On a dead calm & clear day (or at least no turb & pretty good vis):
* find a good aiming point on the horizon while flying into or out of wind (ie no drift) and a spot or dirt on the windscreen directly in front of you.
* At cruise power & speed in level flight, trim in pitch 1st then, while holding the wings level, use your feet to keep your chosen windscreen spot aligned with the horizon aim point. It may take a few minutes to work out what pressure you need if it is very slight. Don't worry about the ball - it could need adjustment too!
* trim the rudder to relieve your foot pressure while still holding the wings level.
* Identify if you need any aileron input to hold the wings level.
Note: Try to have the aircraft's lateral weight distributed evenly - so no near full one side vs near empty other side fuel tanks
On the ground get your maint. blokes to adjust the rigging and try again. If either the rudder trim or roll rigging is displaced a lot to achieve S&L trimmed flight then you might have a bent airframe.
Last edited by Tinstaafl; 28th Jul 2013 at 23:44.