balance is thus established between a release of high winds through the flaps and the centrifugal force of rotation of the flaps 36 that is the centrifugal force of a flap and counterweight assembly is reduced by rotor speed reduction caused by the by pass of air through the flaps 36 rather than allowing its passage through the blades 16 thereby resulting in regulation of rotational speed in addition to such by pass of air through the gate flaps 36 for regulation of speed the blades 53 can be made automatically adjustable in position to adjust the amount of air passing between them in this regard by biasing each of the featherable blades such as with a spring a predetermined pattern of different degrees of release of air between them can be established at different rotor speeds that is by providing for automatic feathering of the blades the effect of high wind forces which would otherwise cause a higher speed of rotation can be subdued three mechanisms are thus operable for regulation of the speed of a rotor under high winds the mechanisms which can be arranged to function simultaneously or in sequence are namely the openable gate flap the featherable blades and the positionable fly weights opening of the gate flaps.