Figure 102. Temperature-altitude-humidity test cycle.
malfunction occur, additional tests are necessary to
(2) Gas-firing mechanism should be tested
insure that the ignition system is reliable at -65 F., the
under the conditions simulating those of
lowest temperature specified.
design requirements. For example, it
may be specified that the firing
j. Drop Tests. Three units previously unfired are
mechanism function when gas pressure is
dropped 6 feet onto a concrete slab. Two of the units
supplied by a specific initiator at the end
are dropped, once on each end (four drops), so as to
of a specific length of hose or that the
strike the concrete with their longitudinal axes
gas-firing mechanisms function when 500
perpendicular to the concrete. The third unit is dropped
psi gas pressure is supplied to the rear of
with its longitudinal axis parallel to the concrete slab,
the firing pin. The firing mechanisms of at
and its lateral attitude is such as to effect maximum
least six devices should be tested at- 65
stress on internal parts. The third unit is disassembled,
70 and 200F.
inspected, reassembled, and dropped again with its
longitudinal axis parallel to the slab. All three units are
(3) Electric firing mechanisms (ignition
disassembled and inspected for internal damage.
elements) must fire with a specific
current, but must not fire with currents
k. Locked-Shut Firings. The three units used in
under a specified value. A minimum of
the drop tests and seven additional units Pre fired
20 elements are evaluated at -65 70
looked shut: two at -65F. and eight at 200F. Failure
and 200 F. for both the no-fire and all-
of any of these devices necessitates modification of the
propellant actuated device and a new evaluation
program for the modified design.
(4) If any firing mechanism fails to meet the
design requirements, the reason should
l. No-Load Firings. When no-load requirements
be determined, and if modification of the
are specified, 10 units are fired under no-load
device is required, a new evaluation
conditions: 2 at -65F. and 8 at 200F. The units then
program must be initiated.
are disassembled and inspected for
i. Ignition System Evaluation. Ten cartridges in
devices are conditioned at -90 F.
propellant ignition at very low temperatures. Should