I loaded an Aerotech HP motor at Dairy Aire but did not get a chance to
launch it. Can I leave it loaded with no igniter for several (say 7)
months. Or, should I take it apart and clean all the grease off? If I leave
it assembled will the orings take a set and not seal at flight time? Will
the teflon grease I used soak into the liner or propellant causing a
problem? I don't have experience with this as of yet. Your help is
I don't think you need to completely unload it. Just back off on the
closures to relieve the pressure on the o-rings, and put it in a ziplock
bag. When you are ready to use it, don't forget to tighten the closures!
Note to this and the other responses:
Do **NOT** back off the closures on the motor if the ejection charge has
been loaded in the motor. Backing off on the closure and then retightening
with BP already on board will result in the BP grains contaminating the
o-ring seal. The results will NOT be pretty.
And it doesn't matter at all which end you back off: unscrewing the nozzle
end still uncompresses the delay / ejection O-ring and contaminates the
If you have NOT installed the BP, then you can do this.
There is anecdotal evidence that a delay of months, or even a year is not a
problem. But I wouldn't recommend anything that long. IIRC the original
poster said 7 months, so I'd disassemble everything, seal the cumbustible
stuff in an airtight ziploc, and clean the grease and BP off the O-rings.
Bob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<<
Kaplow Klips & Baffle: http://nira-rocketry.org/Document/MayJun00.pdf
Good point, Bob. If there is BP in there, backing off the closures
would be a bad thing.
So, Caneman (I know who you are!), bring that motor to me. I'll see
to it that it gets burned in a timely manner... 8^)
James, is that you? You could add the motor to your pile of HP motors so we
are even safer from stray rockets because the pile of motors to hide behind
is taller! Joking aside, I had not put the BP charge in because I did not
want it spilling all over if the paper cap came off. So I was ok with
either backing of the closures or dissasembling and cleaning grease of the
liner. I did the latter.
Thanks for the help!
From the FAQ under "Help" at the http://www.aerotech-rocketry.com/ site
compression set of the delay element. If it is necessary to store the motor
before a launch, loosen the aft closure slightly (about one turn) to reduce the
pre-loading of the delay o-rings.
Take a look at the warranty and you'll note:
before flight ...
Yes and no. Depends on the reload and the liner.
If your reload uses a paper liner, pull it apart. Some H reloads from
Aerotech use a paper liner. The grease will soak the liner over time and
when you fire it, it will burn through and trash your casing and/or your
rocket. If your reload is AT and uses the black phenolic liner, they seem
to be alright to leave loaded. Back off the ends so there is no pressure on
the o-rings. I would also take out the delay element just as a precaution.
The slight amount of grease you applied to the forward rubber washer might
soak into the delay causing problems. Make sure to label it in a zip lock
so you know what it is when you go to use it. :)
Many people have suggested greasing the ID of the casing to make it easier
to remove the spent liner and cleaning the casing becomes a snap. I have
tried it with the last few launches and it works great. That is why there
is grease on the liner.
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