This is how to apply this balancing method to our jet wings :

Of course, balancing rotor blades needs more precision than our wings, so here is the simplified method for our planes with separate wing halves :

1. Check the weight of each wing very accurately and calculate the difference. In my case, this was 23 grams. I should add 23 grams to the LIGHTEST wing, and at the same time make sure the CG of each wing is the same.

2. Take a tube which is large enough for the wings to tip back and forth when rolling the tube (this tube is replacing the role of the main shaft of the heli as in the video (= minutes 7.30 to 9.00 on the video)). This can be a plastic tube of about 2"-3" diameter. On wings without tip tanks, diameter can be less.

3. Make a mark on the wings approximately on where you think the CG will be of the wing halves. This reference length mark is measured from both the wing roots of the wings. This mark will serve to observe that both wings are at equal point rolling over the tube. Of course, this length mark must be measured very accurately so that they are identical on both wings.

4. Take the heaviest wing first, and roll it on the tube and check the location where the wing tips down and back. This is now the CG point of the heaviest wing. (= minute 8.30 on the video). Mark that point for easy reference as your CG balance point. (You'll have to put the wing upside down, as the oleo leg will tend to fall down on the table otherwise.)

5. Purpose is that you should add the lead (= the famous 23 grams) to the lightest wing, while making sure the CG of the lightest wing is exactly the same as the CG of the heavier wing. This is the vital point of DYNAMICALLY balancing the wings.

6. Put both wings on the tube now and roll the tube back and forth and move the 23 gram over the surface of the lightest wing until you'll find that both wings are tipping down at exactly the same point. This is where you should glue the lead inside the wing. Of course, if you use 5 grams of epoxy glue, only add 18 grams of lead to reach a total of 23 grams.


Small hint : I do not like to make marks on my planes either, but if you put some paper tape where you're going to mark with a pencil, you can remove this tape easily afterwards.


I hope this trick is very useful to you too, I have applied it to most of my planes now and some did show a major improvement in flight.
The champs ALWAYS balance their models on all axes, in particular in F3A competition.
This method is a bit more sophisticated than a simple statical balancing, and without doubt the way to go for high-G jets.

Too bad if we let the difference between a excellent jet and a bad jet over to some coincidence and good luck balancing ! Perfect CG is the key to superb flight characteristics.

Nicolas.