Stuck motor

[Chilly]

I've got a spent G40 stuck in my LOC Stovi and it won't come out! I used masking-tape retention and it worked a little too well. The motor only came out about 1 1/2" and now it won't budge...maybe the tape's rolled up on itself or something.

Any ideas for removing it without crushing the outer tubes?

I've had a lot of trouble removing taped motors and the thought of having this trouble with an RMS bugs me. Are they any easier to use tape on?

 

[BlueNinja]

Maybe you could stick a stick down in the tube and whack it witha hammer to pound it out.

 

[rstaff3]

A dowel that is ~29mm in diameter would probably work best. I've had good luck screwing a screw into the nozzle opening and yanking with pliers. I keep a suitably sized screw in the range box and have never failed to get the motor out...or hurt the rocket.

Since RMS cases have thrust rings integral to them, you won't need tape for the boost phase. I recommend you install a pair of threaded inserts and use motor clips to hold the case in on ejection You can buy a pair from Giant Leap, or you can pick up aluminum mirror clips from your local hardware store. Depending on how much motor tube is exdending from the aft CR, you might need a standoff to adjust the height of the mirror clips.

 

[shockwaveriderz]

use a wood dowel to push it out or a coat hanger to pull it out

 

[Ryan S.]

I take a copper pipe and push it through the top of the rocket so it hits the back of the motor. Then I flip the rocket upside down so the pipe is on the grouund then slam the rocket on the pipe until the motor comes out. I find this to be the best way because you wer putting minimal stress on the rocket (the slamming is actually on the motor) so you are less likly to damage it

 

[astrowolf67]

There have been some good methods suggested so far. If it's the glue from the tape that has it locked in, you might be able to heat the area up with a hair dryer to soften it up enough to get it out. Other methods, push it back in some, then try to remove it again with a twisting motion, without pausing once it starts coming out. Remove the aft thrust ring (if applicable), and try to push it out the top?

 

[teflonrocketry1]

Remove the aft thrust ring and as much of the spent liner as you can. Then heat the inside of the casing with a hair dryer. After the casing gets warm you should be able to pull it right out.

Bruce S. Levison, NAR #69055

 

[Rocketjunkie]

Originally posted by teflonrocketry1
Remove the aft thrust ring and as much of the spent liner as you can.

The G40 is a phenolic cased single use motor.
Probably the best way is to use a 1" wood dowel from the front and a hammer on the wood to tap it out. Have someone hold the rocket or strap it down.

 

[Chilly]

The dowel and hammer method worked like a charm. Thanks guys (I love this place)!

I am SO done with masking tape! Tonight I cut a couple of plugs from a 1" dowel to fit in two of the outboard tubes on the Stovi. I drilled them to fit some blind nuts and thumbscrews for storm door clips, and everything dry-fit great. Tomorrow I'll epoxy it all in place. It's almost like those storm door clips were made for motor retention!

My next project is a Mini BBX and I don't know what to do about it. I want positive retention but plan to fly it with the Terrier booster later on. Someone on EMRR recommended the Slimline retainers...anybody have any experience with that?

 

[Zippy]

I've got my Mini BBX fitted with the Slimline. I don't have the Terrier yet but it looks like there's room for the coupler to slide in.
When I built it I adjusted the placement of the motor tube so the Slimline ends where the motor casing normally would. It looks great too.

 

[Chilly]

That's a good idea but it's hard to visualize right now. I'll probably start a thread on the BBX when the time comes, soon as my Saturn V is finished. I plan to build an electronics bay in it and have never done that before.

I epoxied two 1cm wooden plugs in the outboard tubes this morning, with the blind nuts set in the rear. They were cut from a 1" dowel so the wood is kind of porous; next I'm going to coat their surfaces with thin epoxy. Once everything's set I'm going to hit the whole rocket with a fresh coat of paint, so it'll be ready to go for my L1 cert when the time comes.