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Aerotech 54mm liner issue
#1
I'm cross posting this from Rocketry Planet.  I don't know if anyone has a new reload of any of the motors mentioned here or not.  Actually, does anyone even fly AT in our club anymore besides me?! :-) 

Quote:Dear AeroTech High Power Product Representative:

AeroTech has become aware of a possible issue that may affect the
reliability of the following 54mm high-power RMS reload kits:

54/1706 K805G-P, 54/2560 K700W-P, 54/2560 K1275R-P

During a recent launch there was an observed case failure of two motors
loaded with AeroTech K700W-P reload kits. These motors used the new
composite paper/Mylar liner. The failure involved a burn-through of the
liner that eventually caused a case rupture during the motor burn. The
motors were flown in a large cluster and used an aggressive ignition method
involving Pyrodex pellets and possibly other elements that may have
contributed to the failures.

While these liners have been static tested and previously flown with no
issues, and there is no direct evidence that the liner was the sole basis of
said failure, we are taking preventative measures to attempt to eliminate
future problems and concerns using these reload kits. Effective immediately
the K805G-P, K700W-P and K1275R-P reload kits will be supplied with phenolic
liners, until and if we can determine that the failures were caused by other
extenuating circumstances such as the aggressive ignition method.

We are requesting that all dealers check their inventory and provide
AeroTech with a list of stock quantities of the above mentioned reload kits
above so we can send replacement phenolic liners.

In addition, we would like to provide you with extra phenolic liners for any
of the above mentioned reload kits that you have sold recently with the
composite liners, but that have not yet been flown, so that they can be
provided to your customers.

Please email your list to our customer service representative at
customerservice@aerotech-rocketry.com. Or you are welcome to call
435-865-7100 Ext. 104 for assistance.

AeroTech appreciates your patience and understanding as we work to resolve
this issue.

Sincerely,

Diane Carlson; Director of Customer Service
Cc: Gary Rosenfield; President
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#2
Nat,
Thanks for posting this.  Yeah, I still fly AT (until CTI gets cheaper) and my liners are the old style, but I only need to worry about this if I actually fly a rocket...
Jeff
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#3
(05-27-2011, 10:00 AM)Jeff Taylor link Wrote:Nat,
Thanks for posting this.  Yeah, I still fly AT (until CTI gets cheaper) and my liners are the old style, but I only need to worry about this if I actually fly a rocket...
Jeff
Yeah, thanks Nat.  Jeff.  Point well taken...IF you fly a rocket.  Tongue
Jim Goggins NAR  L3
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#4
This is bs the liner can't be the problem, it is a bad mix and they won't fess up to it. By the time the flame gets to the liner the motor should be burned out!!!!
Bill Clune L2 | NAR#88583
MARS Club|SRC|METRA|MDRA - Forever
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#5
Bates grains burn on their ends too.  The liner sees fire in those cracks which get larger as the burn progresses.

Bates design keeps the burn fairly neutral because it shrinks the core from the ends while the core is expanding.

N
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#6
i have burned 38mm 6 grain motors without liners, right in the case. it is not the liners!!
Bill Clune L2 | NAR#88583
MARS Club|SRC|METRA|MDRA - Forever
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#7
(05-31-2011, 09:35 PM)Bill Clune link Wrote:i have burned 38mm 6 grain motors without liners, right in the case. it is not the liners!!
Are you supposed to do that? 
Jim Goggins NAR  L3
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#8
It is research the answer is only if your an IDIOT, but i wanted to see if it could handle not having a liner. it did but i think it is the reason LOKI anodized there cases blue!! ;D
Bill Clune L2 | NAR#88583
MARS Club|SRC|METRA|MDRA - Forever
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#9
Does the blue color resist the onslaught of idiot?  ;D

Er, I mean, the heat and fire....

Did you cast into cut pieces of liner, or were the grains REALLY rattling around loose in there?

N
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#10
Bill's loads only burn for 0.3s, liner probably not needed or noticed.  Try a moonburner without a liner and see what happens.
John Derimiggio
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