Rigging question

[JCD'auge]

I maintain a Sport Cub for Mr Russ Luigs in Bandera, Texas. Recently he noticed the aircraft required him to hold right rudder to center the ball. On it's own it flies about half a bubble out to the right. The airplane has not been damaged in any way other than a slight paint scrape on the left wing tip which strangely matches a yellow streak on the hangar door. I found the right rudder pedal return spring was stretched and almost out of the attach hole in the pedal. Replaced both springs with no effect. Can find no other defects on the airframe that would indicate a rigging change. Any suggestions?

[Pete D]

Does the aircraft have a rudder trim tab? A lot of the early ones do not. I doubt it is something that has changed, it probably has always done this. A rudder trim tab is easy to install if you don't have one. If you call up and order one, specify the aircraft color and it can be sent out pre-painted so all you have to do is drill 3 holes and put 3 screws in. It is easy for the owner to fine tune to get it to fly ball-centered.

Sometimes flying at different RPMs can make a bit difference in how centered the ball is. For example, at 2650 RPM vs 2300 RPM, the ball will most likely be in different places when your feet are off the pedals.

Pete D.

[JCD'auge]

Thanks, and no the aircraft does not have a trim tab---yet. I can find no discrepancies with the cables or controls, so a tab is probably the fix.

[couleeone]

The trim tab worked real well for 7AK, #6

[foxstardoc]

We added a rudder trim tab on N674KM and it solved the problem.
Ken