The New Hobbyist

Information For
The New Rocket Hobbyist

If you are new to the sport, interested in how one gets started, or just curious about how model and high power rockets work, the following should help. It is information gleaned from our members and includes descriptions, suggestions, and tips to make your entry into and progression within the sport a successful and rewarding experience.

Model rockets come in a wide range of configurations and capabilities, from the basic single stage rocket to highly sophisticated designs with electronic timers, altimeters, cameras, transmitters, and GPS devices. It doesn't, however, take a rocket scientist to get involved with and enjoy the hobby. It's easier than you think!

The Albuquerque Rocket Society also has many experienced members that are anxious to provide assistance when needed. Sharing information and member development is an integral part of our sport and you will never be at a loss for ideas on how to accomplish your rocket building and deployment goals! :-)

The Basic Model Rocket

The simplest model rocket consists of a rocket body (with fins attached), a nose cone, an enclosed parachute (attached with "shock" cords to both the rocket body and nose cone), and a rocket motor.

The Flight

Upon ignition, the rocket is propelled upward by the rocket motor. After a specific time interval, close to the point the rocket reaches apogee (the highest altitude in the flight and when the rocket is at its slowest velocity), an ejection charge separates the nose cone from the rocket body and deploys the parachute. The nose cone and rocket body (secured by tethers to the parachute) descend to the ground for a gentle landing.

Ground Equipment

Launching a model rocket requires some basic ground equipment. A typical low power launch system consists of a launch rod to hold the rocket vertical prior to launch (and to stabilize the rocket until it attains flying speed), a stand to hold the launch rod, a blast deflector (to prevent the exhaust from igniting surrounding combustibles), a launch controller (a switching mechanism to fire the rocket motor), and a voltage source (typically a battery or batteries totaling 6 volts or greater).

Rocket Motors

Rocket motors come in a wide range of sizes to accommodate a variety of rocket sizes and capabilities. They are categorized by their total impulse (power) and physical dimensions. Low power rocket motors are generally single use devices and contain the parachute ejection charge (whereas high power motors are propellant reloadable and require a separate system for deploying the parachute).

Low power model rocket motors are designated using a series of letters and numbers to indicate their total impulse, average thrust, and ejection delay time.

Launch Site Dimensions

Safety is paramount. Individuals should be at least 15 feet away from the launch pad when launching an A to D size rocket, 30 feet when launching an E or F. Launching in a clear and appropriately sized field allows for safety should a malfunction occur, and provides for a recovery free from obstacles such as trees, power lines, and houses. The following are guidelines for use when selecting a launch site (Minimum Site Dimensions refer to the length and width of the site).

The Launch

Insert the rocket motor into the rear of the rocket body, ensuring the nozzle end is facing aft (see the motor instructions) and the motor is secured with the motor retainer clip.

Place the equivalent of two body diameters of recovery wadding (loosely packed) into the body tube to protect the parachute from the ejection charge.

Pack the parachute according to the instructions and insert it into the body tube.

Insert the nose cone. The nose cone should be snug enough that you can hold the rocket by the nose cone without it separating, but loose enough that by giving it a quick shake, the rocket body will separate from the nose cone. Adjust the fit by lightly sanding the nose cone (for a looser fit) or adding a small amount of painter's tape to the nose cone (to tighten).

Place the rocket on the launch pad by inserting the launch rod through the launch lugs located on the side of the rocket.

Insert the igniter into the motor (see instructions) securing it with a piece of painter's tape. Connect the controller's electrical clips to the igniter, ensuring they are not touching one another.

Move a safe distance away from the launch pad, and initiate a countdown ("5, 4, 3, 2, 1, LAUNCH") so observers are aware a launch is in progress. Depress the "Fire" button.

Recovery

Keep your eye on the rocket for the entire flight, from launch until touchdown. As the rocket touches down, make note of a landmark or object directly behind the touchdown point (from your perspective). Also make note of the approximate distance between you and your rocket's location. Walk in a straight line directly toward the chosen landmark, and you will easily locate your rocket.

Moving Up to High Power

High power refers to launching rockets with a weight of greater than 53oz or motors with an average thrust of greater than 80 N-secs (a large "G"). There are certification levels for doing so to ensure the requisite skills are present to safely launch large rockets.

Step One: Come to one of the Albuquerque Rocket Society's monthly launches. If you wish to try your skills at launching a low power rocket, the Society had all the ground equipment to do so (no need for you to purchase a launch system), and you may launch your low power rocket for free. There are always experienced rocketeers in attendance who will assist you and ensure your rocket is ready for launch. Also, there are generally motor vendors at the launches, should you need a motor or igniters. The launches are also a good place to observe high power in action, from rocket preparation, to launch and recovery.

Step Two: Join the Albuquerque Rocket Society (you may do so at the launch). The club is a non-profit group of rocketeers with various backgrounds and skill levels. The cost is only $40.00 per year (prorated the first year) and provides free high power launching for its members as well as access to the web site's members area and inclusion into the email list server (an excellent way to ask questions of members and keep abreast of what is going on within the club). To launch high power rockets, it will also be necessary to join either the Tripoli Rocketry Association or the National Association of Rocketry. These are the governing organizations for the sport and facilitate the certification process necessary for moving up within high power.

Step Three: Purchase a good high power handbook. "Modern High Power Rocketry II" by Mark Canepa is an excellent choice, as it covers virtually every aspect of the sport, from introduction to the sport to attaining a Level 3 certification (the highest certification level).

Step Four: There's a lot to learn, so begin with a Level 1 kit. There are numerous excellent quality kits from a variety of manufacturers (see the Rocket Links section for links to several good ones).

The High Power Rocket

Most Level 1 and Level 2 high power rockets can be configured exactly as the basic model rocket shown at the top of the page, in that the motors contain the ejection charge. Level 3 rocket motors, however, do not have an integral ejection charge, and provisions must be made for an electronic altimeter or timer to fire the ejection charge. This necessitates the addition of an altimeter bay to the basic design to contain the altimeter or timer.

The High Power Flight

The flight sequence for high power rockets is typically the same as for low power rockets. However, larger motors often result in higher flights. Higher flights means a longer descent time and, as a result, a greater recovery distance. To reduce this distance, high power rockets are often equipped with two parachutes, a drogue and a main. The drogue parachute deploys at apogee and being smaller than the main, results in a faster descent and therefore, less drift. At a user determined altitude (generally between 500 and 1000 feet), a second ejection occurs that deploys the main parachute for a gentle landing. This "dual deploy" flight sequence is as follows:

The Dual Deploy Rocket

The typical dual deploy rocket requires the addition of a drogue parachute in the rocket body aft of the altimeter bay.

High Power Ground Equipment

Simply put, larger rockets require larger launch pads. Popular configurations include 80/20 rail systems (on left) and tower arrangements (on right).

High Power Rocket Motors

High power rocket motors refer to motors with an average thrust of greater than 80 Newtons and a total thrust (impulse) of up to 40,960 N-sec. Most high power motors are "reloadable" and are comprised of a reusable tube (the "motor") and a "reload" consisting of the motor propellant (called the "grains"), the nozzle, the delay (or smoke) grain, and needed o-rings. Note: "G" impulse motors are included here as high power motors. The "G" category spans low to high power as some have average impulses of greater than 80 Newtons.

Launching a rocket containing a large G, H, or I motor requires a Level 1 Certification. A Level 2 Certification is required for a J, K, or L motor, and a Level 3 Certification is required for an M, N, or O. An FAA waiver (clearance) is also required for launching high power rockets to ensure aircraft are notified of the activities and are routed clear of the flight area.

The two major rocket motor manufacturers are Aerotech and Cesaroni (CTI). Their motors are labeled differently as indicated below.

A "J" motor with an average thrust of 350 N would be labeled as follows:
Aerotech: J350W (the "W" denotes the propellant type, in this case, "White Lightning").
Cesaroni: 650J350 (the 650 denotes the total impulse in N-sec)
Note: Total impulse in N-sec = average thrust in Newtons x burn time in seconds

High Power Launch Site Dimensions

A complex rocket is defined as a rocket that is multi-staged or propelled by two or more rocket motors.

Enhancing The Experience

Experimentation is a big part of rocketry. Designing, building, launching, and recovering a new design or one enhanced with accessories adds to the enjoyment of the sport. Some of the possibilities include, but are certainly not limited to, the following:

1) Multi-stages (more than one motor ignited sequentially)
2) Clusters (more than one motor ignited simultaneously)
3) Combination multi-stages and clusters
4) Installed still and video cameras
5) Transmitters and GPS devices (to assist with recovery)
6) Unique rocket and fin designs
7) Data collection (altitude, G forces, velocity, temperatures, etc.)
8) Scale model rocketry (exact scale models of military and NASA rockets)
9) Setting altitude and speed records
10) Achieving high power certifications