Lever 1 is connected by turning pairs A and B to rod a of piston 8 and to link 7 which turns about fixed axis C. Roller 9, mounted at the end of rod b of piston 6, rolls and slides in slot d of landing flap 10 which turns about fixed axis D. When lever 1 is oscillated, pump 2 draws in fluid from tank 3 and delivers it to one end of power cylinder 4. Fluid from the opposite end of the cylinder is forced out through rotary valve 5 and drains back to tank 3. Valve 5 can be turned to reverse the direction of motion of piston 6. Piston 6 and, with it, landing flap 10 of the plane can be locked in any intermediate position by ceasing to pump and setting valve 5 in the neutral position.
$3964$LHP,Co$