One great way to answer such questions is to participate in rocketry competition. Rocket contests are almost as old as the hobby itself. The first U.S. National Association of Rocketry Annual Meet (abbreviated NARAM) was held in 1959. There are also local contests and rocketry record trials held throughout the the year. Any contest has to have rules, and rocketry is no exception. The official rulebook for rocketry contests is the U.S. NAR's Model Rocket Sporting Code. It lists almost 30 different competition events, all of which can be flown in different age categories to prevent less experienced modellers from competing against seasoned veterans. Many of the contest categories break down by engine sizes as well. A local version will be posted as soon as possible. Streamer Duration One such basic competition event is called Streamer Duration, which calls for the contestant to launch and safely recover a streamer model in a particular engine class. For instance, at this year's NARAM, the event is called B-Engine Streamer Duration. Streamer Duration competition is limited to single-stage models with one streamer as the only recovery device. The object is to achieve the longest flight duration. Flight time is measured using a stopwatch. A designated timer starts the watch at first motion of the rocket on the launch pad and stops the watch when the model touches down. What type of streamer can be used? A legal streamer is a piece of paper, plastic film, or cloth cut to a rectangular shape. The streamer must be at least five times as long as it is wide and have a minimum area of 100 square centimetres. A single line has to connect the streamer to the model and it must be attached at the narrow end of the streamer. The rules get more specific to ensure that everyone is using a fair, common approach. It may sound easy, but Streamer Duration can actually be one of the more challenging rocketry contest events. Plenty of modellers in national competition get disqualified because their streamers rip off their rockets or their shock cords break. Successful entries are narrow, low-drag models launched out of a tower or off a device known as a piston launcher. Streamers are often made from tracing paper and folded in an accordion-like pattern so they flap back and forth in the wind. Using a commercially available B motor, the top national competitors can achieve several minutes of flight time. The best flight duration in each age division wins. And at NARAM, the trophies are really big! Streamer Duration is a fun event you can hold with your friends. Follow the rules above and make sure everyone uses an engine from the same category (A, B or C). If you don't have a stopwatch, use someone's watch with a sweep second hand or a digital timer. Competitors are usually allowed to make two flight attempts. You can make your own rules concerning whether you want to allow contestants to average their two flight times together or simply take the best score.
Why an egg? The egg is meant to simulate a miniature astronaut who must be properly protected in order to withstand the forces of launch and landing. Like other duration events, the flight is timed from first motion at launch until the rocket touches down. A parachute must be used for recovery. After flight, the contestant must open his or her egg capsule in front of a judge, who inspects the egg for cracks. If there is any damage, the flight is disqualified and the contestant tries one last time. A B motor is the minimum power that can be used, due to the weight of the egg. Contestants use some pretty exotic egg capsules to protect their payload. Foam padding, cotton balls and all sorts of bizarre contraptions can be seen at national contests. One tip is to brace the egg between two pieces of foam pipe insulation from a hardware store. Most eggs that break suffer their fate at landing, so make sure the side of the egg doesn't touch the egg capsule. Experienced modellers put the egg in a plastic bag, so a cracked egg doesn't leave a gooey mess. Spot Landing Open Spot Landing is the most common form of this competition event in that it allows the modeller to use a parachute or streamer for recovery. You could also limit contestants to use of a particular recovery system. Models must fly normally and in accordance with the safety rules, so it is not okay to "lob" your model toward the landing spot by using a ballistic trajectory.
This event sounds simple, and it actually is the least complicated event in most competitions. However, the challenge of interpreting wind speed and direction, not to mention the inevitable urge to angle the launch pad to the safety limit of 30 degrees from vertical, causes many a modeller to over- or undershoot the landing point. Try these events the next time you fly with a buddy and want to add a little adventure to your rocketry experience. Good luck, and may the best rocket scientist win! Larry Shenosky has been a model rocketry enthusiast for 30 years. He has served on the board of the National Association of Rocketry and edited the Association's national rocketry magazine, now known as Sport Rocketry. |
If you have been flying rockets for any length of time, you have probably wondered how your building and flying skills stack up against those of other
modellers. Which rocket design will fly highest on a given engine? Is there a special parachute that will keep your rocket in the air longer?
Egg Lofting Duration
Spot Landing requires someone with a tape measure to check the distance between the designated spot and the tip of the rocket's nose cone. The one flight that lands closest is the winner. Any engine may be used to compete in a Spot Landing event, and no practice flights are allowed.