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Phantom, Futaba T8J and gains...

Discussion in 'Phantom 2 Help' started by richlizard, Oct 11, 2013.

  1. richlizard

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    Hi all.

    I think this may be my first post and I have ended up here after watching pretty much all of thathpiguy's videos on youtube. Apologies if this has been answered before, but I have searched and searched for help for dummies but no luck.

    I have a DJI Phantom and Futaba T8J transmitter.

    Probably like most people, I have constantly added bits to my setup and the weight has changed constantly of what I am trying to control in the sky. I found that my simple hover was beginning to wobble and jerk around a bit.

    So after a bit of advice, someone suggested I downloaded the latest firmware for my gimbal, the Aeroxcraft. I did this and updated it. I have no idea what it was before or what changed, but now my phantom jumped all over the place. It would even vibrate with the motors off while stationary on my desk!! By twiddling around, I found out that this was down to the voltage setting being too high. I took a stab and halved it and the vibrations stopped. But I had no idea if I now had ideal settings or not.

    Still with me?

    Now someone started telling me about this thing called GAIN. (That was before someone told me you don't need to worry about this nonsense, just get cf props and balance them!!) I have read and read and still don't really know what anyone is talking about regarding gains. The best way I could learn was to look at demos. I saw that with gain too high, the phantom would wobble all over and read that with gains too low, the phantom would be sluggish.

    So how do you find out what is best for your own setup? I have been putting it up really high and getting wobbles. So I reduced it... and got wobbles. My mind has been playing tricks with me, but I found one particular video (and read lots of people do the same, but no proof!) where the guy flies his craft and adjusts the gains while flying on his Futaba transmitter. It makes sense that this is the only way to really see if you are benefitting from changing the gains.

    So this is where I am... can someone PLEASE tell me how to do this in what should now be apparent as basic a language as possible!

    From various videos, I have most of my switches set, but have nothing on those little black switches where most of them are for trim.

    I really would appreciate the help as even indoors right now, my phantom seems to have a mind of its own (with fully balanced props I might add).

    Thanks guys.
    Rich
     
  2. Gizmo3000

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    Location:
    Sherman Oaks, CA
    Gains are tricky things to grasp, . even I haven't done much with them. (my Phantom seems to fly ok with near stock settings).

    apparently it just stakes some trial and error , bump up the gains until you get oscillation and then turn them down 10% they say.

    with the Futaba we have the ability to remotely change them tho, (which I've never tried).
    But here's a video that shows it (with sub titles I guess)
    http://www.youtube.com/watch?v=ITJhJ34BiMc

    which CF props are you using?
     
  3. richlizard

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    Thanks Gizmo.

    I have read lots of times that when adding extra weight it is good to adjust the gains higher.

    The video you have posted is the one I referred to when I said I had seen it done whilst the craft is flying. It is precisely that which I would like to do.

    As it is, my phantom hops all over the place, even indoors flying on Atti where you would think it would hover like a table on legs!

    I have bought these props... http://www.ebay.co.uk/itm/2pairs-8x...om-/251306535073?ssPageName=ADME:L:OC:GB:3160

    I am tempted to go back to my original ones just to see if it is these props that are causing the problem.

    Cheers
    Rich
     
  4. Gizmo3000

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    Those props look like they move the same amount of air as the stock props
    but ya never know. couldn't hurt to try the stock props again.
    with these new brushless gimbals with dampeners, they're much more forgiving.

    what gain settings are you using right now? and how heavy is your Phantom in total weight?
     
  5. richlizard

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    The props are actually exactly the same weight as the stock props which surprised me a little. As for balancing, they were all over the shop but now pretty much perfect.

    I have now gone back to the default gains of 100 all round. But as mentioned before, it is really difficult to see what is and isn't improving things when you have to keep stopping and plugging it in to the PC. This is why I wanted to use the Futaba to adjust the gains so I could actually see what is happening in real time.

    The overall weight is 1170g

    I will take a video of it 'hovering' in my shack with no wind, with new props and then old props with various gains. Maybe I am just being too pedantic.

    Cheers
    Rich
     
  6. richlizard

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    I took some video of my copter bouncing around the shack, but thought better of it to waste time uploading when something definitely needed to change.

    I traced things back to when I messed with the firmware for my gimbal, so I went into the setting there and twiddled a little.

    I had just filmed some footy over the road and thought I would test it with these new settings.

    I am actually pretty pleased with the position hold and smoothness of this clip with no editing. So perhaps I have learned my lesson. Stop tweaking!!

    http://www.youtube.com/watch?v=rU9DmMAIeP0&feature=youtu.be
     
  7. MKheng

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    Always gotta tweak...