If you’ve wondered how to keep flying with snow on the ground, here’s your answerBy Graham H. Hicks | Photos by Ed BartonFrom the February 1989 issue of Model Aviation.They’re easy and fast to make, and they'll add very little weight to your airplane. Since skis impart a degree of stability to your model that wheels do not, you may find as I did that they reduce the ground looping tendency on takeoff and landing. These plywood skis are lighter than any of the metal ones I have seen. They also use a "knee action" positioning system that is closer to full-scale than the torque rod system. …