Rocket Motor Coding

There are many types of Rocket motors and they come in many sizes. The size of each motor is measured in "total impulse" and are designated by letters of the alphabet.

Each letter gives a range of total impulse and each motor size, and as the letters go up so the total impulse of the corresponding motor doubles.

E.G. A "B" motor has twice the total impulse of an "A" motor, and a "C" motor has twice the total impulse of a "B" motor, etc, etc.

**For a Chart of Rocket Motor Impulses (Click Here)**

So a rocket motors power is indicated by a letter. However a motor of any impulse range can be configured by the manufacture to deliver the energy in a multitude of different ways, this is done by changing the composition of the Fuel/oxidizer.

Along with a letter there is often a series of numbers, see above Picture.

The amount of energy and thrust characteristics of a motor is determined by the series of numbers on the motors label, in the above example the motor is a J impulse, with a total thrust of 648 and an average thrust of 285 newton's, the 15 is the length of time in seconds after motor burnout that the ejection charge will fire(this is adjustable with a pro DAT tool).