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Re: Sometimes physics is fun



On 10/29/2003 02:26 PM, Michael Edmiston wrote:

Years of experience.

Years of experience with a special case is not
equivalent to proof of the general case.

General case = chemical rocket
Special case = Estes rocket

Therefore I think the distinguishing factor between John's statements
about chemical-reaction propulsion versus Gary's statements about
compressed-air-water propulsion boils down to making a distinction
between a chemical rocket (controlled burn) versus a chemical gun
(maximum detonation rate).

Guns and rockets are different, but the differences are
more subtle than that, and in the limit of "sprint"
rockets the distinctions become subtle indeed.

You do *not* want any kind of detonation in a gun.
You do *not* want maximum burn rate in a gun.

Ballistic smokeless powder is _grained_ and _coated_ to
control the rate.

Reference e.g.
Tenney L. Davis _Chemistry of Powder and Explosives_

I emphasize that anyone who wants to develop high-performance
"sprint" or "drag race" devices should have adult supervision,
and should obtain adequate specialized training, and should
consult a lawyer as to the restrictions on creation/posession/use
of such things ... not to mention the civil liability issues.