Corporation P-59 Airacomet with updated national insignia, after August 1943. (U.S. Air Force photo)
Bell Aircraft Corporation XP-59A Airacomet 42-108784. (U.S. Air Force photo)

Stanley made three more flights that day, as high as 100 feet (30.5 meters). The following day, Army Air Corps test pilot Colonel Laurence C. Craigie conducted the “official” first flight, reaching an altitude of 10,000 feet (3,048 meters).

A Bell XP-59A Airacomet prototype in flight near Muroc Army Airfield, 1942. (U.S. Air Force)

Three XP-59A prototypes were built. The number one ship, 42-108784, was affectionately nicknamed Miss Fire, because of the initial difficulty in getting the engines to start.

The Bell XP-59A was conventional single-place airplane with retractable tricycle landing gear. It was primarily of metal construction, though the control surfaces were fabric-covered. The prototype was 38 feet, 10 inches (11.836 meters) long with a wingspan of 49 feet, 0 inches (14.935 meters) and overall height of 12 feet, 3¾ inches (3.753 meters), at rest. The leading edge of the wings were swept aft  7°. The angle of incidence was +2° with -2° twist and 2½° dihedral. The horizontal stabilizer had a span of 16 feet, 8 inches (5.080 meters). Its angle of incidence was +1½° with no dihedral. The vertical fin had 0° offset. The empty weight of the XP-59A was 7,319 pounds (3,320 kilograms) and its maximum gross weight was 10,089 pounds (4,576 kilograms).

A cutaway display of a General Electric I-A turbojet engine. The compressor and turbine are on a single shaft (center). One of the combustion chambers is sectioned at the upper left. (National Museum of the United States Air Force)
A cutaway display of a General Electric I-A turbojet engine. The single-stage centrifugal compressor and single-stage axial-flow turbine are on a single shaft (center). One of the annular combustion chambers is sectioned at the upper left. (National Museum of the United States Air Force)

The experimental fighter was initially powered by two General Electric Type I-A centrifugal reverse-flow turbojet engines, serial numbers 170121 (left) and 170131 (right), each producing 1,250 pounds of thrust (5.561 kilonewtons) at 15,000 r.p.m. These were copies of the British Whittle W.2B engines. They were heavy, underpowered and unreliable.

Performance of the XP-59A was disappointing with a maximum speed of 350 miles per hour (563 kilometers per hour) at Sea Level and 389 miles per hour (626 kilometers per hour) at 35,160 feet (10,717 meters), significantly slower than many piston-engined fighters.

Three XP-59A prototypes and thirteen YP-59A preproduction airplanes were built. The P-59 was ordered into production and Bell Aircraft Corporation built thirty P-59A and twenty P-59B fighters. These were armed with one M4 37mm autocannon with 44 rounds of ammunition and three Browning AN-M2 .50-caliber machine guns with 200 rounds per gun.

Although a YP-59A had set an unofficial altitude record of 47,600 feet (14,508 meters), the Airacomet was so outclassed by standard production fighters that no more were ordered.

Lawrence D. ("Larry") Bell with his XP-59A Airacomet at Muroc Dry Lake. (Robert F. Dorr Collection)
Lawrence D. Bell with his XP-59A Airacomet at Muroc Dry Lake. (Robert F. Dorr Collection)

The race for a jet engine-powered fighter had been ongoing for several years, and the United States’ XP-59A was trailing behind. The first jet airplane, the Heinkel He 178, had made its first flight in Germany three years earlier, on 27 August 1939, though it was a proof-of-concept article, not an operational military aircraft. In the United Kingdom, the Gloster E/28.39, also a proof-of-concept aircraft, though more advanced than the Heinkel, made its first flight, 15 May 1941. The world’s first operational jet fighter, the Messerschmitt Me 262, made its first flight on 18 July 1942. It was nearly two years before production Me 262s entered combat, but they were devastating against bomber formations. The Gloster Meteor, the Allies’ first jet fighter, first flew 5 March 1943, and deliveries to fighter squadrons began in July 1944. The de Havilland DH.100 Vampire made its first flight 20 September 1943, but it did not become operational until after the end of World War II.

The XP-59A flew nearly five months before its British cousin, but would not be assigned to an operational squadron, the 445th Fighter Squadron, 412th Fighter Group, until June 1945.

The first American military jet aircraft, Bell XP-59A Airacomet 42-108784, was preserved by the Army at Muroc, and the engines at Wright Field, Ohio. In 1978, these were given to the Smithsonian Institution National Air and Space Museum where the prototype was later restored and placed on display.g9

The first American jet-powered aircraft, Bell XP-59A Airacomet 42-108784 on display at the National Air and Space Museum. (NASM)

© 2018, Bryan R. Swopes

27 August 1939

Illustration (or retouched photograph) of Heinkel He 178 V1 in flight with landing gear extended.
Erich Karl Warsitz, 1942

27 August 1939: Flugkapitän Erich Karl Warsitz, a Luftwaffe pilot assigned to the Ministry of Aviation (Reichsluftfahrtministerium) as a test pilot, made the first flight of the Heinkel He 178 V1, a proof-of-concept prototype jet-propelled airplane.

Heinkel Flugzeugwerke had built a small, single-seat, single-engine high-wing monoplane with retractable landing gear. The He 178 had the air intake at the nose and the engine exhaust out the tail, a configuration that would become the standard layout for most single-engine jet aircraft in the future. The airplane was constructed of wood and aluminum.

The He 178 V1 was 7.48 meters (24.54 feet) long, with a wingspan of 7.20 meters (23.62 feet) and height of 2.10 meters (6.89 feet). The wing area was 7.90 square meters (85.03 square feet). The prototype had an empty weight of 1,620 kilograms (3,572 pounds) and its gross weight was 1,998 kilograms (4,406 pounds).

Illustration of Heinkel He 178 V1 in flight with landing gear retracted.
Hans J. P. von Ohain

The airplane was powered by a Heinkel Strahltriebwerk HeS 3B turbojet engine, which had been designed by Hans Joachim Pabst von Ohain. The HeS 3B used a single-stage axial-flow inducer, single-stage centrifugal-flow compressor, reverse-flow combustor cans, and a single-stage radial-inflow turbine. The engine produced 1,102 pounds of thrust (4.902 kilonewtons) at 11,600 r.p.m., burning Diesel fuel. The engine’s maximum speed was 13,000 r.p.m. The HeS 3B was 1.480 meters (4.856 feet) long, 0.930 meters (3.051 feet) in diameter and weighed 360 kilograms (794 pounds).

Heinkel Strahltriebwerk HeS 3B engine, cutaway example. (Deutsches Museum)

The He 178 V1 was designed for a cruise speed of 580 kilometers per hour (360 miles per hour) and maximum speed of 700 kilometers per hour (435 miles per hour). During flight testing, the highest speed reached was 632 kilometers per hour (393 miles per hour). Its estimated range was 200 kilometers (124 miles).

Captain Warsitz made two short circuits of the airfield then came in for a landing. This was the very first flight of an aircraft powered only by a jet engine.

(Left to right) Erich Karl Warsitz, Ernst Heinrich Heinkel, and Hans Joachim Pabst von Ohain, at dinner party celebrating the first flight of the Heinkel He 178. (NASM)

The He 178 was placed in the Deutsches Technikmuseum in Berlin, Germany. It was destroyed during a bombing raid in 1943.

Illustration of a Heinkel He 178, front view, high oblique. This may be the second prototype, V2.
Illustration showing left profile of the Heinkel He 178 V1
Illustration showing left front quarter of the Heinkel He 178 V1. Note the open cockpit.
Heinkel He 178, left rear quarter. This may be the second prototype, V2.
Heinkel He 178, rear, high oblique. This may be the second prototype, V2.

© 2018, Bryan R. Swopes