Rocket Fuels
Trevor Finnie
+ sugar be suitable for making large rockets engines? I've had great success
using it in very small engines using the instuctions available from
Teleflite. (200-300m altitude from an engine 3/8" by 3")
Trev.
x
chemicals. They sell it for $3.85 / lb., $17.70 / 5lbs. Their phone #
is: (703)554-4543
Bill Nelson
: Where does one obtain zinc dust and is it expensive? BTW would KNO3 + sulfur
: + sugar be suitable for making large rockets engines? I've had great success
: using it in very small engines using the instuctions available from
: Teleflite. (200-300m altitude from an engine 3/8" by 3")
Zinc/sulfur is a bomb just waiting to explode. The mixture tends to burn far
too fast, and with far too much chamber pressure, to be useable in model
rocket motors.
The nitrate/sugar/sulfur mixture will work for larger motors - although not
for very large ones. Going much past a G or H motor would probably be quite
difficult.
If you are going to experiment with larger motors, I would suggest going up
one step at a time. In other words, double the propellant, and work with
that until you get good consistant results - then double it again and start
over.
Larger motors are quite sensitive to temperature cycling, and you are likely
to have a lot of failures due to such cycling. Other disadvantages is a much
longer drying time (if you moisten the mixture before pressing) - and much
more difficulty getting a solid grain without voids or ununiform density.
Bill
x
>
>Zinc/sulfur is a bomb just waiting to explode. The mixture tends to
burn far
>too fast, and with far too much chamber pressure, to be useable in
model
>rocket motors.
Oh Please! You must be kidding! Zinc / sulfur rockets have been around
longer than Estes. Most old timers love these things. Nothing compares
to the smoke / flame of a Zn/S rocket. They don't explode any more or
less than any other rocket engine. I've probably made close to 30 Zn/S
engines and I'm still waiting for one to fail.
-Bob
Bill Nelson
Yep, and there were many young people either maimed or killed while
experimenting with them.
They DO explode quite frequently - even the modern firings using heavy
duty stainless steel casings.
If you do not have a lot of failures, then they are not very efficient.
In other words, your nozzle is probably much too large.
I like them too. As you say, there is a lot of flame and smoke - mostly
due to a fair share of the propellant being blown out of the nozzle
before it burns.
The fuel is also fairly static sensitive.
Your experience is NOT typical. The Smoke Creek test site is littered
with the remains of such attempts.
Yes, I made them in the late 50s and early 60s - when it was all the
craze. No more. The Isp is poor and the peak pressures much too high.
Bill
x
>
>x (desb...@ix.netcom.com) wrote:
>: In <44sq4s$b...@odo.PEAK.ORG> bi...@PEAK.ORG (Bill Nelson) writes:
>
>: >Zinc/sulfur is a bomb just waiting to explode. The mixture tends to
>: burn far
>: >too fast, and with far too much chamber pressure, to be useable in
>: model
>: >rocket motors.
>
>: Oh Please! You must be kidding! Zinc / sulfur rockets have been
around
>: longer than Estes. Most old timers love these things. Nothing
compares
>: to the smoke / flame of a Zn/S rocket. They don't explode any more
or
>: less than any other rocket engine. I've probably made close to 30
Zn/S
>: engines and I'm still waiting for one to fail.
>
>Yep, and there were many young people either maimed or killed while
>experimenting with them.
The uninformed should not "experiment" with high energy fuels. Either
you know what your doing or you don't do it.
>They DO explode quite frequently - even the modern firings using heavy
>duty stainless steel casings.
Properly designed and built rocket engines by definition, do not
explode. Mine do not. Yes, I use stainless steel casings, what do you
use, aluminum?
>If you do not have a lot of failures, then they are not very
efficient.
>In other words, your nozzle is probably much too large.
No Bill, I just know what I'm doing unlike the people you refer to. My
motors are quite efficient for Zn/S and the nozzle dimensions are just
where they should be.
>I like them too. As you say, there is a lot of flame and smoke -
mostly
>due to a fair share of the propellant being blown out of the nozzle
>before it burns.
All the smoke is due to the fact that the exaust is composed almost
entirely of zinc sulfide. There is minimal unburnt propellant ejected.
>The fuel is also fairly static sensitive.
As compared to what, Concrete? A 35Kv discharge at .01Ma. ignited AP
fuel and did not ignite Zn/S fuel. Where do you get these "facts"?
>Your experience is NOT typical. The Smoke Creek test site is littered
>with the remains of such attempts.
All that tells me is the folks playing with Zn/S motors at Smoke Creek
should switch to something they are more familiar with. I hear those
water rockets you pump up are quite safe. Perhaps you guys should stick
with those.
>Yes, I made them in the late 50s and early 60s - when it was all the
>craze. No more. The Isp is poor and the peak pressures much too high.
>
>Bill
I've built Lox/Kerosene, Zn/S, Blackpowder, H2O2 and various hybrid
motors. All have their advantages and disadvantages. All are potential
bombs if not designed & built properly. As with anything dangerous, you
just have to know what your doing or you get burned.
-Bob
Bill Nelson
: In <44vtij$p...@odo.PEAK.ORG> bi...@PEAK.ORG (Bill Nelson) writes:
: >
: >Yep, and there were many young people either maimed or killed while
: >experimenting with them.
: The uninformed should not "experiment" with high energy fuels. Either
: you know what your doing or you don't do it.
Agreed - or you need to be working under the guidance of someone who does.
Most people who want to experiment do not have the luxury of working with
the RRS.
: >They DO explode quite frequently - even the modern firings using heavy
: >duty stainless steel casings.
: Properly designed and built rocket engines by definition, do not
: explode. Mine do not. Yes, I use stainless steel casings, what do you
: use, aluminum?
There are no guarantees. Even the most carefully built motor can fail, due
to a number of reasons. While you (using RRS facilities) are well protected,
most experimenters would not be.
I don't build motors with such high chamber pressures any more - so have
no need for steel casings. The aluminum casings I use are designed to fail
by blowing an end closure - rather than rupturing a casing, if the pressures
get too high. Also, the composite fuels I use are not nearly as sensitive
to spark/flame/friction/impact as the Zn/S fuels. Nor do they burn very well
when not pressurized.
: >I like them too. As you say, there is a lot of flame and smoke -
: mostly
: >due to a fair share of the propellant being blown out of the nozzle
: >before it burns.
: All the smoke is due to the fact that the exaust is composed almost
: entirely of zinc sulfide. There is minimal unburnt propellant ejected.
Hm, this goes counter to all I have read and experienced. Do you use a
binder to keep the fuel one solid mass?
: >The fuel is also fairly static sensitive.
: As compared to what, Concrete? A 35Kv discharge at .01Ma. ignited AP
: fuel and did not ignite Zn/S fuel. Where do you get these "facts"?
I could start with Brinley, as well as all the other references which
state that the fuel can be ignited by a spark - even one generated by
tooling.
: >Your experience is NOT typical. The Smoke Creek test site is littered
: >with the remains of such attempts.
: All that tells me is the folks playing with Zn/S motors at Smoke Creek
: should switch to something they are more familiar with. I hear those
: water rockets you pump up are quite safe. Perhaps you guys should stick
: with those.
The point is - the same thing will happen to people who do not have expert
guidance. Without the proper facilities, injuries and deaths will occur,
just like they have in the past.
: >Yes, I made them in the late 50s and early 60s - when it was all the
: >craze. No more. The Isp is poor and the peak pressures much too high.
: I've built Lox/Kerosene, Zn/S, Blackpowder, H2O2 and various hybrid
: motors. All have their advantages and disadvantages. All are potential
: bombs if not designed & built properly. As with anything dangerous, you
: just have to know what your doing or you get burned.
Agreed. However, knowing what you are doing is no guarantee of safety,
although it will greatly improve your odds.
Bill
Joan Barlow
Could some one send me an e-mail on how to make up a
Nitrate/Sugar/sulfur propellant eg. quantities, procedures, equipment.
BOBROWSKI
cost of a good plastic surgeon.
x
writes:
>The components of model rocket motors are extremely cheap, compared to
the
>cost of a good plastic surgeon.
I had no idea plastic surgeons could be used as rocket fuel. What
proportion of oxidizer to plastic surgeon do you use?
-Bob
Ralph Strauser
s > From: sil...@ix.netcom.com (The Silent Observer)
s > Subject: re: Rocket Fuels
s > This method was touched on briefly in Brinley's book (not the best
s > source, but some useful information, if you can figure out what's good
s > and what's crap). I see two major questions, mainly about >why< it
s > works, assuming it does.
s > First, how does a tissue "bulkhead" keep several pounds of powder from
s > shifting under a couple hundred Gs? Second, related, how does a tissue
s > bulkhead keep chamber pressure of a couple thousand psi from blowing
s > through to pack the powder forward ahead of the combustion front?
It seems to me that it works because the powder is in smaller masses
the way i understand it as mass double weight tripples so using hypo-
thetical numbers. if one cubic foot of powder weighs one pound then
two cubic feet would weigh 3 pounds. so even though you have 6 cubic
feet of fuel for a total weight of 36 pounds you would only have 1
pound on each tissue bulkhead. as to the strength of the paper I have
seen some of the model aircraft tissue stand up to weights that i thought
would be sure to puncture it but didn't as the weight was spread out
rather than concentrated at one point.
This is all theory of course so if someone out this has real numbers
please feel free to correct me.
Ralph.S...@p10.f34.n105.z1.fidonet.org
Ralph.S...@Comm-Dat.Com
Lord Sagan On Twisted Sky BBS.
... Any body seen my tagline...?
The Silent Observer
(dsp...@primenet.com) says...
>
>Back in the early 1950s, the Pacific Rocket Society's Cal Tech
>chapter did some work with the combination. They found that
>by segmenting the total charge they got more reliable and
>consistant operation.
>
>What they did was to make propellant packets from heavy
>cardboard tubing , tissue paper and the Zinc/Sulphur mixture.
>Similar to the powder bags that the Navy uses in their large
>caliber guns.
>
<snip>
This method was touched on briefly in Brinley's book (not the best
source, but some useful information, if you can figure out what's good
and what's crap). I see two major questions, mainly about >why< it
works, assuming it does.
First, how does a tissue "bulkhead" keep several pounds of powder from
shifting under a couple hundred Gs? Second, related, how does a tissue
bulkhead keep chamber pressure of a couple thousand psi from blowing
through to pack the powder forward ahead of the combustion front?
In other words, it seems a sensible method, but I wonder if tissue paper
is strong enough. Has anyone else tried this method?
--
+----------------------------------------------------------------------+
| sil...@ix.netcom.com | Mass advertising on the Internet may become |
| Owner/Operator of | necessary, eventually ... |
| TableTop Publications | ...but it will still be an evil! |
+----------------------------------------------------------------------+
| All opinions expressed are my own, and should in no way be mistaken |
| for those of the reader. |
+----------------------------------------------------------------------+
David P. Dpahr
Sulphur as a propellant.
Back in the early 1950s, the Pacific Rocket Society's Cal Tech
chapter did some work with the combination. They found that
by segmenting the total charge they got more reliable and
consistant operation.
What they did was to make propellant packets from heavy
cardboard tubing , tissue paper and the Zinc/Sulphur mixture.
Similar to the powder bags that the Navy uses in their large
caliber guns.
A cardboard tube, with an O.D. that would just slip into the aluminum
motor tube and 1\8 or 1\4 inch wall thickness, was cut into approx
3 inch lengths and one end was sealed with a sheet of tissue paper and
the excess paper trimmed. After the glue had dried, a measured amount
of the Zinc/Sulphur mixture was put into the tube segment and the open
end was sealed with another piece of tissue paper and the paper again,
trimmed.
When the rocket was to be fueled, all that was required was to slip
the packets into the motor tube and close it up. I don't recall if the
nozzel was tight against the bottom packet or if they had a spacer
in place. For firing, an igniter was placed against the bottom face of
the bottom packet.
This method of loading the motor has several advantages:
1. It didn't require trying to pour a large quantity of the mixture
into the motor tube.
2. The powder density was constant throughout the length of
the motor, therefore combustion was more uniform, throughout
the burn.
3. As the bottom powder burned, the possibility of the upper
mixture trying to move into the lower part of the motor, via
the mixtures own weight and acceleration was reduced.
4. As the propellant burned, the 'chamber pressure' had less chance
of trying to pack the mixture ahead of the flame front.
I wasn't a member of the PRS. I was a member of a student chapter
of the old American Rocket Society. in the mid-50s. One of our
grad-student members, David G. Elliot, had been a member of the PRS
when he was an undergrad at Cal Tech,. Dave gave a film resentation of
some of the Zinc/Sulphur work he had done with the PRS. He also showed
some film of a Hydrogen-Peroxide rocket that they had tried and lost
when it shed its fins , they guessed, going through Mach-1. This one
employed a booster and was aerodynamically tested in one of Cal Techs
wind tunnels.
I don't know if the PRS left any papers regarding their work with
Cal Tech. If someone has access to Cal Tech's archieves they might
find something.
Sorry about the length, but I thought the information might be of
interest.
David P. Spahr
dsp...@primenet.com
The Silent Observer
(Ralph.S...@p10.f34.n105.z1.fidonet.org) says...
>
>
>It seems to me that it works because the powder is in smaller masses
>the way i understand it as mass double weight tripples
What?? Try this at home: put a full gallon milk jug on your scale, and
record the weight (should be about 8 pounds). Now, put a second jug on,
along with the first. Would you agree, you've doubled the mass standing
on the scale? Okay, now, check the weight -- should be just twice what
you had before, something like 16 pounds.
You're probably confusing mass vs. weight with the square-cube law,
which says that as you scale an object larger or smaller, the area is
proportional to the square of the scale factor, but the mass is
proportional to the >cube< of the scale factor -- so if I built a motor
with doubled fuel grain dimensions, it'd have four times the burn area
(and hence, assuming a properly optimized nozzle, four times the
thrust), but eight times the propellant mass (and hence, something like
half the acceleration, but that's another line of reasoning).
>you would only have 1
>pound on each tissue bulkhead. as to the strength of the paper I have
>seen some of the model aircraft tissue stand up to weights that i
thought
>would be sure to puncture it but didn't as the weight was spread out
>rather than concentrated at one point.
> This is all theory of course so if someone out this has real numbers
>please feel free to correct me.
This part would be fairly solid reasoning (each tissue layer only
supporting the propellant in its own section) for G forces, assuming the
tissue doesn't flex and none of the bulkheads burst -- rather a large
assumption, I think -- but still doesn't deal with the pressure
question.
Besides that, at an acceleration (common in Zn/S rockets) of 100 Gs,
that one pound of propellant in (say) the third section has, even only
on its own weight, 100 lbs of force pressing on the tissure. I don't
think aircraft tisse, or even Silkspan (R), could take that kind of
pressure...
Bill Nelson
: It seems to me that it works because the powder is in smaller masses
: the way i understand it as mass double weight tripples so using hypo-
: thetical numbers. if one cubic foot of powder weighs one pound then
: two cubic feet would weigh 3 pounds. so even though you have 6 cubic
: feet of fuel for a total weight of 36 pounds you would only have 1
: pound on each tissue bulkhead. as to the strength of the paper I have
: seen some of the model aircraft tissue stand up to weights that i thought
: would be sure to puncture it but didn't as the weight was spread out
: rather than concentrated at one point.
: This is all theory of course so if someone out this has real numbers
: please feel free to correct me.
The mass/weight part makes absolutely no sense at all. I think you are
confusing the mass/surface-area relationship.
If one cubic foot of fuel weighed one pound, then 6 cubic feet of fuel
(at the same density) will weigh 6 pounds.
Bill
Paul
surgeon.<<
Agreed, but done carefully motors can be made 'at home' and with
relative safety. Certainly, commercial companies can produce
good, reliable motors at a price lower than most motors can be
made for, after accounting for all the time involved as well as
the machines required. But the experimentation involved in
producing one's one motors is a part of the hobby that MANY of us
BARs are quite interested in.
Certainly questions of legality may be involved. Equally
certainly this is NOT an aspect of the hobby for children to be
involved in withour STRICT parental guidance! I wouln't consider
'mentoring' any child not my own in motor production.
However, with those disclaimers in mind, ADULTS should be able to
experiment with motor construction, using common sense and with
concern for safety at all times!
Paul Gennrich
--
Paul
Paul & Victoria Heisner
<DGnKy...@news.hawaii.edu>, he...@pulua.hcc.hawaii.edu (Helen
Rapozo) would say...
>In article <460u98$oul$1...@mhafn.production.compuserve.com> Paul <76171...@CompuServe.COM> writes:
>>Bobrowski wrote: >> The components of model rocket motors are
>>extremely cheap, compared to the cost of a good plastic
>>surgeon.<<
>>
>>the machines required. But the experimentation involved in
>>producing one's one motors is a part of the hobby that MANY of us
>>BARs are quite interested in.
>****************
>Excuse me, please count this BAR (me) out of this.
Me too.... I know the first time I saw an Aerotech go off, I imagined
that going off in my kitchen and kissed my store bought engine!!! My
favorite fuel recipe includes a pen, checkbook, and a hobby shop....
;->
Vicki
Vicki Heisner
vhei...@ainet.com
LUNAR #365
Hmmm...guess that makes me New Years Eve!!!
Paul
You answered to my post: >> But the experimentation involved in
>producing one's one motors is a part of the hobby that MANY of
us >BARs are quite interested in.
****************
Excuse me, please count this BAR (me) out of this. <<
I certainly would never think of insisting that anyone not
interested in motor construction HAS to be involved in it. But,
Helen, I'd hope that your lack of interest in this aspect of the
hobby won't cause you to look askance at those of us who ARE
interested in it.
I don't advocate the building of motors by youngsters, who likely
lack good judgement and certainly lack experience. but I'd hope
you'll 'permit' those of us who are mature adults to continue
with a very interesting aspect of HPR.
Keep the pointy ends up!
Paul Gennrich
--
Paul
kapl...@hccompare.com
> I certainly would never think of insisting that anyone not
> interested in motor construction HAS to be involved in it. But,
> Helen, I'd hope that your lack of interest in this aspect of the
> hobby won't cause you to look askance at those of us who ARE
> interested in it.
>
> I don't advocate the building of motors by youngsters, who likely
> lack good judgement and certainly lack experience. but I'd hope
> you'll 'permit' those of us who are mature adults to continue
> with a very interesting aspect of HPR.
PLEASE, do not confuse model rocketry (NFPA 1122) or HPR (NFPA 1127) with
manufacturing your own motors (amateur rocketry).
If you have the advanced technical knowledge, equipment, safety procedures,
facilities, and comply with zillions of federal, state, and local
regulations, amateur rocketry can be a challenge. If you lack any of the
requirements it can be suicidal.
Bob Kaplow INTERNET: kapl...@hccompare.com
USPO: HealthCare COMPARE Corp, 5ISD, 3200 Highland Av. Downers Grove, IL 60515
TPC: (708) 241-7919 x5327 ICBM: 41°49'48" North 88°0'51" West
"Ideas are more dangerous than guns. We wouldn't let our enemies have guns,
why should we let them have ideas?" Stalin
Disclaimer: If this message is caught or killed, the secretary will disavow
any knowledge of my actions. These bits will self destruct in 5 seconds....
Mark Johnson
>I don't advocate the building of motors by youngsters, who likely
>lack good judgement and certainly lack experience. but I'd hope
>you'll 'permit' those of us who are mature adults to continue
>with a very interesting aspect of HPR.
I haven't looked at the draft of NFPA 1127, which provides a definition of HPR
that will become the legal definition in NFPA-adopting states. However, if
it's what I *think* it is, building motors isn't a part of 1127's definition.
I know that the 1122 Safety Code (the NAR/HIA/NFPA Code for *Model* Rockets)
makes specific mention of "factory made" motors, with some kind of a loophole
to cover reloadable technology. I assume that 1127 does much the same thing.
Now, I have absolutely no objection to non-professionals building and testing
motors in isolation. It's a great way to practice "rocket science" without a
million-dollar budget and the backing of a major chemical or aerospace
company. I'm sure its practitioners find it enjoyable. But let's call it what
it is: Amateur Rocketry.
Amateur rocketry is a recognized and reasonably-well-defined activity,
although the boundaries in terms of size are certainly getting blurry. It is
most definitely distinct from what we grew to call "basement bombing" in the
1960's and 70's...an activity of which I most assuredly do *NOT* approve, nor
participate in.
=============
Mark Johnson USnail: Symbios Logic, Inc
E-mail: Mark.J...@symbios.com OEM RAID Business Team
Voice: (316) 636-8189 [V+654-8189] 3718 N. Rock Rd.
Visit our web page: http://www.symbios.com Wichita, KS 67226
kapl...@hccompare.com
> experience and actually come to me for advice. Yes, I do build motors(AP), and
> I even flew some at LDRS 14. I've never even come close to hurting myself or
> having an accident because I have the good judgement that comes with years of
> experience. Sometimes I tend to think it's the older guys that don't know
> what they're doing.
The most dangerous individals in ANY hobby are the ones who THINK they know
what they are doing. Those with vast experience and equipment can build
motors safely. Ignorant folks like myself know enough to stay away from the
dangerous stuff. Its the folks who get one mail order book that has as many
liability disclaimers as actual instructions, and think they are rocket
experts that are going to hurt themselves.
Bob Kaplow INTERNET: kapl...@hccompare.com
USPO: HealthCare COMPARE Corp, 5ISD, 3200 Highland Av. Downers Grove, IL 60515
TPC: (708) 241-7919 x5327 ICBM: 41°49'48" North 88°0'51" West
"If you would like to smoke, please feel free to step outside."
PSA flight attendant on route to LA
Justin Gleiter
In article <1995Oct28....@hccompare.com>, <kapl...@hccompare.com>
writes:
> The most dangerous individals in ANY hobby are the ones who THINK they know
> what they are doing. Those with vast experience and equipment can build
> motors safely.
Hmmm...How do you think these people got the experience of building motors?
Ever read the intro to Kosdon's catalog? You don't have to work for the
government to get experience in this type of thing. Most manufacturers
started their motor making as a hobby. Even Vern Estes did!
>Ignorant folks like myself know enough to stay away from the
> dangerous stuff.
Dangerous in rocketry is a relative term. It wouldn't be tough to argue that
flying off the shelf rocketry equiptment wasn't dangerous. Why do you think
that we have to go to isolated fields and apply for waivers from the FAA?
> Its the folks who get one mail order book that has as many
> liability disclaimers as actual instructions, and think they are rocket
> experts that are going to hurt themselves.
>
As far as I know, nobody has ever been hurt in making a composite motor. Can
you give an example?
Justin
Bill Nelson
: > Its the folks who get one mail order book that has as many
: > liability disclaimers as actual instructions, and think they are rocket
: > experts that are going to hurt themselves.
: >
: As far as I know, nobody has ever been hurt in making a composite motor. Can
: you give an example?
People have been killed making composite motors. The practice is not risk
free. Although I cannot think of the person's name right now, there was at
least one incident where a person turned his house and basement into a
debris filled crater in the ground. He was part of the debris.
Bill
kapl...@hccompare.com
> I don't advocate the building of motors by youngsters, who likely
> lack good judgement and certainly lack experience. but I'd hope
> you'll 'permit' those of us who are mature adults to continue
> with a very interesting aspect of HPR.
As it is currently defined by 1127, TRA, and the NAR, building your own
motors is NOT a model rocket activity. It is either a legitimate amateur
rocket activity or a very foolish activity, depending on who is doing what.
Neither of them are part of model rocketry. If you want to partake in
amateur rocketry, please do so somewhere else, with all the safeguards,
permits, etc. as our insurance does not cover it.
Bob Kaplow INTERNET: kapl...@hccompare.com
USPO: HealthCare COMPARE Corp, 5ISD, 3200 Highland Av. Downers Grove, IL 60515
TPC: (708) 241-7919 x5327 ICBM: 41°49'48" North 88°0'51" West
"Will uninstall Windows 95 for food!"
Mark Johnson
>The most dangerous individals in ANY hobby are the ones who THINK they know
>what they are doing. Those with vast experience and equipment can build
>motors safely. Ignorant folks like myself know enough to stay away from the
>dangerous stuff. Its the folks who get one mail order book that has as many
>liability disclaimers as actual instructions, and think they are rocket
>experts that are going to hurt themselves.
Amen. I had a brief conversation about all the current interest in HPR with
my old rocket-mentor from the 1970's, Irv Wait, who developed the Enerjet
composite motors and used to build stuff from model rocket size up to about
400 lb-sec. He retired from rocket work about 4 years ago.
Anyways, his take on HPR is that "there are a whole lot of guys out there who
have no business messing with this stuff." He was professionally trained as an
engineer of some kind, and worked for one of the Utah-based rocket
manufacturers as well as doing rocket motors and rocket-motor-like gas
generators for Standard Oil in the 1960's, prior to striking out on his own.
Like Bob, I *know* I'm not an expert. I probably know more about it than most
people, but I consider my knowledge to be just enough to get me injured or
killed. I know a bit about propellants, a bit more about nozzles, and nearly
NOTHING at all about the design of pressure vessels. If I were to try to
design and build a motor from the ground up, it would be a matter of time
before I blew one up. More than that, I don't have the space to conduct such
experiments. That was another of Irv's strong points...he did his experimental
motor work on the back side of a 160 acre farm, not in town or on a small
suburban lot. More than that, he made sure all the nearby neighbors knew what
he was doing, and handled any objections they had. I can't stress enough that
even for AP composites, you cannot, in my opinion, safely build and test them
in a residential neighborhood. No way. It's probably not legal either,
although your mileage may vary with local fire codes.
All that being said, I can't stop anybody from doing this stuff...only
encourage genuine safety. Before you start building motors, ask the pros what
they had to go through to get their licenses, permits, and such...and what
they do in terms of safety precautions.
[And you ain't gonna do it in *my* neighborhood, either!]
==========
Michael Edelman
: People have been killed making composite motors. The practice is not risk
: free. Although I cannot think of the person's name right now, there was at
: least one incident where a person turned his house and basement into a
: debris filled crater in the ground. He was part of the debris.
...that's how urban legends get started. No name, no date, no facts of the
matter...just "I know of a case where...":
Most of the fuels used in making castible composites are pretty safe. Of
course, someone *could* have been hammering a whistle mix....!
--mike
Bill Nelson
: Bill Nelson (bi...@PEAK.ORG) wrote:
: : People have been killed making composite motors. The practice is not risk
: : free. Although I cannot think of the person's name right now, there was at
: : least one incident where a person turned his house and basement into a
: : debris filled crater in the ground. He was part of the debris.
: ...that's how urban legends get started. No name, no date, no facts of the
: matter...just "I know of a case where...":
It is a fact. Just because I am getting senile, and losing my memory, does
not change that.
: Most of the fuels used in making castible composites are pretty safe. Of
: course, someone *could* have been hammering a whistle mix....!
They are reasonably safe after being mixed with the binder/fuel. Before
that, the perchlorate/aluminum approximate a very oxygen rich flash powder.
Maybe someone will remember more about the incident, and post more details.
I may even run across a cite - but I am not going to spend a month or two
trying to find it.
I am well aware of how legends get started. I have been a regular poster
to alt.folklore.urban, almost from day one. I have done my share to shoot
down such legends - so do not post stories to which I have not seen decent
documentation.
Bill
Michael Edelman
: : : People have been killed making composite motors. The practice is not risk
: : : free. Although I cannot think of the person's name right now, there was at
: : : least one incident where a person turned his house and basement into a
: : : debris filled crater in the ground. He was part of the debris.
: : ...that's how urban legends get started. No name, no date, no facts of the
: : matter...just "I know of a case where...":
: It is a fact. Just because I am getting senile, and losing my memory, does
: not change that.
Without documentation, it's just a legend.
: : Most of the fuels used in making castible composites are pretty safe. Of
: : course, someone *could* have been hammering a whistle mix....!
: They are reasonably safe after being mixed with the binder/fuel. Before
: that, the perchlorate/aluminum approximate a very oxygen rich flash powder.
Exactly. Mixing perchlorates and AL without the phlegmatizing effects
of a resin binder is just stupid. DOne the right way it's quite safe.
: I am well aware of how legends get started. I have been a regular poster
: to alt.folklore.urban, almost from day one. I have done my share to shoot
: down such legends - so do not post stories to which I have not seen decent
: documentation.
I take it there's a personal pronoun missing from that last clause.
Yes, people get injured making composites...from ignoring safety. The latest
HPR has an editorial from Someone Who SHould Have Known Better. He
was carrting a few ounces of Zn/S in a *plastic* bag when it ignited,
severly burning him. That's three mistakes- plastic bag, mixing ahead of
time, and using ZnS, if you ask me. Might as well use flash.
I use composites instead of BP because of the greater safety margin- and I
only experiment with motors that would be considered A or smaller.
--mike
Michael Edelman
: > Most of the fuels used in making castible composites are pretty safe. Of
: > course, someone *could* have been hammering a whistle mix....!
: > --mike
: Fine, Mike. If you think it takes bovine stupidity to make a serious mistake
: using accepted propellant compositions, I suggest you read the editor's
: column in the latest HPR. Granted, it's not a composite at issue there, but
: is isn't whistle mix by a long shot.
Y'know, Larry, it would be easier to conduct this debate if you let me
express my own arguments instead of making them up for me ;-)
The editorial in the current HPR concerns an accident involving loose
ZnS- which is *NOT* a castable composite! And what I said was that
most of the fuels used in making such compounds are pretty safe. Just
look at the quote above.
ZnS is a dangerous material to begin with, but the editor himself notes
that he commited a number of foolish errors, including mixing the Zn and
S ahead of time and carrying it around the house in a plastic bag!
: You seem to be starting your own legend, here - that propellant formulation
: *is* risk-free.
*Sigh*.
One more time: Read what I wrote and stop arguing over things I never said.
It's difficult enough to keep track of everything *I* saidf without having
to account for the ficticious arguments you keep inventing for me.
: moment example may have been less than convincing. I'm not taking a hard
: position on propellant formulation here (as I have in the past), but it is
: *certainly* not risk-free, and it shouldn't be attempted by the young, the
: foolish, the undercapitalized... nor by the cock-sure.
Undercapitalized? Hardly. There are many formulations that don't need
vaccuum degassing or other specialized tools. All composites require
care in handling and an appreciation for the hazards involved, but
making A-sized composites requires only a safe workplace, wood, plastic or
paper mixing tools and casings and the wisdom to follow safe procedures.
Trouble happens when people foolishly start to ignore safe procedures. If
you can safely shoot muzzle-loading arms- and here we're talking about
ramming black powder- you can safely make composite engines using similar
volumes of much less sensitive propellants.
--mike
: -Larry (who fails on two of four counts, and knows it) Curcio
C. D. Tavares
> > Fine, Mike. If you think it takes bovine stupidity to make a serious mistake
> > using accepted propellant compositions, I suggest you read the editor's
> > column in the latest HPR.
> I'm sure everybody on this newsgroup knows the risks.
I'm even less sure now than I was five minutes ago, and I didn't really
believe it then, either.
> If the human race never took any risks we would have been extinct
> long ago.
One could make the same claim about unnecessary or foolish risks, too.
--
c...@rocket.sw.stratus.com --If you presume that I speak for my company,
http://users.aol.com/Tavares/ write today for my special Investors' Packet!