The Rolls-Royce RB.41 Nene is a 1940s British centrifugal compressorturbojet engine. The Nene was a complete redesign, rather than a scaled-up Rolls-Royce Derwent,[1] with a design target of 5,000lbf (22kN), making it the most powerful engine of its era. First run in 1944, it was Rolls-Royce's third jet engine to enter production, and first ran less than 6 months from the start of design. It was named after the River Nene in keeping with the company's tradition of naming its jet engines after rivers.
The design saw relatively little use in British aircraft designs, being passed over in favour of the axial-flowAvon that followed it. Its only widespread use in the UK was in the Hawker Sea Hawk and the Supermarine Attacker. In the US it was built under licence as the Pratt & Whitney J42, and it powered the Grumman F9F Panther. Its most widespread use was in the form of the Klimov VK-1, a reverse-engineered, modified and enlarged version which produced around 6,000lbf (27kN) of thrust, and powered the Russian built Mikoyan-Gurevich MiG-15, a highly successful fighter aircraft which was produced in vast numbers.
An uprated version of the Nene was produced as the Rolls-Royce Tay.
Design and development
An FMA IAe 33 Pulqui II without tail section, showing its Rolls-Royce Nene II turbojet
The Nene was designed as a result of a June 1944 visit to the US by Stanley Hooker. He discovered that General Electric already had two engine types running, an axial and a centrifugal, of 4,000lbf (18kN) thrust. He was determined to produce a higher thrust engine and subsequently obtained a Ministry of Aircraft Production contract for an engine of 4,200 lbf (19 kN) thrust with the understanding that 5,000lbf (22kN) would be the design target. Hooker, Adrian Lombard, Pearson and Morley designed a new engine, the B.41 later called the Nene, rather than scaling up the Derwent.[1]
The double-sided impeller was 28.8 inches (73cm) in diameter, compared to 20.68in (52.5cm) for the Derwent I, to produce an airflow of 80lb/s (36kg/s), while the overall diameter of the engine was 49.5 inches (126cm). A scaled up Derwent of the same thrust would have had a 60-inch (150cm) diameter. The compressor casing was based on Whittle's Type 16 W.2/500 compressor case which was more aerodynamically efficient than that on the Derwent but also eliminated cracking. Other design advances included nine new low pressure-drop/high efficiency combustion chambers developed by Lucas and a small impeller for rear bearing and turbine disc cooling.[2] The first engine start was attempted on 27 October 1944. A number of snags delayed the run until nearly midnight, when with almost the entire day and night shift staff watching, an attempt was made to start the engine. To the frustration of everyone with a vested interest in it starting the engine refused to light - positioning the igniter was a trial-and-error affair at the time. On a subsequent attempt, Denis Drew, who had come from Lucas, the combustion specialists, and took a wide interest in engine development problems, removed one of the igniters and instead used the flame from an oxy-acetylene torch to ignite the fuel in the combustion chamber.
The igniter had to be close enough to the fuel spray to ignite it when starting, but not overheat when subjected to the continuous flame temperature when the engine was running. The larger diameter of the Nene combustion chambers found this to be a problem, and the first-run needed to ignite with a flame rather than the spark energy that was considered sufficient at that time. The Nene was subsequently fitted with two torch, or flame, igniters which had a fuel spray next to an igniter.[3] The flame would project into the main combustor fuel spray. Torch igniters were superseded by surface discharge igniter plugs with a considerably greater energy release rate than a flame.[4]
The engine was run up to just over 4,000lbf (18kN), and a cheer went up around the assembled personnel. However the engine was running hotter than expected and would not reach 5,000 lb, as it was built, without overheating the turbine. Pearson, the performance engineer, insisted that no more running be done without fitting the guide vanes that were available for the impeller intake. Upon Hooker's arrival next morning, and informed that the inlet vanes had been fitted during the night, Hooker was overjoyed to see the thrust gauge needle registering 5,000lbf (22kN) at the same temperature that had only given 4,000 lb the previous night, making the B.41 the highest thrust jet engine in the world. Weight was around 1,600lb (730kg).[5]
Inlet guide vanes had been in use in Whittle engines for some time. They improve the overall performance of the engine significantly by "helping the air round the corner".[6] However they were made from thin sheet metal and often broke damaging the engine. For Hooker they were a worrying mechanical problem which he did not want so they were not fitted when the Derwent entered service, although the turbine had to run 90 degC hotter to give the take-off thrust of 2,000 lb. He was still concerned with the durability of the vanes so the first Nene was initially built without them.[7]
The Nene was based on the "straight-through" version of the basic Whittle-style layout, with the flow going directly through the engine from front to rear, as opposed to a "reverse-flow" type,[8] which reverses the direction of air flow through the combustor section so that the turbine stage can be mounted within the combustor section; this allows for a more compact engine, but increases the combustor pressure losses which has an adverse effect on engine performance.[9] Less thrust is generated with the same fuel flow. It was during the design of the Nene that Rolls decided to give their engines numbers as well as names, with the Welland and Derwent keeping their original Rover models, B/23 and B/26. It was later decided that these model designations looked too much like RAF bomber designations (i.e. "English Electric Canberra B.Mk 2" would often be shortened to "Canberra B.2"), and "R" was added to the front, the "R" signifying "Rolls" and the original Rover "B" signifying Barnoldswick.[10] This RB designation scheme continued into the late 20th Century, with turbofan designs such as the RB.199, RB.203 and RB.211; the most recent family of Rolls-Royce turbofans (a development of the RB.211) goes under the simple designation "Rolls-Royce Trent", with variants given their own designator number or letter series (i.e. Trent 500, Trent 900, Trent 1000, Trent XWB, etc.).
The Rolls-Royce Avro Lancastrian Nene test bed in 1948 fitted with the jet engines in the outboard position
Early airborne tests of the Nene were undertaken in an Avro Lancastrian operated by Rolls-Royce from their Hucknall airfield. The two outboard Rolls-Royce Merlins were replaced by the jet engine. The Nene's first flight however was in a modified Lockheed XP-80 Shooting Star.[11]
After seeing the Nene running, at an after work drink at the Swan & Royal Hotel, Clitheroe, and hearing the complaints about a lack of any official application for the engine, someone - thought to be Whittle - suggested that the Nene be scaled-down to fit a Meteor nacelle. J.P. Herriot or Lombard did the calculation on a tablecloth and announced a thrust of 3,650lbf (16.2kN). At this time they were attempting to increase the Derwent's thrust from 2,200 to 2,450lbf (9.8 to 10.9kN), and the idea seemed "too good to be true". On hearing this, Hooker did a quick calculation and announced, "We've got a 600-mph [970km/h] Meteor".[12]
Drawings for the 0.855 scale Nene, now known as the Derwent V, were started on 1 January 1945 and on 7 June the engine began a 100-hour test at 2,600lbf (12kN), soon reaching 3,500lbf (16kN). Weight was 1,250lb (570kg). By 1946 thrust had been increased to 4,200lbf (19kN) using Nimonic 90 turbine blades.[12]
The development of the Nene was continued with this scaled-down version, the Derwent V having no direct relationship to the earlier Derwent series. On 7 November 1945, the first official air speed record by a jet aircraft was set by a Meteor F.3 of 606 miles per hour (975km/h) powered by the scaled-down Nene.
Service use
Pratt & Whitney J42
The Nene doubled the thrust of the earlier generation engines, with early versions providing about 5,000lbf (22.2kN), but remained generally similar in most ways. This should have suggested that it would be widely used in various designs, but the Gloster Meteor proved so successful with its Derwents that the Air Ministry felt there was no pressing need to improve upon it. Instead a series of much more capable designs using the Rolls-Royce Avon were studied, and the Nene generally languished.
A total of twenty-five Nenes were sold to the Soviet Union as a gesture of goodwill - with reservation to not use for military purposes - with the agreement of Stafford Cripps. Rolls-Royce were given permission in September 1946 to sell 10 Nene engines to the USSR, and in March 1947 to sell a further 15. The price was fixed under a commercial contract. A total of 55 jet engines were sold to the Soviets in 1947.[13][14] Seventeen Soviet engineers trained at the Rolls-Royce factory in Derby in 1947 to maintain and repair the engine. The Soviets reneged on the promise to not use it for military purposes,[14] and reverse engineered the Nene to develop the Klimov RD-45, and a larger version, the Klimov VK-1, which soon appeared in various Soviet fighters including Mikoyan-Gurevich MiG-15.
Pratt & Whitney acquired a licence to produce the Nene as the Pratt & Whitney J42, and it powered the Grumman F9F Panther which first flew in November 1947.[15]
The Nene was used to power the first civil jet aircraft, the Nene Viking,[16] a modified Vickers Viking, the single example of which first flew on 6 April 1948 from Wisley Airfield.[17][pageneeded]
Hispano-Suiza in France built the Nene under licence as the Hispano-Suiza Nene, with limited production before concentrating on the larger Rolls-Royce Tay/Hispano-Suiza Verdon.
The Rolls-Royce RB211 is a British family of high-bypass turbofan engines made by Rolls-Royce. The engines are capable of generating 41,030 to 59,450 lbf of thrust. The RB211 engine was the first production three-spool engine and turned Rolls-Royce from a significant player in the aero-engine industry into a global leader.
The Rolls-Royce Pegasus is a British turbofan engine originally designed by Bristol Siddeley. It was manufactured by Rolls-Royce plc. The engine is not only able to power a jet aircraft forward, but also to direct thrust downwards via swivelling nozzles. Lightly loaded aircraft equipped with this engine can manoeuvre like a helicopter. In particular, they can perform vertical takeoffs and landings. In US service, the engine is designated F402.
The Rolls-Royce Olympus was the world's second two-spool axial-flow turbojet aircraft engine design, first run in May 1950 and preceded only by the Pratt & Whitney J57, first-run in January 1950. It is best known as the powerplant of the Avro Vulcan and later models in the Concorde SST.
The Rolls-Royce RB.183 Tay is a medium-bypass turbofan engine, developed from the RB.183 Mk 555 Spey core and using a fan scaled directly from the Rolls-Royce RB.211-535E4 to produce versions with a bypass ratio of 3.1:1 or greater. The IP compressor and LP turbine were designed using technology from the RB.211 programme. The engine was first run in August 1984. The Tay 650 had a new HP turbine which incorporated new technology which had been proven with the RB.211-535E4. This engine also had a new combustor for improved durability. The Tay family is used on a number of airliners and larger business jets, including the Gulfstream IV family, Fokker 70 and Fokker 100, with a later version being used to re-engine Boeing 727-100s.
The Rolls-Royce RB.44 Tay is a British turbojet engine of the 1940s, an enlarged version of the Rolls-Royce Nene designed at the request of Pratt & Whitney. It saw no use by British production aircraft but the design was licence built by Pratt & Whitney as the J48, and by Hispano-Suiza as the Verdon.
The Rolls-Royce Spey is a low-bypass turbofan engine originally designed and manufactured by Rolls-Royce that has been in widespread service for over 40 years. A co-development version of the Spey between Rolls-Royce and Allison in the 1960s is the Allison TF41.
The Pratt & Whitney J57 is an axial-flow turbojet engine developed by Pratt & Whitney in the early 1950s. The J57 was the first 10,000 lbf (45 kN) thrust class engine in the United States. It is a two spool engine.
The Rolls-Royce RB.53 Dart is a turboprop engine designed and manufactured by Rolls-Royce Limited. First run in 1946, it powered the Vickers Viscount on its maiden flight in 1948. A flight on July 29 of that year, which carried 14 paying passengers between Northolt and Paris–Le Bourget Airport in a Dart-powered Viscount, was the first regularly scheduled airline flight by a turbine-powered aircraft. The Viscount was the first turboprop-powered aircraft to enter airline service - British European Airways (BEA) in 1953.
The Rolls-Royce Avon was the first axial flow jet engine designed and produced by Rolls-Royce. Introduced in 1950, the engine went on to become one of their most successful post-World War II engine designs. It was used in a wide variety of aircraft, both military and civilian, as well as versions for stationary and maritime power.
The Rolls-Royce RB.37 Derwent is a 1940s British centrifugal compressor turbojet engine, the second Rolls-Royce jet engine to enter production. It was an improved version of the Rolls-Royce Welland, which itself was a renamed version of Frank Whittle's Power Jets W.2B. Rolls-Royce inherited the Derwent design from Rover when they took over their jet engine development in 1943.
Sir Stanley George Hooker, CBE, FRS, DPhil, BSc, FRAeS, MIMechE, FAAAS, was an English mathematician and jet engine engineer. He was employed first at Rolls-Royce where he worked on the earliest designs such as the Welland and Derwent, and later at Bristol Aero Engines where he helped bring the troubled Proteus turboprop and the Olympus turbojet to market. He then designed the famous Pegasus vectored thrust turbofan used in the Hawker Siddeley Harrier.
The Rolls-Royce RB.23 Welland was Britain's first production jet engine. It entered production in 1943 for the Gloster Meteor. The name Welland is taken from the River Welland, in keeping with the Rolls-Royce policy of naming early jet engines after rivers based on the idea of continuous flow, air through the engine and water in a river.
The Klimov VK-1 was the first Soviet jet engine to see significant production. It was developed by Vladimir Yakovlevich Klimov and first produced by the GAZ 116 works. Derived from the Rolls-Royce Nene, the engine was also built under licence in China as the Wopen WP-5.
The Bristol Siddeley Orpheus is a single-spool turbojet developed by Bristol Siddeley for various light fighter/trainer applications such as the Folland Gnat and the Fiat G.91. Later, the Orpheus formed the core of the first Bristol Pegasus vectored thrust turbofan used in the Harrier family.
The Pratt & Whitney J48 is a turbojet engine developed by Pratt & Whitney as a license-built version of the Rolls-Royce Tay. The Tay/J48 was an enlarged development of the Rolls-Royce Nene.
The Rolls-Royce RB.50 Trent was the first Rolls-Royce turboprop engine.
The Pratt & Whitney JT12 is a small turbojet engine. The Pratt & Whitney T73 is a related turboshaft engine.
The Rolls-Royce RB.141 Medway was a large low-bypass turbofan engine designed, manufactured and tested in prototype form by Rolls-Royce in the early-1960s. The project was cancelled due to changes in market requirements that also led to the development and production of the smaller but similar Rolls-Royce Spey, and the cancellation of the Armstrong Whitworth AW.681 military transport aircraft project.
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.
The Power Jets W.2 was a British turbojet engine designed by Frank Whittle and Power Jets Ltd. Like the earlier Power Jets W.1, the reverse-flow combustion configuration included a double-sided centrifugal compressor, 10 combustion chambers and an axial-flow turbine with air-cooled disc. It entered production as the Rolls-Royce Welland and was the first UK jet engine to power operational aircraft, the Gloster Meteor.
References
1 2 "Rolls-Royce Aero Engines" Bill Gunston, Patrick Stephens Limited 1989, ISBN1-85260-037-3, p.111
↑ "Not Much Of An Engineer" Sir Stanley Hooker, Airlife Publishing 2002, ISBN1-85310-285-7, p.88
↑ Gas Turbines and Jet Propulsion For Aircraft,Geoffrey Smith, Fourth Edition 1946, Published by Flight, Dorset House, Stamford Street, London S.E.1., p.75 and Fig.77
↑ Gunston, Bill (1980). The Illustrated Encyclopedia of Commercial Aircraft.
1 2 3 4 5 Wilkinson, Paul H. (1950). Aircraft engines of the World 1950 (11thed.). London: Sir Isaac Pitman & Sons Ltd. pp.56–57.
1 2 3 4 5 Wilkinson, Paul H. (1957). Aircraft engines of the World 1957 (15thed.). London: Sir Isaac Pitman & Sons Ltd. pp.65–69.
↑ "Engines List". City of Norwich Aviation Museum. Retrieved 27 August 2023.
↑ Wilkinson, Paul H. (1946). Aircraft Engines of the world 1946. London: Sir Isaac Pitman & Sons. pp.298–299.
Bibliography
Bridgman, L, (ed.) (1998) Jane's fighting aircraft of World War II. Crescent. ISBN0-517-67964-7
Buttler, Tony (July–August 2001). "Turbojets for Stalin: Some Facts Behind the Sale of British Jet Engines to Russia". Air Enthusiast. No.94. pp.73–77. ISSN0143-5450.
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