My UH12R : The Hull




Making the hull

This is a shot up into the nose of the hovercraft where you can see the lift ducting.
The cockpit sides where then attached and the seam between the side and deck was glassed.
Here's a view of the inside. Those two boards are where the tandem seat will be after the steering rod is mounted between them.
Fore and aft shots. Notice in the aft shot the green steering cable that will be attached to the rudders. The thrust duct will be centered around the thrust shaft which will be just barely above the rear thrust shaft bearing mount visible here. The duct will be 48" in diameter. The rope is used to hang the aft end of the craft from the ceiling of the garage via a pulley. Is it me, or does this beast look kinda like Frankenstein's monster?
A hovercraft picture that really turns me on. Full frontal nudity! (Get it? No paint.) ;-)
A rear view.
a side view.
Since the plans are very vague about the position and location of Rib 1 (the piece of wood at the very front of the craft), I took a close-up head-on of the front...
And the side.
Here's a picture of the dome that supports the duct supports. Notice the easy access to the rear bearing mount and thrust engine that will sit beneath it.

As the plans leave it, the floor of the 12R is not very strong and wouldn't tolerate much use or general wear and tear for very long especially for someone of my... uh... weight class. So, after conferring with a gentleman by the name of Rob who is also building a 12R (and is almost done after only a few months!), we decided that floor reinforcement stringers would be the best and simplest solution. The stringers are 1" pine strips screwed to ribs 3, 4, and 5 edgewise with more screws fastened from the inside of the craft to the stringers. Also, the stringers are glued to the bottom. After walking on the floor the past few days while working on the craft, I'm gaining confidence that no further reinforcement will be necessary at this time.


The seat simply consists of a piece of 1/4" plywood spanning two 1x4's. Also, I think I'm going to bolt one o' them boat or airplane seats to it for cruising comfort.

So, anyway, I sat there on my new seat looking out over the top of the craft and decided that I needed a windshield. I opted for a simple windshield consisting of a hoop of 1/2" EMT, a sheet of 1/16" Lexan, and a plywood strip to screw the lexan to the top of the craft. I selected a simple angle of 45 degrees and a height of around 15" from the top and then built this contraption to find out how far out on the nose the windshield would have to be mounted.
I then measured the top of the nose from side to side and calculated an arc of a circle that would extend out the correct distance and end at each corner of the cockpit. I set my jigsaw at about a 27 degree angle and cut 2 arcs out of 1/4" ply. I glued the first arc to the nose and the second arc to the top of the first arc to get a rise of about 1/2". The reason I didn't just use 1/2" ply is that it's difficult to bend and would easily disfigure the 1/8 ply on the nose.
Next, I drew an arc on a piece of cardboard that extended 18" (15" tall windshield with 3" rise on the nose) with each end ending at the edges of the cockpit. I used that drawing as a template to bend the 1/2" EMT. I then flattened then ends and bolted the arc to Rib 3.
I then used a straight edge between the EMT and the plywood arc to find the true angle at which the outside edge of the plywood arc must be set so that the 1/16" sheet of Lexan lays flat against the angled side of the arc. I used my Dremel tool with a sanding attachment to quickly form the correct angle. I then filled any gaps with filler so that water couldn't seap under the windshield mount.
Finally I was able to primer the entire craft with several coats of a primer that the paint guy at the local Kwal-Howells said would stick to anything. You see, since what I don't know about paint would fill a book, I had a mental delimma about what type of paint to use because I used polyester resin to seal the bottom and epoxy resin to make all of the ducting and controls. The problem is that I heard that epoxy doesn't stick to polyester and thus epoxy based paint won't stick to the bottom. "Like I care", I said to myself and went ahead and selected the epoxy paint... that is until I found that the epoxy paint available locally only in a couple of colors (black, white, red). Finally, I decided on a simple, cheap, alkyd enamel. The paint guy said that with this super primer, the enamel will stick to anything and it did. However, it also was sucked into the wood (great for sealing) but caused the tiny grain cracks in the ply to expand making for a rather ugly finish at close inspection. Looks good from a couple of feet away though. Heres my recommendation: Seal the top with polyester resin or epoxy resin (I'd go with polyester next time myself), prime over that, and then paint with enamel. This shot of the craft is in bad light and doesn't really reflect the true Teal color. The bottom was painted yellow since I had an extra can sitting on a shelf. That way, when I can tell onlookers that if the craft turns from teal to yellow, send help.
After painting the entire top and sides of the craft teal (the colors were of my wife's choosing), I asked my friend Jack to come up with a design for the sides. He laid out a design on paper and I made a scale drawing of the design in Autocad and printed it out on my dot-matrix printer to use as a template allowing for 1/2" of masking tape to form the lines. I taped the design on the sides and covered the areas surrounding with newspaper to protect against stray splatter and spray.
I sprayed on 3 coats of Royal Plum, pulled off the mask and this is how it turned out. The colors are a little odd but it doesn't look bad... not bad at all.