Help me understand Roll

I have a few questions about controlling roll that are not clear to me. If a plane rolls outward in level and inverted flight, this is a tip weight problem, like too much. If it rolls inward during level and inverted flight, this is also a tip weight problem, like too little. Now here is what I'm trying to understand. If in level flight the plane rolls inward and inverted it rolls outward, I have been told this could be due to a aerodynamic problem such as a warp in the wing, and one way to compensate for it is to tweak the flaps in opposite directions. I can see where this would kinda work in level flight when the plane is being flown at near a constant speed, but when doing the pattern, the air speed is anything but constant, not to mention the drag that would be induced by having the flaps deflected in level flight.
Someone suggested to me to lower the leadout position for this problem and no extra drag would be induced from not having to tweak the flaps. I was told the opposite was true if the problem was opposite (plane rolls outward in level and inward in inverted: raise the leadout position). Can someone explain how this works? And if it does work, are there any adjustable leadouts that allow for verticle adjustment? All I have seen are ones that adjust fore and aft, to control yaw. Please help me understand this.

Bill What you said about wing tip weight is correct.What you have described is a out board flap that is lifting more than the inboard. Most old classic planes have to much lift on the inboard and roll out with down flap.Example the 52 Nobler with the much larger inboard flap need a wart to equal out the lift.If this is a proven design you can tape the hinge line on the inboard flap to help increase the lift on that side. Most designs will lift more on the inboard side so they sometimes have a wider flap on the outside.What plane is this and how long is each wing panel and are the flaps the same size.I have seen people fool around for weeks and never get there plane to flying level through the turns as one wing flap is lifting more that the other.Hope this helps.
Ed

Eddy, I am not having this problem at this time, I'm just trying to understand the concepts. I'm just talking about level flight at this time. I have seen many times at the field when inverted and level up right flight had opposite wing tips up one way and down the other, that it was suggested to tweek the flaps. This is the first time I have ever heard of verticle placement of the leadouts, and was wondering if it works, and how???

The best way to cancel a warp is by dewarping the structure. Tweaking the flaps is not usually too bad a way. By tweaking the flaps, I mean bending some asymmetry into the flaps or the flap control linkage. A trim tab would do the same thing, but is uglier. Either of these methods can cancel a moderate amount of warp uniformly in all conditions except near maximum lift in either direction. One wing will stall first in tight inside corners; the other will stall first in tight outside corners. So you can't get your money's worth out of the wing.

Having the vertical position of the leadouts relative the cg cancel a warp (or vice versa) would appear to work: both rolling moments are proportional to speed, but bad things can happen. The vertical leadout position dominates when there's a lot of line tension, and the warp takes over when line tension is low. Just flying level, the moment due to leadout position would be greater relative to the moment due to the warp when the airplane is going downwind, and less going upwind. One could imagine using some sort of aerodynamic moment as a crude fix to counter incorrect leadout position, but moving the leadouts is not a good way to counter a warp.

There is also the matter of vertically adjustable leadout guides coming loose during a contest, but I shall discreetly not mention that.

If there is no warp in the wing raising or lowering the leadouts to match the vertical CG will eliminate the problem of high one way/low the other. To see if this is the problem hang the plane by the leadouts and check with a plumb line that the wing is vertical. Any mis alignment will be magnified by the centrifigal force during flight.

If the wing hangs vertical then there is a warp. This will have to be eliminated or the flaps will have to be tweaked.

>If there is no warp in the wing raising or lowering the
>leadouts to match the vertical CG will eliminate the problem
>of high one way/low the other. To see if this is the
>problem hang the plane by the leadouts and check with a
>plumb line that the wing is vertical. Any mis alignment
>will be magnified by the centrifigal force during flight.
>
>If the wing hangs vertical then there is a warp. This will
>have to be eliminated or the flaps will have to be tweaked.

Here we have the answer from Carl. Moving the leadouts up or down is not the same as correcting for a warp. If there is a warp, that warp will still exist when you change the vertical leadout position. And if the leadouts are incorrectly placed, then warping the flaps is not the answer, either.

As to the first, hang the plane by the lines as Carl suggests. If the wing hangs vertical with a plumb line, then the vertical placement of the leadouts is correct and should not be changed. If the plane hangs at an angle and you cannot change the leadout location vertically, you can help things by going to lighter or heavier wheels or some such to bring the vertical CG as close into alignment as possible.

Now, as to warping the flaps, the only reason for doing this is because the wing, itself, (Or tail) is warped or the flaps or elevator are misaligned. Twisting the flaps in the opposite direction merely compensates for the misalignment that already exists(as much as possible). Here is a case where two wrongs can make a right, but it is much better to have kept the first wrong from happening.

Just remember, the reason twisting the flaps works is because there is already a twist or misalignment somewhere else. And that wing warp (if that is what it is) will react to speed just as much as the opposite twist in the flaps will. So one cancels out the other (hopefully) and, with the plane now properly trimmmed, you go on to win the Walker Cup and enter the worlds and...(oops, sorry, it is time to wake up. It's morning and the coffee is brewing.)

Don't mix apples and oranges.

Leadout placing (above or below the wing's centerline) is a solution for a too high or too low vertical CG.

Mike Starret's ELIMINATOR, for instance has a very low CG, and the plans indicate the leadouts coming out of the wing 1/8" below the centerline.

About the plane rolling outwards (inboard wing lifting) this was a method devised by Bob Palmer to keep line tension on maneuvers, but nowadays nobody want to have more flap on the inboard wing than on the outboard one.

On loops it would be OK, but on an eight the plane had to roll a LOT on the intersection, causing more trouble than benefiits.

Modern designs usually are simetrical or have a longer inboard wing, but more flap on the outboard wing.

If it rolls towards you, ad more tip wheight.

I ssugest you go to www.control-line.org and download Paul Walker's trim chart.