I *think* one of the historical reasons folks suggest loosening the
closures is for Aerotech motors with paper liners. Compressing the o-ring
in Aerotech motors requires that the liner be compressed as well, and the
concern is that the cardboard may slowly deform, leaving the o-ring
effectively floating and not sealing. This would mostly be a concern on the
hobbyline motors that do not have a full grain stack. It's not a concern on
phenolic liner Aerotech motors or motors that seal by putting the o-ring
between a closure and the case (CTI, any snap ring hardware, etc).
-Andrew
On Mon, Apr 5, 2021 at 10:31 AM Jason Muckenthaler <
dmarc-noreply@xxxxxxxxxxxxx> wrote:
Thanks Richard - i appreciate all of the feedback. “Just give you the
motors...” that was good!
Sent from my iPhone
On Apr 5, 2021, at 10:28 AM, richard dierking <applerocketry@xxxxxxxxxxx>
wrote:
So, I bet you could loosen the threads (not now of course) or keep the
threads tight when you can’t use a motor. To be safe, I think you should
give me the motors Jason and I’ll test them for you.
Sorry, just kidding and looks like there is yet another controversy that
will probably never die. :-)
But, I’m curious, what would AT say?
Richard
On Apr 4, 2021, at 10:26 AM, Kurt Gugisberg <kurtgug@xxxxxxxxx> wrote:
I agree with Rick. I've not released pressure on the O rings for motors
that sat for a year under compression. No failures. Put the cap on the
end of the nozzle and you have a sealed system that keeps out moisture. No
problem.
Kurt
On Sun, Apr 4, 2021 at 10:22 AM Rick D. <rocketrick@xxxxxxxxx> wrote:
Ron,
I respectfully disagree. O-ring seals are designed to remain under
compression indefinitely. Loosening and re-tightening them is a recipe for
disaster, as those are the moments where the O-ring has a chance to get
damaged.
Just sitting there forever under compression is what they are designed to
do. Let them do it.
Cheers,
Rick Dickinson
On Sun, Apr 4, 2021, 9:07 AM Ron McGough <rrmagoo7@xxxxxxxxxxx> wrote:
There is one thing that wasn’t mentioned concerning this post. If a
flier is unable to fly due to current weather or the latest (and longest
issue) pandemic closure and said flyer has assembled reloadable motors that
can’t be used it is always wise to loosen the closures just a bit to remove
compression from the orings. Just be sure to retighten them when you’re
actually ready to fly them.
Ron McGough
Sent from Mail
<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgo.microsoft.com%2Ffwlink%2F%3FLinkId%3D550986&data=04%7C01%7C%7Ca31d0e8bd7204bd0f04408d8f78edd45%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637531540264503926%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=I3lPvrWiUevMjkiSK2dut%2B8ewBrrux9ozFPmnSPdxz8%3D&reserved=0>
for Windows 10
*From: *Jason Muckenthaler <dmarc-noreply@xxxxxxxxxxxxx>
*Sent: *Saturday, April 3, 2021 3:58 PM
*To: *roc-chat@xxxxxxxxxxxxx
*Subject: *[roc-chat] Re: AT Motor Loaded pre-COVID
That all sounds prudent - I left my motors in a cool, dark place in the
garage cabinets.
On Apr 3, 2021, at 3:44 PM, DAVID ROBB <robbdm@xxxxxxxxxxx> wrote:
Last year, I attended a large March launch that was impacted bywind. I was not able to launch two Aerotech K456DM, two J800T, one J460T,
three G138T, J350W and one L1040M. When I returned home, I disassembled,
placed all the gains in freezer bags and sealed away for another day. I
was concern about the ability of white lightening and blue thunder to
quickly ignite since they are used in two stages and air starts. Another
launch came up in October. I assemble as normal (regressed) and flew
without a problem.
Good luck.
==================
David M. Robb
dmarc-noreply@xxxxxxxxxxxxx> wrote:On 04/03/2021 12:32 PM Jason Muckenthaler <
one is a K and the other is an L. Now that we have a launch opportunity,I have had a few 75mm Aerotech motors loaded since January of 2020 -
I’m curious if these motors are safe to launch. I plan to open the motors
and re-grease the O-rings - do folks have any experience with motors packed
for a long time prior to launch?
Thanks,
Jason
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