DROGUE DEPLOYMENT CATAPULT.—
The drogue deployment catapult (fig. 5-12) is
mounted outboard of the RH main beam of the
ejection seat. Its function is to deploy the
stabilization drogue and bridle assembly rapidly
without becoming entangled with the seat. The
firing of the drogue deployment catapult is
controlled by the electronic sequencer to ensure
that the seat has cleared the aircraft before the
drogue is deployed. The drogue deployment
catapult consists of a cylindrical body containing
an electrically operated impulse cartridge
(CCU-101/A), a two-piece telescopic piston
assembly, and an enlarged upper end, into which
is fitted a drogue and canister assembly.
The drogue and canister assembly contains a
1.45mm (57-inch) diameter ribbon drogue,
pressure packed into a 210mm (8.25-inch) long
light alloy cylinder, closed at the upper end. The
canister assembly is closed by an end cap attached
to the drogue strap. At the lower end of the end
cap, a link assembly is attached by the same bolt
that secures the drogue strap. When installed on
the ejection seat, the link assembly attaches to the
drogue bridle, and the canister assembly is
retained in the body by a threaded locking ring.
At the upper end of the catapult body is riveted
a threaded ring on to which the locking ring is
screwed when installing the drogue canister.
MULTIPURPOSE INITIATORS.— Two
multipurpose initiators (IMP) (fig. 5-13) are
attached to the lower outer faces of the seat’s main
beams. During the ejection sequence, the IMPs
supply gas pressure to operate the barostatic
release unit delay mechanism, the underseat rocket
motor, the pitot deployment mechanisms, and the
internally mounted start switch assemblies.
Each IMP comprises a body, machined and
drilled to accept a start switch, a static lanyard
Figure 5-12.-Drogue deployment catapult.
5-12
