the instructions on my hangar 9 super stick 60 say to measure the cg 1\8 behind the main spar of the wing it says the main spar spans the wing underneath the back edge of the wing sheating i dont know what this means i always before measured back so far from the leading edge on all my other planes could someone explain this procedure to me or atleast tell me what it would be from the leading edge of this model plane

The wing is sheeted with balsa from the leading edge back to the spar - about one third of the chord of the wing. So the instructions are trying to tell you that the spar is at the spot on the wing where the balsa sheeting ends and the open covering begins. Your ideal CG location is just behind the spar. Does this help? In other words, feel the underside of the wing out at the wing tip. starting at the leading edge run your finger along the underside toward the rear of the wing. About one third of the way back, you will feel the transition from solid balsa sheeting to just covering over air. At this point, you have found the rear edge of the spar. the CG is 1/8 behind that point.

These aren't the best pictures but hopefully they will help. since your plane is covered, you might not be able to see the edge of the sheeting clearly. In that case, just feel for it.

Basically, the spars are the "beams" that run the length of the wing and provide strength. The leading edge sheeting forms the front section of the wing on both top and bottom and usually stops at the spar.

Once you find the spot, measure back 1/8 and make a mark. That's where the plane should balance.

thanks that explains it! i knew what the spar was but i couldnt figure out the sheating and it made it sound like to me it was at the back edge of the wing and i thought that was going to be way back for the cg! thank you very much for your help gonna go back to the basement and balance it before bed!!

those things run a bit tale heavy depending on the engine you are going to use,try to keep all of your radio equipment as far forward as you can.i finally had to mount my engine further out than recommended to balance mine i have had two of them and they both came out tale heavy.i used a os 91fx in my second one.i read if you make them a tale draggier that that helps the balance point also.

i used a os 61 in mine and it was a little heavy in the front