What is the difference between a horizontal axis wind turbine (HAWT) and a vertical axis wind turbine (VAWT)?
The traditional style of wind turbine, and the ones currently used for wind farms, are horizontal axis wind turbines, so called because the blades revolve around an axis which is horizontal. The silent wind turbine by Luethi Enterprises is a vertical axis wind turbine, that is, the blades revolve around an axis which is vertical.