How do I remove an unfired friction-fitted engine

I recently succeeded in getting an Estes D12-3 motor stuck in the lower stage of a Estes CC Express, and am trying to figure out how to remove it.

The Ideas that I've brainstormed so far include:
Building a rocket top with a recovery system to fit over the first stage and attach it in some way. Launch and remove the engine afterwards. Problems: I don't know if I can find a body tube that slides over the main body. Also, I don't know how to from a strong enough temporary attachment that won't be blown off by the deployment charge. (Dubiously safe)

Take a drill and drill out the gunpowder before unwinding the paper from the inside. Problems: Is it possible that the drill would get hot enough to ignite the powder? I don't want to lose any fingers. (Possibly unsafe?)

Soak the gunpowder by dripping water in from above, and scrape out the moist stuff. Problems. I haven't figured out how I can expose the powder to water without soaking the rocket stage. I also think that this would take way to long. (Don't know how to execute)

If anyone has solutions to this problem, or any information to help me develope my ideas, I would really appreciate it.

First, don't use a drill! That seems so wrong in many ways.

Have you tried using a pair of pliers to grip the paper casing? What about trying to use a dowel to push it out from the top side?

Kevin

if the plier don't work, use a wood dowl in push it out from the top

It does, doesn't it

I've tried the dowel. If I push the dowel too hard, I start bending the top of the body tube. I'll try to get a grip with a pair of pliers and see if that works. Thanks for the advice

Try pushing out from the top with a wooden dowel. You want wood or some other non-sparking material. You want the largest diameter dowel that will fit so that the force is distributed over a wider area.

If it doesn't come out with a reasonable amount of force, use pliers. Be careful in the amount of force on the pliers, as you can crush the clay nozzle and thus render the motor unsafe for flight.

Greg

Sharpe said:

It does, doesn't it

I've tried the dowel. If I push the dowel too hard, I start bending the top of the body tube. I'll try to get a grip with a pair of pliers and see if that works. Thanks for the advice

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tap on it instead of push , not too hard , it take only few

Wooden dowel or a shower curtain rod.

Looking at the booster (lower) stage my CC Express, there is a thrust ring at the very bottom of the motor mount tube. In order to get the motor out, you would have to push up against the clay nozzle to get the motor out. If it were me, I might try a "static test".

The motor mount is nothing more than a section of BT50 body tube. If you can acquire a length of BT50 body tube at least 6" long, you could slip it over the exposed portion of the D12-3 motor. This "extender" could then be secured to something at chest height that won't move (like a fence post, stop sign etc.) with the nozzle of the motor pointing up. Insert an igniter and fire the motor. The motor should go through its burn and sequence and the ejection through the extension tube, with the ejection materials harmlessly exiting down. You would then have a spent D12 casing that you could twist and pull out of the booster using a set of needle nose pliers.

Of course, this assumes that no one calls a cop. Welcome to model rocketry! :wink:

Oh, heck... what could possibly go wrong just launching it with a 3 second delay on the lower stage? Just wear a helmet!

Or maybe not...

I actually do not have any experience with 2 stage rockets, but if you just securely taped the two stages together and did not put an engine in the upper stage, would the ejection pass through the empty upper stage motor mount with enough force to deploy the upper stage chute? Both pieces would come down taped together under the upper stage chute?

Area66 said:

tap on it instead of push , not too hard , it take only few

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I tried this. Worked perfectly. Thank you so much!

ThirstyBarbarian said:

I actually do not have any experience with 2 stage rockets, but if you just securely taped the two stages together and did not put an engine in the upper stage, would the ejection pass through the empty upper stage motor mount with enough force to deploy the upper stage chute? Both pieces would come down taped together under the upper stage chute?

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I would be curious to try that. That D12 currently doesn't have any other rocket to fit in...

Sharpe said:

I tried this. Worked perfectly. Thank you so much!

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I was going to recommend that too. It's like when you get a Cartridge Case stuck in the Chamber of a Rifle. The light gentle Taps eventually get it there little by little.

Sharpe said:

I recently succeeded in getting an Estes D12-3 motor stuck in the lower stage of a Estes CC Express, and am trying to figure out how to remove it.

The Ideas that I've brainstormed so far include:
Building a rocket top with a recovery system to fit over the first stage and attach it in some way. Launch and remove the engine afterwards. Problems: I don't know if I can find a body tube that slides over the main body. Also, I don't know how to from a strong enough temporary attachment that won't be blown off by the deployment charge. (Dubiously safe)

Take a drill and drill out the gunpowder before unwinding the paper from the inside. Problems: Is it possible that the drill would get hot enough to ignite the powder? I don't want to lose any fingers. (Possibly unsafe?)

Soak the gunpowder by dripping water in from above, and scrape out the moist stuff. Problems. I haven't figured out how I can expose the powder to water without soaking the rocket stage. I also think that this would take way to long. (Don't know how to execute)

If anyone has solutions to this problem, or any information to help me develope my ideas, I would really appreciate it.

Click to expand...

Instead of any of these options, trash the stage and build a new one.

The drill option is particularly bad: drilling indeed does generate heat. Heat around BP is a very ungood thing. Plus the motor you would be destroying is almost certainly more expensive than it would be to build a new stage.

The water-dripping option isn't much better; most likely the main thing you will accomplish will be to warp and ruin the lower stage as well as damage (but probably not competely neutralize) the motor.

Seriously, use the wooden dowel method. Push firmly and smoothly. If the motor doesn't move, grasp the stage harder and push more firmly.

If this doesn't work after the first or second time you will undoubtedly crunch and crumple the booster stage. When this occurs, cut the fins off with an X-acto for use on your replacement stage, then just use pliers and the X-acto to rip and tear what's left of the stage off the motor.

PS, this is why I hate hate hate friction fitting, and have pretty much modified all my builds so as to avoid using it.

PPS: I see your problem is solved. The dowel method combined with tapping will usually work after other options have failed.

Nevermind.

put it the refrigerator. the cooler temperature might just give enough contraction to remove the motor.

Does friction fit really have to be that tight?? I know you don't want the motor to drop out, but to me, that just seems excessive, especially in the case of a booster.

T-Rex said:

Does friction fit really have to be that tight?? I know you don't want the motor to drop out, but to me, that just seems excessive, especially in the case of a booster.

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No, it doesn't. I friction fit all the time.

jimzcatz said:

No, it doesn't. I friction fit all the time.

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Agreed!

If its hard to insert the motor, it is going to be just as difficult getting it out!

Jerome

I see your problem is solved, but I wanted to present another option...

Others pointed out that you DO NOT want to drill or modify the motor... doing that is asking for a trip to ER and the fire department to visit. Not good, and violates the safety code.

Dripping water in will only swell the motor and totally ruin the stage/rocket. Forget that. Might as well trash it.

The wood dowel is the best solution, which I see is what worked.

BUT, if you have NO other choice, and can't get it out any other way, you COULD always just STATIC FIRE the thing... put the stage NOZZLE UP and securely attached to some stuff (set between concrete blocks, or taped to something heavy and immovable like a pipe in the ground, or blocks, or something of that sort-- you want to make sure that the thing doesn't move or flop around and start chasing you around the yard or ricochet off something and fly across the yard and hit the window or house or car or worse yet any of these things belonging to a neighbor!) Install an ignitor, and fire the motor. The motor will burn and the thrust will simply blow straight up, and then it'll burn out, and blow a gentle flame and smoke during the delay time, and then the ejection charge will blow... if the stage is sitting flat on the ground, it will probably send the stage airborne from the ejection charge... so it's better to be blocked up somewhat to give it room to vent, and also secured so it can't move backwards (upwards) as well as downwards under thrust. Once the ejection charge goes off, the inert spent casing can be removed by whatever means necessary.

Course this wastes the motor, but if you can't get it out any other way...

Later! OL JR

Not with black powder motors.

They are swollen from the loading process.

After firing, they get smaller because the cardboard casing can relax back toward the original unloaded and unstretched size.

That is why i never put the masking tape for friction fitting on the middle or lower end of the motor casing since that is swollen and it will shrink and allow the motor to eject after firing. i install masking tape around the top of the motor casing and it extends up and over the top edge where i can roll it over to form a smooth lip that will not roll up on itself (which can make the motor get stuck in the body tube very badly).

JeromeK99 said:

Agreed!

If its hard to insert the motor, it is going to be just as difficult getting it out!

Jerome

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Ok.. I suppose I didn't use enough words to properly explain my simple point (the message left was the second attempt at posting.. the first one didn't take).


What I failed to pass along is the following...

Using too much tape (or incorrectly as later explained) is bad. If you have to really force the motor in, you are doing something wrong and should not continue. The goal is to be snug enough to hold the motor in through its flight and landing, but not to make it difficult (or nearly impossible) to remove it later.

Friction fitting is not hard to do once you've done it a few times. The plain and simple point is you do not need excessive force to insert or remove a motor if done in a correct manner.

Caution is always required even when attempting the proper friction fit (at the top). A very common problem is the motor tube will peel back the tape causing the adhesive side of the peeled portion to now be against the motor tube as well as now doubling the amount of tape on one spot. So you have now taped the motor and tube together as well as doubling the desired "wedge" thickness. If this happens it is wise to stop and fix your tape before ramming it in. An easy way to combat this is to place your tape at an angle and slightly twist your motor in as inserting.


I do not claim that my way is the only way or best possible solution to a problem. only that it is my solution that has worked for me!
It is always good to hear how others solve a problem. You might just learn something! I know I do!


Jerome

You can usually eliminate the need for friction fitting in ANY rocket or rocket stage by moving the placement of the motor block about a quarter-inch to the rear and just using a sleeve of tape to secure the motor.

Occasionally this complicates staging if you are using the cellophane-tape method, but all it usually means is you must insert the motors, tape them together, then secure the lower stage, all in a very specific order.

JStarStar said:

You can usually eliminate the need for friction fitting in ANY rocket or rocket stage by moving the placement of the motor block about a quarter-inch to the rear and just using a sleeve of tape to secure the motor.

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Don't you need to move the entire motor mount back so that, with 1/4" of motor mount tube now exposed, you have something to which you can tape the motor? Also note that this involves moving the motor (probably the heaviest component of most small model rockets) back, which will move the CG back and may affect stability.

Occasionally this complicates staging if you are using the cellophane-tape method, but all it usually means is you must insert the motors, tape them together, then secure the lower stage, all in a very specific order.

Click to expand...

You have to do that anyway if the booster's thrust ring is at the bottom.

adrian said:

Don't you need to move the entire motor mount back so that, with 1/4" of motor mount tube now exposed, you have something to which you can tape the motor? Also note that this involves moving the motor (probably the heaviest component of most small model rockets) back, which will move the CG back and may affect stability.

Click to expand...

Yes, you have to move the entire mount back. Yes, there are some CG implications, but usually very minor. In the case of a minimum-diameter BT-20 18mm airframe, 1/4" is 1/3 of one caliber, so if moving the motor mount back 1/4" is going to throw you into stability problems, you probably already had these problems to start out with.