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From Air Vectors

"By October 1940, the Air Ministry was interested enough in the Whittle engine to arrange for production of the W.2B by Rover. Unfortunately, the term "misarranged" is probably more appropriate, since Power Jets and Rover worked at all times at cross purposes, with the confusion aggravated by contrary instructions from the British Ministry of Production. The jet engine development effort slowly strangled on its own red tape until 1942, when Rolls-Royce's Ernest Hives took S.B. Wilks of Rover out to lunch and, as the story has it, asked Wilks: "Give us this jet job and we'll give you our tank-engine factory in Nottingham."
Rolls-Royce wanted the jet engine and knew what they wanted to do with it, and indeed, beyond the end of the millennium, still does. In fact, the company's own engineering staff had been working on jet propulsion since 1939, and in making the swap Rover was giving away something they didn't really want, while Rolls-Royce was obtaining a treasure.
A W.2B engine, plugged into the tail of a Vickers Wellington bomber, was test-flown that November, and after further improvements was test-flown in the second G.40 Gloster Whittle in March 1943. The W.2B was providing 7.11 kN (725 kgp / 1,600 lbf) thrust by this time. Rolls-Royce worked with Whittle to finally get an uprated version of the W.2B engine in production as the "Welland I".
* The Whittle WU, W.1, and W.2B were all "centrifugal-flow" engines, which used a turbine similar to a pump impeller to force air into a set of combustion chambers or "combustors" ringed around the engine core. The flow of air went through the combustors from back to front, with such a "reverse flow" arrangement reducing the length of the engine. These engines had only the broadest resemblance to a modern military turbojet engine, but the same design concepts would not be out of place in a modern helicopter turboshaft engine.
Rolls-Royce then reworked the Whittle design to feature straight-through air flow through the combustors and better fuel and oil systems, resulting in the "Derwent I", providing 8.83 kN (900 kgp / 2,000 lbf) thrust. The Derwent was refined in various versions up to the Mark IV, which provided 10.8 kN (1,100 kgp / 2,450 lbf) thrust.
* Stanley Hooker, who had been in charge of the Rolls-Royce design team that refined the Derwent, visited the US in the spring of 1944 and found that the General Electric company was developing two turbojet engines with thrust ratings of 17.6 kN (1,800 kgp / 4,000 lbf) or higher. Hooker, realizing that the British had been thinking small, went back to Britain and initiated a fast-track project to build a new, much more powerful centrifugal-flow engine. The result was the "RB.41 Nene", which was first bench-tested in October 1944 and provided 22.3 kN (2,270 kgp / 5,000 lbf) thrust. The Nene was the world's most powerful engine at the time, and it was also simple, cheap, and reliable. The Nene was manufactured in large numbers, with versions made in Canada, Australia, France, the US, and the USSR.
The Nene was such a good engine that Rolls-Royce decided to build a scaled-down version, which was designated the "Derwent 5", though it had little direct relationship to earlier Derwent marks. The Derwent 5 was first bench-tested in June 1945, with the test engine providing 11.8 kN (1,200 kgp / 2,650 lbf) thrust.
* In the meantime, since early 1941 de Havilland had been working on their own centrifugal-flow turbojet engine -- derived from earlier Whittle patents, not the W.1 design. The result was the de Havilland "Halford H.1", which was first bench-tested in April 1942. By late 1943, the H.1 had been refined into the "Goblin" engine, which provided 10.2 kN (1,040 kgp / 2,300 lbf) thrust and would power the de Havilland Vampire fighter. "

So, the POD is simple. Rolls Royce gets the job to produce Jet Engines from the start. This shaves at least one full year off development cycle. This gives a production Derwent in 1943, and a Nene and Derwent V in 1944. The Meteor F3 goes into action in late 1943 over France and in mid 1944 we have the Meteor F4 and the Nene Powered Vampire F2. Consequences for the LW?
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