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DJI P2 Props and Dynamic Balancing Them

Discussion in 'Phantom 2 Discussion' started by Xrover, Jun 4, 2014.

  1. Xrover

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    I've got 5 sets of props for my P2. 4 DJI White and 1 DJI Grey.
    I get minor vibration on the GoPro video. The amount of vibration varied depending on which set of blades I used. I bought a DuBro Truspin Prop Balancer and the P2 reverse thread balancing shaft from Atlanta Hobby. The shaft is a bit too short and barely hangs on the DuBro. I had a new shaft (6") custom made which works much better.

    The DJI Props are pretty well balanced from the factory so trying to get a really smooth slow roll on the DuBro Wheels is a bit challenging. But, with a bit of practice you will get the feel of it and it will work. I was always just balancing the props horizontally. I tried sanding the underside of the heavy blade but decided to add a piece of scotch tape to the underside of the lighter blade instead. The tape can be removed anytime, the sanding is permanent.

    I found out that just horizontally balancing the DJI blades is not enough. They are pretty well horizontally balanced.
    The Vertical Balance is where I saw big problems. After doing the Horizontal Balance then you do the Vertical Balance.

    40% of my blades were vertically out of balance. That is a Prop Hub issue. The Prop Hubs I have found are not true and that is where I see a problem.

    The Grey Blades were Horizontally pretty good but Vertically way off. I had to remove so much material on the hubs that I decided to toss the Grey Blades.
    Most of the White Blades Hubs were pretty close with a few exceptions.

    After searching and searching online for a good article on reducing vibration on Multirotors I came across this Gem.
    I finished Dynamically balancing my blades last night and had to set aside a few that were so bad with the hub center.

    I flew my newly balanced blades today. It did make about a 70% improvement. You can also hear the motors sound much smoother and make that intermittent raspy noise.

    Check out this article.

    http://www.rcgroups.com/forums/showthread.php?t=1921918
     
  2. Ozzyguy

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    Re: DJI Props and Balancing

    OK 3 things I've noticed about the article.
    1- don't sand or remove material from the light side of the hub. this will make vibration worse.
    2 trueing the hub would only work on props with a separate locking nut on top. Props with an integrated nut cannot be realigned in this fashion as it's all to do with how the plastic was moulded around the nut at the factory.
    If it was out of alignment when it set it can't be changed. This is because the nut screws on with the same orientation to the shaft every time (Unless you manage to cross threads). removing material from a high side underneath will do nothing.
    3-If you have props with a separate nut I would recommend you true them first. This is because any material you remove will affect the balance of the prop. Meaning all you hard work balancing may need to be repeated.
     
  3. Xrover

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    Re: DJI Props and Balancing

    Where did you read where it say's to remove material from the light side of the blade? That of course would make it worse.
    The post is really about balancing not truing the hub. Plastic material around the bottom sides of the P2 hubs can be sanded to get the hub to be balanced.

    We all have our opinions. Just saying the process worked for me.
     
  4. WessexWyvern

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    Re: DJI Props and Balancing

    It's interesting that some people don't need to balance their props where as others do. Mine have taken a bit of a battering due to a few newbie errors when I first got the Phantom as well as trying to land it on it's carry case (or not as the case maybe) in unrealistic wind speeds scraping the dirt on a few occasions.
    I wonder if it's not the props at all but the fact that the yaw motor can contact the battery which would negate any benefit of having dampers on the gimbal mount?
    I'm not challenging your assumptions - in fact I'm paying close attention to the jello threads that are posted but for the moment I seem to be fortunate in that I don't seem to be getting any jello yet I doubt that my props or hubs are particularly well balanced at all?
     
  5. damoncooper

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    Q: is there any simple ootb solution I can just buy for balancing P2 props yet?

    I've seen the multitude of threads about contacting Bob's uncle for a special rod etc, then saw that Bob's uncle stopped making them and people are trading them, seen the threads about balancing on a glass or whatever.

    Sure would be nice to point and shoot to buy a balancer that just worked with our props.
     
  6. Buk

    Buk

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  7. damoncooper

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  8. Ozzyguy

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    Re: DJI Props and Balancing

    No need to get defensive. You'll note I said hub not blade. Here's where it says it but obviously i made some miscommunication. I'm just offering tips in case someone new tries it and is completely confused. .I agree with the method just a few things i notice that may trip some up. Its 90% the way i do my props.
     

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  9. Xrover

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    No worriies Mate!
     
  10. Ozzyguy

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    Ha I see you speak the local language!
     
  11. sputnik

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    Here is the prop balancing method that I have been successfully using for over a year:

    I don't balance my props.
     
  12. tom3holer

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    That system looks straight forward and efficient.

    Tom