RE: 1/2a Hovercraft!
Brilliant hovercraft controls, badenglish. I like the door control, very good idea. That with the rudders must give pretty good speed and directional control.
I made one using a 26" bicycle tube as a skirt. The deck is 1/2" foam, the engine is a Cox .049 facing directly upwards in a duct made of a gallon jug's middle third, and it has no controls. I start it up and kick it around like a giant air hockey puck. Where the bicycle rim normally contacts the tube, on the inside of the tube, I cut about 15 holes 3/8" in diameter to let air into the skirt and pressurize it, then a few 1/4" holes are in the bottom of the tube to allow a little air out, and let dirt out, and also to allow me to fasten the skirt to the foam. It's hilarious to watch it spin around and ricochet off the curbs like air hockey.
Tom