Now that I'm home from work, some further reading on this:
*(Note: John Deakin flew C-46s for Air America in SE Asia)
The one thing the C-46 is really famous for is lousy directional control on the takeoff and landing roll. Its rudder is extremely ineffective at low speeds on the runway, even after the tail is up on takeoff. Even under ideal conditions with the wind right down the runway, or with no wind at all, the airplane might suddenly, for no reason whatsoever, head for the side of the runway rather briskly. If you slam in full rudder to stop it, that rudder is totally ineffective. The only solution is to yank back the opposite throttle to stop the nose. And when the nose starts back, you have to get the throttle back up again to get the beast under control. That particular quirk has bitten more potential C-46 pilots than anything else.
The C-47 doesn’t have the same problem. The rudder area on the C-46 is about 30 percent of the vertical surface area, leaving about 70 percent for the vertical stabilizer. The C-47 is reversed, giving it better directional control than the C-46 at low speeds.
Also, the C-46 is a very fat airplane, so when it’s moving down the runway the fat fuselage blocks a lot of airflow over the vertical surfaces. The small rudder doesn’t get much airflow, which limits its effectiveness. The C-47 has a much narrower fuselage, which allows more air to flow over the vertical surfaces, and it has a larger rudder to boot.
You can easily taxi a C-47 at moderate speed, 10 knots or so, and have rudder control with the free swiveling tail wheel. The C-46 rudder has absolutely no noticeable effect when taxiing.
The C-46 has monstrous ailerons, consequently the adverse yaw effect is much greater than on other airplanes. The result is that if you roll the wheel to the left for a left bank, the nose actually goes to the right if you don’t apply a fair amount of rudder to resist it. In most airplanes on a crosswind takeoff, you use the ailerons into the wind to help a little bit. With the C-46 it’s absolutely crucial to use the aileron very heavily to roll it into the wind.*
(taken from the CAF website).