I've never really been satisfied in explanations about the structural differences between my Model 2 (ser# 707) and subsequent models. Factory says mine is actually a kind of 2 1/2, with larger diam carry through tubes on spars and gear and also with extra diagonal tubing welded along the frame where the bungee's attach.

I also remember something about how they increased subsequent gross weights by making the struts out of larger diameter, thicker walled tubing and attaching them further out along the spars but nobody seems to know how much larger or how much further.

So, could someone with a model 3 and also a 4 take the time to measure the diameter of their strut tubing and also the length from the attach bolt on the fuselage weldment behind the the seat to the attach bolt on the front spar bracket?

Thanks,
Chris Carlisle
Model 2, 582, C box
Sioux Falls, SD