My Fun Project

[ReinMan]

I've been living on the water for a few years now, and decided I needed a means to get out on the lake.

But I'm not a boat guy; I see those poor bastards winterizing their boats, summerizing their boat; and basically dumping cash into a hole in the water.

And I'm a year-round kind of guy, so a boat wasn't going to cut it...

So, I'm building a hovercraft. Here's the first round of pics - hull construction.

It will 15' long, 8' wide, and carry a 700-1000lb payload 11" above the water or ground.

[scott]

Very cool!

How are you going to power it?

[ReinMan]

Got my hands on a Kawasaki KZ750 engine and rebuilt it.

It's good for 75-80hp for a thrust propeller.

For lift, a 15hp Briggs & Stratton lawnmower engine.

[Frostbit]

Way cool!! Love the concept.

[phillygirl]

So cool!!

[Bob Loblaw 3.0]

Awesome.

[Michele]

Very cool.

[deudyurondame]

Got my hands on a Kawasaki KZ750 engine and rebuilt it.

It's good for 75-80hp for a thrust propeller.

For lift, a 15hp Briggs & Stratton lawnmower engine.

That's all you need for lift?

[Adam]

That's all you need for lift?

Makes sense to me, with a skirt. You only need a fraction of an inch of air for "lift," and spread out over a relatively large area, I would think that the "lift" fan would have a multiplicative effect, rather like a very large piston in a hydraulic system pushed by a very small piston.

[ReinMan]

It's all about cfm for lift.

Static pressure under the skirt will be measured in tenths of psi.

The cfm requirement is about 8,000 cfm for a 1/2" gap. The relationship is not linear, however.

Airflow required will quadruple to double that gap, and horsepower increases as a cube function...

Essentially you calculate cushion pressure as weight/area; then gap area as perimeter x gap; and arrive at a velocity of air through the gap required to create the pressure drop equal to the cushion pressure.

Velocity x gap area then equals cubic feet per minute air flow required.