Thanks, Russ; a good tip. And yes, I'm working on the cheapest options (a) to keep costs down, (b) to recycle things that would be thrown away, and (c) because spending a fortune on shiny new bits to capture 'free' energy strikes me as perverse!
Re your water wheel; You may already have come to the same conclusion, but if not I mention something I learned at Quarry Bank Mill, Styal (Near Jodrell Bank, S of Manchester, UK... where are you writing from?). That is a late 1800's brick-built cotton mill now in the hands of the National Trust. It had a HUGE water wheel. It turned slowly, but with a lot of torque; like 1000's of horse-power! It was impracticable to gear-up the axle as a 'drive-shaft' to power machinery, so they put a gear ring insde the edge of the wheel. That turned a small pinion wheel (much faster), which turned the machinery in the mill. You may have to substitute belts for gear teeth, unless you have precision lathe equipment, but the principle of using the circumference rather than the axle might give you a higher rotation speed, which suits alternators. And a polypropylene rope, spliced in a continuous ring, might be a suitable 'drive-belt' as a 12' diameter is a bit large for a car fan-belt from Halfords.... Just a thought....
I'll check out the "Windmills and Windmotors" book. It sounds up my street.
Thanks,
Sunnyjohn