cable anchor damper assembly, and the indicator
lights are located on the arresting engine control
panel.
The end of the purchase cable is attached to the
operating piston rod, which is attached to the
operating piston. When the force on the operating
piston, due to engine cylinder pressure, is greater
than the tensile force in the purchase cable, the
piston moves away from its BATTTERY position.
Movement of the operating piston into the cylinder
removes the cable slack during the first portion of
the arrestment. When the slack is taken up, the
operating piston resists the return of the cable, thus
keeping it taut and preventing excessive cable
vibration.
Upon engagement of the deck pendant by the
aircraft, the engine crosshead is accelerated toward
the fixed sheaves. This movement forces the ram
into the arresting engine cylinder, increasing the
fluid pressure in both the engine cylinder and the
operating head of each cable anchor damper. See
figure 3-18.
Because of the acceleration rate of the engine
crosshead, the tension in the purchase cable (2)
between the engine sheaves and the cable anchor
dampers decreases momentarily. The instant the
tensile force in the cable becomes less than the
force on the operating piston (4), fluid pressure
moves the operating piston away from its
BATTERY position until all slack is removed and
the cable tension is again greater than the fluid
pressure force acting on the operating piston. The
flow control valve is a clapper-type check valve that
allows free flow of the fluid one way and a restricted
flow in the opposite direction. The engine fluid has
free flow through the flow control valve (1) to the
operating end of each cable anchor damper. When
the tension of the purchase cable is transmitted to
the cable anchor ends, the fluid pressure on the
operating pistons is overcome by this cable tension,
and the operating pistons are pulled back toward
BATTERY position. Resistance to their return is
furnished by the engine fluid pressure and the
controlled flow of fluid through the flow control
valves back to the engine cylinder. A 2-inch buffer
stroke between the operating pistons and flanges
Figure 3-18—Cable anchor damper fluid flow (arrestment).
3-22
