On Jan 20, 6:22*am, David Billington
wrote:

Whittle did have ideas for axial flow turbines and what we now know as
the turbo fan, ...

"The Airplane Engine", by Lionel S. Marks, 1922, page 442:

"Gas turbines have been under active development for over fifteen
years but the difficulties inherent in them have not as yet been
overcome without sacrificing their potential efficiencies. The
principal troubles are those resulting from the high temperatures to
which the combustion chambers, nozzles, and buckets are
subjected....Over-all thermal efficiencies are usually about 5 per
cent, although an unsubstantiated value of 20 per cent has been
claimed for a 1,000-h.p. unit....Its simplicity and light weight have
attracted many inventors, but there are no indications that it is ever
likely to become practically available."

1922 - 15 = 1907

There are drawings of piston engines showing up to six valves per
cylinder and double overhead cams, plus some really exotic multiple-
crankshaft arrangements including a supercharged, direct injection,
opposed piston two stroke that became the WW2 US submarine engine. The
best specific gas consumption was apparently a little under 0.5 Lb /
Hp-Hr with compression ratios held down by the low octane rating to
6:1 or less.

Jim Wilkins