THE COOLSCIENTIST

The floppy-mill

Wouldn’t it be nice to have a practical, inexpensive, multiple-use, wind-powered energy source? The Floppy-Mill is a vertical-axis wind mill that provides high torque, at medium RPM. It is easy to construct, and operates regardless of the direction of the wind. It can be used to pump water, generate electricity, or power a boat or land vehicle. And its speed is self-limiting to protect it during high winds.

In the picture, there are two large paddles, {like sheets of plywood} (a) and (c) on horizontal shaft (p). Horizontal shaft (p) is free to turn approximately 90º, in bearings (f), mounted into a tall vertical shaft (e). When the wind is at your back, paddle (a) is pushed away from you and around behind shaft (e). That pushes paddle (c) forward, toward you.

As soon as (a) comes around on the left side of vertical shaft (e), the wind begins to push the off-set paddle (a) upward past position (b) and eventually up to position (c) where the other paddle had been. At the same time, horizontal shaft (p) is twisted, making paddle (c) swing down, where the wind catches it and pushes it past position (d) and eventually into the position where (a) had been, and the cycle continues. There is a stop on each paddle at (s) so that the paddles cannot swing past shaft (e).

Vertical shaft (e) can be as tall as needed. It being held in place by guy wires, (j) and (k) connected to a bearing (m) that allows shaft (e) to turn freely. There should also be another set of identical guy wires, (at right angles) so that there are at least four support wires. At the bottom is a thrust bearing (w) to hold the weight of the mill while allowing it to turn freely. An excellent choice is a recycled rear wheel assembly from a front-wheel-drive car, or a front wheel from a rear-wheel-drive car.

The non-moving frame part of the wheel can be solidly fastened to the vehicle, or placed in cement (x) having rebar driven into the ground to keep the bottom of (e) from coming loose and kicking out to the side.

To get more power, one or more paddle-sets can be added. They should be spread around shaft (e) so as to catch the wind that the first paddle set misses. The position of the paddles relative to their swinging shaft (p) can also be adjusted up and down for gaining maximum power. But the paddle part below shaft (p) must be larger than the part above (p).

Pulley or gear (g) delivers mechanical power to unit (h) for whatever purpose the mill is being used. It could be a pump, a generator or other mechanical device. Unless you happen to have a suitable set of gears, a large pulley at (g) can be connected with a belt to the smaller pulley on (h). However, most belt-driven machinery, such as an automobile alternator, require a horizontal shaft axis, so use very long belts that can be twisted easily to power horizontal unit (h).

The Floppy Mill can run many things. It can be connected to the propeller on a boat or the wheels on a land vehicle that can theoretically go half the velocity of the wind, directly into the wind.

We are very vulnerable. If a terrorist blows up a pipeline in Arabia, our price of energy goes through the roof. It has been announced that a search is currently underway to find solutions to the growing energy crisis. Might it be found in a large number of small units spread along the power grid, rather than building one big unit that would itself be vulnerable to attack?

Wouldn’t it be a fun project for the school kids to show how easy it is to become energy independent? If there are teachers or others interested in building demonstration floppy mills, or anything else talked about in these CoolScientist articles, contact me at coolscientist@rmrc.org. We may be able to help. (John N. Hait)

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