Composite paraffin rocket?

[r***@gmail.com]

Anybody done any experiments with paraffin fuel and a solid oxidizer?

I have an inexpensive source for potassium nitrate (wish I could find
an inexpensive source for other oxidizers, ammonium perchlorate, ...),
and was thinking about making some composite paraffin motors.
Seems like it should work fine.

If you've built/tested some paraffin motors, please post
results/pictures/...

Thanks!

[Dave Grayvis]

Post by r***@gmail.com
Anybody done any experiments with paraffin fuel and a solid oxidizer?
I have an inexpensive source for potassium nitrate (wish I could find
an inexpensive source for other oxidizers, ammonium perchlorate, ...),
and was thinking about making some composite paraffin motors.
Seems like it should work fine.
If you've built/tested some paraffin motors, please post
results/pictures/...
Thanks!

I'm curious, what's the melting point of your paraffin?

[jj]

It would crack and your rocket would explode.

[Lloyd E. Sponenburgh]

Post by jj
It would crack and your rocket would explode.

I believe it would not. Most paraffin waxes have a bit of oil present as a
plasticizer. Unless the motor were quite cold, or the solids loading quite
high, the charge should show some elasticity. Asphaltum motors are quite
reliable, if low on impulse.

I'd be much more concerned with the transparency of paraffin allowing IR
from the flame to penetrate and subsequently to melt the charge ahead of the
flame front. It might be necessary to add an opacifier like carbon black to
prevent that.

LLoyd

[Dave Grayvis]

Post by Lloyd E. Sponenburgh

Post by jj
It would crack and your rocket would explode.

I believe it would not. Most paraffin waxes have a bit of oil present as a
plasticizer. Unless the motor were quite cold, or the solids loading quite
high, the charge should show some elasticity. Asphaltum motors are quite
reliable, if low on impulse.
I'd be much more concerned with the transparency of paraffin allowing IR
from the flame to penetrate and subsequently to melt the charge ahead of the
flame front. It might be necessary to add an opacifier like carbon black to
prevent that.
LLoyd

That would be My concern also.

[r***@gmail.com]

Post by Lloyd E. Sponenburgh
I'd be much more concerned with the transparency of paraffin allowing IR
from the flame to penetrate and subsequently to melt the charge ahead of the
flame front. It might be necessary to add an opacifier like carbon black to
prevent that.

I'm not sure of the melting point of the parrafin, but I will try to
investigate. Need to pick up some thermometers. The paraffin I have
readily available is just store bought paraffin wax from Safeway or
Orchard Supply. Comes in 1 pound boxes.

Good point about the opacity.
Carbon black is easy enough to add to the mix.
Looking at this image presumably of the Stanford/NASA Ames paraffin
fuel grain, it doesn't look particularly dark/opaque (it is opaque, but
looks like mostly due to the thickness of it):
http://www.sciencenews.org/articles/20030322/bob9.asp

Any idea on the ratio of oxidizer to fuel to use as a starting point?
65/35 -ish?

Could also do paraffin/sucrose/carbon/KNO3 mix or other compositions.

Thanks!

PS- Anybody here have a CNC lathe that is willing to turn a few
nozzles?

[m***@hotmail.com]

For what its worth: I made 6 pound whistle rockets about 8 or 10 years
ago and used fully refined paraffin (before I found out about
vaseline). They all blew up. I then changed catalysts from red IO to
rutile (for sound and IR opacity) and had fewer blow up. Then I tried
adding 3% graphite powder and had none blow up. They smoked REALLY bad,
which was kind of a nice effect. When I switched to vaseline,
everything was faster, easier, and far cheaper. The vaseline rockets
carried twice the payload. I never dialed in the wax rockets, but feel
that there is much research needed to fully realize their potential.

Regina

[r***@gmail.com]

Vaseline/petroleum jelly mixture/formulations please...

[Lex]

Post by r***@gmail.com

Post by Lloyd E. Sponenburgh
I'd be much more concerned with the transparency of paraffin allowing IR
from the flame to penetrate and subsequently to melt the charge ahead of the
flame front. It might be necessary to add an opacifier like carbon black to
prevent that.

I'm not sure of the melting point of the parrafin, but I will try to
investigate. Need to pick up some thermometers. The paraffin I have
readily available is just store bought paraffin wax from Safeway or
Orchard Supply. Comes in 1 pound boxes.
Good point about the opacity.
Carbon black is easy enough to add to the mix.
Looking at this image presumably of the Stanford/NASA Ames paraffin
fuel grain, it doesn't look particularly dark/opaque (it is opaque, but
http://www.sciencenews.org/articles/20030322/bob9.asp
Any idea on the ratio of oxidizer to fuel to use as a starting point?
65/35 -ish?
Could also do paraffin/sucrose/carbon/KNO3 mix or other compositions.
Thanks!
PS- Anybody here have a CNC lathe that is willing to turn a few
nozzles?

The carbon black is in there though, as you can see in this quote from the
article.

"The wax that the Stanford scientists chose isn't exactly dinner-table
candle wax, but it's pretty close. It includes a small amount of carbon
black, a fine soot, to block radiation from heating and softening the
inside of the material."
*** Free account sponsored by SecureIX.com ***
*** Encrypt your Internet usage with a free VPN account from http://www.SecureIX.com ***

[rapana]

Hi .I have a PDF for parrafin .If you have ,i send .Sorry for my bad
english :)
Write on my e-mail : ***@gmail.com .
And oxigen/fuel ratio for hybrids is in border : 4:1 (ideal) 5:1 6:1 .

[John Reilly]

I never tried paraffin but tried the GALCIT 61-C asphalt fuel with
KCLO4 with a very rudimentary nozzle many years ago. I tried it simply
because it sounded so simple to make and cast. This was used in the
early 1940s on JATO (jet assisted take off) units for the navy carrier
planes as I recall. If you Google up "GALCIT" (Guggenheim Aeronautical
Laboratory California Institute of Technology, you'll find a lot of
info on the early solid composite fuels and why they settled on
polysulfide rubber (Thiokol) with ammonium rather than potassium
perchlorate. The formula for the Caltetec #61-C is KCLO3 76%, Fuel
24%.. The "fuel" is a mix of 70% n 18 degree asphalt mixed and melted
with 30% SAE 10 weight oil. I used a waer bath to melt the fuel and
mix in the perchlorate. Yep! The rocket motor blew up on static
firing the first and last I tried. A note to the unwise kiddos: if you
make this stuff, and it catches fire, you have the equivalent of a
sticky NAPALM to try to get off your skin. And yes, the boys at Caltec
tried NAPALM with perchlorate as well.

John

[John Reilly]

Whoops, that was KCLO4 not KCLO3!

John

[h***@yahoo.com]

"DANGER , WILL ROBINSON!" (Remember that classic line?)

It strikes me that some of the formulations mentioned so far in this
thread have a frightening similarity to compositions that Tenney Davis
speaks of on pages 360-366 of his classic text. Cheddite 60B in
particular, has a detonation velocity estimated at 2774-2843
meters/second when encased in paper, or about 1/2 that of solid TNT.

Some rocketry enthusiast are aware of this fact, while others are not.
Anyone experimenting with composite oxidizer/hrdrocarbon mixtures
should be aware of the high explosive risk associated with such
propellents, since the possibility of unexpected detonation is a very
real hazard.

For obvious reasons I have not posted the components of the more common
Cheddite compositions, but some closely approximate compositions
already discussed in this thread. For anyone experimenting with such
mixtures, a close reading of Davis is both a required and reasonable
exercise in safety, since a high order detonation "would be bad" (see
"Ghostbusters" for an explanation of precisely what "would be bad"
signifies).

Stay safe, and kindest regards. Harry C.

[Mike Swisher]

John -

Have you (or anyone else here) a copy of the 1937 paper by J. W. Parsons
(inventor of the JATO) surveying various solid-fuel combinations? It was
classified for many years but is supposed to be in the open literature now. I
don't think it was ever published.

The two biographies of Parsons in print are next to worthless with regard to his
accomplishments in military pyrotechnics and aerospace - they're more concerned
with the sensational stuff surrounding Parsons's many amours, his involvement
with the occult, and how L. Ron Hubbard snookered him out of his money and ran
off with his mistress (all this before founding Scientology!).




In article <***@o13g2000cwo.googlegroups.com>, John Reilly
says...

Post by John Reilly
I never tried paraffin but tried the GALCIT 61-C asphalt fuel with
KCLO4 with a very rudimentary nozzle many years ago. I tried it simply
because it sounded so simple to make and cast. This was used in the
early 1940s on JATO (jet assisted take off) units for the navy carrier
planes as I recall. If you Google up "GALCIT" (Guggenheim Aeronautical
Laboratory California Institute of Technology, you'll find a lot of
info on the early solid composite fuels and why they settled on
polysulfide rubber (Thiokol) with ammonium rather than potassium
perchlorate. The formula for the Caltetec #61-C is KCLO3 76%, Fuel
24%.. The "fuel" is a mix of 70% n 18 degree asphalt mixed and melted
with 30% SAE 10 weight oil. I used a waer bath to melt the fuel and
mix in the perchlorate. Yep! The rocket motor blew up on static
firing the first and last I tried. A note to the unwise kiddos: if you
make this stuff, and it catches fire, you have the equivalent of a
sticky NAPALM to try to get off your skin. And yes, the boys at Caltec
tried NAPALM with perchlorate as well.
John

[John Reilly]

No, I wasn't aware of it nor do I know anything about him (Parsons). I
will dig around though, now that you've mentioned it. Sounds very
interesting and that time (late 30s early 40s) are interesting as there
was such a race of rocket and weapons technology going on with the war
in Europe. The fact that old L. Ron "snookered" him is amusing but not
surprising for THAT snake! The Church of Scientology! Why couldn't
I have thought of a great racket like that?

P.T Barnum (S.J.)

[Rick]

Didn't the Mythbusters use paraffin and carbon black in their hybrid
Confederate rocket? It didn't go very far, but it made a hell of a
ruckus getting there! Lots of noise and smoke!

Post by r***@gmail.com
Anybody done any experiments with paraffin fuel and a solid oxidizer?
I have an inexpensive source for potassium nitrate (wish I could find
an inexpensive source for other oxidizers, ammonium perchlorate, ...),
and was thinking about making some composite paraffin motors.
Seems like it should work fine.
If you've built/tested some paraffin motors, please post
results/pictures/...
Thanks!

[Bill Westfield]

I don't believe that a mixture of paraffin and KNO3 actually burns, in any
ratio. Exotic (or not so exoitic) additives and catalysts may help, but
it would probably take a lot of work to find out.

BillW