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Troop 439 Bulletin

Volume 1, Number 3, October 23rd, 2001
All things are ready, if our minds be so. - Shakespeare

Meeting: Model Rocketry

After an opening by the Hawks, the group gathered around the blackboard for the program, which was presented by Alex Kovacic and Peter Morris.
The two of them began by displaying some rockets which they had brought, and spoke about launching them. They described the purpose of the metal guiding pole, and also the level of power each class of engine provides. The standard A engine provides 2.5 Newton-seconds of force, and it doubles for each letter, with B at 5 Ns, C at 10 Ns, up to G at 160 Ns, which requires the purchaser to be 18 or over. There are more, up to P, but they require a special permit to buy. The P engines are AS powerful as those in the Sidewinder missles!
Alex had brought a couple of rockets he designed himself.One was an early model, with a Saran-Wrap tube body and a half-Easter-egg nose cone. He had made one before, but the engine was defective, and that one curved off down the field and rammed into the ground at high velocity. The other was more sophisticated, and was more elegant in design. He talked about the concept of the 'Center of Pressure', which is the point which the air pressure on each side of balances. So, when the model flies through the air, the air's net push is centered at the center of pressure. The equations are very complex; Alex said that it takes him an hour to work it out by hand, and five seconds on the computer (Guess which he uses?). He reccommended the book, "Handbook of Model Rocketry", by G. Harry Stine, as the generally accepted "Bible of model rocketry".He is a member of a model rocketry club which meets one Friday night a month. If you contact him ( alexkovacic@aol.com ), he will give you the information.

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