PSA: Using a SU motor? Make sure you glue the thrust ring in place.

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ChrisAttebery

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I caught this over the weekend at LUNAR's Snow Ranch launch. I believe it was an H115.

[YOUTUBE]Or1wiTGPCBo[/YOUTUBE]
 
The same thing happened for the EZI-65 drag race at ThunderStruck. It was a I280DM motor. 4 rockets in the race and 3 were fine (I was one of the lucky ones), but one shot up through the rocket and went flying towards the flight line. Fortunately no one was hurt.
 
Yep; nothing cool about motors on the loose. The one Randy mentioned flew by very near me; a couple people thought it hit us. Not sure how close it got, but it was loud in my right ear and I saw sparks and smoke directly over my right shoulder.

Aerotech says they'll do a better job with glue in the future; in the meantime I'm not sure how many are out there in the real world ready to fly through rockets and towards spectators. As Chris says, double check those "pre-installed" thrust rings!

-Eric-
 
Right after it happened I heard the owner say something along the lines of "I didn't check it, was I supposed to glue it?"
 
Yep; nothing cool about motors on the loose. The one Randy mentioned flew by very near me; a couple people thought it hit us. Not sure how close it got, but it was loud in my right ear and I saw sparks and smoke directly over my right shoulder.

Aerotech says they'll do a better job with glue in the future; in the meantime I'm not sure how many are out there in the real world ready to fly through rockets and towards spectators. As Chris says, double check those "pre-installed" thrust rings!

-Eric-

Yep, that one was WAY too close for comfort. Glad it missed you Eric! BTW, need to send you a few pics of the first rocket you flew Saturday.
 
I have flew 3 of the 38mm DMS motors so far with no problems, J270,I500,I280, I read a bout problems with some of the early motors so I give mine a good pull tug make sure they are glued on well.
 
Agreed, never trust glue more than tape. I have been using tape thrust rings since I first started, about 1990

Guys I totally agree. I've personally flown up to L motors with masking tape thrust rings; I know others have flown O's with tape rings.

The problem comes with "ready to fly" motors that supposedly have the thrust rings installed. It's much like reloadable hardware where the thrust ring/ aft closure is proud of the motor's diameter; you simply expect that feature to function and certainly not fly through the rocket. It certainly wasn't my motor that nearly whacked me; nor do I blame the flyer for believing that the thrust ring was truly installed as it was supposed to be.

It SHOULD be a reasonable assumption that if a thrust ring is pre-installed from the manufacturer, that it will sufficiently hold and transfer thrust to the airframe.

To reiterate, I use masking tape thrust rings too, but that does not discount the fact that flyers should check preinstalled rings and supplement, replace, or reinforce as necessary.

-Eric-
 
It was an about 25 year old IBCO motor that I picked up at BALLS from Bruce Kelly last year. Reliability, even when new, was iffy but this one worked.

Cool! We also picked up several vintage motor from Bruce at Balls. A friend even came home with a 3" Vulcan baby M Smoky Sam. Love the oldies!

-Eric-
 
It was an about 25 year old IBCO motor that I picked up at BALLS from Bruce Kelly last year. Reliability, even when new, was iffy but this one worked.

Cool!!!! Did you get a vid of that? Been scouring your YouTube page waiting on vids from last weekend;)
 
Cool!!!! Did you get a vid of that? Been scouring your YouTube page waiting on vids from last weekend;)
Yes I did. Replaced my desktop and in the process of transferring all my programs to the new machine. (Data was easy - move the hard drive :)) Will get videos up soon.
 
I've used both tape and mmt tube glued on with CA glue and have yet to have a problem . . . knocking on wood. I've seen those yellow plastic pre-installed thrust rings; they are two-part and they come off quite easily . . . I have used CA glue on them too.
 
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