wind to water generator

[noelex 77]

I have been given an old wind generator (Salmini )and am considering modifying it to a water generator. Any suggestions as to what pitch of prop to use ?
I was hoping an old outboard prop would be feasible.
Thanks John

[pogo]

Originally Posted by noelex 77

I have been given an old wind generator (Salmini )and am considering modifying it to a water generator. Any suggestions as to what pitch of prop to use ?
I was hoping an old outboard prop would be feasible.
Thanks John

Practically speaking, a "prop shop" guy can estimate how many rpm's a "propellor pitch" will turn in a given distance. So at 5 knots (average sailboat speed presumed) the distance and rpm could be forcast. Adjust the pitch to conform to the generator's maximum efficiency RPM and determine if any adjustment prop pitch/gearing is needed between the prop and the gen.

Would seem a good place to start to me.

I am not an engineer, but I suspect you can make it work. It would be a fun project. Go for it, if you get it to work, I am certain an engineer can figure out WHY it works.

[donradcliffe]

Depends what RPM the generator needs to turn at, but an outboard prop should work. A very rough guess is that the generator needs about 600 rpm, or 10 rps. Given that 6 knots is 10 ft/sec, or 120 in/sec, a 12 inch pitch would be right except for slip. Assume slip is 33%, and that gives you an 8 inch pitch.

My Ferris wind/water generator uses a 3-blade prop about 8 inches in diameter, pitch not measureable.

[Rick Sargent]

Hamilton FFerris has a water drive conversion kit that everybody swears by at 5/6kts for a top rated 20amps.
You could see if they have any decent specs for it. Though, as previosly stated the generator will have to be a close match up for he same performance..
Rick