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Thread: Balance Master

  1. #1
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    Default Balance Master

    Has anyone tried this? https://www.youtube.com/watch?v=iZ8GqUNUcbM

  2. #2
    Senior Member efwd's Avatar
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    Default Re: Balance Master

    Yes, some people have tried it. Larry just put one on Mangy Fox and he gave it great reviews. Others have used them on trucks etc etc. It works. Search it here on the forum and you should find the thread. It was just last week that Larry posted on it I believe.
    Eddie Forward
    Flying
    SS7, 912iS, Garmin G3X

  3. #3
    Super Moderator Av8r3400's Avatar
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    Default Re: Balance Master

    I’ve got about 5 hours on it now. Combined with a 72” 2-blade Luga prop. She is smooooooooth.

    Even the dreaded 2500-3500 normal vibration is totally gone!
    Last edited by Av8r3400; 12-23-2019 at 06:10 AM.
    Av8r3400
    Kitfox Model IV
    The Mangy Fox
    912UL 105hp Zipper
    YouTube Videos

  4. #4
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    Default Re: Balance Master

    I guess maybe I'm just trying to improve something that ain't broken. Mine is very smooth thru the whole rpm range. I have a model 4/912ul with the Kiev 3 blade. Leaf has this and it seems like a good price compared to the price that others are asking. https://www.leadingedgeairfoils.com/propellers/balance-master/propeller-balance-master-6-hole-prop-black-anodized.html (I don't know why this won't highlight.)(Not sure if this is the right one since it doesn't say 912)
    It's cheaper than the coolant cap that I recently ordered. My flyin buddy, also with a model 4/912, has a rough midrange. He has a Warp Drive prop. Lots of work, even new carburetors haven't completely cured the problem. I'm really trying to spend some of his money hoping it will cure his problem. I think I'd probably get one myself just to insure mine is as smooth as possible. Should help the gearbox live longer too.

  5. #5
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    Default Re: Balance Master

    Wow! That's half the price of what I have seen.

  6. #6
    Super Moderator Av8r3400's Avatar
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    Default Re: Balance Master

    Quote Originally Posted by jrthomas View Post
    ... https://www.leadingedgeairfoils.com/propellers/balance-master/propeller-balance-master-6-hole-prop-black-anodized.html...

    I do not believe this is the one for a 912. The photo may not be of the actual unit, but the center hole and slot proportions are not correct for a 912. All of the other sources for a 912 ring are between $150 and $200.
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    Av8r3400
    Kitfox Model IV
    The Mangy Fox
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  7. #7
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    Default Re: Balance Master

    Looking at this $76 balance master, it says it fits the 75mm and 100 mm bolt pattern. The way I see it, this means it would fit on a rotax 2 stroke gearbox with the 1" boss in the center and it looks like the bolt slots are for an 8 mm (5/16") bolt. The real early 912s had a boss that measures about 1 5/16" and has 100mm bolt pattern, and the later 912s are about 1 3/4" boss with 101.6 mm bolt pattern. Long story short, I think Larry is correct. JImChuk

  8. #8
    Senior Member jrevens's Avatar
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    Default Re: Balance Master

    There has been a recent conversation about these devices on Shadowrider's build log... thought I'd bring it back over here. Larry's comments, as well as the fact that Hal Stockman was involved means a lot to me, and is also why I decided to get one and hopefully do a little testing. The price is not unreasonable, and worth it to me if there is truly some advantage over a good dynamic balancing job. Regardless of the fact that Balance Masters says you should not dynamically balance before using it, and that any weights should be removed, that just doesn't make any sense in my mind. Here are some comments from a Pilots of America forum back in 2015, where they were discussing these devices. I believe these were not Rotax powered aircraft. I thought they might be interesting to this group. The comment about seeing "smooth operation throughout the operational range (after a dynamic balancing) if they show smooth on the ground" is consistent with my experience. There is generally a good improvement throughout the range. The one stating that "If I balance an engine say at 2400 RPM to .04 IPS and test again at 2000 RPM it is going to be way off" has not been my experience at all... I see it as best at the balanced RPM, but usually not "way off" at other speeds. Also, the "Seat-O-Pants Meter" comment was accurate, IMO -



    "I balance props too using the DynaVibe. Thus I was interested in these things when I first heard about them. Reading about them over time, the most interesting and believable article was one in which a person adept at prop balancing compared using a Balance Master with the results of a conventional dynamic balance, on a prop/engine that had been deliberately put in an out-of-balance condition. The results as I recall were that the Balance Master improved the situation, rendering .11 -.13 IPS. With the Balance Master removed, the person with the balancing equipment was able to get it easily below .07. My take on them, just reading . . . all second hand . . . is that they can improve an out-of-balance condition, but will not improve it as well as a good dynamic balance job."




    "But the dynamic balance is only good at a certain RPM, and on the ground. I am very interested to see if these work at all RPM ranges and pitch angle of the props.
    I have a plane that I can get down to .07 IPS, but in the air it is still rough. I am leaning towards a constant speed prop issue rather than and out of balance issue. I'm hoping this gizmo will help.
    I might be overly optimistic, but it will be fun to see."




    "Where I'm going with this is once it is balanced, any excessive vibration is likely not a result of simple dynamics. Our engines generally operate in a fairly narrow RPM range so balancing it at a particular RPM is not a big deal."


    "I'm curious about how many folks experience vibration problems after a dynamic balance? What I've seen is that the engine/prop are smooth throughout the operational range if they show smooth on the ground. Maybe not perfect throughout the operational range but pretty darn good."



    "Balancing certainly makes a difference, but anyone that dynamically balances knows that the balance is only good at a certain RPM. If I balance an engine say at 2400 RPM to .04 IPS and test again at 2000 RPM it is going to be way off. I have seen it go to .15 IPS easily. This "constant balancer" should work at all RPM ranges."



    "Do you think you're finding a harmonic? I don't think so. On certified equipment the RPM with that type of problem would be either "avoid" or prohibited.
    I think you're seeing an engine problem which might be a simple thing like slightly fouled plugs or an intermittent plug wire failure.

    Possibly harmonic, but in my experience all airplane engines with props seem to do this. This is why we balance to cruise RPM, or as high as we can get static.

    The difference between .15 & .04 IPS to the pilot (seat-o-pants meter) is pretty small. They might not even be able to feel it depending on the airframe."

    John Evens
    Arvada, CO
    Kitfox SS7 N27JE
    EAA Lifetime
    Chap. 43 honorary Lifetime

  9. #9
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    Default Re: Balance Master

    Thanks John. Curious to see your results. Also I am going to put the weights back on mine that had me down to .05 and see if what it feels like with the BM and I will report back. Sorry no official data will be recorded other than seat of my pants.
    Dustin Dickerson

    Building 7ss STI x 2
    Oratex
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    N53TF......FLYING!

  10. #10
    Senior Member Dorsal's Avatar
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    Default Re: Balance Master

    Mine just arrived today, the comments that it may smooth out some of the transition rpms is what convinced me to try it. Will report measured results (ips/rpm) when my traveling Dynavibe is back home.
    Dorsal ~~^~~
    Series 7 - Tri-Gear
    912 ULS Warp Drive

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