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.
Soon:
- Next meeting, on October 29th, is Hunting, with Charlie Anderson and
Jimmy Ritzman.
- The campout in November, the 17th to the 18th, is a backpacking trip
on the Appalachian trail.
- Troop Committee meeting on October 30th at Mr. Cleland's house. Tell
your parents!
- The bulletin still needs a title! Send suggestions to rad-rob@lycos.com .