4.3.21.....my first CATO

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Reinhard

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RMS I-211, ejection went off with ignition. Destroyed my "go-to" rocket. No more RMS for me, although I know it was probably something I did wrong.
Sorry for your rocket. One easy way to achieve this result is by assembling the delay backwards. If the delay o-ring is on the delay spacer instead of the delay element itself, the forward closure won't be sealed properly, leading to a blow by on ignition. The parts go together nicely this way too, so it won't necessarily feel wrong when it is assembled this way.
If you haven't disassembled/cleaned your forward closure yet, documenting of the relative location of the remains (spacer, insulator, o-ring, etc) would be a good idea.
That's only one possible explanation, but in my opinion, the easiest user error to make.

Reinhard
 

Steve Shannon

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RMS I-211, ejection went off with ignition. Destroyed my "go-to" rocket. No more RMS for me, although I know it was probably something I did wrong.


View attachment 458273
Many of us have done something like that. In my case it was the way I assembled the delay grain and o-rings in the forward closure. The o-ring must go around or against the delay grain. It must not go around the delay spacer.
I hope you will try RMS again sometime.
 

PayLoad

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Dammit, just remembered there was a Fligtsketch Mini attached here. Goodbye, flightsketch mini, I barely knew ye....

IMG_8886.JPG
 

PayLoad

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OK - we can rebuild her. We have the technology, er, Dremel. We can make it better than it was....
Plunger deployment destroyed (burned) two fins completely off, nosecone mounting points destroyed, paint literally cracked off the damn thing.

I have to have her ready to fly again by Saturday. Yes this Saturday
 

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Steve Shannon

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Probably but it always helps to have instructions in front of you when assembling motor.
Even after all these years of building RMS motors, I still tape the instructions to the table so I can see them while I assemble the motor. I’ve never used a DMS and the few malfunctions I’ve had in RMS motors were directly traceable to my mistakes.
 

modeltrains

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Oh dear!
I guess, umm, "It's all in a day's rocket science"?
Ya know, this thing brings up a quote someone has used as a signature somewhere, but I can't quite pin down what quote and where ...
 

KenECoyote

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Everyone makes mistakes...the smart ones learn from them and persevere.

The crazy ones persevere for the challenge of "not...losing...one...single...rocket!!!" ;)
 

PayLoad

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I feel GOOD as I feel like I'm Michael P., CATO Detective. I feel stupid because on taking the CATO'd motor apart slowly, I found the problem in about 4 seconds. Human Error (on my part)

That O-Ring don't belong there.....
 

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3stoogesrocketry

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Stuff happens. It sucks you lost your rocket learning. I have been there.
 

crossfire

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I feel GOOD as I feel like I'm Michael P., CATO Detective. I feel stupid because on taking the CATO'd motor apart slowly, I found the problem in about 4 seconds. Human Error (on my part)

That O-Ring don't belong there.....
So where it the ring belong?
 

Sandy H.

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I honestly admit that I lost 2 rockets to H97 assembly issues. The bad part is that I identified the mistake when disassembling. . . I did bad brain math on which is bigger: 3/32" or 1/16". . . swapped the o-rings. The worse part is that a few months later I was building the second one and told myself "Don't forget, the 3/32" o-ring is the small one, don't put it on the wrong end.' The worst part is that I'm a friggin engineer and grew up in a machine shop, so I actually know this stuff.

I blame myself 100%, but also I slightly blame slot-cars from my youth. The axle sizes were 3/32" (small) and 1/8" (big), so when I see 3/32" written down, I always think small. . . that started when I was 5 or 6, well before I started using machinery, knew fractions or went to college. . .

I'm pretty sure i won't make that mistake again. I chose to stop buying H97's. :)

Sandy.
 

K'Tesh

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Sorry to see your rocket got damaged. I'm glad to see you've been able to rebuilt it.

Pointy Side Up!!!
 

crossfire

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I'll be quite honest - On disassembly, It appears I put it together with my eyes closed & never read the directions. Multiple errors on my part.

This Saturday flying an RMS+ H268R in the same bird
That's why I like to assemble my motors at home
 

Steve Shannon

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I'll be quite honest - On disassembly, It appears I put it together with my eyes closed & never read the directions. Multiple errors on my part.

This Saturday flying an RMS+ H268R in the same bird
Great job learning from the experience. Have fun Saturday!
 

Antares JS

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I can't speak for 29mm RMS, but on 38mm RMS, the forward O-ring fits nicely around the delay well lip on the forward closure, the aft O-ring fits nicely around the nozzle, the small one goes around the delay element, and if you have a seal disc, the really skinny one goes in the groove on that.
 

dr wogz

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As a tech writer, I'm conscious of ensure things can't be mixed up or misunderstood. I think it's a bad on AT's side, that they list the O-rings by size, yet don't indicate 'fore / aft', and don't follow it thru the text. This little thing, an easy copy & paste in thier instructions, can mitigate potential mistakes..
 

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