The 25-kW downwind turbine was designed by Coy Harris and built in his shop in Lubbock, Texas.

The photos here were from the installation of the prototype in 1979. I’ve seen photos of what must be later versions with an attractive nacelle.

The design was unique for the typical downwind turbines of the day. Harris’ approach was to use a dihedral angle in the blade spar that connected the blades to the hub. The dihedral allowed aerodynamic pressure on the blades to flip them to the feathered position when power was lost. This was a clever way to address the threat of overspeed during a power failure.

The turbine was also unusual in that it took the mechanical power of the rotor and transferred it to ground level via a shaft so the turbine could be used in wind-assisted irrigation on the high plains.

The turbine wasn’t successfully commercially and later Harris became director of the American Wind Power Center in Lubbock.