Are "PLUGGED" Motors Legal To Fly ?

[aerostadt]

Question : Since the F10 is an Apogee motor and Tim Van Milligan, owner of Apogee, is actively plugging single-use motors on YouTube, can plugging be considered as an "approved procedure" by the Manufacturer ?

Motors. I will use only certified, commercially-made model rocket motors, and will not tamper with these motors or use them for any purposes except those recommended by the manufacturer.

Technically, Tim is not the manufacturer. It is my understanding that Aerotech makes the Medalist motors for Apogee. As I recall there was another thread like this one within the past several months. I got the impression from that thread (and actually this thread, too) that a flyer could jeopardize the insurance of a club launch by using a plugged SU composite motor. I am somewhat puzzled by Tim's video. It seems like he is telling a flyer how to do this, but he is not really advocating someone to do it.

 

[vcp]

On 18mm motors, I 3D printed little 'top hat' shaped plugs that friction-fit into the motors. Besides the friction-fit, the brim of the hat is clamped between the motor and the motor mount. A small tab hanging 'below' the hat allows fingertip removal.

 

[Stefan2k4]

On 18mm motors, I 3D printed little 'top hat' shaped plugs that friction-fit into the motors. Besides the friction-fit, the brim of the hat is clamped between the motor and the motor mount. A small tab hanging 'below' the hat allows fingertip removal.

That sounds like an excellent idea and a great way to eliminate the issue.

Another thought on the "plugging" of black powder motors with epoxy, hot glue, etc., is could the heat of curing cause issues similar to the issues thermal cycling can cause that increase the risk of CATOs? With slow curing epoxies perhaps that would not be an issue, but with fast curing expoxies, CA, or hot glue, which someone mentioned earlier in the thread, could the temperature fluctuation and possible temperature gradients perhaps lead to cracking or separation between the grain and the casing? Maybe not an issue, but who knows.

 

[CoyoteNumber2]

Another thought on the "plugging" of black powder motors with epoxy, hot glue, etc., is could the heat of curing cause issues similar to the issues thermal cycling can cause that increase the risk of CATOs? With slow curing epoxies perhaps that would not be an issue, but with fast curing expoxies, CA, or hot glue, which someone mentioned earlier in the thread, could the temperature fluctuation and possible temperature gradients perhaps lead to cracking or separation between the grain and the casing? Maybe not an issue, but who knows.

Not a problem with 5-minute epoxy in my experience.

 

[AfterBurners]

Yukon
NEVER EVER use a knife to scratch out the Bp ejection charge !!
A hard plastic part maybe . But I would advise not to do it.

I am 61 and in my younger years ( late 60s ) I got the same idea to remove the ejection charge
from a motor and things did not go to well. Luckily I did not have the motor end pointed
in the direction of my face.

What happened was when I was using a hobby knife to scratch out the ejection charge the ejection charge ignited and started the propellant charge to burn backwards from top of motor to nozzle .Before the propellant had completed burning the Estes paper case ruptured and split down the side.

All of this happened while the motor was IN MY HAND !!! The results were a slightly sunburned hand that throbbed for a few hours and stopped . No fingers lost thank god it was a small "C" motor . The only damage was to my pants and drawers !

So please be safe out there sometimes even the simplest things can hurt you ,

Bobby

Just buy the plugged motors seriously ... as stated above it can be dangerous. I wouldn't mess with it.

 

[jimzcatz]

dont plug them just remove the bp

Tripoli does not allow research bp motors so no.

having several manufacturers give me eadvice over the years I would ave no trouble with their suggestions as being ok.

 

[Ez2cDave]

Just buy the plugged motors seriously ... as stated above it can be dangerous. I wouldn't mess with it.

Which BP motors are those ?

Estes, currently, only makes the A10-PT and those are for "Rocket-Powered Racers & R/C Rocket Gliders ( which they do not sell )', according to the Model Rocket Engine Performance Chart in the 2020 catalog, pgs. 70-71.

Theoretically, Estes does not "authorize" them for use in all rockets.

Dave F.

 

[cerving]

For BP motors, use the -0 version and stuff a little dog barf in the space above the charge, then tape it up. 100% compliant and easier than messing with epoxy. For AP motors, just dump the powder and replace the cap.