Hello !
I've successfuly had my first crash! Everything on the plane is fixed by now but for one thing: the prop. It broke and i don't know how to take it off - i presume i don't need to use alot of strength. The spinner came off pretty easily but the prop - i just don't understand how to turn it without turning the shaft - the prop is attached to the drive hub and i can't turn one without turning the other. -Help- by the way it's an OS 46 LA..
thanks

Go buy yourself a pair of channel lock pliers and get an adjustable wrench and BLAMO ! turn the nut with the adjustable wrench and hold the shaft collar with the channel locks. GL

Who put it on for you ?

You have access to the broken prop hub I take It? Use those channel locks to hold on to the prop hub not the aluminum hub because you will bend it or at least nick it up pretty badly. Hold on to that broken prop hub and turn the nut counter clockwise. It should turn right off once you break the torque bond holding the nut against the prop and hub.

DS.

hi CGRetired, how is the Excelleron going? Has it had its maiden flight yet ?

Rather than using pliers use a tyrap or ziptie inserted into the exhaust port to hold the piston and shaft from turning while removing prop.

I've sometimes had luck "locking" the piston by pumping glow fuel into the chamber, typically via the exhaust port or by removing the glow plug. If the latter, you must replace the plug. The liquid will prevent the piston from moving past TDC. You should then beable to break the prop free from the drive hub as the hub won't want to turn anymore. The liquid can also be easily poured out the exhaust port once done removing the prop. I've never had any issue from this method and I would assume this is an acceptable practice as I have seen tools that screw into the glow plug port that cause an interference fit preventing the piston to pass TDC. Cheers.

JohnW's method sounds great. I never thought of an intentional hydraulic lock. Clever. If that doesn't work, use an old tooth brush handle or other soft plastic stuck in the exhaust port like delman suggested. You may need to whittle down the handle a little to fie in far enough to block piston travel.

DO NOT USE METAL UNDER ANY CIRCUMSTANCES IN THE EXHAUST PORT.

Hi Mr. Genius. Thanks for asking! Nope, not quite finished. I had been debating on putting a YS-110 on board, but the waiting time for those engines is a bit out of reality so I am going to continue and stick with the Evo 100.

Progress so far.. well, I had to fabricate a servo tray.. don't know what happened to the one that came with the ARF, but that was no big deal. I have the main gear installed, wing completed (with servo's installed), elevator, rudder hinged, tail wheel installed, one half of the pull-pull run completed. What remains is to put the elevator and rudder control horns/arms on, then finish installing the servo's and the other pull-pulls, the engine throttle, canope, cowl, then go over it one more time to make sure I didn't forget anything, then adjust all, or check adjustment for throws and so on, then it's maiden time.

I would imagine, if the weather holds out, I will have it airborne after I return from the Thanksgiving weekend in Massachusetts with my mom and brother.

DS

Hmmm.. I would think that using that much torque to remove a tight prop nut by hydraulic lock method may bend the connecting rod or piston rod or something. Not so???

DS.

use the copper glow plug washer inserted into the exhaust port to lock the piston while removing the nut.this is suggested technigue by clearance lee.i have used the hydraulic lock method when tightening rotors on ducted fan engines where there is no aceess to the exhust port due to the pipe being installed..just make sure all the fuel is drained out before trying to start with an electric starter,turn it over by hand a few times to make sure

Tou're right sbd-5 and I do recall see Mr. Lee sying that before. I just didn't want any steel like screwdriver blades in there. Soft copper is good or probably brass fuel line would probably be just fine too.

CGRetired - I hope our parts aren't that poorly made. Wouldn't want to hit it with a starter in that condition but a slowly applied application should break the nut loose OK.

Very good advice! Try holding the prop (or remnants) first, then if that does not work try the methods that prevent movement of the piston. Use of pliers on any part you don't wish to mar is usually a bad idea.

jess

If the aluminum hub breaks or bends from holding it with channel locks you will be in a world of hurt when it heats up from friction and you are flying 300 feet in the air ! GL

You miss the point, RC- The question is not bending or breaking the hub/drive washer, but unnecessarily nicking/marking/defacing the rim with plier marks. Perhaps you have heard the term "Plier Mechanics" or "Hammer Mechanics"? These terms derive from the usage, by those who know no better, of incorrect tools for the job, often resulting in damage or defacing of the parts worked upon.

Many of those who enjoy model aviation also take pride in craftsmanship and proper usage of tools. Obviously, however this is not now a prerequisite of the hobby.

Enjoy your hobby,

jess

All of this is irrelevent , I use tools every day as mentioned above , the most uneducated person would know to wrap the hub with something before using channel locks on it , IF THEY even cared about a few marks . The choice is yours , do it the way you like and GL.

I had to do a google search to find out what channel locks were...it seems it's an American generic term for any kind of pliers. Not a good idea.

Likewise, I wouldn't go putting anything in the exhaust port if I could help it because any binding will be on one edge of the piston and could deform it (well, maybe on a cast iron piston you might get away with it ). A hydraulic lock with fuel at least spreads the load evenly across the whole piston and won't try to rock it to one side.

It probably won't take much force to break the remains of that prop free because I'll bet it was a tightish fit to begin with and needed to be wound on over the plain area of the crankshaft. For a hydraulic lock, fill the cylinder so the piston locks about half way up the stroke. This puts the angle of the rod at about 90 degrees to the crankshaft and gives less strain on everything.

[quote]ORIGINAL: RC-FIEND

I use tools every day as mentioned above , the most uneducated person would know to wrap the hub with something before using channel locks on it , IF THEY even cared about a few marks .


I am sure you use the tools well, as you use them every day. I am also sure, that as a craftsman you care about tool marks.

I am pleased that we agree on this matter.

jess

What we all like to call channel locks are actually adjustable tongue and groove pliers like the ones on the Channellock web site
http://www.channellock.com/acb/store..._Groove_C3.cfm
Maybe channellock invented or patented the design and the brand became the name of the tool?

If you have an extra prop nut. Just tighten them together on the engine shaft. Hold the outer nut with a wrench, and unscrew the prop. by hand.
If a spinner is installed the spinner backplate will stop the prop from unscrewing.
You can also use a two jaw pulley remover, from the auto parts store. Remove the supplied jaws, and replace them with zip ties, wrapped around the tools' frame, to the back of the propeller hub (crisscross them). Then carefully thread the pullers' screw onto the engines' propshaft, protecting it with a small piece of wood, or plastic to protect the end of the shaft from damage.
Then gently apply pressure with the pullers' screw. In small increments, until the prop pops loose.
Of course tower hobbies also sells a complete puller set to make this job much easier

Definitely not any kind of pliers .


Just hold the double ended broken prop with the channel locks and unscrew the nuts with a box wrench.

causing hydraulic lock , and sticking something in the exhaust port is just to much damn work for me to even try doing this to free a nut.

JessieJ we don't agree, I can care less about some marks on the hub, the nut , the engine block , etc . I am not that prissy to worry about small marks on the hub VS worring about getting back in the air.

I have broken both ends off of a prop only once, and I think I just held the prop with my hand and turn the nut with a box wrench to get it off , GL.

why not a pencil torch? I used one many times because I use a drop of blue locktite, It dont take much heat to remove it. It wont even warm up the crank.

Thanks, that's what I thought might have been meant by that. In Oz we call them multi-grips.

You can always use the time tested method. Remove the carb and insert an end of old nylon toothbrush into the crankshaft slot. You'll end up with a positive lock and no chance of damage to the engine parts.

GAWD people, we've given this poor man about a million ways to perfore a task that a monkey could perform. I really like the way this post has gone, especially when one poster says something to the effect that we don't even have to be knoweledgable about tools anymore in the hobby--I guess the hobby would be better off if it were just a bunch of 80 year old men who only know about doing it the "goold -ol fashioned, hard way." What does that have to do with the OP's question.

man, just get ahold of the prop hub with some channel locks and take the damn thing off. It's simple. We worry about a few scratches on that prop driver, but don't think twice about sticking a screwdriver, or bread tie into the cylinder to "lock" the piston. UNBELIEVABLE. Listen to yourselves.

Everyone has an opinion, and are thoroughly convinced that there's is better than yours.

I think the man has enough information to remove his poor, broken prop. Let's turn our energy into helping someone else with a problem.

Let the flaming begin...

You are correct, RC. we don't agree. I would be ashamed of such shoddy work.

jess