Lets compare the general performance of the F4U-1A and F4U-1D. Data taken with 25% fuel, zero burn rate. Clean configuration. Note that a bomb rack essentially nullifies the advantages the F4U-1A has over the F4U-1D in terms of drag.
Max Speed, Sea Level.
F4U-1A: 366 mph
F4U-1D: 354 mph
Max Speed, 10k.
F4U-1A: 392 mph
F4U-1D: 380 mph
Max Speed, 15k.
F4U-1A: 412 mph
F4U-1D: 402 mph
Max Speed, 20K.
F4U-1A: 419 mph
F4U-1D: 409 mph
Sea Level Acceleration, 150 mph to 250 mph.
F4U-1A: 23.37 seconds
F4U-1D: 24.42 seconds
Note that the -1D accelerates slightly faster from 150 mph to 200 mph. However, due to less drag, the F4U-1A catches up by 220 mph and is slightly ahead by 250 mph.
Time to Climb From Sea Level to 10K.
F4U-1A: 2:30.34
F4U-1D: 2:27.96
This is directly related to the F4U-1A carrying more fuel weight at 25% capacity, which more than offsets the slightly greater weight of the F4U-1D basic airframe.
Minimum Turn Radius, Sea Level, Full Flaps.
F4U-1A: 422 feet
F4U-1D: 427 feet
In terms of dogfighting, the differences between these two are insignificant, being totally dependent upon weight of fuel and ammo. Invariably, pilot skill is a far bigger factor.
In general terms, the F4U-1A is a slightly better fighter than the F4U-1D. On the other hand, the F4U-1D is a far superior attack aircraft. With performance differences not being large, the F4U-1D is clearly the better all-around aircraft. So, it basically comes down to your purpose. For pure air-to-air fighting, take the -1A. For Jabo, then switching to air-to-air, take the -1D. My personal taste leads me to prefer the -1C over the other two. Its air-to-ground under-wing load is only slightly less than the -1D, and the four 20mm cannons more than make up for that. The -1C's lethality more than offsets the reduction in turn radius (443 feet), acceleration and climb associated with the greater weight of the cannons and their ammo. Either way, you won't go wrong selecting any of these fighters.
My regards,
Widewing