Brakedrum Windmill Plans Year 2000 Edition

By Paul Gipe

A review by Paul Gipe

Hugh Piggott’s plans for turning a used brakedrum into a windmill is welcome addition to the literature on small wind turbines. “Brakedrum Windmill” is especially valuable because plans for building your own wind turbine have not kept pace with the technology. Most plans date from the 1970s–or even earlier.

Since the publication of Brakedrum Windmill, Hugh Piggott has introduced plans for an “axial-flux” generator. Hugh’s plans How to Build a Wind Turbine are available directly from Scoraig Wind Electric and include measurements in both metric and “English” units. Hugh offers workshops in Great Britain and North America on how to build this wind turbine. For details contact Hugh directly.

Better yet, the plans in this booklet are for a wind turbine that really works from someone who lives with and depends on wind energy. The brakedrum windmill is a proven design that Hugh has operated at a remote, windswept headland in northwest Scotland since 1993. His site on the Scoraig Peninsula is so windy in fact that several commercial wind turbines failed within a few years (some, unfortunately, much sooner). Hugh’s prototype of the brakedrum windmill in these plans has operated so reliably that he substantially increased its output within a few years after installation. And it continues to run to this day.

The beauty of these plans can be found in Hugh’s use of conveniently handy scrap yard parts. The design is based on rear brake drums used by Ford trucks widely available in both Britain (the transit van) and North America (the F250).

Another plus is Hugh’s elimination of slip rings and yaw bearings. Slip rings often bedevil the design of commercial wind turbines as well as home builts. They’re not necessary and seldom found on many wind turbines built in Europe. Hugh wisely avoided them, instead substituting a simple pendant cable. This greatly simplifies this design as does Hugh’s use of pipe-on-pipe for a simple and hardy yaw system that allows the turbine to respond to changes in wind direction.

Hugh’s brakedrum windmill also incorporates the durable “inside out” alternator design found in the popular–and successful–small wind turbines built by Bergey Windpower and World Power Technologies. With this alternator configuration there’s no need to build a complicated hub that attaches the blades awkwardly to a small diameter shaft as in some other designs. Instead a simple plywood sandwich holds the blades tightly to the rotor and this assembly is mounted directly to the generator housing: the brake drum. In wind turbines it doesn’t get more straight-forward than this.

And like all reliable commercial wind turbines today these plans use “self-furling” to protect the product of your labor in high winds. Hugh’s an expert on this technique to limit the speed of the wind turbine’s rotor and the simple design found in these plans would be helpful to not a few commercial wind turbine companies who haven’t quite mastered the art.

“Brakedrum Windmill” includes detailed instructions for building the entire wind turbine, from carving your own blades for a 7-foot (2.1 meter) diameter rotor to building your own permanent-magnet, direct-drive alternator capable of generating real power. By following these plans you will construct a genuine wind turbine–not just a toy–that can reliably churn out 300 to 400 watts.

“Brakedrum Windmill Plans” are a great companion to Hugh’s “Windpower Workshop.” Both are a valuable addition to any windmiller’s library.

Paul Gipe
Wulf Test Field
Tehachapi, California