There's a thing I just read on British engines during World War 2 which was about Rolls Royce, who took the engine development of Whittles W.2B off Rover. They were producing it to produce 1800 lbs worth of thrust, after visiting America and realising that America were producing them at 4000lbs or more they came back and designed the Rolls Royce Nene engine from scratch which produced 5000lbs worth of thrust and it was the most powerful engine in the world.
The same engine was used in the MiG-15. And this engine was being designed in November 1941.