sir, if you have an overlay of f4u1c vs yak9u could you post it please
I get killed by hogs in da and an overlay might help.
df54,
The F4U is a formidable opponent, regardless of what you fly against it. If neither aircraft had flaps, it would be a different story because when both aircraft have the flaps fully retracted, the Yak has the advantage. However, when flaps are employed, the advantage swings to the F4U series. At speeds above corner velocity it can match the Yak, but it can employ flaps at 250mph, so it gains an advantage immediately the speed of the fight drops below corner speed. The Yak can't employ flaps until 170mph, when the F4U will already be turning inside it, and when both aircraft reach full flaps the F4U maintains a significant advantage. The EM diagram below is an overlay for the F4U1D v Yak9U with full flaps:

You will notice that the F4U dominates the fight at low speed. For example, with both aircraft at 150mph, the F4U has an instantaneous turn rate advantage of 8dps, with a significantly smaller turn radius. When both aircraft reach their best sustained turn, the turn rates are almost the same, but the F4U will still be able to turn inside the Yak, and most fights won't get that far.
If you fly the Yak against the F4U in the DA under standard rules you will be flying at a disadvantage, so you will probably only succeed against weaker pilots. You can succeed against the F4U in the MA, but you will need to balance its performance advantage before you engage.
Hope that helps...
Badboy