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There is a scientific paper comparing sleeve versus poppet valves on the Aircraft Engine Historic Society Website. I am a member and read the document probably 10 years ago. I cannot locate it right now and I don't believe I can share it here anyways.Pictures I have seen of the H24 also seem to show a fairly compact engine - probably due to the lack of heads.
Care to post some sources (bar what Setright says)?All the time RR was playing politics and some in the Air Ministry were dancing to their tune, which resulted in unfair decisions against Napier and Bristol. The RR Eagle development was aided greatly after the Air Ministry removed an engine and all documentation from Napiers and sent it to RR.
Sources?The Centaurus was also held back by the AM,
The staff were not exactly excited about working underground.
"Fedden" Bill Gunston
"By Precision into Power" Vessey
Productivity and morale do have some connection.
There are no poppet valve H24s in that list. I assume most of the advantage over an equivalent displacement V12 or R14/18 is just in having smaller cylinders that can be run at higher rpm [edit: compare the Sabre and Hercules, or the Eagle and Centaurus, all sleeve valve], and any extra advantage to the sleeve valve per se is paid for with higher weight as Simon Thomas said. (Also I think late war R-2600s were making 1900hp?)Take note of the BHP per displacement of the H24 engines (in particular) vs the equivalent size poppet valve engines.
RR kept going with the Eagle and Pennine into 1945 and maybe later for the Eagle?By 1943 the jet engine was looking like the future, so there was no point anyone else spending millions and tying up resources, who were already stretched far too thin, to develop a sleeve valve engine.
Vessey, p143. First paragraph, second line.Not in the mood to do wild goose chasing.
Interesting discussions, I had already read the first, but it only touches on sleeve valves in passing?These threads talk more to the issue, you will have to hunt around a bit to find the exact discussions.
In retrospect, were the BMW radial engine developments a mistake?
So the RLM(?) decreed in the early-mid 30'ies that BMW should drop work on liquid cooled aero engines and instead focus on radials. In a way a sensible decision from the perspective of not putting all the eggs in one basked, considering Daimler and Junkers were already focused on inlines. But...ww2aircraft.net Jumo 213 vs. Napier Sabre
Being the peak engine developments of their specific countries which one was more modern, had more potential, was more efficient, more powerful, overall better?ww2aircraft.net
I wouldn't expect so as it's really two flat 12 cylinder arrangements and flat (horizontally opposed) designsWould it be particularly hard to build an H24 with 4 poppet valves/cylinder?
It might have been a case of seeing if they had missed something, crossing their "T"s and dotting their "i"s so to speak.But I still don't understand what RR were thinking with the Eagle and Pennine years later.
Probably not. The H-24 with poppet valves, even if not 4 valves per cylinder had considerable interest if not sales.Would it be particularly hard to build an H24 with 4 poppet valves/cylinder?
Thanks, I'll look it up.Vessey, p143. First paragraph, second line.
Also, as far as I know the R-2600 with 1800-1900 BHP for TO was not a production engine?