Propellants on the explosives list

High exponent.

Mike Fisher

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 are.

The ATF isn't going after modroc BP motors, just APCP motors.

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?

Thanks!

The ATF is not going after modroc APCP motors either.

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.

Mike Fisher

Believe me, that's enough. Equilibrium chamber pressure is proportional to

(BurningSurfaceArea/NozzleThroatArea)^(1/(1-n))

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.

"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."

Rocket propellant, be it APCP, KPCP, or whatever does not meet this definition.

Thus the lawsuit...

Ok, that makes sense. Thanks for the info.