Abstract: One embodiment comprising a motoring propeller (21) attached to a rotatable motoring shaft (22) which in turn is connected to a motor (26) and a generating propeller (23) attached to a rotatable generating shaft (24) which in turn is connected to a generator (25). Operation of the motor (26) results in the motoring propeller (21) to rotate and generate an accelerating slipstream towards the generating propeller (23) which results in the generator (25) rotating to convert recovered rotational energy into other forms of useable energy. The motoring propeller (21) may also be represented as rotating spokes of a wheel rim with the generating propeller (23) situated inside or near the wheel rim space where it freely rotates as a result of the slipstream impacting its blades. The motor (26) may be an electric motor or an internal combustion engine. The generator (25) output is available for charging batteries or powering electrical loads.