Model Rocketry

Building and flying model rockets is an exciting hobby that has attracted tens of thousands of enthusiasts. The model rocket, as it has become known, was invented in 1954 by Orville Carlisle, a licensed pyrotechnics expert, and his brother Robert, a model airplane builder. They were inspired by a series of magazine articles written by the aerospace engineer G. Harry Stine.

In his articles, Stine had lamented the dangers involved when young people experimented with rockets. With no real guidelines or source of safe materials to work with, amateur rocketeers were getting seriously injured—and even killed— working with dangerous chemicals and explosives. The situation had become so serious that many lawmakers were considering banning amateur rocket making.

Young rocketeers of the twenty-first century enjoy the safe launch of a model rocket along with former vice president Al Gore and former Minnesota governor Jesse Ventura.

Other scientists had experimented with using solid-fuel rockets to help boost the takeoff of heavy aircraft. This technique—later called JATO—was perfected during World War II. It helped aircraft that were either too heavy to get airborne on their own or had to take off from runways too short to allow them to accelerate enough. Although not used as often as they were a few decades ago, JATO units are still occasionally employed in special circumstances.

Carlisle realized that the answer lay in a series of commercially manufactured, standardized motors. These could then be used safely by the hobbyists in whatever rocket design they created. The motors would come in assorted sizes so rocket makers could pick the one that worked best for their rocket. Carlisle sent samples of these motors to Stine—who was then working as the range safety officer at the White Sands Missile Range in New Mexico—who tested them successfully. Stine eventually became not only an enthusiastic amateur rocketeer but one of the hobby's most enthusiastic promoters.

The typical rocket motor consists of a heavy paper cylinder. At one end is a clay nozzle, then the pro-pellant, followed by a nonpropel-

lant that burns but does not any thrust. This is called the coast (or delay) phase. Finally, an ejection charge is used to deploy the rocket's parachute. Because of the excellence of the motor's design as well as the strict adherence of model rocketeers to safety rules, literally hundreds of millions of motors have been used in the past fifty years without serious accident.

The motor is, of course, only part of a model rocket. The rest consists of a tube—usually card-board—that contains a mount for the engine, stabilizing fins, a parachute, and a nose cone. The rocket may also contain a pay-load. This might consist, for instance, of a small camera that will automatically snap a photo at the highest point of the rocket's flight.

Rockets also test the strength of containers meant to carry hazardous nuclear wastes. The U.S. Department of Energy smashes these containers with every type of vehicle available. To get these vehicles going fast enough to simulate a real wreck, they are often accelerated by rockets. Full-size locomotive engines have even been accelerated with rockets, sending them hurtling down the tracks to collide with a truck carrying an empty nuclear waste container. A

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