Aerotech J350 RMS EZ Failure

IIRC the one I mentioned earlier about the BSD Thor was an undrilled delay.

Seems not to be a problem from user.

I also had a I357T EZ failure last October. I've built dozens of 38/360 motors without a problem, but my first (and last) EZ reload cost me a RW Lil'Rascal & recovery hardware. I got a new case and forward closure for my trouble, but the remains of the rocket remain in my garage. I will never fly an EZ again.

Were the EZ reloads 'grandfathered' into certification, or was each EZ reload TMT/CAR tested before a new certification granted?

So, without an on site dealer with delay assembly parts, what is the best way to prevent these failures till this get sorted out? Would the end burner style forward closure be the best way to approach it?

That's one way, and what I do, you lose tracking smoke if you do that, another way is to plug the ez unit with epoxy, since the failure seems to be burn by of the delay element..or order delay element parts ahead of time and use the normal closure or the standard plugged closure.

Frank

...Loki looks better and better to me day after day. I've been a staunch AT supporter for years but not so much anymore. I don't need to destroy my rockets through faulty design...

Viperfixr said:

Were the EZ reloads 'grandfathered' into certification, or was each EZ reload TMT/CAR tested before a new certification granted?

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TMT sent Aerotech a letter granting certification to the 38mm RMS EZ closure in any 38mm reload. It does not describe what tests they performed.

NFPA 1125 requires testing of a minimum of three motors if they have user adjustable delays. One at maximum, one at minimum, and one at an intermediate time. There is no evidence available indicating that this testing was ever performed for the RMS-EZ configuration in any motor.

I should also note that in spite of my making a fuss about it last year the RMS-EZ reloads have not yet appeared in the NAR combined list. While you will find "J350W-S,M,L" (in two core sizes) you will not find a "J350W-14A".

UhClem said:

TMT sent Aerotech a letter granting certification to the 38mm RMS EZ closure in any 38mm reload. It does not describe what tests they performed.

NFPA 1125 requires testing of a minimum of three motors if they have user adjustable delays. One at maximum, one at minimum, and one at an intermediate time. There is no evidence available indicating that this testing was ever performed for the RMS-EZ configuration in any motor.

I should also note that in spite of my making a fuss about it last year the RMS-EZ reloads have not yet appeared in the NAR combined list. While you will find "J350W-S,M,L" (in two core sizes) you will not find a "J350W-14A".

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Are the delay grains the same for both the EZ and the regular RMS, if so its the forward closure that changed and from the sounds of it that would not require re-testing...or not (speculation totally on my part)

terryg said:

So, without an on site dealer with delay assembly parts, what is the best way to prevent these failures till this get sorted out? Would the end burner style forward closure be the best way to approach it?

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Abstinence is the only 100% effective method… :duck:

I would guess someone from AT will be at LDRS in 2 days. Flyers need to ask them questions.

Big thanks to Aerotech and Karl Baumann. They replaced the J350 and sent the new "Complete Reload Delay Kit."

I don't understand why AT is sending out the delay kits. Are they saying they know the EZ systems has big problems and will top making them? That is the way it looks to me.

crossfire said:

I don't understand why AT is sending out the delay kits. Are they saying they know the EZ systems has big problems and will top making them? That is the way it looks to me.

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They are sending all "new" reloads with original RMS+ delays and with the EZ bulkhead delays because lots of us wish to assemble our own delays and use our aluminum forward closures. Meanwhile for those that just have the EZ loads we also have the option now to get a CRDK so we can make up our delays. Also the CRDK kits can be had to replace short and medium delays in our older reloads we have, to have a long delay. CRDK's are long delay.

I had a I357T burn thru the delay immediately on lift off at 2015 NXRS. No damage to the two stage rocket but, I'll not be using using their provided forward delays closures again any on my DD flights... will be using 38 mm end burner plugged threaded forward closures instead. This is the first time I've had an issue after in about 8 flights with I357Ts in the new configuration. I like the performance of the I357T but don't want to risk another flight.

I also saw a J350 claim another victim. A seasoned flyer and regular user of AT motors had one eject during or right at the end of the burn.
I spoke to him and it was a backup to his DD. That was at NOVAAR's demo at the July 4th celebration just before the fireworks. That was additional pyrotechnics show no one wanted to see.

This is one reason I wanted the RMS+ back. These issues are limited to nonexistent with plugged closures. Only standard catos to worry about then.

Not sure if you guys saw this. It was posted on the AT open thread and on their website:

7/13/2015
RMS-EZ Notice
Dear Dealers and Customers,

This notice is to inform you of a potential issue with the recently released AeroTech 38mm "RMS-EZ" reload kits with the modular forward bulkheads. We have been made aware of a small number of early ejection events occurring while using these kits. These incidents do not appear to be tied to any particular lot number(s) but instead seem to be related to the temperature cycling of a particular batch of adhesive used to bond the delay element into the modular forward bulkhead. We were able to duplicate the problem at our facility by repeatedly temperature cycling certain RMS-EZ reload kits over a period of several days.

RCS/AeroTech is actively researching the delay adhesive issue, but until a solution is found we request that flyers and dealers use one of the recently-released RMS-Plus "Complete Reload Delay Kits” (CRDKs) instead of the modular bulkhead supplied with the RMS-EZ kit. The CRDKs are being distributed free of charge to all RCS/AeroTech customers and can be installed in standard legacy 38mm RMS forward closures. The time delay of each CRDK can be adjusted using the AeroTech RMS Delay Drilling Tool (RDDT). All the CRDKs are supplied in the longest delay time available for the particular intended motor configuration.

Also, RCS will begin shipping the RMS-EZ kits in the RMS-Plus configuration with the same shipping tube, but clearly marked as “RMS-Plus” reloads. When RMS-EZ reload kit shipments resume, they will also include a matching CRDK so that consumers will have the option of using either delay charge solution for their rockets.

Dealers are asked to inventory their stock and advise us of the number of CRDKs they will need to retrofit RMS-EZ reload kits covered by this notice. Additionally, customers possessing any RMS-EZ reload kits are asked first to contact their respective dealer to obtain the CRDKs, if that is not convenient then they can contact RCS directly.

We apologize for any inconvenience this may have caused for our dealers and their customers, and we thank you for your continued support.

Best regards,

Karl Baumann
Vice President
RCS RMC, Inc.

rcktnut said:

The RMS-EZ claims yet another rocket. Hoping your rocket was not damaged too much.

RMS-EZ - makes flying more exciting, do you have a bad one or not?

RMS-EZ - eliminates user error in assembly of the delay components - we do that for you.

RMS-EZ- saves you 2-3 minutes assembly of the delay components - so you can spend hours on repairing your rocket, if repairable.

RMS-EZ - replaces the boring, reliable, RMS+

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I agree. I have only flown one I-211 and it destroyed my L1 rocket (not a cert flight one of a dozen flights on the I-211 since cert at LDRS 30) because of deployment at motor burnout. I didn't report it to AeroTech I probably should have. I still have all the parts and pictures. Anyway I won't fly another RMS-EZ motor not worth it to save a few minutes for something that has never been a problem for me. The delay assy couldn't be easier to me. That said I have never flown a CTI or Loki motor either so I can't compare to them. I loved the I-211 it was a cool flight to about 1500 ft and the medium delay was perfect. Never had to worry about deployment or anything with the rocket. NOT the case anymore. AeroTech bring back the standard RMS. If it ain't broke don't fix it!!!!! I'll get of my soapbox. Return to your regular scheduled programming. :madnote:

I am kind of puzzled by the cause of these failures. In the standard RMS+ configuration the delay grain is pressed into the delay O ring and front seal gasket (against the front of the closure). In the EZ setup is the glue the only thing holding the delay grain in place (i.e. is there now no front wall of the closure for the O ring to seal against)?

terryg said:

I am kind of puzzled by the cause of these failures. In the standard RMS+ configuration the delay grain is pressed into the delay O ring and front seal gasket (against the front of the closure). In the EZ setup is the glue the only thing holding the delay grain in place (i.e. is there now no front wall of the closure for the O ring to seal against)?

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Looking at the AT instructions, looks like they are just "gluing" a delay grain in the bulkhead for the EZ's. Evidently the glue alone is not up to its job of preventing blow by. I would think that if they would design the bulkhead and use the same components as the RMS+ in them, it would work. They could assemble the delay components at their plant into the bulkhead by friction fit or put a piece of tape over the end to hold the components in place until motor assembly. Assembly this way without fooling with "glue" would be easier for them I think.
https://www.aerotech-rocketry.com/u...076209_RMS-38_120-360 2-Page Inst 6-27-13.pdf

In some of my previous posts you can see that I was very much against being forced into using the EZ system especially after seeing so many failures. I would agree with what some others have already said, just drop the idea altogether. I will never use them, but if they can get the problem with them solved, so be it. As long as we have a choice of EZ or RMS + I will be very happy.