Sensitivity to Firing Stimuli

3.1.5.2.1 Sensitivity to Firing Current Electrical sensitivity of an EED shall be as low as feasible consistent with its application. The use of prime-charge formulations that have high ignition temperatures is recommended for reducing the sensitivity of EED to current. For low-voltage EED, the bridge-wire resistance should be 1.0 ohm unless the available power is not adequate to provide ignition at this resistance this resistance generally provides the optimum insensitivity balance between...

Bridgewire Prime Charge Design

Bridgewire Prime Charge Design

The resistive element in a low-voltage EED may be attached between the terminals or from a terminal to a conductive ground (e.g., the initiator case). The elements most frequently used are small wires (0.0005 to 0.005 in. in diameter) but thin films, plated bridges, and conductive compositions have been used successfully. By use of small-diameter, high-resistance wires with primer compositions having low ignition tempera tures, ignition can be accomplished with the application of as little as...

Basic Requirements Heat Flux and Pressure

The energy release system shall provide the heat flux to the motor propellant and the pressure in the motor chamber necessary to ignite the propellant and produce sustained combustion within the required time limit. Because pyrogen and pelleted pyrotechnic igniters comprise the bulk of igniters currently used in operational motors, the major portion of this section on recommended practices is devoted to these types. References are provided for other systems considered of potential value for...

Bulkhead DonorAcceptor Charge Design

The TBI shall include an integral bulkhead with donor and acceptor charges located externally and internally, respectively, so that propagation through the bulkhead without adverse effect on the bulkhead integrity is ensured. The recommended design parameters for through-bulkhead initiators are included in reference 62 and references 109 through 111. The recommendations are summarized as follows 1 Suggested housing-barrier material is steel. 2 Barrier thickness should be 0.100 to 0.150 in. for...

Through Bulkhead Initiators

As is frequently the case in the ignition field, the application of a through-bulkhead initiator TBI has preceded a comprehensive theoretical explanation of the behavior of the components involved. However, some success has been reported in relating the detonation-to-deflagration transition to the detonating velocity and resulting shock pressure. A simplified illustration of a TBI is provided in figure 6. Acceptor charge 5 8 - 18 UNF-2A Closure Sealant Ignition charge Integral diaphragm Figure...

Pelleted Pyrotechnics

Solid Rocket Motor Igniters

In the broadest sense, the term pyrotechnic describes a large variety of igniter types. For purposes of this monograph, however, this group of igniters is limited to pyrotechnics in the form of pellets or large grains. Examples of these types are shown in figures 8 and 9. Figure 8. Pyrodyne igniter. Igniter body Booster charge Figure 8. Pyrodyne igniter. Igniter body Booster charge In the pelleted pyrotechnic, the pellets are retained for the bulk of their burning time by either a wire mesh or...

Restartable Solid Rocket Motor

Initiator, Electrical Design and Evaluation of. Military Specification MIL-I-23659, Rev. B, Amend, no. 1, May 17, 1967. 2. Anon. Basic Evaluation Test for Use in Development of Electrically Initiated Explosive Components for Use in Fuzes. Military Standard MIL-STD-322, Oct. 15, 1962. 3. Anon. Environmental Testing Aeronautical and Associated Equipment, General Specification for. Military Specification MIL-E-5272, Rev. C, Amend, no. 1, Jan. 20, 1960. 4. Anon. Fuze and Fuze Components,...