Getting Started in High Power Rocketry

Getting started in high-power rocketry doesn’t have to feel intimidating. There’s plenty to learn, but most student groups begin with limited experience and grow into it step by step. As you work through the basics, your confidence builds, and what looked complicated at first starts to make sense. The process is part of the enjoyment: you learn by doing, solving real problems alongside classmates who are figuring it out with you.

As you move from mid-power flights into the requirements for high-power certifications, you’ll find that the path is more approachable than it appears. You don’t have to master everything at once. Break the work into manageable pieces, lean on mentors when needed, and take each milestone as it comes. It’s challenging in all the right ways, and when you keep a steady pace, the whole experience becomes both rewarding and genuinely fun.

Low Power, Medium Power, High Power, and Certification Levels

Model rocket motors are generally broken down into two groups, low power and medium power.  Low power motor are designated A through D and can often be purchased at discount and hobby stores.  Medium power motors are designated E through G and can also be purchased at these stores, but with less availability.  There is no certification required to purchase or fly low and medium power rocket motors.

High power rocket motors are designated H and above.  High power motors are usually not available at discount and hobby stores.  High power motors are best purchased from rocket vendors either online or at a local launch.  High Power Rocketry (HPR) is self-regulated by those in the hobby as an alternative to government regulation.  TRA and other national rocket organizations have agreed on a tiered certification program to regulate the use of HPR motors.  Level 1 certification allows a person to purchase and fly H and I powered motors.  Level 2 provides for use of  J, K, and L powered motors.  Level 3 certification allows a person to use M power and larger motors.  Motor vendors normally ask for certification level evidence in the form of your TRA membership card (which displays the certification level) when purchasing HPR motors.

Junior Members (12-17 yr old)

Junior members 12 to 17 years old can participate in the Tripoli Mentoring Program and certify as Junior Level 1. 

Student Members (18 – 25 yr old)

If you are age 18 to 25 and a student, you can join Tripoli as a student member, which is discounted from the senior membership rate.  Student and senior members participate in the regular certification process to fly HPR rockets and motors. 

Note that HPR certification is an individual activity, NOT a team activity.  ALL certification rockets must be built, prepped, and flown solely by the individual certifying.

Start With Mid-Power Rocket

If you are a student or senior member starting out in HPR with no prior experience in rocketry, it is highly recommended that you first build a medium power rocket and fly it on a E, F, or G motor.  This is a good way to learn rocketry skills with less expensive motors.  With planning, a mid-power rocket with a 29mm motor tube can be used for a Level 1 certification.

Most kits do not include a parachute or motor retainer.  You will likely have to determine the correct size parachute to use and buy it separately.  The motor retainer prevents the motor from moving forward under thrust or moving backward when the ejection charge fires.  You will likely have to purchase a motor retainer in addition to your kit, and consider the retainer installation before building the kit.

FAA Rocket Class Designations

The U.S. Federal Aviation Administration (FAA) has defined three classes of amateur rockets.  Class 1 rockets (Model Rockets) use no more than 125 grams (4.4 ounces) of propellant and weigh no more than1,500 grams (53 ounces) including propellant.  Class 2 rockets (High Power Rockets – HPR) can have motors with up to 40,960 N-s (9,208 pound-seconds) of total impulse.  Class 3 rockets have motors with more than 40,960 N-s (9,208 pound-seconds) of total impulse.  No FAA waiver is required to launch Class 1 rockets.  An FAA waiver is required to launch Class 2 and Class 3 rockets.

HPR motors

HPR motors come mostly in standard size diameters of 29mm, 38mm, 54mm, 75mm, and 98mm.  Within each diameter there are different lengths depending on the total impulse of the motor.  For a given motor diameter and length there may be different motors with slightly different total impulse depending on the propellant type.  There are propellants that produce different colors of flame and smoke, with some motors emitting sparks during the burn.

Here are defined classes of HPR motors based on the total impulse of the motor.

Motor Class	Total Impulse (N-s)	TRA Certification Level	Typical Motor Diameter (mm)	Motor Deployment Capable	FAA Rocket Class
H	160.1 – 320	1	29, 38	Yes	2
I	320.1 – 640	1	29, 38, 54	Yes	2
J	640.1 – 1,280	2	38, 54	Yes	2
K	1,280.1 – 2,560	2	54, 75, 98	Sometimes	2
L	2,560.1 – 5,120	2	54, 75, 98	Sometimes	2
M	5,120.1 – 10,240	3	75, 98	No	2
N	10,240.1 – 20,480	3	98	No	2
O	20,480.1 – 40,960	3	98, 152	No	2
P	40,960.1 – 81,920	3		No	3
Q	81,920.1 – 163,840	3		No	3

HPR motors can be either single use or reloadable.  Single use motors are expendable and the motor case is thrown away after the propellant has burned.  Reloadable motors utilize reuseable motor hardware that consists of a case and closures, and sometimes a seal disc.  A reload kit for that specific size motor hardware comes with nozzle, motor liner, propellant grains, delay grain, O-rings, and a small amount of Black Powder (BP) for an ejection charge.  The motor is built (assembled) using the motor hardware and the reload kit.  After burning the motor, it should be disassembled, the used reload parts thrown away, and the motor hardware cleaned.  

Initial Thrust to Weight Ratio

Stability

Rail Guides