attaching eyebolt to AT single-use motor

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jkovac

jkovac

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I'm pretty sure there was a thread about this at one point, but I can't seem to find it now.

I want to attach an eyebolt to an Aerotech L1000 to be used as a recovery attachment point I have flown the rocket it will be used in a number of times with reloadable AT motors, and use a tapped forward closure with an eyebolt in it to attach the recovery harness. I'd like to basically do the same thing with a single-use, and would appreciate any input on the best way to screw/glue the eyebolt into the smoke delay end of the motor.
 
rfjustin said:
How heavy is the rocket in question? Minimum diameter by chance?
Click to expand...

Close to MD. 2.6" Madcow Tomach w/54mm motor mount. Dry weight is 28 oz. L1000 is 77.4 oz pre-flight, 28 oz. when spent.
 
Given the kind of loads you're talking about, I wouldn't trust screwing/gluing an eyebolt into the plastic forward closure on a DMS. Especially with a L1000... both of the ones I've fired had forward closure failures, the first one was right after ignition, the second one was at the end of the burn (I didn't know about it until I got home and removed the motor). The only thing that saved my Rocketry Warehouse G3 was that I built it with a hard point coupler with a U-bolt just ahead of the motor, when the closures let loose they didn't go anywhere. The first cato actually ripped the Aeropack retainer ring off the mount... everything went out the back end.
 
Why not just do a regular Y harness with Kevlar?
 
cerving said:
Given the kind of loads you're talking about, I wouldn't trust screwing/gluing an eyebolt into the plastic forward closure on a DMS. Especially with a L1000... both of the ones I've fired had forward closure failures, the first one was right after ignition, the second one was at the end of the burn (I didn't know about it until I got home and removed the motor). The only thing that saved my Rocketry Warehouse G3 was that I built it with a hard point coupler with a U-bolt just ahead of the motor, when the closures let loose they didn't go anywhere. The first cato actually ripped the Aeropack retainer ring off the mount... everything went out the back end.
Click to expand...

Thanks Cris. I've heard about the L1000 failures with older lots. My understanding is that they've fixed that and newer lots are OK.

I wish I could find the thread where someone said they'd glued an eyebolt to DMS motors many times as a recovery attachment point, and never had an issue. But I do understand your concern over trusting that attachment.
 
djs said:
Why not just do a regular Y harness with Kevlar?
Click to expand...

The rocket is already built, so I can't attach anything to the forward centering ring. I suppose I could use a piece of coupler and attach a Y-harness that way. This will likely be the only time I fly a single-use motor in this rocket, so I was hoping to hear people had done the eyebolt in the disposable motor approach successfully, since it's simpler, but so far no one has said that.
 
So you don't have a harness in it currently?

You might be able to use something like this, where it's epoxied in, and used as the anchor point. Note- you would only be able to use electronic ejection with this, and it might limit your space for motors:

https://www.allrockets.ca/Build/Minimum-Diameter-Retainers

This isn't the right size, but I bet you could find one or have someone make you one.

Random question- why build it without a harness?
 
djs said:
So you don't have a harness in it currently?

You might be able to use something like this, where it's epoxied in, and used as the anchor point. Note- you would only be able to use electronic ejection with this, and it might limit your space for motors:

https://www.allrockets.ca/Build/Minimum-Diameter-Retainers

This isn't the right size, but I bet you could find one or have someone make you one.

Random question- why build it without a harness?
Click to expand...

Correct, no harness in it currently. I built it with the intention of using only reloadable motors, and I use a tapped threaded forward closure with a threadlocked eyebolt as the recovery attachment point for those.

I just flew a true minimum diameter rocket at Black Rock a few weeks ago, and used one of those retainers in the link you provided. It worked great, but it can only work as-is with one length motor (in this case it was a K250). I did buy one of the extenders they make so I could fly it with a 54/2560 case too, but I haven't tried that yet.
 
jkovac said:
I'm pretty sure there was a thread about this at one point, but I can't seem to find it now.

I want to attach an eyebolt to an Aerotech L1000 to be used as a recovery attachment point I have flown the rocket it will be used in a number of times with reloadable AT motors, and use a tapped forward closure with an eyebolt in it to attach the recovery harness. I'd like to basically do the same thing with a single-use, and would appreciate any input on the best way to screw/glue the eyebolt into the smoke delay end of the motor.
Click to expand...



I seen that thread also. I believe tfish had pictures of the way he did it. Looked like he just epoxied an eye bolt in the forward bulkhead. PM him.
 
Here is how I did it. 20170127_101127.jpg20170127_101243.jpg20170127_131538.jpg
The Kevlar is just a loop. This is a 54mm single use. I don't think that
filling the hole with JBweld is necessary but what the heck.
 
I was thinking about some kind of cotter pin type solution, like you did here. i'm assuming it worked out well?

Just make sure you don't have any powder in the well before drilling! :)
 
I've done that with CTI 54mm plugged motors. I just drilled the well and ran the kevlar through the holes I drilled like Tony did.
 

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