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Model Forum / General / Rockets / January 2006



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historical detective story:Uni-Jet

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shockwaveriderz - 26 Jan 2006 23:33 GMT
Back in 1964-1965 a company by the name of Uni-Jet made some 13mm x 57mm
solid propellant motors. These were 1/2A2-x size motors.

Here's what G.Harry Stine had to say about them:

"George Molson used a very different and highly unusual solid propellant,
and
the reliability of his Un-Jet engines suffered as a result. The thrust time
curve was dependent upon the number of days that had elapsed since the
engine had been made. At a certain time after manufacture, the thrust-time
spike at ignition became extremely high...and the nozzle left the party.
Sometimes the paper casing ended up looking like a peeled banana. "

If you would like to see some pics , please go here and scroll to the
bottom:

http://www.jdwindsor.net/rocketry/html/misc.htm

You will notice that the casing states not to burn or incinerate and also
has the standard "soak in water" to destroy.....

I am not a pyrotechnician/motor maker and thats why I am asking the question
here as I
know there are a number of very knowledgeable people here.  Based upon the
above description, are there any clues to what the propellant mixture might
have be?

thanks in advance

shockie B)
Jerry Irvine - 27 Jan 2006 02:03 GMT
> Back in 1964-1965 a company by the name of Uni-Jet made some 13mm x 57mm
> solid propellant motors. These were 1/2A2-x size motors.
[quoted text clipped - 26 lines]
>
> shockie B)

Likely BP.

Signature

Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to:01rocket@gte.net>
Please bring GROWTH back to consumer rocketry.
Produce then publish.  http://www.usrockets.com

shockwaveriderz - 27 Jan 2006 17:59 GMT
jerry: does the description give any idication as to what was causing the
described results after a period of time?  Could/would  it have been some
hygroscopic effect?

As over time lets say the propellant absorbed mositure....would that account
for the described catos?

Perhaps he was not applying enough pressure to packing the BP in the
casings, and then with mositure the propellant became unattached from the
casing?

could it be a formulation problem? what is meant by highly unusal and
different ? instead of the 3 basic ingredients of BP, perhaps he used
potassium percholrate?  or ammoinium nitrate or sodium nitrate instead of
potassium nitrate?

just wondering

shockie B)

>> Back in 1964-1965 a company by the name of Uni-Jet made some 13mm x 57mm
>> solid propellant motors. These were 1/2A2-x size motors.
[quoted text clipped - 33 lines]
>
> Likely BP.
Jerry Irvine - 30 Jan 2006 13:22 GMT
> jerry: does the description give any idication as to what was causing the
> described results after a period of time?  Could/would  it have been some
> hygroscopic effect?

The BP curing over time made the propellant "better" and for a moment
the nozzle was the right size. But when cured the nozzle is too small.
Do not fire them. Tell the manufacturer (using a time machine) to
increase the nozzle size.

Note that both the Estes D13 and E10 suffered the same fate. We now have
the D12 and the E9.

Tech Jerry

Tell Estes to caugh up the E40!

> As over time lets say the propellant absorbed mositure....would that account
> for the described catos?
[quoted text clipped - 49 lines]
> >
> > Likely BP.

Signature

Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to:01rocket@gte.net>
Please bring GROWTH back to consumer rocketry.
Produce then publish.  http://www.usrockets.com

Fred Shecter - 30 Jan 2006 15:38 GMT
Estes never had an E10.

It was an E15. And it had a very teeny nozzle.

-Fred Shecter
http://search.ebay.com/_W0QQfgtpZ1QQfrppZ25QQfsooZ1QQfsopZ1QQsassZshreadvector

Signature

"""Remove "zorch" from address (2 places) to reply.

>
>> jerry: does the description give any idication as to what was causing the
[quoted text clipped - 66 lines]
>> >
>> > Likely BP.
Jerry Irvine - 30 Jan 2006 16:17 GMT
> Estes never had an E10.
>
> It was an E15. And it had a very teeny nozzle.

Correct. Please pardon my error.

Tech Jerry

> -Fred Shecter
> http://search.ebay.com/_W0QQfgtpZ1QQfrppZ25QQfsooZ1QQfsopZ1QQsassZshreadvector
[quoted text clipped - 73 lines]
> >> >
> >> > Likely BP.

Signature

Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to:01rocket@gte.net>
Please bring GROWTH back to consumer rocketry.
Produce then publish.  http://www.usrockets.com

Tater Schuld - 30 Jan 2006 17:20 GMT
>> Estes never had an E10.
>>
[quoted text clipped - 3 lines]
>
> Tech Jerry

careful Jerry, some people might think you've gone soft  :)
shockwaveriderz - 30 Jan 2006 22:21 GMT
jerry:

thanks... I wonder if these engines had formed combustion chambers as do all
other BP rocket engines?  would the dimensions of this change as the
propellant cured?  Since these engines were made in Albany, NY if these were
allowed to air cure over time , the temperatures and humidities probably
varied widely? Anybody ever seen a thrust time curve of these engines? I
assume they were end burners with the characteristic thrust spike ?

shockie B)

shockie B)

>> jerry: does the description give any idication as to what was causing the
>> described results after a period of time?  Could/would  it have been some
[quoted text clipped - 70 lines]
>> >
>> > Likely BP.
Jerry Irvine - 30 Jan 2006 23:32 GMT
> jerry:
>
> thanks... I wonder if these engines had formed combustion chambers as do all
> other BP rocket engines?  would the dimensions of this change as the
> propellant cured?  

Not much.

Tech Jerry

Signature

Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to:01rocket@gte.net>
Please bring GROWTH back to consumer rocketry.
Produce then publish.  http://www.usrockets.com

Bob Kaplow - 27 Jan 2006 02:16 GMT
> Back in 1964-1965 a company by the name of Uni-Jet made some 13mm x 57mm
> solid propellant motors. These were 1/2A2-x size motors.

FYI, I have an assortment of these in my collection. I got them at a NARAM
auction, and my guess is they came from Harry...

Signature

 Bob Kaplow   NAR # 18L   >>> To reply, there's no internet on Mars (yet)! <<<
Kaplow Klips & Baffle:    http://nira-rocketry.org/Document/MayJun00.pdf
   www.encompasserve.org/~kaplow_r/    www.nira-rocketry.org    www.nar.org

       You [should] not examine legislation in the light of the
       benefits it will convey if properly administered, but in the
       light of the wrongs it would do and the harm it would cause if
       improperly administered -- Lyndon Johnson, former President of
       the U.S.

 
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