Servos for my TF Giant Corsair
wulf190
I don't have the TF F4U, but I do have a Ziroli. I wouldn't go with anything less than 70oz of torque. You do have an advantage on warbirds in that very little actual deflection is necessary. This will allow you to use a shorter arm on the servo and a longer hole on the control surface horn (improve your mechanical advantage).
I broke down and purchased the 106 oz hitec digital for my bird - they are the size of a standard servo, but have high torque and better holding power.
Dave