Figure 1-4.--Rocket motor initiator mounting.
and the inboard (left side) rocket nozzle is larger to
flexible hose to a rocket motor initiator attached to the
ensure the seats eject to the right. The attachment bolts
left upper side of the seat structure (fig. 1-4).
for each rocket motor vary in size to ensure the
installation of the correct rocket motor to its related seat
and proper divergent trajectories.
The rocket motor unit is a sealed unit; therefore,
The rocket nozzles of the ECMO #2 rocket motor
do not attempt to remove the rocket motor igniter
(DODIC M940) are symmetrical and the divergent
effect is zero. The divergent angle is predetermined to
ensure adequate distance between crewmembers
during sequenced ejections.
Each rocket motor consists of a center body to
which is attached 14 tubes, 10 facing forward and 4
For rocket motor handling, identification and
facing aft. One of the forward facing tubes contains a
service life, refer to NAVAIR 11-100-1.1, General Use
primer-fired igniter cartridge and is initiated by the gas
Cartridge and Cartridge Actuated Devices for Aircraft.
generated by the impulse cartridge (DODIC M783).
The remaining 13 tubes contain rocket propellant. Six
ROCKET MOTOR INITIATOR
rocket efflux nozzles are attached, three at either end of
the center body, each nozzle being sealed by a blowout
The rocket motor initiator is mounted on a plate,
disk. Projecting aft from the center body is an arm that
which is secured to the drogue gun assembly mount-
contains a cam follower; the cam follower engages the
ing bolts (fig. 1-5). The unit is divided into two
inclined track attached to the left main beam of the
ejection seat structure. This provides a pivoting action
to the rocket motor, which adjusts the nozzle angle to
compensate for the change in the seat-occupant center
of gravity due to raising or lowering of the seat bucket.
At either outboard end of the center body is a threaded
hole to which the attaching bolts fit.
The rocket motor (DODIC M938) of the pilot and
ECMO #3 seats are identical. The inboard (right side)
nozzle of the rocket motor is larger to ensure the seats
eject to the left. ECMO #1 rocket motor (DODIC
M939) is a mirror image of the pilot seat rocket motor
Figure 1-5.--Rocket motor initiator.