Another trick to make your plane turn tighter is to dynamically balance your wing/plane, and set your rudder trim (yes, rudder trim, even though we don't have moveable rudders, we do have yaw/rudder trim by adjusting the vertical stab)

To do this, first statically balance the plane laterally, adding weight to the light wingtip as necessary.

Increase your elevator throw a bit from what you'd normally use (you want to induce some snaprolls here).

In the air, fly level, then roll up in to a fairly steep right bank, nearly 90 degrees, and haul back on the elevator. You want to turn as tight as you can while staying level, no climbing or diving, just a hard constant turn. Slowly tighten up the turn with more and more elevator until the plane snaps. It will either "snap up" or "snap down", meaning it will "snap up" by rolling out of the turn and pop upwards, or it will "snap down" by rolling inverted and heading for the ground.

Now do it again. Do several times. The plane will probibly go the same way each time.

Now, do several times, this time rolling left (or right if you went left the first time).

Most planes will go "up" when turning one direction, and "down" when going the other. If you go "up" in a left turn and down in a right turn, you need right rudder or your right wingtip needs weight.

When the plane is balanced, it will always go "up" or always go "down" regardless of which way the plane is turning.

You can also do the same test by pulling lots of loops and seeing if you always snaproll in the same direction. Properly balanced, plane will go nearly 50-50 if you enter the loop perfectly level, and straight in to the wind, with out any disturbance.

I just find the level turns easier to perform, and easier to see what happened, and know which way the plane went.

This kind of tuning of the plane can do some dramatic things to your turning radius. I've had planes where I could add as much as 20% more elevator throw after this kind of trimming. That's a LOT of turn in combat.

(of course, it's possible that "best" trimming techniques may vary with flying style. I don't loop much, I prefer to turn level rather than loop)