You can masasse the formulation any way you want, the relevant point is the
use of modified asphalts with AP, alum can be optional, it just helps in
processability and of course performance. I know anything below 90u AP has
its legal issues so I base mine on 90/200 and 400 even 600 if you want a
lower burn rate. Density,specific gravity is another plus as some asphalt
exceeds SG of 1. Not many binders can claim that.
So just get your hands black and have some fun teaching a rocket dog new
tricks.
GN
Ken
On Sat, Feb 27, 2021 at 12:24 AM Tyler Adkison <tyler.adkison@xxxxxxxxx>
wrote:
That formula wouldn't really work for most amateurs, as stuff like 25
micron AP is impractical to source and 18% aluminum is a bit much for my
tastes. It would probably be worthwhile to substitute the 200 micron AP for
400 micron, the 25 micron for 90. 5 micron spherical aluminum is easy to
source and cheap. Would this resulting prop work? I have no idea, as I have
yet to try it. Perhaps, someday.
On Fri, Feb 26, 2021 at 9:07 PM roxanna Mason <rocketmaster.ken@xxxxxxxxx>
wrote:
Found it, the Edwards AFRL report on modified asphalt propellants.
Ken
On Fri, Feb 26, 2021 at 6:58 PM Dr Edward Jones <RocketPioneer@xxxxxxxxx>
wrote:
Thanks a LOT, Ken. What's the typical burn rate and nominal Pc? And
would not KP in same granulations and oxidizer ratio be of good Isp,
with much faster burn rate?
How do AP and KP compare in terms of burn rate exponent n?