F4U airspeed analysis has always been a pain to me because of unusual inconsistency of data as my late forum friend Renrich, who will be sorely missed, would have agreed. In this case, max airspeed, as reported by Ray Wagner's "American Combat Planes", a usually reliable source, is 417 mph. This is also reflected in Navy test of the F4U-1 with water, which shows max airspeed in Mil power (no water) as about the same.
http://www.wwiiaircraftperformance....ted, there is other data showing differently.
I do follow you thoughts - the 20-30mph airspeed difference for the planes that should be as similar/identical as possible does induce some head scratching
I do have a problem with the comparison test you referenced. The data on the F4U looks suspect. A max speed of 408 mph with water is quite low as shown by the above test and others. Information in the test may explain this. It stated that the F4U engine overheated during high power test, maybe due to too much leaning. This may indicate an engine problem or an improper setting. Also, the test of the two Navy birds was at overload fighter weight. Had the F4U been loaded at the same level as the Fw 190, that is, with 138 gallons of fuel, it would have weighed over 1000 lbs less! This would have a major impact on climb and a smaller one on airspeed. This comparison would provide a more accurate airframe to airframe test. I believe this weight difference also applies to the F6F.
Either that (the bolded part), or the comparison with planes executing tests with same fuel fraction?
All in all, I still believe that my comment is reasonable.
No sweat, your comments are reasonable and worth reading