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Can't remove the prop flange from the crankshaft

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  • Can't remove the prop flange from the crankshaft

    Looks like this annual is full of bad news... the wheel pants have cracks, all the cables need to be replaced, and the prop, a flottorp, may be impossible to overhaul although I found a shop that may do it (but I need the yellow tag).
    The last thing is the flange of the prop is solidly rusted on the crankshaft... and may be impossible to remove. The IA and me tried everything ie heat it up, soak with LP2/WD40 and use that blaster compound.
    I may have to scrap the plane i.e part it out if that flange can't get out.
    Got a tailwheel rating out of it and got it for cheap too and the engine + everything seems well preserved but I won't invest into an IRAN engine op if that flange is welded to it.
    It sucks someone neglected this good bird to the extent the prop stayed on there forever.
    Any ideas? experiences? I love it certainly but besides selling it as a project or parting it out I don't see a way out.

  • #2
    The information in this article is very helpful for removing propeller hubs. Having a punch made and making a key for the snap ring are both very important.

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    • #3
      There are 2 issues here:

      1) The exposed tapered crankshaft is probably corroded and literally welded to the flange.

      2) The procedure described in the link isn't too difficult but we both suspect someone messed up the snap ring and the lip that hold it in place on an inspection... in fact this was the first indication of trouble. Subsequent inspection didn't bother checking the prop hub and removing the prop because of that mess up and the prop may have been on the plane for decades.

      If the exposed crankshaft is corroded game over... I am looking at an overhaul and crankshaft replacement.

      Sucks someone didn't bother to do the above right and this is now a showstopper of sorts.

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      • #4
        I sent the link to the IA and he confirmed this is what he tried to do almost as verbatim described. The problem is systemic corrosion of the exposed tapered crankshaft up to structural compromise.

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        • #5
          The key wedge is required to keep the snap ring from compressing, make sure it's a tight fit. If you can't get to budge extract the snap ring completely and clean up the edge. These rings are punched out and have one curved edge and a sharper edge where the die exits. File the edges if not sharp and install the snap ring with the sharp edge out. Slowly add force to the prop nut and give it a rap with a steel hammer add a little more force to the nut and swat it again. Keep this up until it pops free, this is how all the prop nuts get screwed up. Fresno has them. Most likely overtightened, the taper will really hold on even if its not keyed. Milling machines use this same tool attachment. Never had to use "man's red fire" to remove one, and some were really a challenge to remove. Don't know what "systemic corrosion" is, but clean the shaft and lubricate before installing the hub. If you can get your hands on Mastinox it is probably the best lube for this area, follow the instructions as it's dangerous to use. Cor-Ban would be a close second. It needs to be tight to the crank, follow the installation instructions. It does't need to be blue balls tight, or they get hard to remove.

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          • #6
            Being a novice at putting a flanged prop hub on I would have used Anti seize .

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            • #7
              A new hope... I got the attachments for the wheel pants yesterday from wag-aero... so at least the wheel pants can be refurbished. If I do the cables and get that damn flange out I am also overhauling the flottorp properller, as I did find a certified repair station able to do it (and the guy there is 86 but still kicking).
              If anyone is close to Tampa maybe help me? the idea of parting out a perfectly good airplane that is historic is fading away/

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              • #8
                There was a great article in the Cub type club notes in Vintage Airplane ( Cont A-65 Taper Hub Removal and replace.pdf ) on removing the hub from a tapered shaft. You HAVE TO USE THE SNAP RING TOOL or the ring will pop out! You also need a 5/8" bolt and 3' pipe to break it loose. Problem is a lot of guys just tighten the nut as hard as they can and make it almost impossible to remove. TORQUE PROPERLY or the next guy will not be able to get the hub off either! I am trying to make a simpler steel rid impact tool but mine wasn't nearly stuck enough to need it this year. Remember, we are SUPPOSED to be checking prop bolt torques twice a year on wood props! I checked around here and most people didn't know it was a requirement!!!

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                • #9
                  OK, PDF didn't attach. Trying again

                  Hank
                  Attached Files

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                  • #10
                    We had a long discussion on the forum about this approximately 10 years ago and Dave Rude provided an Aeronca service bulletin on tightening the hub nut. I don't have a copy here at the house but will make a copy when i get to the airport tomorrow and try to repost it here. It would be helpful if the Vintage Airplane procedure and the Aeronca service bulletin could be added to the reference section of the forum.

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                    • #11
                      Any update on this above? I was able to pull out the old prop successfully and now putting the new one in.

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                      • #12
                        Here is a copy of the Champion (Aeronca) service bulliten:
                        Attached Files

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