Robert Q. Riley Enterprises: Product Design & Development

Build it yourself from plans

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Tri-Fler on lake

Tri-Flyer parked on hill.

Rear view of Tri-Flyer shoing three rudders and high-speed trim wing.

Two Tri-Flyers running side by side on lake


Plans Include...

6 - 17 x 22 in.
60-page photo-
    illustrated bookle

Price... $45

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Robert Q Riley Enterprises

A High-Performance, Three-Place Hovercraft
You Build from Plans


Two tri-flyers skimming across lake.

Order Plans Now
- $45

(order a second item to get a discount & free shipping)
These are the original Popular Mechanics plans

"The secret of Tri-Flyer's highly efficient power system
comes from carefully optimizing the relationship
between weight, thrust and drag."

Popular Mechanics Magazine

  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 wing 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.  When trimmed in the pitch direction, Tri-Flyer achieves maximum speed.  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 PlansTri-Flyer was featured in Popular Mechanics magazine.  Click on the small images in the left margin to see larger images.



Length: 190 inch
Width:  78 inch
Height (on cushion): 72 inch
Empty Weight: 450 lbs
Flotation: 1500 lbs
Construction: Wood monocoque
Construction Time: 150-300 hours
Seating: Three (central pilot, two behind  the pilot)

Lift System
Engine: Briggs & Stratton or Tecumseh
Power: 8 hp to 10 hp
Type: Four-cycle, vertical shaft,
    aluminum case
Weight: 40-50 lbs
Drive: Direct
Fan: 26 inch diameter, 4 blade, 18-20  pitch

Control System
Yaw Control: Multiple rudders in propwash
Pitch Trim: Horizontal airfoil in propwash
Type: Fully-articulated joystick

Thrust System
Engine: As desired
Power: 40-80 hp
Type: Two-cycle, aluminum case
Weight: Up to 100 lbs
Drive: Multiple vee-belt, 2.64:1 ratio
Propeller: 54 inch diameter, 2 blade,
    36 pitch

Payload: Up to 800 lbs
Hover Height: 8 inch (obstacle
Thrust: 125 to 400 lbs*
Climb Grab: 15 to 45 degrees*
Speed: 40-70 mph over water,*
    40-80 mph over land, ice, and snow*

*Depends on the power of the thrust engine


To Order Plans

  • Mail: Use the online Order Form to automatically calculate shipping charges and provide a total amount. Click on the "Order Tri-Flyer Plans" link above, then press "Add Item to Cart." Fill in your shipping information. You cannot proceed to the Confirmation Page (for freight calculations) without making entries in the credit card fields. If you prefer to enter your credit card information later, simply enter a series of spaces in the Credit card fields then press "Proceed to Confirmation." Print the Confirmation Page and enter any missing information.  Mail your confirmation page to us, along with your check, money order, or credit card information. (Outside the U.S., please make payment in U.S. funds using a credit card or International Money Order.)

  • By Phone:  Weekdays 8:00 am to 6:00 pm MST:  480-685-3225.

                     Shipments to U.S. destinations go by First Class or Priority Mail (depending on weight).
                     Shipments to destinations outside the U.S. go by mail: "Airmail, Letter-Post."
                     Arizona residents, add 10.2% sales tax.

Robert Q. Riley Enterprises, LLC.
P.O. Box 14465
Phoenix, AZ 85063-4465
Technical Questions:  480-685-3225


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P.O. Box 14465, Phoenix, AZ 85063-4465
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