spring-loaded sleeve. The end of a key operated
spring-loaded piston. When operated during the
spring-loaded plunger protrudes into the bore below the
ejection sequence, gas pressure from within the
sleeve and a transverse drilling in the valve body breaks
catapult acts on the latch pistons, overcoming the
through the vertical bore opposite and level with the
springs and retaining the multipurpose initiator static
spring-loaded plunger. The bore of the valve fits over
lanyard lower end fittings.
the ejection gun initiator inlet connector, depressing the
Piston
sleeve against the spring. The valve is held to the inlet
connector by the spring-loaded plunger and a key
The piston consists of a light alloy tube, attached to
operated quick-release pin that passes through the
the lower end of a necked end fitted with piston rings to
transverse drilling and engages in a circular groove in
provide a gas seal between the piston and the barrel. At
the inlet connector. O-ring seals maintain gas integrity
the upper end of the piston is a breech into which is
between the components.
inserted the ejection gun initiator. The breech has a
groove machined around its outer diameter into which
MAIN BEAM ASSEMBLY
the plunger of the top latch mechanism on the seat main
The main beam assembly is manufactured almost
beams engages when the seat is installed on the
entirely from light alloy and is comprised of two
catapult. A V-groove in the top of the breech engages a
parallel main beams bridged by top and bottom
dowel on the seat top cross-beam when the seat is
cross-beams and a top latch assembly. A shoulder
installed in the aircraft.
harness reel is mounted across the front face of the main
Catapult Manifold Valve
beams and provides extra rigidity. An electronic
sequencer is mounted above the shoulder harness reel.
The catapult manifold valve (fig. 2-6) is a body
Bolted to the inside face of each main beam are three
with two gas inlet ports, each with a check valve,
slippers, which engage in the guide rails on the catapult.
connected by drillings to a vertical bore. The top of the
Two seat bucket runner guides are attached to the front
bore is sealed by a screwed cap and incorporates a
face of the each main beam and accommodate the top
Figure 2-6.--Ejection gun initiator JAU-56/A and catapult manifold valve.
2-6
