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Give me your Aerotech LMS tips

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AeroTech

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Hard to say from watching a video.

It definitely popped. I was there yesterday and heard it.

Did you drill the delay grain or perhaps forget to grease the o-rings by chance? I've built a bunch of the G-79 LMS motors but haven't had any issues. I see Aerotech was posting here in this thread, they can probably tell what happened from the video and might chime in.
 

Joshua F Thomas

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It definitely popped. I was there yesterday and heard it.

Did you drill the delay grain or perhaps forget to grease the o-rings by chance? I've built a bunch of the G-79 LMS motors but haven't had any issues. I see Aerotech was posting here in this thread, they can probably tell what happened from the video and might chime in.
I didn't do any drilling, and I did indeed grease the o-ring. Someone else said it might have been the ejection powder getting past the delay. I'm going to try with the G78 LMS I also have and see if that turns out better.
 

TheTank

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I didn't do any drilling, and I did indeed grease the o-ring. Someone else said it might have been the ejection powder getting past the delay. I'm going to try with the G78 LMS I also have and see if that turns out better.
Sounds like a plan. I have gotten several of them from Russ. I usually load them up and the vacuum bag them so I dont have to worry about moisture if I store them for a while.
 

3stoogesrocketry

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I don't see any indication of a charge going off . First photo shows the motor shutting down. Second shows the nose cone off , no indication of a charge going off .
Third is the chute fully inflated milliseconds before the booster flew threw your lines collapsing the chute.
 

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jrap330

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It's an iphone, on a windy day in a big field, and the audio pickup isn't great. Both my wife and I heard it quite well. The only reason you can hear *me* is that I'm holding the phone a few inches from my face.
Het Josh......your first composite motor launch? Congrats.
 

Joshua F Thomas

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I don't see any indication of a charge going off . First photo shows the motor shutting down. Second shows the nose cone off , no indication of a charge going off .
Third is the chute fully inflated milliseconds before the booster flew threw your lines collapsing the chute.
It’s good that we have your internet video analysis to tell us what happened. The multiple people present at the field when it happened and heard the ejection were not sure. /sarcasm
 

Joshua F Thomas

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Sounds like a plan. I have gotten several of them from Russ. I usually load them up and the vacuum bag them so I dont have to worry about moisture if I store them for a while.
I hadn’t thought about moisture, but I’ll stick to just assembling them the day before I need them.

The DMS appear to be pre-assembled except for the ejection charge, is that right?
 

TheTank

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I hadn’t thought about moisture, but I’ll stick to just assembling them the day before I need them.

The DMS appear to be pre-assembled except for the ejection charge, is that right?
Correct. DMS are really an assembled single-use with the ability to control the ejection charge. Even with the LMS motors, I have assembled them a month or two before I use them on occasion and just keep them in a cool, dry place.
 

rcktnut

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I see no flame from the nozzle after burnout and then some flame right at the time ejection occurs. Looks to me like the ejection charge went off at that time.
 

3stoogesrocketry

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I see no flame from the nozzle after burnout and then some flame right at the time ejection occurs. Looks to me like the ejection charge went off at that time.

I *think* that is a sun glare artifact in both the first and second picture coming off the left fin. In the 3rd picture (6 seconds) there is still smoke coming out of the base of the rocket , would not happen after the charge blows . Watch the video again . There is smoke coming out of the base of the rocket all the way down to about 20 feet off the ground when there is a faint pop , about 4 seconds after the chute deployed , then no more smoke .
 

Joshua F Thomas

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The charge went off. It was heard by many. I can also confirm from examination of the motor and the rocket that the charge went off.
 

dpower

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I miss the LMS motors - I used quite a few F27-8 LMS, drilling the delay to -6.
 
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