Tri-Flyer
A High-Performance, Three-Place Hovercraft

Grab the fully articulated, aircraft-style joystick, twist the throttle grip and blast off. Suddenly you're flying at more than 75 mph over land or water, soaring over 8-inch obstacles, even climbing 45-degree hills. You're riding Tri-Flyer, a high-tech, super-performing hovercraft that you can build from plans.
         It's built of wood station formers and stringers, which are covered with an 1/8-inch plywood skin; much like the construction of a wooden boat. Lift comes from a 10-hp vertical-shaft mower engine driving a 26-inch, 4-bladed fan that forces air underneath the hull. The Tri-Flyer will lift three occupants - a total payload of 800 pounds. A separate snowmobile type engine (40-hp to 80-hp) powers a ducted prop in the rear, which delivers up to 400 pounds of thrust. With an 80-hp engine, you can climb a 45 degree grade (single occupant).
         Tri-Flyer's highly efficient power system comes from carefully optimizing the relationship between weight, thrust, and drag.  Three rudders and a horizontal pitch-control assembly mounted on the duct provide the control. The three rudders give directional control, and the horizontal pitch airfoil supplies the correct fore-and-aft trim.  All controls, including throttles, are routed to the 3-axis control stick.
         Tri-Flyer can fly over land, water, ice and snow. She can land on ice that is too thin to walk on, and in water where she'll float, just like an ordinary boat.
         Expect to spend 150 to 300 hours building Tri-Flyer, and about $700 in materials, not counting the engines and fans.  The cost of engines will depend on whether you purchase them new or used.  Plans give the source for purchasing the fans. Required building skills are minimal. Tri-Flyer is built much like a wooden boat.
         Tri-Flyer was featured in Popular Mechanics magazine, May 1986.