Seems that it would have to be more than that. A high exponent can be
managed with a reasonable chamber pressure by adjusting the Kn. Would the
problem be that for commercial manufacturers, you can't ue the same nozzle
size for different burn rate catalysts because of the high exponent?
I hear that the exponent is nearly unworkable.
Define "reasonable chamber pressure". I know several people that have
tried to run Kp motors at low pressures. At one nozzle throat size,
they would chuff. At the next throat size down, they would cato. I
hear that Kosdon has gotten them to work. Feel free to let us know how
it turns out.
At any rate, just because they are not listed, it does not mean that
they escape the regulations of the ATF. The orange book is written so
that it is basically all inclusive. Basically if all of the propellant
manufacturers switched over to ANCP, the ATF would be just as vigilant
on regulating it as they have been on APCP. Then we'd have a lower ISP
propellant, with the same regulations. Not a good option IMO.
Believe me, that's enough. Equilibrium chamber
pressure is proportional to
where n is the pressure exponent. With KN, chamber
pressure can increase with the fourth or fifth power of
burning surface area.
Also, the nozzle fouls and it blows up. The nozzle erodes
and it fizzles.
High exponents are bad news.
Not one of them by itself is an explosive but that wouldn't stop them
from listing them. We are all going to be making our own engines soon
because BP is an explosive and that's what most of the hobby rockets
"While the list is
comprehensive, it is not all-inclusive.
The fact that an explosive material is
not on the list does not mean that it is
not within the coverage of the law if it
otherwise meets the statutory
definitions in 18 U.S.C. 841."
David W. Schultz
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