MIL-DTL-82945B (OS)
3.4.1.1.6 Catapult separation velocity. Catapult separation velocity is defined as the average velocity of
the simulated ejected weight propelled horizontally at catapult separation measured over the interval from
separation to 12 inches after separation.
3.4.1.1.7 Catapult dynamic response index (DRI). The DRI is representative of the maximum dynamic
compression of the vertebral column of the human body. In physical terms, the DRI is calculated by
mathematically describing the human body in terms of an analogous, lumped parameter mechanical
model consisting of a mass, spring, and damper. The DRI is determined from the equations (1) and (2).
d 2
d
d 2z
2 n
n 2
2
(1)
dt
dt
dt
n 2 max
DRI
(2)
g
Where:
δ = compression of spring
ζ = 0.224 (damping ration of the model)
ωn = 52.9 radians/sec (undamped natural frequency of the model)
d 2z
catapult acceleration
dt 2
Substituting given numerical values, these equations become:
d 2
d
d 2z
2798 2
23.7
dt 2
dt
dt
DRI 86.9 max
3.4.1.1.8 Catapult launch time. Catapult launch time is the time between the first indication of thrust on
the thrust-time curve until separation.
3.4.1.1.9 Catapult axial thrust. The maximum thrust from the thrust-time curve that occurs during the
catapult launch time.
6
For Parts Inquires submit RFQ to Parts Hangar, Inc.
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business