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Make a ‘Bespoke’

Wind Turbine

Beth Tilston and Will Harley offer a step by step guide to building a wind turbine from a bicycle wheel

The idea of building a wind turbine from a bicycle wheel started, like most good ideas, in the pub. Fortunately the idea survived into the cold light of day and with Will providing innovation and mechanical knowhow and Beth providing enthusiasm, a willing pair of hands and a shed to mount it on, a trickle-charge wind turbine made from a Sturmey Archer dynohub wheel was born.

We built our turbine for use at the allotment where we co-work. Being trickle-charge, the turbine will never be a constant source of power (we couldn’t run the house lights from it) but it is perfect for the allotment as we aren’t there all the time. Being in a windy spot on the side of a hill (aren’t they always), the turbine slowly charges the battery so that on the days we are at the plot, we can listen to the radio, charge mobile phones, run LED lights and even run laptops.

Permaculture Magazine No. 63

Equipment ❖ Angle grinder or hacksaw ❖ Stanley Knife ❖ Saw(s) ❖ Drill ❖ Paint brushes www.permaculture.co.ukThe GuideHere’s our step by step guide to building a trickle charge turbine from a dynohub bicycle wheel. You will need:

Components ❖ Dynohub wheel ❖ Old bike with forks long enough to accept the wheel ❖ Two-core electrical cable ❖ Crimp ends ❖ Estate agent board or similar ❖ Cable ties ❖ Bolts ❖ Brake cable ❖ Paint suitable for outdoor use ❖ 50 x 50mm (2 x 2in) wooden pole to use as a mast, 2-3m (6.5-9.8ft) long ❖ Large jubilee clips Electronic Components Needed For Rectifierv Capacitor 1,000 micro farad VH50E ❖ Bridge rectifier 60V 2A AQ98G ❖ Blocking diode N91CA 3A schottky barrier ❖ Veroboard on which to build the circuit

Also Required ❖ Step up circuit to run at 12V ❖ 12V battery

1. Find A Dynohub Bicycle Wheel As volunteers at Cranks, a not-for-profit bike workshop in Kemptown in Brighton, we had easy access to dynohub wheels but even without a bike workshop to hand, sourcing a dynohub should not be too difficult. You can find one on eBay, at the local scrapyard and also second hand bike workshops. Modern dynohubs are available but are a bit more expensive so it’s cheaper to find an old one if you can.

Sturmey Archer dynohubs are easily available as a great many were built, but they have fallen out of favour due to their weight and age. They are useful because a) they tend to come ready installed into a wheel into which blades can be laced and b) they are a permanent magnet generator with a moving magnet and static coils. Also, being designed for bicycles they are pretty weatherproof and have bearings designed to take the weight of a person, making them very strong. They are also designed to give a good output at low rpm.

Opposite: top: Finished wind turbine. bottom left: Sturmey Archer dynohub wheel with first fan blade attached.

Above: Fitting fan blades.

Top right: Turbine showing cable led through centre of headset to avoid fouling.

Right: Drilling attachment holes in fan blades.

2. Find A Headset & Forks, Connect Power Cable To hold the turbine wheel and allow it to rotate into the wind, the forks and headset were used from an old bicycle. We used an angle grinder for this task for speed but a hacksaw with a fresh blade could be used. It can be advantageous to leave the stubs of the top tube and the down tube attached to help with mounting the headset on the mast.

The only critical dimension is that the fork should be able to take the size of wheel used. A two-core electrical cable was connected to the two terminals of the dynohub, led down through the centre of the headset and secured with cable ties on the way down the fork. This allows the turbine to rotate through 360 degrees without fouling the cable. 3. Add Blades We made the blade from estate agent board and cut it to be the right size to fit between the hub and the rim of the wheel that we were using. Any durable material with a bit of flexibility could be used – for example other types of plastic sheet or drainpipe. We fitted the blades by cable, tying them to the spokes through holes drilled in them. The way the wheel is laced will probably give you a natural angle to fit the blades. It’s important to fix them all angled the same way! If you can introduce some twist to the blades, all the better (to make the tips of the blades closer to the angle of the rim and the roots of the blades closer to the angle of the axle).

www.permaculture.co.uk

No. 63 Permaculture Magazine