How many paddles on a wheel ?

[befnme]

On a water wheel to gain speed do you use more paddles ? Is it opposite of a wind turbine ? Even with a dam I can only get a few inches of head on this stream and i have to use a bottom feed to spin my wheel. top feed is impossible there is not enough decline. My wheel is using 26" bike rims and has 8 four inch paddles.

[zeusmorg]

  Designing an undershot wheel takes into consideration the flow rate of your stream, to maximize the power you need to make your waterwheel as wide as possible within the tolerance of your stream. A decent site that will give you the calculations you need is: http://www.backwoodshome.com/articles/behrens17.html

 I would imagine that you could place more paddles on that wheel to make it more efficient.

 I wouldn't expect a lot of energy from an undershot, but it is better than none. You will probably have to gear up the rotation in some manner to get usable power. I'm also doubting that the bearings in your bike hubs will last long under those conditions.

[Flux]

With a bike wheel used as an undershot wheel I will be surprised if you manage to extract 5W. I doubt that playing with paddles will make significant difference if you have two immersed at any time.

Flux

[befnme]

Do you mean i should only have 1 at a time in the water. I saw where some1 on here made it from wheelchair wheels and it did fine.

[finnsawyer]

You don't give any info about the stream width.  You could funnel the water to the paddles.  This would speed up the up the water and give more potential power.  Give it a try.  As part of this valuable advice, however, I must require you to report back your results, if any.

[zeusmorg]

  You didn't read that site i posted, did you?

[befnme]

yes, I did read it. Some of the figures there are a little tricky to understand. Like I have no way to figure the flow rate of the stream.

[befnme]

Yesterday evening I used a "v" type dam and was able to raise the level behind the dam by about 8-10 inches. I still have a considerable amount of bypass water going under the dam due to logs and such. What I did do however did increase the speed of my wheel. Today I am using sand to try and clog the holes under my dam and see what happens. And yes i will report back.

[spinningmagnets]

If you could post a close pic of your wheel and a pic of the site from about 30 ft away, I believe you would get several helpful suggestions to improve the output.

Would you like to try generating a few 12-volt Watts with it?

[Gog]

For experimental purposes.

You can seal your dam bottom by laying a tarp or fertilizer bags along the bottom over the lumps

and up your dam wall.The water pressure will mould the material and seal around the obstructions.

you can then shovel sand , dirt etc on top to help hold the front edge down in higher flows.

Remmember to tie everything back to something solid so it doesnt end up in the neihbors place due

to flooding.........don't ask.

If you can get to two feet of head then a breast shot may be possible.

The usual question,,, how much head , flow do you have ?

cheers

Keith

[elvin1949]

befnme

 Go back to that link.At the end it says more by that author click on it. Read the first and third  article to. They explain

later

Elvin  

[befnme]

Back to square 1. Today I ripped out the tin "v" dam I had. It was leaking everywhere. I replaced it with a single 4'x8' sheet of 14 guage sheet steel. I had the fab co. cut a 15" diamater hole only 2" from the top. I jut happen to have a halved peice of 15" pvc water main. I drove some "t" fencing posts into the creek bottom to help hold the water pressure back. I put the steel on the pressure side of the posts and drove it into the bottom. That gave me about 1.3' of head. The water on the down side started lowering, and by raising the mounts for my wheel, it never even touched the water below. Thats good news because the pipe I used fit perfectly in the hole in the steel and now I am dumping all of that pressure directly on the 5 oclock paddle. With no water resistance to deal with it spins very well. However I can only get 2+ volts so I am adding more paddles. Now my pipe is dumping a stream 6" wide and at about 6-7 gallons per minute. It dosen't seem like much but I have a bypass in place so that I don'thold too much water back and dry up the stream down the land. I will post pics soon. Thanks for all the help guys.

[Flux]

You say you have 1.3ft head and a flow of 7gpm

That gives you potentially 1.75W at 100% efficiency.

Unless you can get a monstrous flow at that sort of head you are not going to get far.

I originally thought you had paddles round one bike wheel, if you can get something 20 ft wide that holds together you might be able to do something.

Flux