Like Humble / Snaphook mentioned, I would try to keep your speed up and keep some alt to give you some options. If you're trying to turn tight while low and slow you're setting yourself up for some disapointment. The corsair is definately capable of some nice slow turns on the deck, it just really isn't capable of sustaining that type of maneuvering for long. Even if you manage to kill the guy you're fighting, you'll be a fat wallowing target for the next bad guy to come along.
The vast majority of my fighting is done in the 225-325 range, with fairly brief dips into the lower speeds. The F4U really shines when it comes to slowing down rapidly to a speed that allows you to turn inside an airplane that is going too fast to turn at its best, but that is desperately trying to slow down and out-turn you. This is best done at an altitude that allows you to dive out if things go poorly. I feel comfortable dropping down to stall speeds if i have a few thousand feet under me.
The downside to this type of turning is that if you intentionally slow down to turn tightly, and your opponent realizes what you're up to, he can keep his speed and zoom up to a position over your head. This will allow him to make things awful difficult for you.
Even so-
My most common kill on spits, N1K's, etc, is to convince them to go as fast as they can, and then rapidly slow down and turn inside them for the kill while they struggle to turn with you. In essence you're using their speed AGAINST them. They die before they get slow enough to really turn well. I find the easiest way to do this is to let them get behind me (sometimes this is accidental), and act like I'm running away. This gets them to go as fast as they can to catch me, because they know that if they don't catch me quick I WILL get away since I'm in a faster plane. This also lets me get them away from the furball, so they can be kilt in privacy. I then nose down a bit, again to get their speed up, and I then fly a "Barrel Roll Defense" type maneuver to get behind them. (See the trainers web page for a description of that maneuver). This puts me behind them, and as they realize this they often panic and try to turn back behind you. This has the effect of making them slow down in front of you and allow you to shoot them through the top of the cockpit. If you fail to make the kill quickly, and the spit driver begins to use verticals while you are too slow to follow, you're in trouble. If you get in a sustained "Lufberry" type circle with the spit, you'll be in trouble. In both cases the spit will eventually hand you your hat. This is why you have that extra height under you- so you can dive out. Again, you don't need to actually run away, since this is now the same situation described at the beginning of the paragraph. You just need to convince him to go as fast as he can, which he'll do, because he thinks you're running away...
An experienced spit (or other) pilot won't fall for this. Like every other ACM, there is at least one counter move that will cause you problems. However, this simple formula (or deviations of it) does work very well in the F4U.
Look up a trainer in the TA- it's a lot easier to learn from them first-hand than it is to do it through reading. The reading helps for sure, but it's only PART of the equation...
If you see me in the MA, don't hesitate to ask me to meet you in the TA!
MtnMan
