Control surface lock for flutter constraint

In combination with an hydraulic actuator for a control surface of an aircraft, comprising:

• i. an hydraulic supply having pressure and return lines;
• ii. control piston means secured to said control surface, responsive to a control input for reciprocable movement in a control piston cylinder and slaved movement of said control surface;
• iii. first and second control chambers receiving and porting fluid upon movement of said control piston;
• and,
• iv. control valve means for providing fluid communication between said pressure line and the respective one of said control chambers receiving said fluid and between the return side of said actuator and the control chamber porting said fluid;
• a control surface lock for flutter constraint in the event of failure of said hydraulic supply, disposed intermediate said return side of said actuator and said return line, said lock comprising:
• a. locking piston means reciprocable in a locking cylinder means and slaved to said control surface for movement therewith;
• b. first and second charged locking chambers, respectively receiving and porting fluid upon movement of said locking piston means;
• c. biased bypass valve means having ports in series fluid flow intermediate said first and second locking chambers, operable between a normally biased, open position allowing flow and a closed position blocking flow;
• and,
• d. flow splitter means having a first fluid path from the return side of said actuator and communicating with said return line and a second fluid path, crossing said first fluid path, in series flow intermediate said first and second locking chambers, whereby fluid ported from said actuator and fluid ported from said locking cylinder means may exchange in said flow splitter means.