tommys is correct about the j&j kit having a built up wing,as I have that kit as well as a skyglass kit that uses foam eing and a fiberglass fuse.took me about 30 years to find a skyglass kit to replace one that I crashed due to a dead rx pack back in 73.the eyeball eas one sweet flying plane Ibought mine second hand ftom a guy that could not slow it down to land.he had a webra blackhead and retracts and was talking about adding doors to the nose cear to add drag.sold it to me for $30.I installed a hp series 72 61{blue fin model} and since I had no retracts and he kept them {rhom airs}I installed fixed gear .sorry to read Art died a few months ago.