Introduction

CARTRIDGE-ACTUATED DEVICES
Cartridges and cartridge-actuated devices (CADs) are small, self-contained energy sources that
are used to do mechanical work. The energy is generated by the burning of a propellant or
pyrotechnic material and is used often to push a piston or initiate an explosive train.
This differentiates cartridges from similar devices, such as rocket igniters, where heat energy,
not mechanical work, is the desired output. Cartridge-actuated devices are simply devices that
utilize cartridges as mechanical power sources. Although guns and explosive destruct devices
might meet this definition, they are not generally regarded as cartridges or cartridge-actuated
devices.
CAD's are used throughout the military services and in private industry. Non-aircraft CAD
applications have included emergency systems for deep diving submersibles and submarines,
propulsion units for mine field markers, release mechanisms for allowing separation of missile
stages, timing systems for hand grenade fuzes, inflation systems for marking locations of buoys,
and "soft" recovery systems for reentry space vehicles. In the private sector many of the
proposed air bag approaches to passive driver restraint systems are CAD's because of the quick
response required and space/weight restrictions. The emergency aerial flare kit carried by many
larger pleasure boats is, in fact, a cartridge actuated device.
The two principal types of cartridges are those that respond instantaneously to the initiation
stimulus and those that provide a delayed response. "Instantaneous" cartridges (delay of less
than 50 milliseconds) are referred to as impulse cartridges. Impulse cartridges are used primarily
in stores release applications; i.e., pushing a bomb or missile away from an aircraft.
Several attributes of cartridges and associated devices (CAD's) have led to the proliferation of
applications in recent years. First, as previously mentioned, cartridges are physically small,
lightweight sources of energy. Theoretical energy densities of cartridges approach that of the
propellants used in the cartridge (ranging to almost 400,000 foot-pounds of energy per pound of
propellant). Cartridges and cartridge-actuated devices require no maintenance once installed,
are in relation to the value of their mission, inexpensive and, perhaps most important, exhibit a
high degree of reliability. Furthermore, they are very versatile, allowing initiation by many
sources, among which are the following:
*Initiation Energy *Initiating Mechanism
* *
*Mechanical *Firing pin
*Ballistic hot gas *Pneumatic hose
*Electrical (high and low voltage) *Electrical cable
*Explosive *Explosive cord
*Laser *Fiber optics

PROPELLANT-ACTUATED SYSTEMS
Propellant-actuated systems include such devices as catapults, rocket catapults, and rocket
motors which are used in military aircrew escape systems. These devices, in conjunction with
various cartridge-actuated devices and other life-support equipment, provide the capability to
eject aircrew men safely from disabled aircraft. All catapults, rocket catapults, and rocket motors
currently in use are solid-propellant devices. The design and function of these devices vary
widely in complexity; however, the purpose of each is to enhance the safe-ejection envelope.
Ejection envelope is a concept that involves the configuration, velocity, altitude and orientation
of an aircraft upon initiation of the ejection sequence. A safe-ejection envelope includes the
various combinations of these factors under which aircrew men can safely eject. High tail
surfaces, exceptionally high speeds, and the advent of multi seat aircraft are developments
which have generated the need for propellant-actuated systems to perform a variety of functions
during the ejection sequence.
Military requirements govern such factors as aircraft configuration and velocity. Therefore, the
escape-system, including its propellant-actuated systems, must be designed in response to
increased aircraft performance capabilities in order to continuously provide the military aircrew
man with an optimum means of emergency egress under all conditions of operation.