Does anyone know the "guts" of the propellant?
Besides the phase change problem with AN and it's much lower Isp; you
need to (unless things have changed a lot) use Mg as the fuel, not
Al. And Mg needs extra processing (coating with linseed oil or such,
well known from pyro stuff). Otherwise it can absorb moisture during
storage and ignite! That would be bad for things. Then you have the
constant worry (PSAN or not) that thermal cycling will cause AN to
undergo it's annoying phase changes thus compromising propellant
integrity.
But these days it's not surprising (sadly) to see a minimal enviro
factor run the show.
And dang, ebven though I was right there didn't get to see the
launch. We're here for our 25th anniversary and she was "damned sure"
not going to waste time for rocket stuff. Ahhhh...
Brian
On Thu, Nov 5, 2015 at 4:09 PM, Troy Prideaux <GEORDI@xxxxxxxxxxxxxxxx> wrote:
I would personally be surprised if we do see a significant transition to AN
based solids. I’ve been involved in studies on AN solids and have followed
some amateurs have a crack at transitioning to AN propellants from AP
solids. The biggest concern I have with AN composites is the uniformity of
the propellant regression or at least obtaining the consistency of a uniform
regression. Too often I’ve witnessed significant stability issues with
extremely “bubbly” surface regression that’s likely caused from surface
penetration of the flame-front which is often a consequence of dry
packing/processing of solid propellants.
Motors operating on quite lowish chamber pressures appear to often avoid
these issues, but as the chamber pressure is increased, these issues become
more frequent and even with propellants that have been meticulously
processed (eg. Pressed under a multi tonne press) to avoid such issues have
yielded hit & miss consistency when operated under moderate-high chamber
pressures.
What’s more, the claims of an industry transition from AP solids to AN
based solids have been constantly provided by advocates over… well… decades!
Probably as long as proponents of SCRAMETS have been boasting their tech be
the next big thing for everything involving air breathing missiles to high
speed transportation. There have been countless studies and plenty of small
government grants/programs for AN proponents to provide a working propulsion
system of usable scale.
I truly hope someone cracks that nut one day, but I’m not holding my
breath.
Troy
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of Lloyd Droppers
Sent: Friday, 6 November 2015 9:33 AM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: [UK OFFICIAL] Re: Re[2]: Re: ORS-4 ("Super Strypi") Hawaii
launc...
It looks like the Super Strypi Environmental Assessment says ammonium
nitrate so I think the article was right.
http://www.govsupport.us/ORSSSEA/Documents/FinalEA.pdf
There has been a fair bit of research into AN based propellant in the past
two decade or so and various rocket do use it successfully. They kicker
appears to be phase stabilizing with various compounds, KNO3 or ZnO, for
dimensional stability, some of the time the AN is then called PSAN.
For a launch vehicle there are a couple of advantages, the material is cheap
and available, negligible environmental impact or health risk, and a low
burn rate which is advantageous for a smallish launch vehicle. Obviously on
the minus side it has lower performance, is harder to igniter and burn well,
and has a higher pressure exponent than APCP. But everything is a tradeoff.
For tactical application I think it is easier to get smokeless propellant
from AN, and it is an insensitive munition.
I'm not saying that you should switch all rockets from AP the AN but the you
can certainly make a functional system out of it. And I would imagine we
will see more AN composites in the future given the trend for tougher
environmental regulations, especially for groundwater contamination.
Lloyd
On Thu, Nov 5, 2015 at 7:19 PM, BrianK ABQ <cielobenazul@xxxxxxxxx> wrote:
A question on the propellant. I only found one article that included
any details and it mentioned an "ammonium nitrate blend". Is that
correct? I'm a solid fuel guy, amatuer but hard at it. I've found by
both research and experience that AN composite propellant is quite
inferior to it's ammonium perchlorate cousin. Was the article wrong?
Did someone figure out a way to soup up ANCP? Or is it a "green
thing?" as ANCP doesn't make HCl ?
Thanks,
Brian
On Wed, Nov 4, 2015 at 7:13 PM, Redacted sender JMKrell for DMARC
<dmarc-noreply@xxxxxxxxxxxxx> wrote:
At the T+ 58-59 second mark the vehicle broke up. Enlarging the observer
video I can see a secondary vapor trail separate from the first stage. The
gyration of the animation is the second & third stages tumbling.
Krell
In a message dated 11/4/2015 5:05:53 P.M. Pacific Standard Time,
monroe@xxxxxxxxxxxxxxxxxx writes:
Burn threw would be consistent with what I thought might be a control
error. Something got the pitch roll couple going. Could be asymmetric
thrust? It appears to me the roll pitch couple was in there from the
start and just got worse as she went. Leaving the rail just might have
caused it as well not enough acceleration to overcome the mass at that
angle. The rail was too short?
I think the animation was probably fair when she came apart the section
with telemetry kept going. The animation update rate probably could not
handle the small bit while it came apart.
The thrust does look asymmetric perhaps on purpose? Are the fins canted?
-------- Original Message --------
Subject: [AR] Re: [UK OFFICIAL] Re: Re[2]: Re: ORS-4 ("Super Strypi")
Hawaii launch delayed
From: "Anthony Cesaroni" <acesaroni@xxxxxxxxxxx>
Date: Wed, November 04, 2015 2:05 pm
To: <arocket@xxxxxxxxxxxxx>
Ken,
I understand that, hence the emoticon. ORS spent close to $45M to get to
that launch. Pretty soon you’re talking real money for a simple rocket.
;-)
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]
On Behalf Of Ken Biba
Sent: Wednesday, November 04, 2015 3:33 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: [UK OFFICIAL] Re: Re[2]: Re: ORS-4 ("Super Strypi")
Hawaii launch delayed
Did not ask you to. Just adding different information.
Ken Biba
Novarum, Inc.
415-577-5496
On Nov 4, 2015, at 12:10 PM, Anthony Cesaroni <acesaroni@xxxxxxxxxxx
<mailto:acesaroni@xxxxxxxxxxx> > wrote:
Not buying it. :)
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>
[mailto:arocket-bounce@xxxxxxxxxxxxx] On Behalf Of KEN BIBA
Sent: Wednesday, November 04, 2015 1:48 PM
To: arocket@xxxxxxxxxxxxx <mailto:arocket@xxxxxxxxxxxxx>
Subject: [AR] Re: [UK OFFICIAL] Re: Re[2]: Re: ORS-4 ("Super Strypi")
Hawaii launch delayed
I have just received from preliminary information from the UH team - it
appears that first stage burn completed successfully, and a deshrouding
maneuver (used by Sandia for suborbital flights) at staging failed to
properly align the second stage - and tumbling began.
More information may change this analysis … but this is current.
K
On Nov 4, 2015, at 9:56 AM, Lars Osborne <lars.osborne@xxxxxxxxx
<mailto:lars.osborne@xxxxxxxxx> > wrote:
Probably FOD. Did anyone else see all the particles in the exhaust?
Thanks,
Lars Osborne
On Wed, Nov 4, 2015 at 9:38 AM, KEN BIBA <kenbiba@xxxxxx
<mailto:kenbiba@xxxxxx> > wrote:
I seem to remember, from my quick research on this flight, that the
intended roll rate for the first stage boost was 2.5 Hz with a suggestion
of
a slowing to 1 Hz at the end of first stage burn. But those were
annotations of a briefing slide of uncertain age.
Also … this flight was actually pulled forward from 2016 - with a
statement that the increased risk was worth it. I wonder if the risk
item
is the cause.
K
On Nov 4, 2015, at 9:22 AM, Paul Mueller <paul.mueller.iii@xxxxxxxxx
<mailto:paul.mueller.iii@xxxxxxxxx> > wrote:
More speculation without data (which is fun!):
We understand gravity turns pretty well--it would be a colossal error if
they set the elevation angle of the launch rail to the wrong setting.
I would think a fin loss would mean the failure would happen much more
quickly, rather than what looked like slowly increasing divergent coning
motion (aka roll-pitch coupling).
I think it was roll-pitch coupling, but not because the roll rate was too
slow. If the roll rate is slow (and there's a decent amount of
aerodynamic
damping), or if the roll rate is very high, there won't be significant
roll-pitch coupling. It's the in-between rate that's resonant with the
pitch
natural frequency (think Bode plots from back in school) that ruins your
day. Many unguided sounding rockets like the Super Loki spin up
immediately
(using a corkscrew rail) to get past the resonant roll rate right from
the
start. It looks to me that the roll rate started out at less than 1 Hz
(60
rpm) (from the onboard video) and then increased to over 2 Hz (120 rpm)
and
then the coning motion started. It lasted for a few seconds before loss
of
video. So the roll rate increased until it reached the pitch-roll
resonant
frequency and it was all over. At least that's my guess!
The animation looked pretty bogus to me--was the center of mass really
that far forward (that close to the nose cone)?
On Wed, Nov 4, 2015 at 9:47 AM, Aplin Alexander T
<ATAPLIN@xxxxxxxxxxxxxxxx <mailto:ATAPLIN@xxxxxxxxxxxxxxxx> > wrote:
Classification: UK OFFICIAL
Handling Instruction: DISCLAIMER - this is a personal e-mail and only
represents the views of the sender
FWIW the Black Arrow had a solid third stage.
On my mind as I had the pleasure of a close encounter with the spare
Black
Arrow on display at the London Science Museum earlier this week).
http://www.sciencemuseum.org.uk/objects/space_technology/1972-325.aspx?keywords=black+arrow
BTW I also saw a Russian TK Lunar lander on (temporary) display at the
‘Cosmonauts’ exhibition there – the contrast in size to the (relatively)
huge US LM mock-up on display elsewhere was striking.
http://www.sciencemuseum.org.uk/visitmuseum/Plan_your_visit/exhibitions/cosmonauts.aspx
Alex Aplin
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