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[Bill Jones <billj AT harborside.com>]

Much like a waterwheel with a baffle, an easily made windwheel can catch 
all the wind power available at any speed.  There's a cheap and simple 
way to imitate an automatic transmission for any wind-driven compressed 
air system.  I call it the pneumatic clutch.

We want our windwheel to freewheel when the wind is between 0 and 5 mph, 
to push water up a short distance when the wind is between 5 and 10 mph, 
to pressurize house water and pump out the deep well when the wind is 
between 10 and 15 mph, and to compress our 125 psi tank during winds 
greater than 15 mph.  The achieve the freewheeling at low wind speeds, 
simply place a roller cam valve in parallel with the compressor 
outflow.  When this valve is not pressed, the compressor ouflow opens to 
the outside, and there is no back pressure on the compressor.  This is 
just like "neutral" on a car.

To make the roller cam valve shift position with higher windspeed, 
simply hang a plywood sheet from a hinge and face it into the wind.  
Mount the valve at an appropriate distance from the hinge, so that the 
plywood sheet presses on the roller when the wind blows hard enough, and 
it should behave just like the old-fashioned pressure-based anemometers 
that were abandoned in favor of the ballerina kind.

This same method can be used to select between the various speeds.  A 
second anemometer with a higher activation threshold is placed so that 
it turns _off_ the flow to the air displacement pump (for pumping water 
- see picture)

http://home.earthlink.net/~clanl/pump.jpg

when the wind speed reaches 10 mph.  Likewise, a third anemometer is 
placed to turn off the flow to the medium-pressure storage tank when the 
wind speed reaches 15 mph.  At that point air can only flow into the 
high-pressure tank.

Of all ideas, this one has the most promise, because it entirely 
eliminates the need to create a precisely balanced spinning turbine, 
making wind technology open to the average person.  I built my first 
model the other day with 2x4 boards holding the plastic sails, and an 
old bar from a weight set that turns on homemade bearings on 4x4 posts.  
The high torque available makes any bearing suitable, desite the 
friction.  My model has only 4x5 foot sails, but it's cheap and easy to 
make them much, much bigger.  No system available can compete in terms 
of cost per watt.

Bill
S. Oregon coast