Topside Construction

The lift duct has now been bonded into the hull with Great Stuff expanding foam. Not shown here is the 6 oz fiberglass cloth that I used to cover the joint in the front where the wood block on the front of the lift duct meets the plywood deck. The stringers denoting the outline of the cockpit are also in place.
The 1/4″ plywood bench seat sides and back are bonded in place here.
Three 1/4″ plywood cross pieces are bonded below the bench seat. The holes will be used to route the steering and throttle cables, as well as wiring.
This triangular nose block was made from 4 pieces of 3/4″ plywood laminated with epoxy. This will serve as the anchor for the large hook that will be used to raise and lower the hovercraft on the trailer with a winch.
Stringers beneath the rear seat. The 12 gallon fuel tank (pictured) will go beneath the rear seat. The center of gravity of the craft is exactly at the front of the rear seat, so extra passengers and the fuel tank sit very close to the CG.
One of the cockpit sides cut from two sheets of 1/8″ plywood joined together. The profile was carefully chosen to make the sides low enough to step over, with a rise near the back to partially cover the engine.
Both cockpit sides epoxied in place.
The back seat decking has now been completed with 1/4″ plywood.
Laying up additional layers of 3″ thick foam around the lift duct. These will be contoured to provide a smooth bell mouth for the lift fan.
The top of the engine cowling is made from the same 1/8″ plywood as the cockpit sides. This had to be clamped carefully to make the sheet take a bend this tight.
The top layer of foam around the lift duct has been contoured so that the sides are flush with the tops of the cockpit walls, and the foam along the centerline is several inches higher. This is partly an aesthetic preference, and also gives the plywood nose skin a slight bend, increasing its strength.
The front nosepiece, made from 1/8″ plywood has now been fitted and epoxied into place. Masking tape keeps the edges down, and cinder blocks apply pressure over the large bond area where the plywood meets the foam around the lift duct.
The front and rear plywood nosepieces are now glued in place. All that remains is the reinforce the joints with fiberglass tape.
I added a large dash made from 1/4″ plywood.
The topside is really starting to come together now.
Reinforcing all plywood joints with 6 oz fiberglass tape. The masking tape at the edges keeps the joints clean and makes things easier during the body work leading up to painting.
I’ve now carved the inlet mouth of the lift duct, starting with a belt sander for quick material removal, and ending with hand sanding.
Fitting the aluminum windshield frame. The posterboard will be used as a stencil for the Lexan windshield.
Windshield frame complete. The two sloping front pieces are made from bolting two aluminum angle bars together. The upper aluminum piece is a 1″ x 1/8″ bar bent to the desired shape. The frame is not very sturdy by itself, but the Lexan will stiffen it up considerably.
I’ve added a 2″ wide lip of 1/4″ plywood around the sides of the cockpit. This gives the cockpit a cleaner look, and will also be used as a surface on which to build the removable canopy.
Plywood/foam sandwich canopy brace. This will attach to the top of the windshield frame, and be the front structural member of the removable canopy.
A pair of window locks (left side shown here) will bolt the canopy down. The canopy will be hinged at the rear.
The two longitudinal canopy structural members are now attached.
Another view of the canopy. It will hinge from the rear, fighter jet style, and can also be completely removed. The top of the canopy is covered, for some protection from the sun. The sides will remain open, otherwise people would cook in a fully enclosed cockpit in Texas.
Bonding 1/8″ plywood to the top of the canopy. This ended up being a slight compound curve, so it was difficult to make the plywood take the correct shape.
A shot with the thrust duct test fitted.