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  1. #1
    Senior Member N867SP's Avatar
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    Default Dynamic Prop Balancing O340

    So I’ve lived with a little vibration for the past 200 hours. Ready to dynamically balance my prop. I own a Dynavibe and have balanced other engines previously. Typically I’d cobble up a bracket to hold the optical sensor and accelerometer and attach it to a case half bolt. The issue I’m having is the plenum on our aircraft. I’d rather balance the prop with the plenum and oil cooler in place. I read that the factory dynamically balances every aircraft that comes off the production line. Would it be possible to get some information on how the factory performs this? Maybe some pictures of their setup?


    Pete Meyer
    Severna Park, MD
    CCK-1865-0078
    ✈️N9PW
    Pete
    ✈️CCK-1865-0078 N9PW
    Severna Park, MD W18

  2. #2
    Administrator Jon Delamarter's Avatar
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    Default Re: Dynamic Prop Balancing O340

    We put the vibration sensor on the bolt just forward of the plenum. We have a plate adapter for the optical sensor that allows us to tape it down to the top of the oil cooler.
    Jon Delamarter
    Customer Support Manager
    Cub Crafters, Inc.
    jond@cubcrafters.com
    Office (509)367-5200

  3. #3
    Senior Member N867SP's Avatar
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    Default Re: Dynamic Prop Balancing O340

    Quote Originally Posted by Jon Delamarter View Post
    We put the vibration sensor on the bolt just forward of the plenum. We have a plate adapter for the optical sensor that allows us to tape it down to the top of the oil cooler.
    Thanks Jon. Pictures possibly?


    Pete Meyer
    Severna Park, MD
    CCK-1865-0078
    ✈️N9PW
    Pete
    ✈️CCK-1865-0078 N9PW
    Severna Park, MD W18

  4. #4
    Senior Member David H's Avatar
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    Default Re: Dynamic Prop Balancing O340

    I have done dynamic balancing on my other aircraft and it was very helpful. I will do this on the CarbonCub. I have my Catto 84x43 in the shop. Waiting for Fuel injected engine from Ly-Con.

    Pics would be helpful.

    Thank you,

    David

  5. #5
    Administrator Jon Delamarter's Avatar
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    Default Re: Dynamic Prop Balancing O340

    I've asked Production to let me know next time they balance the prop on a Carbon Cub so I can take pics.
    Jon Delamarter
    Customer Support Manager
    Cub Crafters, Inc.
    jond@cubcrafters.com
    Office (509)367-5200

  6. #6
    Senior Member Dan L's Avatar
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    Default Re: Dynamic Prop Balancing O340

    Aircraft Spruce had a recent sale on the Dynavibe Classic model and I decided to pick one up. I had a top overhaul on my O-340 this fall including new pistons and could tell there was more vibration than it had been. When I’d first changed to the 84x42.5 Catto I’d had it balanced by a shop an hour away and they got it down to .060 IPS.

    I’ve watched the balancing process a half dozen times or so and looked at a few you tube videos on the Dynavibe model. In the end I was able to get it balanced down to .080 IPS but it took me quite a few trial runs to get there. I started at .41 so it was a significant improvement.

    It is interesting that seemingly minor changes like going from a thin washer to a thick washer can make a big change when you’re getting close to the final solution.

    I like the Dynavibe unit. It’s easy to use and tells you where the weight is needed. This model does not tell you how much weight is required but their more expensive version does.

    5105516F-0538-49F8-8516-E0DD6D9475BF.jpg

    0047AF01-57EB-400C-B918-2D2E9192D2CD.jpg

    34DF04C1-3E39-44C1-8D21-9776E6F0CD80.jpg

    Here’s a few pictures of my setup.

    Also worth mentioning is that in the three times I had props balanced on this EX by others, prior to this balance, we reinstalled the top cowl between trial runs. That kept the section of the bottom cowl behind the spinner from getting blown back into the starter gear. Removing the bottom cowl completely didn’t seem like a good idea because the air intake into the carb would be unfiltered.

    This time I make a temporary filter setup from 3” and 2” PVC and a small engine filter from NAPA. This allowed a lot quicker periods between test runs.

    DE87178C-CD46-4F5A-B487-493ECED83F9E.jpg
    Flying Carbon Cub EX #11 since 2011

  7. #7
    Senior Member
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    Default Re: Dynamic Prop Balancing O340

    Quote Originally Posted by N867SP View Post
    So I’ve lived with a little vibration for the past 200 hours. Ready to dynamically balance my prop. I own a Dynavibe and have balanced other engines previously. Typically I’d cobble up a bracket to hold the optical sensor and accelerometer and attach it to a case half bolt. The issue I’m having is the plenum on our aircraft. I’d rather balance the prop with the plenum and oil cooler in place. I read that the factory dynamically balances every aircraft that comes off the production line. Would it be possible to get some information on how the factory performs this? Maybe some pictures of their setup?


    Pete Meyer
    Severna Park, MD
    CCK-1865-0078
    ✈️N9PW
    Have you had good success with the Dynavibe. Looks like about 3 balance jobs would pay for one.

  8. #8
    Junior Member
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    Default Re: Dynamic Prop Balancing O340

    Awesome Pictures! If anyone wants to rent a Dynavibe, BCAtools.com rents them out by the week.

  9. #9
    Administrator Jon Delamarter's Avatar
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    Default Re: Dynamic Prop Balancing O340

    Jon Delamarter
    Customer Support Manager
    Cub Crafters, Inc.
    jond@cubcrafters.com
    Office (509)367-5200

  10. #10
    Junior Member
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    Seattle, WA
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    Default Re: Dynamic Prop Balancing O340

    Hey Jon, do I recognize that plane?
    JimG

    FX3 - N18JG

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