Understood. It also sounds like you’ve invested a fair amount of time in
addition to the hardware. I wish I could be of assistance.
Good luck.
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: Friday, July 12, 2019 5:07 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Vacuum processing of solid propellant
Anthony:
I’m certainly not planning on making this a business but if somebody wants the
IP it’s available....
Buying a commercial booster makes sense retrospectively but wasn’t an obvious
choice at the beginning. Setting aside the ancillary issues (storing and
working around a fueled solid rocket, for example) there’s the financing
problem: that $65k is the six thousand per year that I set aside for rockets
times the almost 11 years I’ve been working on this...I don’t expect anyone who
would finance a rocket on that basis.
Bill
On Fri, Jul 12, 2019 at 2:56 PM Anthony Cesaroni <anthony@xxxxxxxxxxx
<mailto:anthony@xxxxxxxxxxx> > wrote:
That’s more than I expected. Why didn’t you just purchase a commercial booster
and focus on the other aspects of the system, or is this something that you
plan to develop and operate on an ongoing basis?
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: Friday, July 12, 2019 4:33 PM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Anthony;
I’ve about $65k in it to date. That bought the piece parts for two boosters,
three upper stages, one dummy upper stage, and three payload sections. There’s
hardware for an Amateur TV video downlink and about $5k worth of Black Magic
flight computer bits.
There is, however, no budget: all of cost, schedule, and technology float.
Bill
On Fri, Jul 12, 2019 at 1:25 PM Anthony Cesaroni <anthony@xxxxxxxxxxx
<mailto:anthony@xxxxxxxxxxx> > wrote:
Bill,
May I ask you what the budget is for this booster?
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: Friday, July 12, 2019 3:10 PM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
A careful review of the history of design changes on my two-stage shows that
the increase in performance from circa 150 km to around 200 km was caused both
by the measured increase in density of the vacuum post processed propellant but
also by the near simultaneous discovery of a modified BATES grain design that
pushed volumetric loading to a little above 86% from a previous about 80%.
After reviewing that history and some additional work I’ve identified a
monolithic grain design that gives 83.5% loading in the upper stage and 85% in
the lower without erosive burning concerns. That is now the baseline and, using
the slightly denser propellant, sims to about 200 km, including 7 lbsm of
ballast.
Bill
On Thu, Jul 11, 2019 at 10:10 PM William Claybaugh <wclaybaugh2@xxxxxxxxx
<mailto:wclaybaugh2@xxxxxxxxx> > wrote:
David:
To be clear, I’m open to there being something wrong somewhere in the
simulations; I’m not claiming this two-stage will do more than 150 klicks when
asked by non-professionals.
If there is something wrong in the sim, I’ve yet to find it...but the results
are hotter than I expected during initial design. But then I’ve managed over
the last two years to stuff about 12% more propellant into it than I initially
thought possible.
Bill
On Thu, Jul 11, 2019 at 10:00 PM David Summers <dvidsum@xxxxxxxxx
<mailto:dvidsum@xxxxxxxxx> > wrote:
Btw, thanks for all this. It sounds like most of the performance gain is
design specific, as in given a fixed design this change makes a large
improvement. Still fascinating!
-David
On Thu, Jul 11, 2019, 5:54 PM William Claybaugh <wclaybaugh2@xxxxxxxxx
<mailto:wclaybaugh2@xxxxxxxxx> > wrote:
Troy:
It’s late on this side of the lake; I’ll shoot you the most current files
tomorrow my time.
Bill
On Thu, Jul 11, 2019 at 9:48 PM Troy Prideaux <troy@xxxxxxxxxxxxxxxxxxxxx
<mailto:troy@xxxxxxxxxxxxxxxxxxxxx> > wrote:
Bill,
Troy:
The two test to date were, as before, near 400 psia and near 750 psia; the 500
psia Isp is an estimate coming out of Burnsim based on the measured Isp at the
two pressures.
The “estimate” part is fine, so long as you appreciate that to claim that the
same propellant in a denser form produces a different specific impulse than the
lower density equivalent can only be truly verified by conducting 2
instrumented static tests measuring both delivered total impulse and pressure
curves that closely match for a true apples to apples comparison. That implies
that the Kn ratio profile likely needs to be adjusted between the 2 tests to
accommodate the reduced mass discharge rate for the reduced density propellant,
but also (conversely) for the difference in burn rate (normally increased for
lower density resulting in an increase in discharge & flow rates). Suboptimal
densities often influence the burn rate exponent too which can further
complicate the comparison or at least achieving useful comparable pressure
curves.
Where I’m coming from (in terms of specific impulse) is the ultimate comparison
is to say I can achieve x isp with this density and I can achieve y isp with
that density both in their optimum configuration ie. expansion ratios matched
as best as possible to the conditions and structural margins likewise.
In a dynamic sense, it does make sense that the higher density / slower burning
propellant will ultimately achieve a higher specific impulse due it working for
a longer time at a higher altitude, but I’m not sure if this was factored into
the simulations?
The 7 second trajectory average increase for the second stage (compared to the
previous “air processed” propellant) is coming out of the trajectory sim and
the estimated 2.5 second gain (at 500 psia) that I assume reflects the higher
aluminum content; I don’t see how density can have an effect on Isp.
Well, yeah, that makes more sense.
I’m happy to share the motor files and RASAero file if you’d like to look them
over.
I’m happy to look over them, up to you Bill.
Cheers,
Troy
Bill
On Thu, Jul 11, 2019 at 7:39 PM Troy Prideaux <
<mailto:troy@xxxxxxxxxxxxxxxxxxxxx> troy@xxxxxxxxxxxxxxxxxxxxx> wrote:
So, just to be clear, the comparison measurements were all done and measured at
*very* similar pressures (*measured pressures*) not implied similar pressures
based on identical Kn profiles?
Also (just to be clear), your implied increase in specific impulse of the upper
stage (7 sec) is entirely based on porosity reduction or is that also
incorporating the additional metal influence.
Regards,
Troy
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
[mailto:arocket-bounce@xxxxxxxxxxxxx ;<mailto:arocket-bounce@xxxxxxxxxxxxx> ] On
Behalf Of William Claybaugh
Sent: Friday, 12 July 2019 11:22 AM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Troy:
The slightly increased Isp is measured in static tests at 2.5 seconds. The
additional flight performance is increasing altitude in the sim.
The baseline 231 seconds (at 500 psia) is measured in over 100 static tests of
the “air processed” propellant. I have to date only two tests of the slightly
denser version but those tests imply 233.5 at 500 psia. (Note that the vacuum
propellant is 10% Al rather than the baseline 7.2%).
I’ll be doing more test w/ more vacuum degassing time once the desert cools
some (read: November); those tests will be at around 400, 700, and 1000 psia
and should provide a better reality check. For now, that is the data I have to
plow into the sims.
I should add that changes in grain design—the effect of a longer first stage
burn having been noted—are also in play here. My very most recent modeling has
extended the booster burn to 11 seconds while adding 3% more propellant
(smaller core); that pushes altitude from 210km to near 230km. I should also
note that 90+ % of the dry mass is weighed; only the payload and ballast are
not currently measured.
Bill
On Thu, Jul 11, 2019 at 6:59 PM Troy Prideaux <
<mailto:troy@xxxxxxxxxxxxxxxxxxxxx> troy@xxxxxxxxxxxxxxxxxxxxx> wrote:
Bill, fair enough. It sounds like a pretty tenuous chain of assumptions, but it
does shed light on the difference. I’m curious on how you arrived at the
assumption that the denser propellant would deliver a noticeable increase in
specific impulse? I can understand how that can occur in small motors where you
might expect noticeable deviations in pressure from varying surface area
exposure, but for a large motor?
Troy
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
[mailto:arocket-bounce@xxxxxxxxxxxxx ;<mailto:arocket-bounce@xxxxxxxxxxxxx> ] On
Behalf Of William Claybaugh
Sent: Friday, 12 July 2019 10:14 AM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Troy, David:
Let me be the first to agree that sims are just sims and reality awaits.
I too was surprised by the seemingly large change and have spent some time
trying to understand it:
First this is a two stage rocket and the effect of higher propellant fraction
is accordingly magnified in a way we don’t see in a single stage.
Second, the propellant is not just denser, it is also slightly higher
performance, a trajectory average of about four seconds for the first stage and
around seven seconds for the upper stage (which lights at around 40k feet and
burns out above 75k feet); this appears to be a significant second order effect.
Lastly, the propellant is slightly slower burning (because of fewer voids).
When optimized w/ my 2-DOF sim the longer burn in the first stage (10 seconds
instead of eight) produces a much lower MaxQ which—in the sim—produces a
notably higher burnout velocity and altitude.
When the coast between burns is adjusted (was 21 seconds, now 12) because of
the higher and faster booster burnout the upper stage gains almost a Mach
number in burnout velocity (was Mach 5.2, now 6.1).
Then it gets tricky: the upper stage violates the two-caliber rule above Mach
5.25. It looks like seven pounds of ballast behind the nose tip take care of
that but it does not look like the aluminum fins survive the ride. I’m
currently looking at titanium leading edges for the upper stage fins.
I don’t know if the sims are reliable (but the program has a long history of
accuracy); I’ll probably be flying one of the upper stages early next year and
then we’ll get a better idea of what to expect.
Let me also address a favorite topic, the cost benefit: this has cost about
$350 in out of pocket infrastructure investment (a vacuum tight lid for the
mixing bowl w/ view port). Everything else—including the vacuum pump, gauges,
and lines—was already in hand.
Bill
On Thu, Jul 11, 2019 at 5:35 PM David Summers < <mailto:dvidsum@xxxxxxxxx>
dvidsum@xxxxxxxxx> wrote:
That is fascinating! Is your propellant mass fraction unusually high? I can't
think of another reason for that result, and I'd like to understand it better.
Thanks!
-David Summers
On Thu, Jul 11, 2019 at 1:15 PM William Claybaugh <
<mailto:wclaybaugh2@xxxxxxxxx> wclaybaugh2@xxxxxxxxx> wrote:
David:
In flight simulations of my two-stage, stuffing 3% more propellant into the
same volume raises the peak altitude from a tad over 150km to 210km in the most
recent runs.
Bill
On Thu, Jul 11, 2019 at 4:47 PM David Summers < <mailto:dvidsum@xxxxxxxxx>
dvidsum@xxxxxxxxx> wrote:
Hoping to take this on a learning tangent:
Why take all the effort to get a few percent higher density? I'd imagine that
it translates to less than 3% higher performance, so wouldn't a simpler process
with a few percent larger chamber be more optimal?
What am I missing? Or is it just a why not go for perfect kind of thing?
Thanks!
-David Summers
On Thu, Jul 11, 2019 at 12:41 PM Troy Prideaux <
<mailto:troy@xxxxxxxxxxxxxxxxxxxxx> troy@xxxxxxxxxxxxxxxxxxxxx> wrote:
If I vaguely recall (I could be mistaken) it was Mark Spiegl (?) who 1st
mentioned this process here about maybe 15 odd years ago. If I recall he was
utilising this process as an amateur and achieving some pretty good results.
Troy
From: arocket-bounce@xxxxxxxxxxxxx <mailto:arocket-bounce@xxxxxxxxxxxxx>
[mailto:arocket-bounce@xxxxxxxxxxxxx ;<mailto:arocket-bounce@xxxxxxxxxxxxx> ] On
Behalf Of Anthony Cesaroni
Sent: Friday, 12 July 2019 6:31 AM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Not with traditional solid constituents and configurations and I’ll leave it at
that.
One technique that does have some merit is centrifugal casting. In this example
you have more energy at your disposal to consolidate the solid loading in the
absence of proper vacuum processing equipment. The propellant mix is prepared
and post degassed using vacuum, turnover and vibration as usual. The prepared
propellant is then transferred into the motor case or casting tube with a cap
on one end. The case is then closed with a cap on the remaining open end and
the whole affair is spun, longitudinally in a spin fixture or a lathe equipped
with explosion proof electrics (I’m sure). The case is spun at moderate speed
until the propellant cures.
After the propellant has cured, a section through the propellant will show very
high solid consolidation with a resin rich condition on the ID surface. The
next step is to use your explosion proof lathe to bore out the excess resin on
the ID and you will have an extraordinarily high solids loaded propellant grain
remaining. Some experimentation is required to optimize the particle morphology
and the speed should be optimized to produce the most consolidation while
minimizing the migration of the smaller diameter particles.
To optimize the process further, one end of the case should be supported by a
roller steady and the dam on that end should have an opening to allow the slow
and well placed transfer of the propellant into the case while it’s spinning
instead of putting the whole mess in there at the beginning. This actually
works and you can achieve some impressive densities using this method.
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 Edward Wranosky
Sent: Thursday, July 11, 2019 3:43 PM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: Vacuum processing of solid propellant
Is there any sort of VARTM like process for manufacturing propellant?
Edward
On Mon, Jul 8, 2019 at 8:39 AM William Claybaugh <wclaybaugh2@xxxxxxxxx
<mailto:wclaybaugh2@xxxxxxxxx> > wrote:
Uwe:
Yeah, as Anthony observed it is air trapped on the solids that produces the
problem.
The AP is tri-modal (200, 400, 600 micron) and mixed via a sieve on-site, lots
of opportunity for air to entrain in that process.
The Al is 5 micron and picks up air rather like a sponge. Wetting it and
degassing might help some but the subsequent final mixing w: the AP is going to
introduce air.
I’m thinking the strategy is going to be to post processing degas a set of
samples (5 minutes, 10, 15) and compare density gain per step. That should
offer a guess as to what can be achieved before the mix sets up.
Bill
On Mon, Jul 8, 2019 at 12:18 AM Uwe Klein <uwe@xxxxxxxxxxxxxxxxxxx
<mailto:uwe@xxxxxxxxxxxxxxxxxxx> > wrote:
Am 07.07.2019 um 19:59 schrieb William Claybaugh:
Uwe:
For safety we can’t mix the Al & AP together;
processing usually
proceeds by mixing the liquids (including catalyst), adding the aluminum
to the liquid mix w/ careful hand stirring), then folding into the AP
followed by final mixing.
Bill
On Sun, Jul 7, 2019 at 11:37 AM Uwe Klein <uwe@xxxxxxxxxxxxxxxxxxx
<mailto:uwe@xxxxxxxxxxxxxxxxxxx>
<mailto:uwe@xxxxxxxxxxxxxxxxxxx ;<mailto:uwe@xxxxxxxxxxxxxxxxxxx> >> wrote:
Am 07.07.2019 um 18:39 schrieb William Claybaugh:
> Does degassing the liquid components before mixing help or does the
> subsequent mixing just reintroduce air?
Use mixing machinery where the mixing implements don't break the
surface. i.e. avoid "whipped cream" effects.
Any fine grained solids will need degassing after they
have been immersed in but not fully wetted by fluid components.
IMU no way around it.
Mix solids superficially, evacuate, add liquids on top.
return pressure to normal.
Then start mixing ( top mentioned prerequisites apply :-)
Uwe
