If you mix under a vacuum, vibration should not be required.
One approach I saw being used by an amateur group in the 90s was to mix the
propellant into a simple cylindrical vacuum chamber that had a shaft connected
to a set of blades inside. The shaft had a rotary seal that permitted the shaft
to move in and out the length of the tube as well as rotate. The tube was made
from clear polymer and was about 6” in diameter and 48” long. I have no idea
how well this worked in practice and what was used to mitigate shaft deflection
and possible blade strike. This was the 90s when HPR was the “wild west” of
rocketry. They published a brochure about it that I may still have in my
Toronto library.
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
<http://www.cesaronitech.com/> 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: Thursday, January 30, 2020 11:08 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Vibratory compaction
Anthony:
Yep. But also about understanding the cost of performance.
I’m also wondering about just doing all the mixing with vibration and vacuum.
It seems possible that for 150 lbm. lots that might be a plausible solution.
Bilk
On Wed, Jan 29, 2020 at 8:19 PM Anthony Cesaroni <anthony@xxxxxxxxxxx
<mailto:anthony@xxxxxxxxxxx> > wrote:
Bill,
Is this about your pursuit of improving propellant density without hving access
to vacuum mixing equipment?
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
<http://www.cesaronitech.com/> http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
<arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx> > On Behalf
Of William Claybaugh
Sent: Wednesday, January 29, 2020 12:51 PM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vibratory compaction
Shane:
Is this done after or during mixing?
If the latter, I—and I suspect others—would be very interested in your process:
for example, how long do you apply vacuum / vibration before casting the
grain(s)? Have you documented the difference in final propellant density?
I found that 10 minutes under vacuum after mixing resulted in density going
from 0.055 to 0.058 lbsm. / cu. in., for a specific propellant formulation, for
example. Do you have a guess as to what additional density might be achieved
from vibration? Note that theoretical is 0.065 for this propellant.
I’m trying to make an economic calculation here: for my next generation
(composite) 6” motors, getting to 0.060 lbsm. / cu. in. Increases propellant
fraction from 70% to 72%; given my estimate of the cost of a vibratory table,
I’m looking to understand if that investment produces greater performance gain
than alternative weight saving investments.
Bill
On Wed, Jan 29, 2020 at 10:34 AM <spcdestiny01@xxxxxxxxx
<mailto:spcdestiny01@xxxxxxxxx> > wrote:
At my school we use the vacuum while it’s on the vibration table to remove all
air bubbles and increase the density.
Hope that helps,
Shane Cullen
Sent from my iPhone
On Jan 29, 2020, at 10:27 AM, William Claybaugh <wclaybaugh2@xxxxxxxxx
<mailto:wclaybaugh2@xxxxxxxxx> > wrote:
Anyone have experience w/ vibratory compaction if solid rocket propellant,
with or without vacuum?
Initial search did not turn up anything specific....
Bill
