There was a guy in Las Vegas who tried to make and sell planes like these, call Giant Ammo Rats..He used a foam core with coroplast covering...He had a booth at the QSAA in las Vegas and put a wing on the ground in front of the booth so people walked on it for three days, without damage...He used the coroplast for the square fuselage also, and held the pieces together with long drywall screws...Biggest problem was finding something to adhere the coroplast to the foam for the wing, and sticking the plywood to the stuff for the firewall.....It had a large wingspan, and mine used a G62 for power..Flew fine...We finally held the wing covering on with 4-40 screws and large flat washers...It' still up in the attic...It DID fly better with regular foam balsa covered wings.....He made some smaller versions, and made floats out of coroplast covered foam....They all worked well....