Gearing up ?
Short introduction, I am a liveaboard sailor currently wintering in Greece. The ( Very old ) boat has two 85 watt solarpannels ( Mppt regulator ) and a Aerogen 3 windgen on top of the yawl mast.
Paid my last electricity bill 25 years ago.
After 13 years of Med cruising we are thinking of visiting the French canals. Winter 2000 we wintered on the canal du Midi, and there, solar power in winter is not sufficient. Very few spots where there are no plane trees who give shade. The Tramontana blows strong on many days so I made some preparations. First I want to make a hinge in the small yawl mast ( 7 meter ) so once moored at the canal bank we can simply fold the small mast and windgen in place. That little gen is just sufficient to power the fridge, nothing more.
I like windgererated toys ( build a water pumping windmill for the garden in the 1970, was a champ windsurfer, had a hang-glider and crashed it, now we sail ) so I build a small windgen for the canals.
Bought a Ametec motor (40 Volt ) and a diode, the rest was build out of scrap. To bend the frame plate we sailed to a remote bay in Turkey, climbed the mountain to a valley where an old abandoned tractor stood. He had two big metal counterweights witch I could use as a vice-mold to bend- hammer the plate into the form I wanted. The hub for the prop was made out of a aluminium engine part of a sunken gullet. Two bladed wing made out of four pieces of an antique bed. Two bladed for easy stowing ( Between the deck beams ) 5,6 feet span.
The old short mast of the sailing dingy is used as a mast, the thing rigged at the port bow when at anchor. Takes five minutes to rig- take down and stow.
I wanted a gen for low wind speeds and was aiming at 3 to 5 Amps, we don't need more. The wing is not painted or varnished up to now, my hope was to build a super silent wing. Owls can fly without making any noise, the slightly rough surface of the wing imitating their special feathers.
First tests in low wind speeds are no good. The wing starts very easy, even before the Aerogen, and generates with low wind speeds 14 to 14,3 volts. Minus 0,6 for the diode, that leaves 13, 7 Volt witch is lower than the tension generated by the solar system and the Aerogen, so no charge. Have no idea of the revs, the wing can not be seen any more and makes just a faint whopping sound.
I need just a few Volts more, think 18 volt would be ok.
Now my question, should I gear up with a toothed belt ? I think the big wing has huge power, should be no problem to gear up a bit.
Could also make a smaller wing, think that would spin faster. Three bladed is no option, no way to store on our small yacht.
The current wing, 6 ° at tips and 19°at the hub is still fairly chunky, 3/8 at the tips, maybe a thinner blade would spin faster, would be very fragile. Cutting the wooden wing I followed the wing profile of the aerogen wing. Flat to slightley concave at the front, wing shaped at the back.
We sail a low tech boat, strings and stick technology, no instruments so no way to measure wind speeds or revs, have not tested the big wing in more than 7 knots of wind ( I guess ) the power in that blade makes me scared.
Help please, revving up and how much ?