That is because the F4U's had a dive brake setting on their landing gear that would only drop the front gear and would keep the tail wheel up. You can drop the front gear at very high speeds but the tail wheel was a little more flimsy. This is just an easy way to execute it in-game.
You're correct that the mains only (and not the tail wheel) were lowered as dive brakes. That wasn't my concern. The gear could be lowered at relatively high speeds compared to other aircraft. I'm just wondering if it's not a bit excessive in AHII.
The following is from:
http://homepage.eircom.net/~frontacs/WBStored/F4UGearAsDivebrakes.html**************************************"Got some more about F4U gear for you. All of the following is taken from the Air Ministry Pilot's notes for the Corsair I-IV for RAF and Royal Navy pilots."Para 44 Flying Limitations(iii) Dive Bombing
Maximum speed (u/c up)... ... ... ... 375 Knots IAS
Maximum speed for lowering u/c (dive brakes)... 250 KIAS
Maximum speed u/c down ... ... ... ... ... 350 KIAS
**************************************It's obvious that the gear was incredibly strong once down and locked, but the max deployment speed is 100kts less. I know there are F4U Manuals out there for sale. Hopefully someone has one and can provide some clarification.