>A number specifying the average thrust ("8");
>A number specifying the time delay between burnout and ejection ("3").
Total Impulse is a measure of the overall total energy contained in a motor, and is measured in Newton-seconds. The letter "C" in our example engine above tells us that there is anywhere from 5.01 to 10.0 N-sec of total impulse available in this engine.
Average thrust is a measure of how slowly or quickly the motor delivers its total energy, and is measured in Newtons. The "6" in our example motor tells us that the energy is delivered at a moderate rate (over about 1.7 seconds). A C4 would deliver weaker thrust over a longer time (about 2.5 seconds), while a C10 would deliver a strong thrust for a shorter time (about a second).
Time Delay allows the rocket to coast to its maximum altitude and slow down before the recovery system (such as a parachute) is activated by the ejection charge.
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