Date: Tue, 21 May 2002 14:22:11 -0500
Subject: Re: It's too quite....
Bill's man-lifter hovercraft reminded me of a device I hadn't thought of in
close to 40 years
In the 1960s I was the only physicist in a group of engineers working in the
Office of Research and Development of the Central Intelligence Agency. At
one of our typical briefings by contractors who wanted to tell us about
possibly useful devices they had developed, one contractor (whose identity
is probably still classified) described a strap-on-the-back helicopter he
had been playing with.
The power source was a free-piston engine he had developed (essentially an
efficient air compressor). With the engine strapped onto a man's back, the
compressed air ran through a hose to a hollow vertical shaft that was free
to rotate. At the top of the shaft (4-5 feet above his head) was a long
hollow rotor blade (15 to 20 feet in diameter) with orifices on the trailing
edges at its ends. The man stood in a clearing and opened the throttle until
the twirling rotor lifted him into the air.
He needed no tail rotor because only the slight friction in the shaft
bearings applied a torque on his body. A 1-2 square foot movable vertical
fin at the back of the engine provided sufficient steering torque. With a
bit of training, a pilot could hover at various altitudes, orient himself to
face different directions, and move horizontally simply by bending forward a
bit. His feet were his landing gear.
ORD was interested in the device for covert infiltration/exfiltration in
Vietnam. It was very quiet -- practically inaudible at more than 100 feet.
We talked to the US Marines about it, thinking it would offer great
personnel mobility, but they weren't interested. They didn't want individual
troops to have that much freedom of mobility.
We tested the device at NASA's research facility down at Langley Field,
Virginia. We fixed up a tether arrangement in a big hanger in which we could
fly all around inside. I got to try it a few times. I really wanted one to
use to commute to work from my home in Bethesda.
I don't know what ever happened to it. I went on to bigger and better
projects which if I told you about I'd have to kill you.
----- Original Message -----
From: "William Beaty"
Sent: Tuesday, May 21, 2002 11:29 AM
Subject: Re: It's too quite....
> Here's something noisy!
> Hey, has everyone seen the "giant airpuck" man-lifter hovercraft? I added
> a version of the plans to my website, and have been receiving mail from
> kids who build these as science fair projects:
> Also, here's a more complicated version from 1990:
> At one of our monthly "weird science" meetings, one regular member broght
> his version to show off. It had a gasoline-engine leaf blower, so we
> tried it out in the ball field across the street. Huge clouds of dirt!
> With a long rope attached, helpers can fling it at hazardous speeds.
> (((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
> William J. Beaty SCIENCE HOBBYIST website
> email@example.com http://amasci.com
> EE/programmer/sci-exhibits science projects, tesla, weird science
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