Experiment: Suspended waterwheel

I constructed a new version of the waterwheel using the idea of suspending it above the water. This would hopefully give finer control of the height of the wheel above the water. Below we see the construction, with a threaded steel bar through two blocks of wood at each end of the axle, a length of hollow steel pipe to keep the vertical connections away from the paddles, a washer, an eyelet screwed into a net curtain wire, and finally a nut on the end. I was hoping that this design would minimise friction on the axle and most of the force would be taken by the taught wire hanging above the waterwheel.

Below is the waterwheel in action. Once again this was a slow section of the river, to test the device in what could be a very slow current in June. It clearly works and turns at a speed that gives time to read the text. There is a bounce on the horizontal line above the device but I’m hoping that if this line was high tensile wire and was tightened more this would reduce. There is still a concern that when more wheels are added, the wire will sag in the middle so the heights of the wheels will vary across the river. The lengths of the vertical wires could be adjusted to cater for this.

Below I lowered the waterwheel into the water to see what would happen if the wire sagged. Clearly, this is another potential issue as the wheel stops turning. However, I’m planning on wider and longer paddles so I’m hoping that with more weight in the paddles rather than the rest of the materials, the paddles will continue to turn in a slower current. However, this has made me consider that I need a faster overall current to be sure all paddles across the river will turn.

Fine-tuning of waterwheel height seems critical so it would be worth including a wire tensioner in the vertical wire such as that below, obtainable from GS Products.

Summary & next steps

This waterwheel was a success and having left it for 10 minutes on the river I’m confident that it will turn for a long period. The key is to have very solid anchor points on the bank to allow a high level of tension to be put in the vertical wire across the river. I’m confident that suspended waterwheels will be more successful than having a taught line through them all as anchor points will be much more secure if they are away from the river bank in firm earth. Also I’m enjoying the architecture appearance of (what will be) steel wire. I will investigate professional wire connectors to enhance the look of the web of wire to avoid using simple knots.

The next stage is the increase the scale of the waterwheel, to the actual proposed size and include larger paddles as discussed. Repeating this with two or ideally three water wheels would be a good next experiment.

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