I bought mine 2nd hand, but with only a dozen flights on it with a G23 glow engine. He wasn't happy with the pull from the ST2300. He also told me the original landing gear was too weak for the weight of this airplane and replaced it with a decent size alum gear, but shaped like a 4-star gear (low to the ground). I needed clearance for a 18-22" prop for my 40cc gasser so I replaced it with the one I have on it. I just took the SPE40 off tonight to replace a broken ring and check the bearings so there won't be an engine or cowl on the front to show you. I'll double check, but I'm pretty sure the 6.5" is to the center of the wing tube from the indent, and I cg'd at 1 finger width in front of that or at about 6" and was a tad nose heavy still. Like opjose said, there is a pretty broad range that this airplane likes. It's best to be less than 6.5" or less to start with. Go safe and start at 5" and keep moving things around until you get the cg where you like flying it for your particular style. I'll put the wings on and snap some photos of the trim scheme for ya tomorrow. DG