I fly all my sport outdoor aircraft (glow) with ailerons only, i.e. I use ailerons to turn. I never couple or coordinate the rudder with the ailerons.

If ground handling is not a concern, can I just glue my A6M2 rudder in place and fly only on ailerons (indoors)?

From : Don Stackhouse

I'd recommend against that. I've tried various Roadkill Series models with just ailerons and with just rudder, and the results have been disappointing.

The exceptions are the Cub and Junior when built with just rudder and extra dihedral, but that is because they were specifically designed to do that.

At higher speeds and lower lift coefficients (such as your glow-powered sport models) you may be able to get away with it. However, as you slow down (such as during landing, or when flying indoors), the adverse yaw will get worse, and tend to cancel out the roll effects of the ailerons, leaving you with poor roll response, or in severe cases no roll response at all. P-factor and slipstream effects will also tend to give you a plane that turns well in one direction but poorly in the other. These factors are generally not as important on the faster sport models you're used to, but on a slower model with a relatively larger prop, they can be more significant.

The A6M2 has a very long tail moment, which is usually good for providing lots of yaw stability, which helps suppress the adverse yaw from the ailerons. However, it also has long, skinny wings with ailerons out at the tips, which tends to make the yaw problems worse. In any case, it's not that much more work to run the pushrod back to the rudder, and it pays off with more options for flight trimming, and with better control response in both directions, as well as providing an easy way to adjust yaw trim. The extra work to hook up the rudder is minor in comparison to the improvement in control and handling. In addition, it also adds some fun maneuvering possibilities, such as the ability to do hammerheads and snap rolls. I'd include the functional rudder if I was building one for Myself.

Don Stackhouse
DJ Aerotech