Welcome! Becoming a registered user of ShortWingPipers.Org is free and easy! Click the "Register" link found in the upper right hand corner of this screen. It's easy and you can then join the fun posting and learning about Short Wing Pipers!

Thanks Thanks:  0
Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: Dynamic Prop Balance

  1. #1
    sierrasplitter's Avatar
    Join Date
    Dec 2018
    Location
    Lakeside California
    Posts
    313
    Post Thanks / Like

    Default Dynamic Prop Balance

    I had a small vibration and started asking around about getting my prop Dynamically balanced anywhere near my home airport . Found a guy up at Cable Airport in Upland California . I flew up today and the guy was done in an hour and a half at most .
    If your not familiar with the process it doesn’t require removing anything , the guy uses electronic sensors and records the vibration footprint of your aircraft . I say this because I think it could help some people on the forum to narrow down what might be causing your vibrations . He says he has data on lots of engines and what the issues turned out to be after repair . That data can be compared to your vibrations to help diagnose the problem if it’s more than an unbalanced prop

    The process was after he installed his sensors on my plane including a tachometer which also records true rpm ( bonus points / i found out my tach is low by 75rpm which makes my static rpm 2475 ! )
    Then you check vibes at 1000,1500 and 2000 rpm . He then added small washers that fit inside the spinner washers . He did say He usually adds small weights to spinner plate too but mine wasn’t too bad . He then checked again at 2000 rpm . Added one more washer at a different spinner screw . And tested again
    Then He painted the back with spray paint but added 3 coats on one side and one on the other . Another 2000 rpm test and we were done
    Cost 160 dollars and my plane feels great !!! I did have a bad vibe at 800 rpm . Gone ! I highly recommend this even if you have to fly a few hours to get to someone

    Bonus - I met a guy with a citabria going the same place as me so we flew formation ��

    0E7E8528-BC10-419D-860D-B44377016BC4.jpeg
    Last edited by sierrasplitter; 02-11-2021 at 08:54 PM.

  2. #2

    Join Date
    Sep 2011
    Posts
    69
    Post Thanks / Like

    Default Re: Dynamic Prop Balance

    Getting it done come summer time with my whirlwind prop, can’t wait!

  3. #3
    moto657's Avatar
    Join Date
    Aug 2018
    Location
    Canyon Lake, CA
    Posts
    57
    Post Thanks / Like

    Default Re: Dynamic Prop Balance

    Awesome info Ray! I’ll definitely be heading to Upland at some point. I want to repitch my prop first. I don’t think there’s anyone local that does it anymore though.

  4. #4
    walt.buskey's Avatar
    Join Date
    Apr 2012
    Location
    Etna, NH
    Posts
    833
    Post Thanks / Like

    Default Re: Dynamic Prop Balance

    That's what my A&P used in trying to find our vibration, a dynamic balancer that he had recently acquired.

    Good thing -- he found there was serious vibration that had apparently been there for years. Unfortunately, it couldn't be eliminated with weights or prop overhaul so we pulled the engine.

    Now being completely overhauled.... But I'm still glad he found it, which caused us to dig further. Engine shop says most likely an un-documented prop strike at some point -- crank prop flange was potato-chipped, significant other damage. (sigh...)

  5. #5
    Administrator Steve Pierce's Avatar
    Join Date
    Nov 2007
    Location
    Graham, Texas, United States
    Posts
    13,441
    Post Thanks / Like
    Blog Entries
    1

    Default Re: Dynamic Prop Balance

    Thanks for the info. Saw the video on Facebook of your formation fly-by.

  6. #6
    Glen Geller's Avatar
    Join Date
    Dec 2007
    Location
    Beaverton, Oregon, United States
    Posts
    1,213
    Post Thanks / Like

    Default Re: Dynamic Prop Balance

    Good report, but I have a question:
    Did the technician install washers to the spinner and backplate screws (forward of the nose bowl), or the flywheel (aft of the nose bowl)?
    I have seen many planes in my group including my own PA22-150 where the nuts/bolts/washers were applied to the flywheel (which has 12 holes evenly spaced just inside of the OD.) I have never seen them installed on the spinner or backplate.

    The accelerometers and diagnostic scope set-up is very cool, and when I had my reconditioned prop installed and balanced it was a real noticeable improvement vs 20+ years since the last time.

    In the Pacific Northwest my IA recommends http://www.nwpropeller.com/ in Puyallup WA, they did a fine job for all of our Tri-Pacers and Cherokees etc.

    I looked for a video showing dynamic prop balancing on a Shortwing, but the following is the closest I could find.
    Think of it as a super Pacer that was exposed to gamma radiation.
    I mean, it's green so maybe?
    https://youtu.be/5t70r2f0G8U

    Cheers,
    GG
    Glen Geller
    1955 PA22-150 "One For Papa!"

  7. #7
    sierrasplitter's Avatar
    Join Date
    Dec 2018
    Location
    Lakeside California
    Posts
    313
    Post Thanks / Like

    Default Re: Dynamic Prop Balance

    Did the technician install washers to the spinner and backplate screws (forward of the nose bowl), or the flywheel (aft of the nose bowl)?
    I have seen many planes in my group including my own PA22-150 where the nuts/bolts/washers were applied to the flywheel (which has 12 holes evenly spaced just inside of the OD.) I have never seen them installed on the spinner or backplate.
    He said my cowl was too close to the flywheel to use weights on the flywheel so he had a set up where he removed a washer from the spinner and added a weight washer there .

    And the Dynavibe unit shown in that video is the exact unit the guy used on my plane.
    Last edited by sierrasplitter; 02-16-2021 at 08:22 AM.

  8. #8
    Tailwind_Fan's Avatar
    Join Date
    May 2019
    Location
    East of the Sierra Nevada Mountains...
    Posts
    168
    Post Thanks / Like

    Default Re: Dynamic Prop Balance

    During my extended annual this fall, my flight instructor (heís also an A&P) Dave was messing around with the balance on his rental Cherokee. He tried a dynamic balance but was disappointed in the outcome. So he got a static balancer. He offered to help me with my propeller too. We wound up with a couple of washers on my propeller bolts, then finished it by adding paint to the tips of my propeller to chase the last few tenths. Honestly, it really helped. So much so it seems as smooth as Daveís dynofocal mount Cherokee.

    -Alana
    Last edited by Tailwind_Fan; 02-18-2021 at 12:26 AM. Reason: Misspelled word

  9. #9

    Join Date
    Feb 2010
    Location
    Eufaula, OK
    Posts
    782
    Post Thanks / Like

    Default Re: Dynamic Prop Balance

    I prefer to put weights on the flywheel because I don’t like drilling holes in spinner back plates (common on constant speed setups) and there is no concern that it will be reassembled in the correct position. Spinner components and props don’t always go back on the way they came off. Sometimes the flywheel is not a good option if there is a long prop extension. I am surprised there wasn’t room for weights on the flywheel of the original poster’s aircraft. Clearance has not been an issue for anything I have done. Washers on prop bolts will work but I seldom have enough bolt length to add washers without changing bolts (which I don’t have on hand) and again the parts need to be tracked/marked to be reinstalled where they belong if they are removed before overhaul.

    I have used spinner screws to attach test weights but haven’t used that as a permanent fix. Here again, fastener length can become an issue if starting with the minimum length and I would be concerned the washers would not be reinstalled to the correct location the next time the spinner was removed (should happen at least once every year). I don’t know about anyone else but when I pull a spinner I pull screws and drop them in a container a few at a time without paying much attention to them.

  10. #10
    sierrasplitter's Avatar
    Join Date
    Dec 2018
    Location
    Lakeside California
    Posts
    313
    Post Thanks / Like

    Default Re: Dynamic Prop Balance

    I would be concerned the washers would not be reinstalled to the correct location the next time the spinner was removed (should happen at least once every year). I don’t know about anyone else but when I pull a spinner I pull screws and drop them in a container a few at a time without paying much attention to them.
    I am the opposite. Based on my daily work I learned a long time ago to mark or make note of where screws go in anything i take apart. And with the guy only being an hour away and 160 bucks for the service if I had to I would do it every time the spinner was removed. Its worth getting the vibrations out so It doesn't carry trough to the rest of the engine/airframe

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •