BRS-6 General Installation Guide - CAFE Foundation

3. The Rocket Assembly
All current BRS rocket motors use stored chemical energy in the form of a solid propellant to
provide the thrust forces necessary to rapidly remove any enclosure cover and extract the
parachute from its container. These rocket motors use a composite propellant, a
heterogeneous mixture of ammonium perchlorate (AP) and aluminum powder (Al), the oxidizer
and fuel. These are the most commonly used types of ingredients in modern solid propellants.
A synthetic rubber binder is also necessary to provide a structural matrix to hold these
ingredients together. Other typical propellant additives include burn rate modifiers to
accelerate or decelerate combustion, curing agents to solidify the propellant at different rates,
plasticizers to improve the processing properties, bonding agents to improve the chemical
properties, and antioxidants to reduce chemical deterioration. The size, shape, and size
distribution of the propellant's solid particles are also key factors in its burning characteristics.
Two versions of our larger rocket assemblies, the BRS600 and BRS900, illustrated in Fig. 3,
consist of the igniter, rocket motor base, and rocket motor. The rocket motor components
consist of the motor case, aft bulkhead, propellant, and nozzle. The motor case/aft bulkhead
contains the propellant and serves as a pressure chamber when the propellant is burning. The
composite propellant is cast into grains, or solid shaped masses that fit snugly inside the motor
case. To provide consistent dimensional tolerances, the grains are cast inside a filament wound
internal liner that also acts as an insulator to limit heat transfer to the motor case.
Our smaller rocket motors, the BRS-300, BRS-301, BRS-440 and BRS-460, do not utilize a rocket
motor base, but instead attach directly to the igniter. They consist of a motor case,
propellant, nozzle, and both an aft bulkhead and forward bulkhead, illustrated in Fig. 4.
BRS-6 General Installation Guide (Models 600 through 1800) Page 10 of 47
BRS Document № 020001-03 Revision D Copyright © 2008, BRS Inc.