[BProckets] Re: BProckets Digest, Vol 2, Issue 8

[Tom Mueller]

>>So my question is why do it? Is there any benifit to
makeing "high power" BP over just screening it and
pressing the rockets?<<

     Like I've said before, the reason I use the "high
power" BP is because I want to get the maximum amount
of thrust out of my motor in order to lift the largest
heading I possibly can (I like to put up 4" ball
shells [450g] on 4 oz. BP rocket motors).  If you are
just looking to make rocket motors to fly, maybe with
a small heading or salute, there isn't much need to
use the "high power" BP.   

As Steve mentioned: >>If one uses the fastest burning
black pwd. that can be made, the spindle sizes would
be very short. I've made black pwd. rockets using 3fg
black pwd. and the spindle was only about 2" long...<<

     I don't entirely agree with this statement.  I've
pressed lots of motors using Dupont meal (arguably one
of the fastest burning BPs) on a standard BP spindle
from Wolter, with a nozzle, and have NEVER once had a
CATO.  I've attributed this to the fact that I press
my motors at very high pressures (on my 4 oz motors, I
press at around 65,000psi at the base of the spindle,
and around 50,000psi at the top of the spindle).  By
pressing at very high pressures, the BP becomes hard
and rigid enough to contain some of the extra forces
created by using the "high power" BP that the paper
tube would not normally be able to contain on its own.
 I have even pressed 7:3 whistle mix on a standard BP
spindle and even that did not CATO.  

Just some thoughts, hope this helps

Tom




		
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