circuit 175 fig7 as discussed hereinafter motor 68 drives union 80 whose output driveshaft 82 is splined to spider 54 within orifice 84 thus as appreciated from fig3 each rotor assembly is rotated by a hydraulic drive motor and tilted for propulsion or steering by a hydraulic cylinder additionally the pitch of each rotor assembly may be varied by a hydraulic cylinder the right side rotor assembly 41 is driven by hydraulic motor 69 and the front rotor assembly is driven by hydraulic motor 71 fig2 an operator station 90 mounted at the top of the frame 25 shrouds the internal combustion drive motor 92 fig6 and supports operator seat 94 seat 94 is comfortably disposed apart from a steering wheel system 100 best seen in fig4 system 100 is supported upon and between a pair of upwardly projecting panels 103 and 105 that support dashboard 106 a steering column 108 projecting through the dashboard 106 mounts steering wheel 109 that may be grasped by the driver the steering wheel directly controls a proportional hydraulic valve 110 fig4 which controls a tilting cylinder 112 fig7 associated with the front rotor assembly 44 that is primarily responsible for steering a suitable lever not shown is mounted to one of the panels 103 or 105 for controlling a conventional cable not shown that leads to the conventional throttle on the internal combustion motor the left and.