[Graham Boak]

I'm afraid that there is a world of difference between having highly promising engines under development, or even in early production, but quite something else to get these into production and then into aircraft and then into service in significant numbers. Compare these promises (for that is what they are) with the historical development of similar engines elsewhere. For example at the same time the British had the Sabre and Vulture already flying in fighter and bomber airframes with production lines established: the Griffon and Centaurus were not so far behind. The Germans had the DB603 running... I agree that there is no reason to doubt the capabilities of the French industry, but equally there is no reason to doubt that they would have been likely to run into very similar problems as faced by other nations. And the service timescales are always longer than the ambitions.