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All the wartime P&W R-2800 powered F4Us as well as Grumman F6Fs had 2 stage mechanical superchargers.
I came across the PATENT for the -32W "sidewinder" type superchargers recently. Makes interesting reading.
The number of the doco is US 2,667,298 and it is titled, "Arrangement of Opposed Superchargers".(Five very nice drawings) It can be downloaded free from the uspto.gov website.
Written by the designers, it gives a lot of insight into the thinking at the time.
All F4Us including the XF4U had two speed, two stage superchargers on the R2800s. See Dean's "America' Hundred Thousand" for a description of how they worked.
Is this true? Did the F4U-1 have no WEP at all?
Side note: Why would air-cooled engines be less inclined to produce higher boost pressures than liquid-cooled? Or at least that's what your note suggests.
Side note: Why would air-cooled engines be less inclined to produce higher boost pressures than liquid-cooled? Or at least that's what your note suggests.
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Pilots flying these engines had an unusual degree of control over their supercharging. P-38, P-39, P-40, P-51 and Spitfire IX pilots had virtually no control, except for the few Mustangs modified to give the pilot direct control over activating the 2nd speed manually.