I am building an LT-40. I have most of it built, but I just joined the 2 wing halves. The left wing balances heavier than the right. I widened the holes on the end of the wing, and added a third smaller one. It is still about 1/2 inch out of balance. How crazy should I get to balance it? The alerons are not on it yet.

Thanks!

I just leave it until the plane is ready. Then I get balance the whole plane at once. This would save you the extra work, as weight from covering, engine, radio gear, fuselage, etc. might alter the balance.
I then balance it horizontally.
Hope this helps.

Once you realize that a covered plane does not balance laterally how do you fix it? Do you cut holes in the covering to add weight?

If I know that the wing is strong enough, I cut into the wing, dump the lead, and a bit extra. Re-check the balance, before seeling it off again.

Very important step you must not over look.
If it wasn't for this huge field of grass my second airplane went down in, it would have been a gonner due to a heavier wing panel. (8yrs ago). Yes it was that heavy, I had to hold full right aileron and still it wanted to bank left, very scary on it's first flight(Super Sportster .40).

Balance the wing with the ailerons on, place the heavier one on the lighter wing panel and add more weight if still needed. I balance my wings while on the fuselage with everything already installed(engine, radio gear, etc.).
Of course if you're plane is already covered, you'll have to cut through the covering if you don't want to have an unsightly lead weight stuck to the bottom of one of the wings.

I just finished all the final balancing and control throw adjustments on my LT-40 about 30 minutes ago. I checked the wing balance with it mounted on the plane. I will have to add 2 ounces to my left wing to get a proper balance. I plan to cut open one of the holes in the wing tip, tape and glue the weight inside then cover that wing tip in red for better visability. I could cover the hole with the original colors but the red will give me a reference while in the air.

I am going to balance it now, when it is not covered. That way I will have to add less weight later, if any.

This is realy a question.

I know my wings are accurate (Not twisted) and balanced. The AIRPLANE balances correctly spanwise. However when I mount the side mounted motor the plane tips to the right. I need over an ounce of weight on the left tip.

Why is it then when I fly the plane with no tip weight I need no aileron offset to balance the effect of the engine weight?

Ed S

I think teh answer is an engine TORQUE thing.

I wondered about that, and guessed the same reason.

This brings up all sorts of trimming permutations of torque, out of balance wings. twisted wings and aileron offset to stop the airplane from rolling.

I will go no further with this subject.

Ed S

Then add right engine thrust angle to the formula and it get really complicated even in normal flight then fly inverted .......... holy cow ????

Ed, trim your plane for level flight, then fly inverted. That's when you'll notice the weight difference. Your plane will cork-screw through loops etc.

For all you guys who are wondering... Finish your plane. Have it ready to fly. THEN balance it, both CG and laterally. shift your batteries or add weight to the nose or tail. Then add wingtip weight if needed (and I've never seen a plane that didn't need some). I usually use split-shots, then once you find the right amount, remove 1 or 2 (depending on their size) to allow for the weight of the epoxy you will be gluing them in with. Now drill or cut a small hole in the bottom of the wingtip and drop in the epoxy-coated weights. Re-check the balance to make sure you got it right. Then apply a small patch of covering over the hole.

( I know it's a heart breaker to put a hole in your new airplane, but there's no sense in doing it before the plane is ready, and no one will ever see the little patch on the under side.)

Or you could keep a loose patch? This might be better.

I don't disagree with the thoughts above, but I have another story. After building a bunch of kits, Arf's, and scratch builts, I have never added any weight to any of them. No nose weight, no tail weight, no wing tip weight. I just move the battery until the CG is within the allowable range and forget about the lateral balance.

With its heavy side mounted engine, I know my 1/4 scale Cap "leans" to the right, but it has no trouble doing LOTS of very smooth aerobatics. I admit I don't fly at a competitive level, but I have not seen any problems caused by lateral imbalance.

Tom