Anthony:
Thanks (again).
As I expect you will appreciate, I am looking to reduce the viscosity of
the “wet” RRS composite mix. Since the Al is at 35 microns, it’s the AP
that becomes the focus. The latter is currently a mix of 400 micron and
200 micron; thus the interest in adding 90 micron and deleting some of the
larger sizes.
Just to complicate things, the current burn rate is too high for the
optimal on my two-stage, so adding oxamide is probably required,
particularly if I end up removing the larger AP particles.
The RRS mix is currently 84% solids and I’m reluctant to go any higher;
thus removing larger AP particle and adding Oxamide while holding the
binder constant. I’m happy to consider alternatives....
I like the CAD modeling suggestion and will try it next week.
Bill
On Sat, Aug 4, 2018 at 10:51 AM Anthony Cesaroni <acesaroni@xxxxxxxxxxx>
wrote:
This is very dependent on the size, distribution and quantity of other
solids in the formulation such as aluminum powder as well as ballistic
modifiers such as SSFO, ALO2, Guignet green etc. If you are using a
surfactant, that also comes into play. Most APCP is more than bi-modal or
trimodal in terms of solids. Only oxidizers seem to be referred to in this
regard.
Most workhorse commercial propellants are bi-modal as far as oxidizers are
concerned BTW. This is primarily for mechanical properties, ballistics and
economics. 200 mu is the baseline feedstock with everything else being site
milled from that. 90 and 400 have expensive surcharges. Those sizes are
sometimes used in specialty formulations such as 90/10/1 for example or in
the case of 400, gas generators, slower burn rate propellants, delays etc.
Until a few years ago, 600 mu and 50 mu varieties were also produced. AP
was also FDA approved for use in cattle feed. It causes thyrosis so the
bovine fattens up quicker for market but I digress.
A good but expensive reference is “ The Handbook of Fillers for Plastics”
by Harry S. Katz. One method I experimented with many years ago to
formulate multi-modal start points was CAD believe it or not. It worked
surprisingly well.
Best.
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
*From:* arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> *On
Behalf Of *William Claybaugh
*Sent:* Friday, August 3, 2018 11:51 AM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Trimodal AP
Any one know the optimum mix of 400 micron, 200 micron, and 90 micron AP?
Bill