Shortround6
Major General
Piston area & piston speed, rpm & pressure,
What is remarkable is that the Sabre was actually built, even if in modest numbers, & saw useful service, unlike
the equivalent P & W attempt , any of the adventurous R-R designs, or the German piston exotics.
The real question is should it have been built or should it have been consigned to the rubbish bin like most of those other engines.
The total cost of the sleeve valve adventure may never be known but it was millions of pounds for not a lot of result.
Some people estimated that the sleeve valve engines cost 2 to 4 times per horsepower what a Merlin did (NOT including research and development) which goes a long long way in explaining why they built so many Merlins and not so many exotic engines.