WHAT IS SPORT ROCKETRY?
Sport rocketry is aerospace engineering in miniature. This popular hobby and educational tool was created in 1957 to provide a safe and inexpensive way for young people to learn the principles of rocket flight. It has grown since then into a worldwide hobby with over five million flights per year, used in 25,000 schools around the United States. Its safety record is extraordinarily good, especially compared to most other outdoor activities. It is recognized and permitted under Federal and all 50 states' laws and regulations, and its safe and inexpensive products are available in toy and hobby stores nationwide. Sport rocketry has inspired two generations of America's young people to pursue careers in technology.
WHAT IS A SPORT ROCKET?
A sport rocket is a reusable, lightweight, non-metallic flight vehicle similar to the one seen in the picture to the left, that is propelled vertically by an electrically-ignited, commercially-made, nationally-certified and non-explosive solid fuel rocket motor. For safety reasons, no rocket hobbyist is ever required or allowed to mix or load chemicals or raw propellant. All sport rocket motors are bought pre-made. Sport rockets are always designed and built to be recovered and flown many times, with the motor being replaced between flights. With a few exceptions, consumer sport rocketry are generally considered to be those rockets that fly on A through G impulse rocket motors. Larger rocket motors require certification through a national rocketry organization.
IS THIS HOBBY SAFE?
Absolutely! Injuries are rare and generally minor. They are almost always the result of failure to follow the basic safety precautions and instructions provided by the manufacturers. Sport rocketry's record shows that it is safer than almost any sport or other outdoor physical activity. The hobby operates under the simple and easy-to-follow Model Rocket and High-Power Rocket Safety Codes of the National Association of Rocketry, which have been fine-tuned by professional engineers and public safety officials over the past 40+ years to maximize user and spectator safety. The foundations of these safety codes are that sport rockets must be electrically ignited from a safe distance with advance warning to all those nearby, must have recovery systems, must be flown vertically in a suitably-sized field with no aircraft in the vicinity, and must never be aimed at a target or used to carry a pyrotechnic payload. All sport rocket motors are subjected to extensive safety and reliability certification testing to strict NFPA standards by the National Association of Rocketry or other national organizations before they are allowed to be sold in the United States.
AREN'T THESE ROCKETS FIREWORKS?
All Federal and state legal codes recognize sport rockets as different from fireworks. Fireworks are single-use recreational products designed solely to produce noise, smoke or visual effects. They have few of the designed-in safety features or pre-consumer national safety testing of a reusable sport rocket, and none of the sport rocket's educational value. Fireworks are fuse-lit, an inherently dangerous ignition method that is specifically forbidden in the hobby of sport rocketry. Sport rockets are prohibited from carrying any form of pyrotechnic payload. Their purpose is to demonstrate flight principles or carry educational payloads, not blow up, make noise, or emit a shower of sparks.
WHO ARE THE EXPERTS?
The oldest and largest organization of sport rocketeers in the United States is the National Association of Rocketry (NAR). This non-profit organization represents the hobby to public safety officials and Federal agencies, and plays a key role in maintaining the safety of the hobby through rocket motor certification testing and safety code development. The NAR also publishes Sport Rocketry Magazine, runs national sport rocketry events and competitions, and offers liability insurance coverage for sport rocketeers and launch site owners. You may reach the NAR at:
National Association of Rocketry
Post Office Box 407
Marion, IA 52302
ADDITIONAL INFORMATION ABOUT THE HOBBY
The National Association of Rocketry (also known as the NAR) is the governing body for the sport/hobby of model rocketry in the United States. It was established in 1957 by Orville Carlisle and G. Harry Stine. It is the oldest and largest model rocketry governing body in the world, with over 80,000 members. This organization hosts a variety of educational programs and model rocketry contests. There are three national NAR events each year:
NARAM - The national contest culminating the rocket contest year.
NARCON - The national convention, with speakers and educational programs.
NSL - National Sport Launch; a large, fun launch.
The NAR also provides insurance for the sport of model rocketry, and maintains a high power rocketry certification program.
Model rocketry is a hobby similar to model airplanes. In the United States today, there are two distinct types of rocket hobbyist.
Amateur rocketry hobbyists experiment with fuels and make their own rocket motors, launching a wide variety of types and sizes of rockets. Amateur rocketeers have been responsible for significant research into hybrid rocket motors, and have built and flown a variety of solid, liquid and hybrid propellant motors. Amateur rockets can be dangerous because non-commercial rocket motors fail more often than commercial rocket motors. Amateur rocketry was an especially popular hobby in the late 1950's, following the launch of Sputnik. An appalling accident rate led individuals such as G. Harry Stine and Vernon Estes to make model rocketry a safe and widespread hobby. The National Association of Rocketry Safety Code is provided with most rocket kits and motors. Since that time, good safety practices have become much more widespread, and amateur rocketry is a very safe hobby, provided proper precautions are taken. Although the use of amateur or home made rocket motors is prohibited at sanctioned NAR launches, the Tripoli Rocketry Association (known as TRA) sanctions some amateur activities, which they call "experimental rocketry," provided certain safety guidelines are followed, and provided the motors are of relatively standard design.
Model and High Power Rocketry
Model rocketry and high power rocketry involve professionally-manufactured solid-fuel or hybrid liquid/solid fuel rocket motors. Since they are professionally designed and constructed, they are far safer. The motors are also tested and approved by the National Association of Rocketry or the Tripoli Rocketry Association and come in standardized sizes and powers.
Small model rocket motors are single use motors, with cardboard bodies and lightweight molded ceramic or clay nozzles, ranging in power class from 1/8 A to E. They contain a black powder propellant. Motors are electrically ignited with a short igniter wire pushed into the nozzle and held in place with flameproof wadding or a plastic plug. On top of the propellant is a tracking delay charge which produces smoke but essentially no thrust as the rocket slows down and arcs over. When the delay charge has burned through, it ignites an ejection charge, which is used to pop off the nose cone of the rocket, pushing out a parachute or a streamer. There are other more complicated recovery devices, but parachutes and streamers are the most common.
What the Numbers Mean
The model rocket motors produced by such companies as Estes and Quest Aerospace have a code (such as A8-3, B6-4, C6-5, D12-7, etc as illustrated in the picture at the left) identifying the type of motor. The letter at the beginning of the code tells its total impulse (measured in Newton-Seconds) compared to other motors. Each letter has up to twice the power of the letter preceding it. This means that a B motor has twice the power of an A, and a C motor would have twice the power of a B motor, and so on. The number that comes after the letter tells the motor's average thrust, measured in Newtons. A higher thrust will result in higher liftoff acceleration, and can be used to launch a heavier model rocket. Within the same class, a higher average thrust also implies a shorter burn time. For example, a B4 will burn longer than a B6. The last number is the delay in seconds between the end of the thrust phase and ignition of the ejection charge. Motors that end in a zero have no delay or ejection charge, and motors that end in a "T" indicate that they are for use in a miniature rocket. Standard A, B and C motors come in a standard case size diameter of 18mm, except for the A impulse motors for miniature rockets, which are only 13mm in diameter. D and E impulse rocket motors are 24mm in diameter.
Model rocketeers experiment with rocket sizes, shapes, payloads, multistage rockets and recovery methods. Some rocketeers build scale models of larger rockets, space launchers or missiles.
Larger rocket motors are also available, using composite propellants made of Ammonium Perchlorate and a rubbery binder substance contained in a hard plastic case. These motors range in impulse from D to the I range. Composite motors produce more impulse per unit weight than do black powder motors. Reloadable motors are also available. These are commercially-produced motors requiring the user to put propellant grains, o-rings and washers, delay grains and ejection charges into a special non-shattering aluminum motor casing with screw-on or snap-in end closures. (An example of a reloadable rocket motor is shown at the left.) The advantage of a reloadable motor is the cost, because the main casing is reusable, reloads cost significantly less than single-use motors of the same impulse. Reloadable motors are available from G through O class.
Model rocketry is enjoyed by many different levels of hobbyists, from grade-school children launching three-inch tall models in a baseball field, to teams of adults launching 200-pound behemoths thousands of feet into the air. Model rocketry is often credited as the most significant source of inspiration for children who eventually become scientists, engineers and astronauts.
High Power Rocketry
High power rockets (HPR) are propelled by larger motors ranging from H to O impulse. These motors are almost always reloadable ones rather than single-use motors. (An example of a large M impulse reloadable rocket motor is seen in the picture to the left.) Recovery and/or second stage ignition may be initiated by small flight control computers, which use a barometer, or sometimes an accelerometer, to detect apogee and open a small parachute, and also to open a main parachute at a pre-set altitude. These rockets carry larger payloads, including cameras and instrumentation. GPS equipment can be carried so that the rocket can be tracked in flight, making the recovery of the rocket less difficult.
Sport Rocketry is a shining example of an activity that is carefully and successfully self regulated through voluntary membership in national and international organizations whose primary goal is the safe enjoyment of amateur rocketry. The National Association of Rocketry (NAR) and the Tripoli Rocketry Association (TRA) are the primary rocketry organizations recognized in the United States; most public rocket launches are held by clubs affiliated with either NAR, Tripoli or both. People interested in sport rocketry are encouraged to join these organizations for the many benefits they offer.
Both NAR and Tripoli have safety codes based largely on the National Fire Protection Association (NFPA) Safety Code. The NFPA codes for rocketry apply to the design of rockets and rocket motors and to launch operations including ignition systems, safe distances and launch site specifications. Rocket launch sites are laid out by volunteers and members of the hosting club to meet all requirements set forth by the NFPA with an eye towards safety. Tripoli and NAR safety codes also require that no rocket contain guidance systems, vertebrate animals or be launched more than 20 degrees from vertical. A complete review of all NAR safety codes may be found at the NAR website. Tripoli safety codes may be requested on Tripoli's website. NFPA code 1122 refers specifically to Model Rocketry; NFPA code 1127 covers High Power Rocketry. For more information on the NFPA and to see codes 1122 and 1127 go to the NFPA website.
The Federal Aviation Administration (FAA) regulates air space which affects most rocketry activities. Model Rockets enjoy relief from FAA regulations via Federal Aviation Regulations Part 101, a copy of which can be viewed on the FAA website.
Rockets weighing less than 3.3 pounds and flying on less than 4.4 ounces of propellant do not require notification of the FAA. Waivers from the FAA are required to fly high power rockets weighing more than 3.3lbs and/or flying on greater than 4.4 ounces of propellant. While anyone may apply to the FAA for a waiver, this process is normally handled by a rocketry club officer, often the Launch Director. When granting waivers, the FAA reviews the normal use of the airspace for which a waiver has been requested to determine the feasibility of rerouting airplanes while launches are being held. Waivers to high altitudes are most readily granted for airspace that is not heavily used therefore, launch sites with high waivers are often many miles from large cities and airline traffic patterns. Waivers are granted in MSL or altitude above mean sea level. Waivers are often referred to in AGL, above ground level, a figure determined by subtracting the elevation of the launch site from the MSL altitude. For more information on the FAA , refer to the website listed above.