Rocket Motor Guide

Rocket Name

Enter the name of the rocket. You can optionally select a rocket from the list that may appear as you type.

Rocket Diameter

Enter the diameter of the rocket's body.

Weight

Enter the weight of the rocket without the motor.

Motor Mount Diameter

Enter the diameter of the rocket's motor mount. This sets the largest diameter motor which will fit.

Motor Mount Length

Enter the length of the rocket's motor mount. This sets the longest motor which will fit.

Drag

Low Normal High

Select the approximate drag of the rocket. Sleeker rockets with a smooth finish will have lower drag.

Semroc Astro-Jr

Semroc - Astro-Jr {Kit} (KA-4) [2004-]

Motor	Weight oz	TTW Average	TTW Peak	Accel f/s²	Speed mph	Rod Len feet	Burnout Time sec	Optimal Delay sec	Time to Apogee sec	Altitude feet
Estes A3T	1.00	11:1	30:1	652.18	133.41	1.2	1.03	3.80	4.63	373
Estes A10T	0.88	12:1	65:1	897.85	123.54	1.1	0.90	3.50	4.20	335
Estes 1/4A3T	0.91	12:1	26:1	570.45	25.79	1.3	0.33	1.20	1.33	24
Apogee 1/4A2	0.83	13:1	28:1	717.63	31.96	1.1	0.30	1.40	1.50	34
Estes 1/2A3T	0.93	16:1	39:1	768.53	60.37	1.1	0.40	2.40	2.60	106

Weight - The total weight of the rocket, with motor, at lift-off.

TTW Average - The average thrust-to-weight ratio of the rocket.

TTW Peak - The peak thrust-to-weight ratio of the rocket.

Accel - The maximum acceleration experienced by the rocket.

Speed - The maximum speed experienced by the rocket.

Rod Len - The minimal rod/rail length for the rocket to reach a safe speed (9 m/s) for free flight.

Optimal Delay - The optimal delay time (equal to the time from burnout to apogee).

Altitude - The altitude at apogee.

Note: These simulation results should be used with caution. Always double-check to ensure that your flight will be safe.

The Rocket Motor Guide helps you choose the right motor to use in your rocket by running a simulation using each of the motors in the RocketReviews.com motor database.