Black Powder Model Rocket Engine (Estes)
Model rocket engines are rated from a baseline of 2.5 Newton-seconds of impulse, denoted as "A". Impulses between letters are rounded up to the next letter. Each successive letter is double the last letter's impulse, so an F engine is 2x the impulse of a E, and 32x that of an A. The letter is followed by a number which gives average thrust, in Newtons. A special permit is required to fly anything larger than G size. Delay is denoted by a number after a dash; this is the delay time in seconds. After the delay, a charge bursts through the top of the engine to deploy the parachute or other recovery system.
Estes has been making model rocket engines since the 1950's. They are simple use and highly reliable. They make engines from 1/2 A though D sizes, as well as dozens of rocket kits to fly them in. They also make booster engines, which have no delay or ejection charge, intended as lower stages.
| Specification | 1/2A6-2 | C6-0 booster | D12-7 |
|---|---|---|---|
| Propellant | Black powder | Black powder | Black powder |
| Total Impulse | 1.25 N-s | 9 N-s | 17 N-s |
| Average Thrust | 6 N | 6 N | 12 N |
| Burn time | .21 s | 1.5 s | 1.42 s |
| Motor Weight | |||
| Propellant weight | 2.6 g | 10.8 g | 21.1 g |
Aerotech : Liquid Rocket Engines 