Estes F15-8 Problem

[JLP1]

Saturday we were at our monthly club launch flying an Estes Star Orbiter on Estes F15-8 motors. This model has 6 flights and has performed flawlessly on each flight. That morning I loaded an F15-8 into the MMT with no problems it went in very smooth and it turn freely in the tube. I'm using the Estes 29mm retainer which screwed down and tightened normally. Did the launch and it looked perfect as usual and according to the Alt3 it achieved an attitude of 1175 feet. Recovery was normal now this is were things went South. I recovered the model and placed it on the stand and went to visit with some friends. I came back about 20 minutes later and started prepping for the next flight. Normally I just unscrew the ring and I can pull the expended motor out with my fingers. But not this time the motor was locked in tight and I mean tight. I tried channel locks and long nose pliers and it would not move. I tried a dowel rod from the other end and no joy. I didn't want to run the risk of wrecking the body tube so I took it home to work on Saturday night. After 3-1/2 hours of tearing away small bits of case and using a hack saw blade to weaken the case I was able to pull out the last 1-1/2" of the case. At no time did I see and signs of case swelling or abnormal engine signs. I did notice some spots going around the case about 1/2" from the front end of the motor that matched some of the very same type of spots in the MMT that looked frazzled like there had been glue or something there then it had been pulled away. I always inspect the motors before use and I will wipe them lightly with a paper towel before insertion and the motor looked good.

Model is 9 months old no recent repairs to the BT or MMT.

Has anybody seen this before ? I still have (4) F15's to use so before I load again I want make sure I address the issue.

Thanks Everybody

 

[Nytrunner]

Sometimes motors can swell after firing. I've had it happen on 24mm E's and even 13mm A's.

Best advice I can give is remove the motor upon recovering the rocket (pliers or gloves so as not to burn yaself) and let it cool before trashing it.

 

[shreadvector]

Hot motor will soften or melt any stray bits of yellow or white glue or paint. When the motor cools down, it gets stuck as the melted material has hardened.

Solution:

1) Prevent any glue/paint inside the motor tube.

2) Remove motor ASAP, while warm/hot.

 

[JLP1]

I didn't think about that, I usually remove the motor within a few minutes of recovery. This time I placed it in the carrier and went over to a buddies table for about 20 minutes. I'm going to lightly sand the MMT and check it with a very bright light. Thanks

 

[ebruce1361]

I had an Estes Mercury Redstone (circa 2002) that had a nasty habit of letting motors slide in okay, but then wouldn't let them go afterward. I was worried that I would eventually have to dismantle the plastic fin/motor mount assembly and effectively destroy the rear half of the rocket to get the casings out. What I did was I began putting in a single puff of locksmith powdered graphite and turning the motor as I inserted it as if I were screwing it in. Even after swelling a bit, the motors came out easier.

Granted, that solution was with paper casing motors, and the cause was likely me being overzealous with glue in those days and thus introduced a crease or bump in the motor tube. Still, I wonder if the same thing could be done with plastic case composite motors. I figure the glue will melt and grab the layer of graphite rather than the motor tube itself.

 

[BEC]

Fred beat me to it.....glue on the inside of the motor mount tube that was softened by the heat and had time to cool down and grab the motor later was the first thing that came into my mind as well. I've started installing motor blocks from the top end whenever I can to minimize the glue smearing around the block one gets from putting them in from the bottom as the instructions generally have you do.

 

[BABAR]

Another tip.
Bring a ziplock bag with you. Take the motor out immediately after flight and drop it in the ziplock. Keeps it from stinking up your car.

That , “I love the smell of black powder!” In the morning only goes so far.

 

[Nytrunner]

That , “I love the smell of black powder!” In the morning only goes so far.

About as far as it takes to turn into sulfur smell