What rocket motor to use??

In this post, I will be giving the Code as well as Impulse Range for motor distinction. It's important to know what motor is best to be used with which rocket. Always starting with rockets like the Estes or Apogee supplied rockets are a great beginner. Most of these can be found at your local hobby store, Hobby Lobby, or even Wal-Mart stores nation wide. You can even find majority of the smaller motors there as well. Prices vary but they aren't that expensive at all. Now the Code motors that are not regulated by BATFE are those that are under G. The (ns) after the number stands for newton-seconds. Here's the list that a Low Explosive User Permit(LEUP) is not required to have to fly:

Code------IMPULSE RANGE---------MINIMUM SITE DIMS(ft)

1/2A----------0.625 - 1.25ns-------------------------50

A--------------1.251 - 2.50ns------------------------100
B--------------2.51 - 5.00ns-------------------------200
C--------------5.01 - 10.00ns------------------------400
D-------------10.01 - 20.00ns------------------------500
E-------------20.01 - 40.00ns-----------------------1,000
F-------------40.01 - 80.00ns-----------------------1,000
G-------------80.01 - 160.00ns----------------------1,000

The above list of motors(otherwise known as engines) are commercially made motors. When you look at the packaging of a model rocket kit, a list of recommended motors to use should be followed. The manufacturers of the rocket have first hand knowledge of what the components can handle and should not be deviated. After some time building and learning how much force a rocket can handle, you will begin to know how to make your own and "beef" it up to withstand the extra forces. But until then, just use the KISS(Keep It Simple Stupid) method. No need rushing into this hobby. Now for the bigger stuff.

CODE--------IMPULSE RANGE----------MINIMUM SITE DIMS(ft)

H--------------160.01 - 320.00ns---------------100/200 for complex
I---------------320.01 - 640.00ns---------------100/200 for complex
J---------------640.01 - 1280.00ns--------------100/200 for complex
K-------------1280.01 - 2560.00ns--------------200/300 for complex
L-------------2560.01 - 5120.00ns--------------300/500 for complex
M------------5120.01 - 10240.00ns-------------500/1000 for complex
N-----------10240.01 - 20480.00ns------------1000/1500 for complex
O-----------20480.01 - 40960.00ns------------1500/2000 for complex

Now these motors require a LEUP to store. You do not need a LEUP to buy from a vendor at a launch but cannot buy them online. There are motor vendors that have some of these motors but are limited to quantity on hand. So when you're ready, get out your checkbook. These motors are not cheap like the smaller ones. Also, like my other posts have included, the Level 1 cert flight can only be done with the H or I motors. After having a successful L1 flight, you are now able to fly on anything from I and below but the Impulse range is the key to stay under. Some applications for rocket can be made to fly with multiple motors firing at the same time. This is known as cluster. You can build and fly any rocket as long as you do not exceed an Impulse of 640.00. So keep that in mind when planning a cluster built rocket.

For Level 2 certification flights, you need to first be Level1 certified by NAR or TRA, pass the written test and then can attempt your flight on the J - L motors only, or between the 640.01 to 5120.00 newton-seconds range. Electronics are not required for L1 nor L2 certifications but it would be good to have a knowledge of them. L2 is where things get pretty intense. You have a wide range of possibilities. Higher altitudes can be achieved since you have higher impulse motors to use. But keep in mind that the higher your rocket flies could also mean loong walks for recovery. For Tripoli L2 members, you have the opportunity to make your own motors. The cost is much cheaper to make your own since you are now cutting out the price to pay a manufacturer to make it for you. But you can still only build motors at the L impulse range or lower. That a whole other topic.

For Level 3 certification flights, you must be L2 certified and this is where the fun begins. Building the rocket must be recorded by 2 Tripoli TAP members or a L3CC Member from NAR. It's easier to certify through TRA than NAR but whatever floats your boat. The rocket can be a kit or scratch built but you MUST use electronics. For the motor, you need to use anything over the 5120.01ns, or M and above. Once that happens and you have a successful launch, the sky is the limit! You are now open to all opportunities available.

Remember that at any level, SAFETY cannot be under-estimated and pushed aside. If something looks wrong, it probably is. There is no room for "redneck ingenuity" in this hobby. If you have left over pieces, take the time and go over everything. If parts are left over while building a motor, don't even think about flying. Unpredictable occurrences WILL happen and you don't want to get hurt or killed nor hurt or kill someone else. This hobby is designed to be fun and safe. Accidents happen but if you pay attention in the beginning and not over-look things, you will have a lot of fun and meet a lot of great people! Happy Flying!!