Removing a stuck prop

I have an APC that is stuck. Fortunately it is stuck on the shaft, and not in the ground. I have been using a large spinner nut, and it looks like there may be such a thing as overtightening.

1. Could I use some sort of bearing puller to remove it, or should I just Dremel it to pieces, with care not to Dremel the shaft or thrust washer (the prop size is an experiment that didn't work, so it's a paint-stirrer at best now anyway).

2. Is it best to ream APCs slightly before installing?

3. When tightening props, is it best to stop short of as tight as you can get it. In Speed the answer is no, but Stunt may be different. Maybe even use a torque wrench?

Thanks in advance,

I understand you to mean that the nut comes off but the prop doesn't--right? If so I think either of your ideas to get the prop off should work. I gather that your prop shaft might have a larger diameter part next to the thrust washer. If so, then it is reasonable to ream out the rear part of the prop hub to allow the clearance, but leave the front part "normal".

It may be that on the APC prop the plastic just "squished" together under pressure. So, on this prop at least, I would guess that you overtightened it. It is usually good, however, to tighten quite well, especially on pipe engines. But maybe not quite as much on an APC.

Now, is is possible to put a popsicle stick in the exhaust and just turn the prop off? Using a wooden stick like this *shouldn't* hurt the engine, but don't go overboard, either. If you break the stick in the exhaust, then try another method. But...that's what I have done.

>It may be that on the APC prop the plastic just "squished"
>together under pressure. So, on this prop at least, I would
>guess that you overtightened it. It is usually good,
>however, to tighten quite well, especially on pipe engines.
>But maybe not quite as much on an APC.
>
>Now, is is possible to put a popsicle stick in the exhaust
>and just turn the prop off? Using a wooden stick like this
>*shouldn't* hurt the engine, but don't go overboard, either.
> If you break the stick in the exhaust, then try another
>method. But...that's what I have done.

Boy that sounds good to hear because I thought I was the only one to try that.
Much better than gripping the drive hub with pliers.

I have been successful in "locking" the cylinder by filling it up with fuel (or some such) and gently turning (counterclockwise) the prop. Don't apply enough force to bend the rod! But it doesn't usually take that much force to get it to turn.
Bill <><

Having seen the production of APC props I doubt very much if it got squished while tightening. They are molded at 30,000psi and spit out like poppy seeds!

You didn't mention the type of engine but I suspect you might have one whose threads are a smidgen smaller in diameter than the last small unthreaded part of the crankshaft or, in some cases, the thrust washer. In tightening the prop you probably forced this prop over this larger diameter with the pressure you are able to apply with the threads (leverage and all that). No such assist is available in pulling it off. Might have to go with a bearing puller.

Try what Len says first. It usually works, and you are Picking The Low Fruit here, too. A piece of soft ply is OK, too.

This usually is the "Enya Syndrome", with their slightly larger than normal metric crankshaft threads. The typical response is to grab the thrust washer with a pair of pliers, and start twisting. So this puts the "Enya Curse Marks" on the thrust washer at no extra charge.

Swap meets are full of Enyas marked such as this.

I'm with Ted: use a gear puller.

AH TRY heating up the prop with a hair dryer...GET IT HOT. and then try. Then if not do what Mr. Newman says with the heat.

Scott(I wish I could spell Leonard so I don't have to call him MR. Newman.)Riese:+

.
>
>Scott(I wish I could spell Leonard so I don't have to call
>him MR. Newman.)Riese:+

You did OK with Leonard. I wish you could spell "Neumann".

>AH TRY heating up the prop with a hair dryer...GET IT HOT.
>and then try. Then if not do what Mr. Newman says with the
>heat.
>
>Scott(I wish I could spell Leonard so I don't have to call
>him MR. Newman.)Riese:+

OK Mr. Smarty Pants. Tell me this: Does the little hole in the middle of the prop try to get bigger or smaller when the material surrounding in expands?

>>AH TRY heating up the prop with a hair dryer...GET IT HOT.
>>and then try. Then if not do what Mr. Newman says with the
>>heat.
>>
>>Scott(I wish I could spell Leonard so I don't have to call
>>him MR. Newman.)Riese:+
>
>OK Mr. Smarty Pants. Tell me this: Does the little hole in
>the middle of the prop try to get bigger or smaller when the
>material surrounding in expands?
>
>
>
>Ted

OK Mr. control line expert type person. I was hoping the MAYBE a little CASTOR might have worked its way into the threads holding the prop tight.
To answer you question I would have to look up the expansion rates of the materials. BUT I'm doing tissue at this time so the world will have to wait.

Scott (my pants told me) Riese

OH ….”NEWMAN” refers to a TV show a few years back….

>>
>>OK Mr. Smarty Pants. Tell me this: Does the little hole in
>>the middle of the prop try to get bigger or smaller when the
>>material surrounding in expands?
>>
>>
>>
>>Ted
>
>OK Mr. control line expert type person. I was hoping the
>MAYBE a little CASTOR might have worked its way into the
>threads holding the prop tight.
>To answer you question I would have to look up the expansion
>rates of the materials. BUT I'm doing tissue at this time so
>the world will have to wait.
>
>Scott (my pants told me) Riese
>
>OH ….”NEWMAN” refers to a TV show a few years back….
Mr. S.P.

OK, so the shaft is going to expand too then. If the shaft gets bigger and the prop gets bigger does the hole try to get smaller but can't?

Ouch, is that a headache coming on?

Ted

Kidding aside. The APC s are made in this big machine that not only compresses the little prop pellets at 30K psi but also steams them up hot enough to melt 'em so they can fill in all the insides of the mold. I wonder how hot the thing would have to get before any expansion took place?

>
>>>
>>>OK Mr. Smarty Pants. Tell me this: Does the little hole in
>>>the middle of the prop try to get bigger or smaller when the
>>>material surrounding in expands?
>>>
>>>
>>>
>>>Ted
>>
>>OK Mr. control line expert type person. I was hoping the
>>MAYBE a little CASTOR might have worked its way into the
>>threads holding the prop tight.
>>To answer you question I would have to look up the expansion
>>rates of the materials. BUT I'm doing tissue at this time so
>>the world will have to wait.
>>
>>Scott (my pants told me) Riese
>>
>>OH ….”NEWMAN” refers to a TV show a few years back….
>Mr. S.P.
>
>OK, so the shaft is going to expand too then. If the shaft
>gets bigger and the prop gets bigger does the hole try to
>get smaller but can't?
>
>Ouch, is that a headache coming on?
>
>Ted
>
>Kidding aside. The APC s are made in this big machine that
>not only compresses the little prop pellets at 30K psi but
>also steams them up hot enough to melt 'em so they can fill
>in all the insides of the mold. I wonder how hot the thing
>would have to get before any expansion took place?

Ron B.
F4Fguy

Ted:The die temp and pressure have nothing to do with it,the hole will grow faster than the shaft by an amount equal to the CHANGE in temp and the difference in coefficients of thermal expansion.Plastics (unless deliberately designed otherwise)generally have thermal expansion coefficients several times that of steel.Also, you can re-pitch APCs with a heat gun.This means the plastic has to reach the yield point at temp.Even if the hole did close,it would relax with heat and take a new set at the shaft diameter.As I see it,the only real problem is in being sure of getting it heated all the way through.

>>
>>>>
>>>>OK Mr. Smarty Pants. Tell me this: Does the little hole in
>>>>the middle of the prop try to get bigger or smaller when the
>>>>material surrounding in expands?
>>>>
>>>>
>>>>
>>>>Ted
>>>
>>>OK Mr. control line expert type person. I was hoping the
>>>MAYBE a little CASTOR might have worked its way into the
>>>threads holding the prop tight.
>>>To answer you question I would have to look up the expansion
>>>rates of the materials. BUT I'm doing tissue at this time so
>>>the world will have to wait.
>>>
>>>Scott (my pants told me) Riese
>>>
>>>OH ….”NEWMAN” refers to a TV show a few years back….
>>Mr. S.P.
>>
>>OK, so the shaft is going to expand too then. If the shaft
>>gets bigger and the prop gets bigger does the hole try to
>>get smaller but can't?
>>
>>Ouch, is that a headache coming on?
>>
>>Ted
>>
>>Kidding aside. The APC s are made in this big machine that
>>not only compresses the little prop pellets at 30K psi but
>>also steams them up hot enough to melt 'em so they can fill
>>in all the insides of the mold. I wonder how hot the thing
>>would have to get before any expansion took place?
>
>Ron B.
>F4Fguy
>
> Ted:The die temp and pressure have nothing to do with
>it,the hole will grow faster than the shaft by an amount
>equal to the CHANGE in temp and the difference in
>coefficients of thermal expansion.Plastics (unless
>deliberately designed otherwise)generally have thermal
>expansion coefficients several times that of steel.Also, you
>can re-pitch APCs with a heat gun.This means the plastic has
>to reach the yield point at temp.Even if the hole did
>close,it would relax with heat and take a new set at the
>shaft diameter.As I see it,the only real problem is in being
>sure of getting it heated all the way through.
>
> Ron B.

RON...THANK YOU.

Kim,

Don't listen to Ted, Len and the other guys,listen to me!

I had the same problem, and my friend Aloisio solved it in 1 minute:

You just turn the prop to a vertical position (paralel to the piston's course) so you have clearance to "bang" the prop.

get a small hanmmer, or any tool that wheighs around a half pound.

From the bottom of the engine (that's the place were you'll have clearance to git the prop from behind witout hittin' anyting on the engine you don't wanna hit) give a blow on the prop's hub, as near as you can to the prop "shoulder".

Turn the prop 180 degrees and hit it again. if nothing happens, use a little more force.

The try yo spin the prop couterclockwise.

if it won't "unscrew", back to the hammer.

Aloisio got my APC prop out in a minute, on the field.

Just be careful not to do anything stupid.

It GOTTA come out, I have used Aloisio's method and it never failed!

Ion

EDIT:

With all the respect due to Ted, Len and all my fellow modelers

hmmmmm don't do anything stupid...but "hit it with a hammer" sounds pretty stupid to me.

>hmmmmm don't do anything stupid...but "hit it with a
>hammer" sounds pretty stupid to me.

I don't mean a sledge hammer, but a light one, and the part to be hit is the prop.

And by "hit", I mean "gentky tap"...;

One thing I can tell you, it works!

I find it dangerous to flood tha chamber and use force, it might get to the pushrod.

When I said to not do anything stupid Imeant "use your common sense...

I know....it was just funny to hear " hit it witha hammer " that is how we used to "fix" things when we were kids.......

I know what you mean...
I remembre this excelent woodwinds repairman in Mew York, Artie Pincus.

He gad a 20 poud sledgehammer hangin' with his tools, and under it there was a note:

"Picollo adjusting tool"

Of course he was a joker.

He also glued a 1 Dollar silver coin at the floor, near the entrance of his shop.

First time you went there you'd see that nice coin and try topick it up, and he would just enjoy the prank, without a word.

The fun for the old customers was to see a new guy walk in, see that coin, look around and try to get it.

Ion,
While it "might" be dangerous to flood the chamber, it does lock up the engine. In my case, I might be able to bend the connecting rod on a 3hp Briggs and Stratton with my hands, but most of us will be smart enough to know how much force to use if we ever do anything mechanical. Actually it will take very little twisting force to turn the prop off the shaft. Again, I will never post anything that I have not personally done, and I know it works. So far, there have been no bent connecting rods I have seen from using this method. No tools are used, and I grab it at the hub to minimize leverage.

Only a suggestion, and the user does so at his/her own risk. See my DISCLAIMER listed below to cover just such a event. But it must also be stated that while I am not any of the other things listed below at the present time, I have been involved in building all types of engines, and other mechanical apparatus, for close to 40 years. Often with out the "proper" tools or parts, but they all worked and lasted. Many until this day.
Don't forget what an "expert" is: e"X": an unknown quantity, coupled with a "spurt": a drip under pressure.
Bill <><

Bill,
Please forgive me if you felt I was doubting the safety of your methods.

You are older (just a little) than me, and you fly and build a lot better.

I should have said, instad of "I find it dangerous", "I'm afraid of"...

Maybe, due to the dificulties to get one's hands on a good engine makes us Brazillians more cautious that needed when handling problems like these.

For example, I am out of screws for my OS.32F, and they are nowhere to be found here.

In the US I can get them for a dozen a dime, and fast and easy.

But, believe me, the method of hittin' the prop with hammer works, and the engine is safe as it could be!

Your disclaimer doesn't necessarily apply to me, but I think the fuel-lock method is a fine idea. I use it.

If it's a four-stroke, you merely need to hook up the battery and flip the engine. You don't even need to loosen the prop nut. The prop and related hardware will pop right off.

I might use a sledge hammer. I come from the Bigger Hammer School of gunsmithing, engine repair, carpentry, etc.

>>
>Just be careful not to do anything stupid.
>
>

You mean like hit the prop with a hammer?

Use the stick method Len has suggested.

I think the concern with the "hammer of you know what" approach is the possibility of hitting it hard enough to bend the shaft. This probably isn't a big concern while the shaft is in the case but anything done to excess can cause unintended consequences. A word to the wise.

I know that Big Art used the hammer method to perform the shaft straightening procedure he used on the .35S. Puts the threaded end of the shaft in the lathe with the device lathe types use to center their work and taps it gently until it tracks straight. Said they were all out a bit.

>I think the concern with the "hammer of you know what" approach is
>the possibility of hitting it hard enough to bend the shaft.

Seems to me a hammer is overkill.
Why not just hit it with a chicken stick
(with the prop nut removed)?

>>I think the concern with the "hammer of you know what" approach is
>>the possibility of hitting it hard enough to bend the shaft.
>
>Seems to me a hammer is overkill.
>Why not just hit it with a chicken stick
>(with the prop nut removed)?

But...my chicken stick is a hammer!

My, My Ted,

Your up early this morning hammering on the keyboard! Hammered that canopy onto the "Special" yet?

Ted, it doen't even have to be a hammer.

I used an "L" shaped key that mesures 10" x 4"and is about 3/8"thick.

Even a hevy screwdrive will do.

You just tap the back fo the prop, near the hub, and it'll end up loosening.

I've learned it on the field, and have done it many times, no problems whatsoever.

Locking the cylinder with a little oil makes sense to me...it would put a lock on the piston, but center the load on the piston and rod better than the stick method. A tapered hand reamer works wonderfully compared to those stepped prop reamers. Just be cautious with how much you take out. I would not doubt that Ion's method would work, and would give it a try. What you are going to do is temporarily stretch the hole, but I would expect it to tighten back up after awhile. Plastic (noun) is plastic (adjective), ya know. Steve

Let's see.

Ion's method will work however I'm not a fan of hammers or pliers within a country mile of my engines. The problem it that we don't know what kind of bearing is in this engine. Hammer blows can damage ball bearings very quickly, but with a plain bearing engine I have "slapped" the prop with a large screwdriver handle. The popscicle stick is my old standby, but if it snips the end off it never comes back out in one piece. I've also done the oil trick and with the exception of being messy it works great. I'd add one thing however. after you've filled the cylinder with oil through the exhaust port, pour a little out so you have some air trapped when you bring the piston up (down). This will cushion the deadheading a bit. You also want to be careful to make sure you're stopping the piston somewhere above 1/2 of the compression stroke if the prop is deadly stuck. This will increase the leverage. In other cases I've removed the head and cut a piece of dowel to put in the cylinder and stop the piston.

Ted, heating the prop hub will expand it away from the shaft. The coefficient of thermal expansion applys to all the material, not just the mean of the hub cross section. Heating crankcases to install bearings in a good example of this. I think however that heating the APC hub might have the added benefit of softening the plastic enough to loosen its grip.

Here is what we have done out at the field to remove a stuck on broken apc prop.
1.Remove the prop nut and washer.

2.Hold the airplane's nose in your your left hand to secure it.

3. Grasp the remaining prop blade in your right hand, and pull it away from the airplane, then push it towards the airplane.

4. Do this several times.

5. The prop should pop loose, and then you can unscrew it from the crankshaft.

This has worked several times for us.

One very useful tool is the Sears battery terminal puller. I've used mine to pop off the drive washers on Magnum engines, among other things. It'd probably work OK for this.

Could put the nut back on, tighten very well, put the spinner back on, then try to start the engine during an official. Gets them loose for me every time...

I would go with a combination of a Battery Post Puller then apply heat useing both steps, I used the oil in the barrel lock up metheod once & it made me a bit nervous never concidered it again.

Hi Kim
An easy way to loosen a prop without damaging anything is to lock two nuts together on the outer end of the crank, hold a wrench on the outer nut, then unscrew the prop.
Good luck!
Mo

Mo is correct this is how I got mine off double nut I now remember the lock up wasn't working.

I do run a ream through the hole in APC props. Some are a hair tight.

Lots and lots of great ideas. Here's mine. Give it to four five year old boys and tell them "do not take the propeller off". Come back in five minutes and it will be off and each will say, he did it!!! and point at the kid next to them. Just pat them on the head, hand them a Baby Flite Streak and leave.

>Lots and lots of great ideas. Here's mine. Give it to four
>five year old boys and tell them "do not take the propeller
>off". Come back in five minutes and it will be off and each
>will say, he did it!!! and point at the kid next to them.
>Just pat them on the head, hand them a Baby Flite Streak and
>leave.

LOL!

>While it "might" be dangerous to flood the chamber, it does
>lock up the engine. In my case, I might be able to bend the
>connecting rod on a 3hp Briggs and Stratton with my hands,
>but most of us will be smart enough to know how much force
>to use if we ever do anything mechanical. Actually it will
>take very little twisting force to turn the prop off the
>shaft. Again, I will never post anything that I have not
>personally done, and I know it works. So far, there have
>been no bent connecting rods I have seen from using this
>method. No tools are used, and I grab it at the hub to
>minimize leverage.

Bill,
I tried it and it worked like a charm. I used automatic transmission fluid (it needed a shot of after-run oil anyway), and a sort of "mental max torque setting" per your message. It took a moderately strong counterclockwise twist to break the prop loose so it could be unthreaded from the shaft, but I doubt that I came near bending the rod. No tools, no need to remove the muffler.

>A tapered hand reamer works wonderfully compared to those
>stepped prop reamers. Just be cautious with how much you
>take out.

Steve,
Good point, since we're talking about removing only a few thou.

>An easy way to loosen a prop without damaging anything is to
>lock two nuts together on the outer end of the crank, hold a
>wrench on the outer nut, then unscrew the prop.

Mo,
Sounds like another good, safe method.

>Don't listen to Ted, Len and the other guys,listen to me!
>hammer

Ion,
Uhhhh . . . yeah.

------

Quite a collection of replies. The guys on the Speed board should be so lucky! All this info and humor too. Leonard, Ted, Mike, and Ty crack me up, and Ion . . . well, doesn't even have to try!

Thanks guys,
Kim

>>While it "might" be dangerous to flood the chamber, it does
>>lock up the engine. In my case, I might be able to bend the
>>connecting rod on a 3hp Briggs and Stratton with my hands,
>>but most of us will be smart enough to know how much force
>>to use if we ever do anything mechanical. Actually it will
>>take very little twisting force to turn the prop off the
>>shaft. Again, I will never post anything that I have not
>>personally done, and I know it works. So far, there have
>>been no bent connecting rods I have seen from using this
>>method. No tools are used, and I grab it at the hub to
>>minimize leverage.
>
>Bill,
>I tried it and it worked like a charm. I used automatic
>transmission fluid (it needed a shot of after-run oil
>anyway), and a sort of "mental max torque setting" per your
>message. It took a moderately strong counterclockwise twist
>to break the prop loose so it could be unthreaded from the
>shaft, but I doubt that I came near bending the rod. No
>tools, no need to remove the muffler.
>
>>A tapered hand reamer works wonderfully compared to those
>>stepped prop reamers. Just be cautious with how much you
>>take out.
>
>Steve,
>Good point, since we're talking about removing only a few
>thou.
>
>>An easy way to loosen a prop without damaging anything is to
>>lock two nuts together on the outer end of the crank, hold a
>>wrench on the outer nut, then unscrew the prop.
>
>Mo,
>Sounds like another good, safe method.
>
>>Don't listen to Ted, Len and the other guys,listen to me!
>>hammer
>
>Ion,
>Uhhhh . . . yeah.
>
>------
>
>Quite a collection of replies. The guys on the Speed board
>should be so lucky! All this info and humor too. Leonard,
>Ted, Mike, and Ty crack me up, and Ion . . . well, doesn't
>even have to try!
>
>Thanks guys,
>Kim

KIM,
Thanks for getting back to us.

Scott(Yes things DO grow)Riese

and Ion . . . well, doesn't even have to try!

Should I feel flatered?

Ion (hit it with a hammer!) Muniz

>and Ion . . . well, doesn't even have to try!
>
>
>Should I feel flatered?
>
>Ion (hit it with a hammer!) Muniz

Ion,

Sure! It's always fun to read messages from a natural comedian!