Abstract: A high speed, downwind horizontal axis wind turbine includes three circumferentially spaced lightweight blades having inner support arms and radially outwardly disposed airfoil configured blade segments which are pivotally connected to the support arms, so as to fold straight downwind under high wind conditions or high rotating speeds. A spring biased control mechanism serves to rotate the airfoil segment of each blade about its longitudinal axis as the blade is folded downwind, so that a simultaneous folding and feathering action is obtained to prevent damage to the turbine in high wind conditions or under high rotating speeds.