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Balancing question..

Discussion in 'Pro/Adv Discussion' started by 9V7W3, May 29, 2016.

  1. 9V7W3

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    So I got my balancer in the mail today.. I took out a set of brand new DJI white props I just bought and started on the first one. I've watched all the videos and everything and as everyone states started horizontally on the first prop.. It was near perfect as far as I could tell.. So then I went vertical.. It spun itself horizontal indicating a heavy hub. I decided to go the clear nail polish route since it seemed the easiest and having it readily available in my wife's arsenal..

    My question is this.. How much nail polish are you all finding you need to use to achieve hub balance? I used what seems to me to be quite a hefty blob which after 30 mins is still tacky, yet the hub is still heavy on the opposite side. Something just didn't seem right to me and before I destroy anymore new props I thought I'd ask. Here's a pic of the amount of polish applied so far. Sorry if it's hard to see but you can kind of see the outline of the glossy area. It's almost completely covering the whole area between the blades.[​IMG]


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  2. BVC

    BVC

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    Do all your props do this?

    Is this really an issue? With as many units sold and almost no one (compared to the masses) checks the balance of their props from DJI and no one from what I've seen posts up faults related to this said issue - is it something we really need to be concerned with?
     
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  3. 9V7W3

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    Well first of all I literally opened my balancer about an hour ago so this is the first prop I've tried.. I didn't want to move on until I asked.

    As far as balancing being worth it or not... Mechanically it makes sense to have perfect balance on anything rotating at such high speeds if not for anything else but the longevity of the motors and even the shell. I've read tons of posts about unbalanced props causing jello in video, louder operational noise, and maybe even contributing to the many shells that are cracking after extended use and motors ripping themselves out of the chassis.

    Will the props work out of the box with no immediate noticeable negative effects? Sure, that's the way I've been flying so far. But this is a hobby just like any and some of us are more OCD and perfectionists than others, I being one of them, and I would like to balance my props properly (no pun intended).

    No offense, but I wasn't asking if balancing the props was worth it, just a question about the methods and experience of others who have done the same.


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  4. dirkclod

    dirkclod Moderator
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    I balance mine and have used polish some but mostly tape now . Have never messed with doing the hubs but you haven't
    destroyed anything . I have just removed it with polish remover if I needed to .
     
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  5. 9V7W3

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    Yea I know I can remove it.. By destroy I meant waste time if I'm doing it wrong haha. I would think even as small as it is a hub being out of balance would create vibration just as the blades would besides the fact that every instructional video I've seen says to do it as well. I'm going to try another prop and see if the hub is out as bad as this one. I'm sure someone on here uses polish on the hubs and can chime in!


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  6. Sinisalo

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    I use sand paper to remove equal amounts of material from the top and bottom of the heavy side's blade and that seems to statically as well as dynamically balance the props for me. I used 400 then 800 grit sand paper, once it was balanced I smoothed out the plastic with 2000 then 3000 grit sand paper and my props are perfectly balanced. You have to be careful not to mess up the leading or trailing edges though.
     
  7. Reed L

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    I use polish but never in globs. Just spread it thin and add more coats if needed as each coat dries. For the hub, you can also polish a bit down the light side of the blade on both sides of the hub as well to even it out. I add the polish and let it sit for 10 minutes before adding another coat. Generally I don't need to add much polish but remember to add even coats across the full blade width when balancing the blades. Paint it on smoothly. I'm thinking that your glob, so to speak, may be affecting your balance, so just a thin even coat each time. I've never had to go more than 3 coats. But... Is Your Balancer Balanced? Be sure to check the rod first and make sure that your balancing machine is perfectly balanced, so the job can be done right the first time.
     
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  8. sdharris

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    Not entirely sure about the references to heavy hubs. I balance by applying tape under the blade between the hub and the 'twist or curve' of the blade. At most I've had to apply two layers as they're rarely off by that much.
     
  9. alokbhargava

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    I use sandpaper 400 and works good. You are right almost all props need balancing. Even hubs are not balanced. If blades are balanced perfectly, hub is a simple task
     
  10. 9V7W3

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    Thanks everyone.. I'll work on it again tonight.. For now going to enjoy a quick flight


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  11. 9V7W3

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    So after trying to balance about 5 pairs of DJI props I've found that about half of them are near perfect (only required some light sanding to one side of the hub) and the other half are very bad, blades included. Even the ones that came with the drone that I just flew with several times were significantly off.


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  12. Reed L

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    Sounds normal :) and that's why we balance them ourselves... I've only had one set that was balanced well on arrival. Even the carbon fiber 9450's were way off and I figured that with DJI saying that they were "tuned" that they would be balanced as well and that's why I bought a set... They were no better balanced then any of the other sets. 50/50 is about right, 50% are balanced really well and need no adjustment and the other half varies from slightly off to totally ridiculous. It's no wonder that so many shells were cracking with all of the vibration being put out by these not to "Tuned" props.
     
  13. 9V7W3

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    Yea that's what I was thinking.. I mean at $6 a pair how much can you really expect.. But one was so far off I decided to toss it but before I did I thought I would see just how ridiculous it was.. After sanding the blade for 10 minutes to finally get them squared away instead of adding weight to the light side I took out my Dremel and went to town on the heavy side of the hub. Well, I ground that side completely **** flat and it STILL was heavy on that side even though the blades were perfectly balanced in both directions horizontally. Like what the actual F..


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  14. Dounin Front

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    I balance my hubs also.

    I've balanced all 8 props that came with my P3 plus 2 DJI CF props as well. Each one needed a little weight. I ended up using electrical tape (available in colors). It's good because it's heavy so you don't need large pieces and it can be moved for perfect balance.

    I only found one hub needing weight and I had to put several layers of tape to make it balance. I double checked to be sure. With so many props to choose from, I just tossed the one with the bad hub. In hindsight, I should have saved it for testing - maybe check flexibility or fatigue.

    And I agree, there should be no debate on whether to check prop balance. It's a good idea and it's what we hobbyists do. Right?
     
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  15. mikesmiley

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    I found the DJI CF props to be way further from true than the stock/standard white plastic props.
     
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  16. BVC

    BVC

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    Sorry if I came off rude. Not my intention. I was just asking general questions as a whole to the forum as I'm concerned myself. Just trying to see an overall bigger picture and if it's really an issue I need to address myself.
     
  17. fropleyqk

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    It's not that complex of a process. I use sandpaper. Gently sand the underside of the heavier blade (staying away from the tip) until its balanced. I spent 10 minutes and balanced 3 sets of props. G2G.