Black Powder Charge Calculations Help

[Donnager]

The containment method will contribute to performance.

Most of my charges are surgical tubing, with BP pinched with zip ties at the end. I've found there's less flammable debris inside the rocket when you get all the BP to burn. The tubing seems to allow the BP to burn pretty completely.

I have burned a good deal of recovery hardware with the cannister type system that only had tape/Dog barf as the sealing agent.

 

[Wrightme43]

I've found this one to be the most accurate BP calculator I've found.

http://www.rockethead.net/black_powder_calculator.htm
First calculate the appropriate PSI required using the lower section. You be given two recommended pressures in PSI, the lower value for a loose-fitting chute and a higher one for a tight-fitting chute.

Then plug the appropriate recommended PSI into the upper calculator along with the length and diameter of the recovery compartment.

The link on the page to the underlying formulae are dead, but the results I've gotten from it have always proven dead-on accurate.

But always do a ground test to verify your solution.

Do not click this link. It has been hacked and is now a redirect to stupid fake ransomware. @cwbullet Please disable link, so others don't have to deal with it.
I am certain it was a valid link, and has been hacked but stupid losers with nothing better to do with their lives.

Sorry OP, I promise this is not aimed at you.