100+ year old Russian windmill farm in Yalutorovsk
The Sensenich Propeller Manufacturing Co. in Lancaster, Pennsylvania was the largest wood propeller company in the world and also forged aluminum alloy propellers for aircraft engines up to about 300 horsepower. They made a special aluminum "climb prop" for my Piper Super Cruiser glider towplane that worked perfectly. A "climb prop" is like having the vehicle in second gear all the time while pulling a heavily loaded trailer. It would haul my Schwiezer 1-26 sailplane up to 3000 feet release altitude in about 6 minutes.
The second wind generator I built used a 12 volt DC, 50 amp automotive generator from a junk yard and I added a thrust bearing to take the propeller load. Sensenich designed and built a seven foot diameter wood propeller for my wind generator. The nice feature about 12 volt DC generators versus 12 volt alternators is that it is easy to design a transistorized heavy duty relay actuated system that turns the generator into a reverse motor so that when a wild passing thunderstorm with gusts in the 30 to 50 miles an hour range comes by, it slows down the propeller and keeps it from going so fast that it destroys itself (litterally explodes from centrifugal force).
I had a heavy duty 30 foot telephone pole installed next to our two room guest house that was adjacent to our doubles tennis court which was directly behind our home in Virginia. The telephone pole had climbing bars every twelve inches which made it easily accessible. It was a perfect mount for the new wind generator. The 12 volt DC generator was bolted onto two inch diameter water pipe and had a 5 ply by 1/2 thick marine plywood weather vane bolted onto the rear as illustrated in the little sketch below.
Generator output was fed down the center of the vertical supporting mast and used three insulated wires, each with 3/16 inch braided wire inside the insultation. The voltage regulator and overspeed sensor were mounted in a weather proof box on the telephone pole about 10 feet below the vertical mounting mast which was another section of two inch diameter water pipe. The voltage regulated generator output was fed down the telephone pole to two 12 volt, 100 amp batteries that drove a 500 watt 12 volt DC to 110-120 volt AC inverter that ran under the lawn to my ham radio room inside our house as shown below.
The wind generator ran quite well with only a little maintenance for a few months. On the semi annual ham radio "Field Day" contests I ran a small six meter transceiver on output from the wind generator to gain extra points for using an auxiliary power source. My home was in Virginia just northwest of Washington, DC on the Potomac River and had fair to good winds during the spring, summer and fall. During the winter months it was much like high on a windy hill and had 30 mile per hour winds most of the time, or so it seemed.
When the first really blustery cold front came through in November, the heavy duty relay in the overspeed circuitry failed. The neat Sensenich wood propellor must have wound itself up to more than 4000 revolutions per minute and exploded and threw chunks of wood nearly a quarter mile away. One piece of propeller wood actually pierced the roof of our guest house below the wind generator.
Though I had a lot of fun building and testing this wind generator if I had it to do all over again I think I might purchase a well tested and reliable commercial wind generator instead of trying to reinvent the wheel!