Tag Archives: Turbojet Engine

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