To: Shy Torque
Just the opposite. If you lose all hydraulics the controls don’t lock up. They are completely free to move due to the opening of the bypass valve inside the servo. When this happens you had better forget about having children as the cyclic will imediately start rotating in a circle driven by the feed back forces in the rotor system.
The Sikorsky S-55 could be flown without hydraulics but the lateral feedback forces were quite high and it made the cyclic difficult to handle. To compensate for this, they incorporated a servo that was powered by engine oil pressure but this servo was in a constant state of bypass as long as there was pressure on the hydraulic system. If the pressure dropped below a certain level (750 PSI I think) the primary servo bypass valves would open and the oil powered servo would come on line and power the two lateral servos which at this time are linkages in the control system.
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The Cat
[This message has been edited by Lu Zuckerman (edited 08 January 2001).]
[This message has been edited by Lu Zuckerman (edited 08 January 2001).]
[This message has been edited by Lu Zuckerman (edited 08 January 2001).]
[This message has been edited by Lu Zuckerman (edited 08 January 2001).]