Quote:
Originally Posted by Graham Boak
You are stepping outside the point of the original comment. Both the Hercules and the Twin Wasp were in the 1300-1500hp class in 1941: that the Hercules was later developed beyond that is a measure of its quality rather than relevant to a discussion on entry-into-service dates. In 1943, both the Double Wasp and the Centaurus were in the 2000hp class (as indeed was the Sabre). Postwar power outputs are irrelevant here.
That the US chose to make bigger engines rather than developing their earlier designs to the utmost is an interesting engineering option: it does not make the long-delayed Centaurus an equivalent to the 3350.
I stand by my initial premise: that British engine production policy in WW2 was biased towards the in-line engine because of a failure of British radial manufacturers to produce competitive engines in the requisite timescale, and that this was because the sleeve-valve approach ran into problems that extended development times.
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The Twin Wasp was mostly a 1200 hp engine during the war (and a 1065 hp engine with 87-octane fuel). You simply cannot consider it to be in any way equivalent to the Hercules which was producing 1600 hp+ by that time. And the same applies to the R-2800 vs. Centaurus situation. With 100/130 fuel and no ADI, the wartime ratings of the latter are considerably higher (by several hundred hp in single stage versions)). That is a fact.
Besides, the other major British radial maker, Armstrong-Siddeley, was not involved in sleeve valves in any way and could have designed a Boak-valved engine, had they wished.