We have been told by Pacific Vets that "Whispering Death" WAS a name given to the Corsair by the Japanese. It was done because the Corsair could dive on ground targets with reduced throttle and the only sond heard was the whispering whine of the supercharger. When our F4U-1 Corsair (the oldest one flying) flies, it sometimes can do the same thing when the pilot throttles back.
In fact, Tom Camp's FM-2 Wildcat does the same thing, only he comes by at cruise power. First you hear the engine, then the supercarger as he passes over the top of you.
In the case of the Corsair, the supercarger is the dominant sound only when the aircraft is well throttled back. Otherwise, the dominant sound is the R-2800 song of power. It may have many characteristics, but the R-2800 DOES sound powerful, and it is, in spades.
Whether or "Whisting Death" it was REALLY a name conferred by the Japanese is someting I can't confirm. I can only say I have heard it said by vets. How many of them ever met a Japanese soldier during WWII is another story, so it also could have been simple American propaganda. Maybe we could hear from some Japanese members on this one? The Japanese had nicknames for many things, but I am not sure they included American fighters!l
The Americans (and all Allies) had CODE names for enemy aircraft, but rarely common nicknames. It might be the same for the Axis, too. I DO know the Germans called the Ilyushin IL-2 a nickname ... the "Cementer" becasue it was so hard to shoot down and seemed to be made of cement! That is from numerous combat accounts. Maybe or maybe not for the Americn fighters ... but, of course, the P-38 was an unusual-looking airplane, so maybe it DID have a nickname.
Perhaps some German members could chime in here ...