A mechanical device system that draws power from the wind by means of near-vertical blades pivotally mounted on a platform rotor that is flush with the ground and rotatable about a vertical axis, Wind forces are generated on the blades causing the platform rotor to turn thereby generating shaft power. An electrical generator coupled to the platform rotor converts the shaft power to electrical power, which is then distributed through conventional transmission means. The power output is maximized for a given wind speed by cyclically controlling each blade rotation to intercept the relative wind vector so as to create maximum blade forces over the periodic cycle. The blade axes are canted to match the rotational speed to the normal speed gradient of the prevailing wind to maintain constant (pi*h*D)/Vw at all levels. The turbine is mounted atop an earth mound tailored to accelerate the flow near the ground to produce an optimum wind speed profile.