page_title: Rolls-Royce Nene
section_title: Design and development
hierarchical_section_title: Rolls-Royce Nene / Design and development
context_page_description: The Rolls-Royce RB.41 Nene is a 1940s British centrifugal compressor turbojet engine. The Nene was a complete redesign, rather than a scaled-up Rolls-Royce Derwent with a design target of 5,000 lbf, making it the most powerful engine of its era. 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 early jet engines after rivers.
  The design saw relatively little use in British aircraft designs, being passed over in favour of the axial-flow Avon 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 6,000 lbf of thrust, and powered the famous Mikoyan-Gurevich MiG-15, a highly successful fighter aircraft which was built in vast numbers.
  A more powerful slightly enlarged version of the Nene was produced as the Rolls-Royce Tay.
context_section_description: The Nene was designed and built as a result of an early 1944 Air Ministry request for an engine of 4,200 lbf thrust, and an engine was schemed-out by Stanley Hooker and Adrian Lombard as the B.40. In the summer of 1944 Hooker visited the US and discovered that General Electric already had two engine types, an axial and a centrifugal, of 4,000 lbf thrust running. On returning to the UK Hooker decided to go for 5,000 lbf of thrust and, working with Lombard, Pearson and Morley, a complete redesign of the B.40 resulted in the B.41, later to be called the Nene.
  The double-sided impeller was 28.8 inches in diameter, compared to 20.68 for the Derwent I, to produce an airflow of 80 lb/s, while the overall diameter of the engine was 49.5 inches. A scaled up Derwent would have a 60-inch 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. 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, without the inlet vanes, which had not yet been fitted. To everyone's dismay the engine refused to light - positioning the igniter was a trial-and-error affair at the time. On the next attempt, Denis Drew unscrewed the igniter and as the starter motor ran the engine up to speed, lit the engine with an oxy-acetylene torch. The engine was run up to 4,000 lbf and more, and a cheer went up around the assembled personnel. Upon Hooker's arrival next morning, and informed that the inlet vanes had been fitted during the night, Hooker was satisfied to see the thrust gauge needle registering 5,000 lbf, making the B.41 the most powerful jet engine in the world. Weight was around 1,600 lb.
  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, 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. 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. 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.).
  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.
  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 3,650 lbf. At this time the
caption: An FMA IAe 33 Pulqui II without tail section, showing its Rolls-Royce Nene II turbojet
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