supported by contact with the surrounding planet gears 54 for rotation of the sun gear 60 relative to the gear box housing 30 about the central axis 36 the sun gear 60 has a hollow bore along its axis and along the axis of its shaft extension a hollow tube 96 fixed to the final stage cover 92 on the gearbox housing 30 passes through the bore of the sun gear 60 and its shaft extension substantially along the axis 36 to conduct control wiring not shown through the gear box 10 to the rotor 20 the sun gear 60 rotates relative to but does not contact the hollow tube 96 the sun gear 60 is substantially smaller in diameter than the planet gears 54 the sun gear 60 has a plurality of external spur or helical gear teeth 61 that are in meshing engagement with the external gear teeth 56 on the planet gears 54 as a result rotation of the planet gears 54 about their axes in response to rotation of the input hub 34 and the planet pinions 42 causes the sun gear 60 to rotate about the central axis 36 the rotational force of the input hub 34 and the planet carrier 40 is thus entirely transmitted through the planet gears 54 to the sun gear 60 driving the sun gear for rotation about the central axis 36 the gearbox 10 also includes a final stage 90 including a final stage end plate 94 the final stage cover 92 an output pinion 70 and a final stage gear 62 the final stage gear 62 is a spur or helical gear.