I have a Giant Scale Planes Edge 540 80". First of all the plane is a big piece of crap. I had to strip it down, reinforce, reglue bad joints, replade balsa stringers with spruce, and finally recover. Now I am in need of the proper CG for it.If anyone has any information, please let me know. Thank you Jim

Jim

I do not have specificv knoweledge of the particular model, however the rule of thumb is 25% of the root chord.

This means if the wing is 12" leading edge to trailing edge at the center section that 3" from the LE would be a good starting place.

25% of 12" = 3"

This is wel proven figure and works well some guys use 30% as well.

Good luck

Try this site, it has a cg calc

http://www.palosrc.com/instructors/cg.htm

Thanks jemo, the cg calc works great.

Yes it does, use MGalvins, starting points of 25% to 30% and you should come up with a good CG.

I'm surprised the gsplanes guys haven't responded- They are very noledgeable about there planes. I think they test fly all there models after putting each one together and making sure everything is as advertised. Mabye you should try emailing them.......

Just as a point of intrest the balance point is 25-30% of the mean aerodynamic chord not the wing root. You need to compensate for both wing taper and sweep. The palo site works well.

Jonny_Rebel, I have e-mailed and called them. All they tell me is that is 25% measured at the root. For some reason they won't give an exact number. The cg calc works great.

jemo, although the leading edge of the wing is straight, do you take in account that the trailing edge is seept? Is that the number I should use for the sweep slot in the cg calc?

The CG is 43/4" to 51/4" 5" is best from leading edge of wing
Milton

You put zero in for the sweep (S). If the sweep is zero and the tip is smaller than the root, the trailing edge sweep is accounted for.

Thanks guys, you have been alot of help. Jim