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Old 04-05-2018, 04:21 AM
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rickoff rickoff is offline
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Join Date: May 2008
Location: Maine, USA
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In response to Carroll

Thanks for your input, Carroll. In post #21 of the Bhaskara's Wheel thread I mentioned this very effect, saying, "Folks who are interested in this concept should keep in mind that an overbalance water wheel should only be expected to turn slowly. If it were to turn anything but slowly then the centrifugal force would work against the flow of water back towards the perimeter sections, and of course that would negate the effects we are hoping to achieve." You are correct in stating that the wheel would tend to be somewhat self-regulating, in that if it was to speed up to anything but a very slow turn then water would stay in the outermost part of the tubes, thus balancing the wheel. At that point the wheel would slow down until enough water could flow back towards the center of the wheel on the right side of the centerline to bring the state of the wheel back into an overbalance condition where rotational force would resume.

Just how slowly we should expect the wheel to turn would of course be dependent on the size of the build. Since the perimeter of a larger build would be moving faster than a smaller build at the same rpm, the rpm of the larger wheel would have to be reduced accordingly. Self regulation would probably do the trick, but to avoid any possibility of a wavering speed, or jerky motion, the driven load upon the wheel would best be optimized to maintain the wheel at a desired rpm that constantly falls within the overbalance zone.

For the 3 inch build on a nearly 4 foot diameter wheel, I'd suspect that the desired rpm might be in the neighborhood of perhaps 10 to 12 rpm, which would be one full revolution in 5 to 6 seconds. For the 6 inch build upon a wheel of close to 8 feet in diameter, the rpm would have to be reduced considerably.

The circumference of an 8 foot wheel is 25.133 feet, which is twice the circumference of a 4 foot wheel. That indicates that the rpm of the 6 inch build would have to be cut down to 5 or 6 rpm, and of course this is just guesswork - it might be even slower. We have to keep in mind that we're after torque - not speed, and the slower the speed of this wheel, the greater the overbalance torque will be. The perfect speed would be the speed where the wheel is just barely moving, as this would allow fastest transfer of water while operating as close to the theoretical observation as possible.

In addition to being a self-regulating wheel, this wheel would also be a self-starter, meaning that if the wheel was held in any position, and then released, it would begin rotating simply because an overbalance condition would always exist.

As I mentioned in my post #2, we haven't even taken into account the additional rotational force that will be created by the hammering, or sloshing effect, of the water as it falls outward and downward to fill a tube. As you can see from the water weight specs that I showed in post #2, there is a substantial water weight falling down the tube (more than 39 pounds with a 6" tube size). When that weight smacks into the bottom of the tube, I'm sure you can realize that there would be quite an impact, and that in itself would probably be enough to advance the wheel to the next position where a tube is about to be filled. On the right side of the centerline you will have tubes sending water back towards the wheel's center, and so there will also be somewhat of a counter-force hammer effect, but because the water is channeled towards the side of the dodecagon sections by the elbows, rather than in a downward trajectory, any such counter-force should be greatly reduced.
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Last edited by rickoff; 09-16-2018 at 01:25 PM. Reason: updated for accuracy
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