Rocket Motor Classification
- Jim Heaney (RIT Student)
Source: https://en.wikipedia.org/wiki/Model_rocket_motor_classification
Rocket motors are classified by their total impulse, or the change in momentum the motor can impart on a system. Some further identifiers are sometimes assigned to certain classes.
Class by Impulse
The class of a motor is determined by what range its impulse falls into, as defined in the table below.
| Class | Total Impulse (lbf*s) |
|---|---|
| Micro | 0–0.07 |
| 1/4A | 0.071–0.14 |
| 1/2A | 0.141–0.28 |
| A | 0.281–0.56 |
| B | 0.561–1.12 |
| C | 1.121–2.25 |
| D | 2.251–4.5 |
| E | 4.51–8.99 |
| F | 8.991–18.0 |
| G | 18.01–36.0 |
| H | 36.01–71.9 |
| I | 71.9–144 |
| J | 144.01–288 |
| K | 288.01–576 |
| L | 576.01–1,151 |
| M | 1,151.01–2,302 |
| N | 2,302.01–4,604 |
| O | 4,604.01–9,208 |
| P | 9,210–18,400 |
| Q | 18,400–36,800 |
| R | 36,800–73,700 |
| S | 73,700–147,000 |
Class by Certification
Each certification level of NAR or TRA allows for a higher motor class to be used. If multiple motors are installed in a single rocket, the sum of their impulse is used. Any rockets with more than 1 motor, or a non-commercial motor are considered "complex rockets" and require Level 2 to launch no matter what.
| Level | Maximum Class |
|---|---|
| Low-Power | G |
| Level 1 | I |
| Level 2 | L |
| Level 3 | S* |
*while the Level 3 certification allows for any sized motor, S is where most scales and insurance policies end