Windmills aren't to be tilted at; they can drive drills, polish glass, saw wood and pound metal -- not to mention generate electricity. So, should you find yourself broken down in the middle of nowhere, you can whip one up using a few old car parts, explains Lewis Dartnell, author of The Knowledge: How to Rebuild our World from Scratch.
Rig up a generator
Windmills can provide you with electrical power for free – but to convert motion into current you'll need a generator. "A car alternator could be a handy solution if you're stuck, producing a steady 12 volts as its spindle is turned," says Dartnell. "It's the drum-shaped component in the internal combustion engine of any car."
Control the spin
Alternators work best when they're spinning fast, but at full pelt your windmill blades won't be able to keep up. "One way to reduce the makeshift generator's excessive RPM is to unwind and replace the alternator spools with thinner wire," advises Dartnell.
Butcher a bikeIf you want to get really Scrapheap Challenge about it, Dartnell recommends controlling the speed with a bicycle chain. "Remove all the gears from the wheel except the largest one," he says. "Then fix an automotive pulley wheel to the large gear with nuts and bolts. Use the same kind of pulley as the one on your alternator – a single-belt version works best."
Make your blades
Ideally, get hold of some sheet metal. "Cut nine strips out of the metal, ten centimetres wide and 1.2 metres long," says Dartnell. "Bend them down lengthways, with a 10° to 15° twist, then secure them all to the bike wheel on the opposite side of the gear. You can bolt them to anything but the axle, which needs to spin freely."
Mount the axle"You'll need to secure your axle bolt," says Dartnell. "A satellite-dish mount would work. Add a section of pole to the base and drill holes for the axle and alternator. Mount the alternator under the wheel pulley, so the pulleys are lined up, then place a belt over both pulleys. When the wind catches the 'sails' they will make the wheel spin, setting the pulley, belt and alternator in motion."
This article was originally published by WIRED UK
