Pegasus

The Pegasus is our newest hovercraft design. It’s made for 2 passengers, and is designed to be extremely fast and simple to build. Construction is either marine plywood or a simple Divinycell or Plascore composite, and it utilizes a ductless lift plenum design and open thrust propeller to eliminate the need for time-consuming ducts. In addition to reducing build time, the large 56″ thrust propeller also generates a huge amount of static thrust from a modest GX390, Predator 420, or similar engine. The 5 hp lift engine turning a 23″ lift fan also provides ample lifting ability for 2 passengers, meaning that this craft can be completed with two very simple and affordable engines. In fact, to reduce weight, we recommend pull start engines be used, which makes the hovercraft even simpler by eliminating all batteries and wiring (except for kill switches) and external fuel tanks and fuel lines.

We’re currently preparing plans for the Pegasus hovercraft, which will include a complete cut sheet, skirt templates, different construction material options (plywood vs. thin sandwich composite) and several options you can use to customize the craft (different seating configurations, two engine mounting schemes, etc.)

We’ll upload more videos soon, but in the meantime, here are a couple of short video clips of the Pegasus in action:

Construction Photos:

These are the main hull panels laid out on the shop floor. This is mostly 1/8″ plywood except for the plough planes, which are 1/4″ plywood for additional strength. The long panels are made out of two pieces of plywood butt-jointed together with a thin strip of plywood glued over the joint for reinforcement.
The Pegasus uses a construction technique similar to the popular “stitch and glue” technique common in wooden boat building. We use small wood cubes and CA glue to temporarily join the hull panels until we fiberglass tape the seams.
The forward bulkhead and sides of the lift plenum are temporarily bonded in place. The plough planes are also in place.
Now we’ve added the remaining 1/4″ plywood ribs and the 3″ thick flotation foam blocks. We recommend extruded polystyrene foam (blue Dow foam or pink Owens Corning Foamular foam), but we used some white EPS foam here because it was available. Most of the internal joints have also been fiberglass taped here.
Another view of the hull so far.
We’ve now bonded the 1/8″ plywood deck on top of the flotation foam blocks. We’ve also temporarily CA glued the plough planes to the ribs.
We used cinder blocks, tools, and scrap plywood to weigh down the top plywood deck while the epoxy cured.
Another view of the hull before the addition of the front and rear top decks.
The top stringers are now CA glued in place.
The complete hull with top stringers bonded in place.
Laminating the forward top deck. The center of the deck, which holds the lift engine, is comprised of a 3″ foam core between 2 plywood layers.
The hole for the 23″ lift fan has now been cut in the front deck, along with two rectangular holes which allow access to the two forward storage compartments. The two forward compartments on either side of the lift plenum can also be sealed to provide additional flotation.
We used wood squares on either side of the lift plenum walls to bond in the forward lift deck.
These are thick bulkheads used to reinforce the rear deck where the engine stand mounts.
The 1/2″ plywood rear deck CA bonded in place. We’ve also rounded the outside corners to prepare for fiberglass tape.
We also rounded the outside edges of the top stringers in preparation for fiberglass tape.
The forward deck is now bonded on place and ready for fiberglass tape. We also rounded the edges for fiberglass taping. We taped all the inside edges inside the lift plenum and forward storage compartments. We also sealed all the inside plywood surfaces with epoxy.
The complete hull so far. Most of the inside edges have been fiberglass taped, but the interior plywood surfaces have not yet been sealed with epoxy.
We cut a 3″ thick EPS foam inlet ring for the lift engine (The inlet lip has not been shaped yet). This is not required, but creates more efficient airflow into the lift fan.
Another view of the completed hull.
We’ve now flipped the hull over. We used epoxy putty to fill small gaps between the plywood panels and then used 3″ fiberglass tape over all the exterior joints
Here we’ve added 1/2″ plywood bases for the UHMW landing skids, and also cut holes in the lift air feed holes in the plenum. Lift air is directed both into the bag skirt and directly into the cushion.
We glassed the landing skid anchors to the bottom hull.
The bottom hull is now sealed with epoxy resin.
Closeup of one of the outside hull joints, with the filler putty and fiberglass tape clearly visible.
The skirt attach strips are made from PVC board ripped into 3/4″ x 3/4″ strips. The strips are bonded to the hull with 3M waterproof construction adhesive.
Another view of the inverted hull with skirt attach strips installed. In the plans we modified the rear of the hull to also include a plough plane, which prevents damage to the rear inner skirt attach strip.
Closeup of the installed skirt attach strips.
The hull bottom as seen from the front, showing detail of the lift air feed holes. If plywood is used for construction, it is important to properly seal the edges of these fill holes, which expose plywood edges to water.
Two of the UHMW landing skids attached with countersunk stainless screws.
This is the lift inlet ring, with an inlet profile sanded on the inner surface to provide smooth airflow into the lift fan.
Sample skirt section showing cushion feed holes.
Slitting one of the skirt section edges to glue to the adjacent edge. The outside surface of the slitted skirt section is glued to the inside edge of the non-slitted skirt section, resulting in a strong and durable bond.
This is the finished skirt seam, ready to be turned inside out and installed on the craft.
The inner edge of the skirt has now been screwed to the inner skirt attach strips using stainless #6 screws every 5 inches.
The outer skirt edges are now attached, completing installation of the bag skirt.
The hull, with skirt installed, back on the ground for installation of the bench seat and topside paint.
There are two options for seating on the Pegasus hovercraft. We chose a bench seat, which we are installing here. The other option is to the leave off the bench seat, and use two movable fishing chairs in a side-by-side seating configuration, which some builders may prefer.
The bench seat nearly complete, with top stringers to support the top deck.
The top deck of the bench seat is now installed, with access holes cut to provide storage under the bench. This is a good location for the battery if an electric start thrust engine is used.
Test fitting the Honda lift engine. The tip clearance is extremely tight inside the lift duct, and since the duct walls are made of foam, incidental contact between the fan blades and duct wall is not a problem.
We fiberglassed the lift inlet.
We chose a two-tone paint scheme, with most of the craft being blue, with a gray accent on the inside. We also used some flakes in the gray paint. We recommend an oil-based paint, which tends to hold up better to accidental gasoline drips on the hull.
The lift engine mounts have now been bolted through the front deck, securing the engine in place.
We used an inexpensive lawn mower throttle to control the lift engine. Also visible here is one of the bearings used to hold the steering handlebar spindle
The thrust engine stand is welded from 16 gauge steel tube and painted. For simplicity, we used the high mount engine option from the plans, which uses an elevated engine (up to 80 lbs) with one of our belt reduction and propeller combinations bolted directly to the engine. The plans also include a low mount engine option, which mounts the engine to the floor and uses a higher offset belt reduction drive.
The nearly complete craft hovering for the first time. The Pegasus is designed to work well with a Honda GX390, Harbor Freight Predator 420, or similar engine. We used a slightly larger engine with external fuel tank for the demo model because we had this larger engine available and it weighs the same (~80 lbs) as the Honda GX390.
The thrust propeller guard cage can be built from inexpensive 1/2″ conduit.
The complete Pegasus hovercraft, minus reduction drive, thrust propeller, and rudders.
The Pegasus is small and light enough to be pulled onto a small trailer with the lift engine off.
The Pegasus is now complete with the propeller and rudders installed. We used molded fiberglass rudders from our Phoenix hovercraft here, but directions to make larger rudders out of sheet aluminum are included in the plans.
The complete Pegasus loaded on its trailer and ready to fly!
This is a photo of the Pegasus hovering and ready for its shakedown flight. At about 325 lbs, this craft is extremely light and performs well with 1-2 people on many surfaces.