Augie11

I use a version of the 'contraption' which is essentially the same. EXCEPT the plane is supported not from the wing dowels but rather from a string attached to the engine crankshaft and the other attached as close to the tail as possible. This is the way it was described in the original article from around 1979. I don't know if the attachment points make any difference but all planes do not have wing dowels and logic tells me that the closer one supports the plane toward the ends of the plane the more accurate the reading. Lateral balance is also very simple with the fore/aft support setup. I've found that the weight necessary to balance the aircraft at the center of the CG range is normally pretty close whether I use the contraption or the pencil through the wings routine. However certain aircraft seem so sensitive to the pencil technique and are much easier to balance on the contraption. The GP Seawind (glow model) sticks in my mind as I balanced one for a friend on the contraption.

Given that, using the contraption, I have never once had a new plane take off and exhibit tail heavy behavior. I use the characteristics from my first few flites to adjust the CG to my preferences but the adjustments have always been minor. Maybe I do spend too much time on CG balancing but after months of building an aircraft why not give it the best chance to fly well? This also includes final checking of all incidences, prop balancing and range checking.