I know you said you don't want to buy them but it beats having to 'reinvent the wheel'. I put a set of Dubro skis on my Super Sportster, and they work perfect for that size of plane. It takes aminute to put them together, and a minute to take the wheels off and install the skis. I actually bought a second set of landing gear so I just switch the gear instead of the wheels/skis. They may cost a little, but it sure beats having to sit inside all day making something when you could be out flying.