Home Made Hovercraft with pictures...

[monte55]

After a few requests for pictures of a hovercraft I built, I finally found them and here you go:

I built this in 1977 when I was much younger and had more hair (actually I still have the same amount of hair, it has just moved to other parts of my body)

Specs: Approx 12 ft long by 5 1/2 ft wide
constructed of 3/8 plywood and wood products with fiberglassed
seams and top.
Air skirt...silver coated, neoprene with nylon thread (very strong
but flexible stuff).
Seams glued with Bostick (sp) 1177 (contact cement)
and stitched by hand.
Two 18hp 2 stroke gas engines...
one engine turning a 30 in duct propeller for lift...direct drive
one engine with belt reduction turning a 42 in propeller for propulsion.
Will float- approx 1000lbs floatation per product literature
Plans were purchased from Universal Hovercraft -this model, I believe
was a UH 12.
Original plans called for a single engine; driving both props.
What I did not like about that was if you lowered your propulsion
prop speed, you also lowered the lift fan speed, which would bottom
out the unit.
That is why I went with two engines...I could stop forward movement
without losing any lift.

Each engine has a voltage output wire which I connected to two panel mount volt meters and calibrated to use as tachs
That is what the two pod looking things ahead of the steering wheel are. Each engine has its own throttle and can be controlled individually.
Propellers and hubs were purchased from a company called Banks Maxwell.
I found the engines locally at a Go Cart supply. They are rated for
18 hp if they have tuned exhaust; which they didn't.
When I made this I had a jig saw, belt sander, hand drill, small tap & die set and not much else.

[monte55]

Actually what we call a hovercraft I believe, was invented by the British and are known as GEM--- ground effect machines.

[jonsam]

Very cool. How was it to fly/drive?

[Handy560]

Thanks for posting the pics Monte. Tell us how it drove and how do you stop?

[monte55]

To stop very qiuckly....hit a building or similar. Your'e floating on a cushion of air and there are no brakes. You can do a 180 and apply full thrust power
to slow you down or shut down lift fan and settle on the skids. If in water, you'll slow down fast with a power shut down. They can go anywhere it's flat
and depending on thrust power, climb grades. I really had no place to use it without a lot of hassle. I love things that use engines, propellers, etc. so this seemed like a good project. If you have access to a large area or frozen lake, it would be a blast. They can go from water to land and keep on going if nothing gets in your way.

[Blackbird455]

How effective was that windshield?

[monte55]

Actually it's a water splash guard which just got in the way and I removed as you can see in the pics.

[burninbriar]

To stop very qiuckly....hit a building or similar. Your'e floating on a cushion of air and there are no brakes. You can do a 180 and apply full thrust power
to slow you down or shut down lift fan and settle on the skids. If in water, you'll slow down fast with a power shut down.

With some cleaver engineering I would think you could design a propeller with an adjustable pitch, enough to actually reverse the thrust, that would effectively slow you down and bring it to a stop. Kind of like a helicopter rotor but less intricate as you would not need it for directional control.

[Blackbird455]

There are quite a few manufacturers out there now that offer small props that have "beta" range pitch control.......in 1977 that would have been nearly impossible to find one that would work on an 18 horse .

[monte55]

I have no idea what a BETA RANGE pitch blade is. Please explain.