Aerotech J350 RMS EZ Failure

[seth_cooper]

Had a premature ejection today with an Aerotech J350. Ejection charge fired immediately after motor burn out. I took pictures as the motor was disassembled. I'm going to upload a video of the flight to YouTube.

 

[rharshberger]

Make sure and contact Aerotech if you have not already. Not sure about a MESS report on this but if so thats done at: https://www.motorcato.org/

 

[seth_cooper]

Make sure and contact Aerotech if you have not already. Not sure about a MESS report on this but if so thats done at: https://www.motorcato.org/

Contacted Aerotech and filed a MESS report before posting.

I forgot to mention, I didn't adjust the delay time on this motor. I was using a dual deploy altimeter and left the motor delay long as a back up.

 

[seth_cooper]

https://youtu.be/1R1fxekC-w0

That's my wife saying "No, no, no" at the end.

 

[rcktnut]

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+

 

[seth_cooper]

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

Aft section was damaged beyond repair. It landed horizontally between 2 fins, body tube now has a slight oval shape! Drogue chute was stripped. E-bay to nose cone was not damaged luckily.

The altimeter battery was "ejected" from the holder. Now I know why people use zip ties.

 

[crossfire]

Has there been a large amount of EZ failures? I haven't heard a while lot of problems. Is it possible the liner was crack before the flight?

 

[Donaldsrockets]

I think it was mentioned somewhere on here that a J570W EZ did the same thing.

When I flew HPR, I never had any trouble with the standard RMS+ motors I flew. I didn't mind assembling the delay assembly either. It wasn't that hard.

 

[bob jablonski]

38m EZ's have been out for around a year.

 

[rcktnut]

There have been lots of reports of RMS-EZ failures. They are scattered through out the propulsion threads. I'll try to get them together in this post. Will add as I have time to sift through them. Let them make the EZ's, but also continue the RMS + for those of us that want to use them. Here's one post, will add more to this post when I have time.

Quote by d-power: I recently flew an I284-14A RMS-EZ, drilled at the "-8" setting, which should have given a 6s delay +/- 1.5s. The delay burned through right at motor burnout, same failure mode as AstronMike. I've flown some DMS motors OK, but haven't needed the "-8" setting before. I checked this UDDT against my other UDDT, and they measure identical. Interestingly, I've never had such a total delay failure like this on old-style non-EZ aerotech motors, so wasn't concerned about motor reliability. Of course, this occurred on my most expensive, most complex build to date, which suffered significant damage.

 

[terryg]

They have already announced a "Complete Reload Delay Kit" (CRDK) on their facebook site. Do you have the lot number of the EZ reload that failed? I have a J350 EZ that I got at Wildman's black saturday sale. With the spacers glued in, I am not sure how these are failing.

 

[crossfire]

Did AT fix the problems with newer EZ reloads?

 

[rcktnut]

They have already announced a "Complete Reload Delay Kit" (CRDK) on their facebook site. Do you have the lot number of the EZ reload that failed? I have a J350 EZ that I got at Wildman's black saturday sale. With the spacers glued in, I am not sure how these are failing.

https://www.rocketryforum.com/showthread.php?70242-Titan-II/page2 Here is another failure, note post # 34. Pics. of failure on posts 39 & 40.

 

[UhClem]

With the spacers glued in, I am not sure how these are failing.

It is hard to tell from the pictures but there appears to be some erosion on the forward o-ring. If that is the case, then the failure is not in the delay element but in the case to closure seal. Which brings up the question:

How was the forward o-ring installed? Was it placed in the case as directed in the instructions or was it put onto the closure and then pushed into the case? The second method could result in part of the o-ring being shaved off.

 

[scsager]

[YOUTUBE]1R1fxekC-w0[/YOUTUBE]


Analysis of video @ 30 frames per second.

Frame 22 – Launcher says “one”.
Frame 53 – approximately one second later – we assume the launcher pushed the button.
Frame 60 - 1st smoke apparent beneath the rocket.
Frame 73 – first flame.
Frame 76 – no flame visible.
Frame 78 – large flame visible. Flight clock = 0 seconds
Frame 79 - 1st rocket motion.
Frame 132 – Calculated motor burnout – 1.8 seconds. Flight clock = 1.8 seconds

Frame 141 – Puff of smoke. Flight clock = 2.1 seconds. Noise spike on audio track.
Frame 142 – rocket noticeably separated. No drogue chute noticeable.
Nose section continues traveling upward, fincan section does not seem to climb much.

Frame 158 – shock cord fully extended. Flight clock = 2.6 seconds. Momentum of nose cone jerks fincan upward violently. At this point we might guess the altimeter battery was knocked out of the battery holder. Nose cone does not separate from payload/ebay. No chute.

Frame 187 – apparent apogee, (guestimate 800’) Fincan has traveled higher than nose section. Flight clock = 3.6 seconds.

Fincan trails nose section all the way to the ground. Falls for about 12.7 seconds.
Frame 569 – Nose section lands Flight clock = 16.3 seconds.

 

[rcktnut]

It is hard to tell from the pictures but there appears to be some erosion on the forward o-ring. If that is the case, then the failure is not in the delay element but in the case to closure seal. Which brings up the question:

How was the forward o-ring installed? Was it placed in the case as directed in the instructions or was it put onto the closure and then pushed into the case? The second method could result in part of the o-ring being shaved off.

If that o-ring was compromised in some way that would present a whole different set of problems. So far looks like all the problems are coming from/ through the delay grain.

 

[pnobile]

A little harsh aren't we about this? CTI also has numerous catoes and failures in their "pre-assembled" line of rocket motors ...people also mess up on reading instructions for assembly of AT and CTI 75mm and 98mm, first thing people blame is the manufacturer, not their own user errors! Anomolies happen is any part of this hobby...bad ematch and it didn't fire your apogee event, person blames ematch, but I blame them for not checking if the ematch was good using an ohm meter before flight.....in any line of pre-assembled rocket motors, the person that is flying that brand of motor has to trust the person who put together that motor did it right, or one would figure they would right ?

https://www.rocketryforum.com/showthread.php?70242-Titan-II/page2 Here is another failure, note post # 34. Pics. of failure on posts 39 & 40.

 

[burkefj]

In my j570 case there was no oring damage, the flame propagated up the side of the delay grain where insufficient glue was used to install it from the factory, I only use a solid long burn closure now with redundant electronics and no motor backup.

Frank

 

[rcktnut]

Quote Originally Posted by rcktnut View Post
https://www.rocketryforum.com/showthr...Titan-II/page2 Here is another failure, note post # 34. Pics. of failure on posts 39 & 40.

A little harsh aren't we about this? CTI also has numerous catoes and failures in their "pre-assembled" line of rocket motors ...people also mess up on reading instructions for assembly of AT and CTI 75mm and 98mm, first thing people blame is the manufacturer, not their own user errors! Anomolies happen is any part of this hobby...bad ematch and it didn't fire your apogee event, person blames ematch, but I blame them for not checking if the ematch was good using an ohm meter before flight.....in any line of pre-assembled rocket motors, the person that is flying that brand of motor has to trust the person who put together that motor did it right, or one would figure they would right ?

I guess I could ease off now, I don't have Facebook, but looks like Aerotech is giving us an option as to which delays/closures we want to use. I'm not trying to bash Aerotech, it just seems that there are pretty many problems with the new EZ loads. I'll be happy now as long as I have the choice to keep assembling my own delays. If something goes wrong, it's my fault, no one else to blame as long as I received the right parts. Aerotech has to be about 98-99 percent of the reloads I have ever flown, love them!! I have a few AMW cases, flew a few of their loads, while they were available, now I fly the AMW by Aerotech loads in them. I bought the CTI 38mm. starter set a few years ago, never bought a load for them yet.

 

[r12ski]

A little harsh aren't we about this? CTI also has numerous catoes and failures in their "pre-assembled" line of rocket motors ...people also mess up on reading instructions for assembly of AT and CTI 75mm and 98mm, first thing people blame is the manufacturer, not their own user errors! Anomolies happen is any part of this hobby...bad ematch and it didn't fire your apogee event, person blames ematch, but I blame them for not checking if the ematch was good using an ohm meter before flight.....in any line of pre-assembled rocket motors, the person that is flying that brand of motor has to trust the person who put together that motor did it right, or one would figure they would right ?

I don't think this is a gang up on AT thread. I think this is out of sincere concern that there might be a problem with the EZ loads. Similar to the Estes E9/E12 issue a couple years ago, it got to be enough to raise eyebrows and rethink putting an E12 in a rocket you cared about.

This is a new product for AT — or at least a new variant of a product — and new products tend to have issues especially early in development. If people don't say anything, how will the manufacturer know if there is a problem?

 

[rharshberger]

I don't think this is a gang up on AT thread. I think this is out of sincere concern that there might be a problem with the EZ loads. Similar to the Estes E9/E12 issue a couple years ago, it got to be enough to raise eyebrows and rethink putting an E12 in a rocket you cared about.

This is a new product for AT — or at least a new variant of a product — and new products tend to have issues especially early in development. If people don't say anything, how will the manufacturer know if there is a problem?

And if we don't confer amongst ourselves about a problem with a product then nobody has any awareness of wether others have had similar issues.

 

[pnobile]

Agreed that there is an issue, but I also agree that relying on someone else making/assembling the motor someone will fly in their rocket they spent a lot of time building, that person can't take the less than a few minutes to assemble their own motor?? And if it doesn't work properly, more likely than not it's the person who loaded the motor as to why it failed, but still there is the chance that something could have failed that was made by the manufacturer. It just always twerks me when someone complains about loading an RMS motor when they spent more time on doing one fillet for that said rocket. Hopefully this issue gets resolved, I fly all different stuff, AT, CTI, Kosdon, AMW, EX...etc too, sh!t happens once in awhile is the way I look at it

 

[seth_cooper]

I didn't start this thread to bash or blame Aerotech. Just wanted to report it and see if anyone had any ideas about the cause. I bought another J350 from our onsite vendor Saturday...I'll just be using a plugged closure next time. No hard feelings between me and Aerotech.

Aerotech requested I send the spent forward assembly to them for examination and they offered to replace the motor (along with the new "Complete reload delay kit").

 

[Loki Research]

I fly all different stuff, AT, CTI, Kosdon, AMW, EX...etc

I'm still trying to get on your motor list Preston. Please let me know what I need to do to make the cut. ;-)

 

[DizWolf]

I think they should leave the motors alone, and offer EZ kits as an option (as no one seems to want them anyways )

 

[fox_racing_guy]

Looks like WV Soar at the Bob Evans farm. I wish I would have went now looks like the weather was OK. I'm sorry about your rocket and I haven't flown any of the new AT EZ delays so I can't offer any insight.

 

[seth_cooper]

Looks like WV Soar at the Bob Evans farm. I wish I would have went now looks like the weather was OK. I'm sorry about your rocket and I haven't flown any of the new AT EZ delays so I can't offer any insight.

It was at Bob Evans farm. Mine was the last flight of the day...it started raining a few minutes later.

 

[rharshberger]

Yesterday I watched another RMS-EZ a J350 claim a vintage-ish 3" BSD Thor belonging to our clubs president. Launched of the rail, then about 10 feet above the rail the rocket lurched a little flew another 100' or so and shredded. Actually the only real damage to the rocket (at least from what I saw) was the fin can section of the airframe will have to be rebuilt, as the interior and exterior are heavily scorched. Given the flight it was almost definitely a RMS-EZ delay/forward closure failure. Thats make 5 of these failures I have heard of in the last two weeks, actually about 8 days.

 

[crossfire]

Just a question are flyers drilling the delay from the top or bp well or from the bottom of the delay element? Not sure if that would matter or not? I would sure think AT would chime in on this soon. There should be a good number of EZ flights at LDRS this week. Time will tell if there are a good amount of failures.

 

[rcktnut]

Just a question are flyers drilling the delay from the top or bp well or from the bottom of the delay element? Not sure if that would matter or not? I would sure think AT would chime in on this soon. There should be a good number of EZ flights at LDRS this week. Time will tell if there are a good amount of failures.

They are drilled from the bp well with the UDDT. There have been failures with drilled and undrilled delays. Just a bad design period. File a MESS report.