I must be doing something wrong. I built a GP Extra 300 exactly according to the plans (see my earlier thread).

It took 30 ounces of lead to balance the plane (using the GP CG balancing stand) at a CG that is 5.75 inches aft of the leading edge of the wing where the LE contacts the exterior fuselage. The GP instructions say the CG should be 3 3/16 inches from the leading edge of the wing at the wing tip. I got the 5.75 number from some notes in this thread.

Does anyone know if this CG location is correct? With the weight necessary to balance at this point the aircraft weighs 17 lbs 7 ox - which is a lot for a glow engine.

Thanks in advance for any help - this web site is an awesome resource for RC!