I acquired a " 1/4 Scale" Cub that was built a while ago and I don't have the manuals and I don't even know what kit it is (was). The wingspan is 88", the chord is 16", the aircraft length is 66" and i'm guessing the weight will be around 13 to 15 pounds. Is there a basis or a good starting point for finding C of G if you don't have the manufactures's recommendations?

Any help would be greatly appreciated!

this might help
http://adamone.rchomepage.com/cg_calc.htm

Its very simple for a straight chord wing such as a Cub and most Cubs are ideally flown at 25% mean aerodynamic chord or simply put the quarter chord.

Measure the distance from the leading edge to the trailing edge, divide this by four and the result is the distance back from the leading edge to set as your target CG.

John