Last weekend at a contest, I was having problems with a slight yaw that was obvious during outside corners. More obvious at the 45 degree corners at the top of the outside squares. Didn't seem to have a lot of effect on the flightpath, but it bugged me. A lot. It was suggested by one trim expert that I trust that it could be because there's an almost undetectable warp in the outboard flap of the plane. Sort of a slight downturn as the flap reached the root. Another guy that is also very good at this stuff suggested that the leadouts were too close together. That rang a bell. If I move the leadouts farther back. Say 1.25" behind the CG, the problem mostly goes away, but the line tension above 45 degrees also pretty much disappears. I had hit a compromise that somewhat minimized the yaw while maintaining some line tension above 45 degrees. It was suggested that if I split the leadouts (make them independently adjustable) that I could keep the front (up) leadout at the best location and move the rear one back to help with the yaw issue. This seemed to make some sense.

So, what to do? What I did was cut a hole in the bottom of the wingtip and remove the leadout slider (not so easy since it was a boxed system with the slider in the middle). I machined two new sliders that each have a set screw. Hopefully, I can finish it up tomorrow and recover the hole I cut and repaint it by the weekend. Then we'll see what we have. Since the new PA plane (currently covered and awaiting fillets and primer) is much the same design, if this works, I'll retrofit it with a similar system. The only question now is, since I have to repaint the bottom of the wingtip, is it worthwhile to go ahead and fix some other minor hanger rash that the plane has accumulated.

Just my thoughts Randy. If the new independent leadout slider works out to be the cats meow. You'll be flyin the SLIDER alot until the new one is done anyway. I say as long as you got the paint mixed and the gun out, go for it. Remove all that hanger rash, why do it twice, because if it flys good you gotta look good. Your just that kinda guy. No less than what I expected.     

I am glad Randy is flying better while I keep getting worst. 23's and twenty fours just  for my squares just don't cut it. Maybe I am just getting old or my scores are.

Got the leadouts all redone and put a patch over the hole. Hope I can sand it out tomorrow and get some more dope on the patch. Then paint it soon. I hope to have the repair done so I can do some flying this weekend, but I'll fly it with the patch just doped if not. I'm dying to see if this works.

Dennis,

This was a standard layout with the down line in the back. Problem was, the leadouts were about a half inch apart in a one piece slider. If you slid the slider back far enough to kill the yaw in the outside corners, all the line tension was gone above 45°. If you slid it forward until you got pretty good tension above 45°, you got a wiggle on hard outside control. I hit a compromise spot where the wiggle was minimized and the line tension was OK, more or less.

On hard outside control, at the end of the turn, the outboard wing was ahead of the inboard wing. The plane has a ton of side area aft of the CG, so it tends to stabilze pretty quickly, but causes a little rocking on the yaw axis.

Paul just suggested that if the leadouts were independently adjustable, then I could locate the line angle in the right place and move the leadouts apart a little at a time using the line angle point as a center until both problems went away. Like I said, we'll see if it works. It was worth trying since nothing else seemed to help.

It's not a bad problem. But it's there and bugs me.

Glad to see it is done, now for the flight reports!

Mongo (who BTW always tries to put the up line in front)