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Gain settings for 1270g Phantom

Discussion in 'General Discussion' started by Retroman, Nov 1, 2013.

  1. Retroman

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    So I have some custom landing skids and a few other bits on my phantom and the total weight is now 1270 grams. As this is a bit over the recommended weight by DJI(which I think is now 1200 grams) I was wondering what changes I should make to the gain settings in the naza assistant software?
    I think I really only need to change the vertical to maybe 110-120 percent but I'm not really sure.

    I'm running on firmware 4.02 with standard motors and props.
    Any ideas folks?
     
  2. miskatonic

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    Your Phantom is probably taking off at nearly 100% throttle, not really maintaining a hover and slowly sinking. Even with dual batteries, upgraded motors and larger props the most you are getting around minutes of hover time (not flight time) and you have to keep your hand on the throttle stick to keep the Phantom in the air.

    Adjusting the gains higher won't help. What it come down to is that your Phantom is simply overweight and will never fly far or maintain a proper hover. If your Phantom were bobbing up and down I could understand adjusting the gains by 20%-30% but an overweight Phantom is simply going to sink to the ground. What you need to do is get rid of the excess weight and trim your Phantom down to around 900g if you can.

    I once had that exact same set of landing gear, gimbal, and battery set up. I am really and truly trying to spare you some hard landings with this advice.
     
  3. Retroman

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    It takes off at about 50-55 percent and maintains altitude fine. Flight time on a 35c battery is about 8-9 mins.
    But I'm thinking if I change the gains I might get better performance at the expense of battery life.
     
  4. miskatonic

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    Wow, okay. I used to have that set of gear and mine weighed in at around the same weight. My landings were spectacular until I put my Phantom on a diet. :lol:

    If it is maintaining altitude then adjusting gains won't do anything. If it is bobbing up and down in the air then adjusting the gains will have some effect but it will be more of a fine tune. If you do decide to adjust gains then try to keep them under about 140%. For a mostly stock Phantom the defaults tend to work best.
     
  5. WReimer

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    Can I ask how many charge/discharge cycles you have on the battery that you're getting this performance out of? The other poster is pretty close to the mark; if you are still getting airborne at 50-55% and 8-9 min flight time with that gross take-off weight, I'm guessing it (the battery) has less than 30 or 40 full charging cycles through it.

    LiPo's are pretty impressive technology; great energy density for their size/weight. They maintain it very well in comparison to NiMh batteries, but they do still begin to lose ground, usually noticeable by 50-60 cycles. If you aren't there yet, you likely will be.
    I don't think you'd want to go up to even 140% gain, but that's just me. I don't think you'll really see much difference at that weight either.
     
  6. martcerv

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    Considering that in GPS and ATTI modes 50% throttle is hover you should always get lift off just above 50%. The actual RPM may be much higher when heavy but no matter how heavy it is 50% will always be hover. If its overweight it will have more trouble holding altitude when also moving forward and in 2nd level battery protection it will drop much faster if overweight and under propped.

    My 1200g setup was getting around 10 minutes slow flying using 2700 or 2800mah batteries using 2200's I was getting 8 1/2 and flying much more aggressively or pretty much flat out lol I would lose a couple minutes. I since added more gear and flying with a new gimbal and even a small battery for this with max weight at 1400g using 2700mah batt gets just over 8 minutes relatively slow flying. This is with tiger motors mt-2216 kv900 and GWS 9050 triblades that are great when phantom is a little obese. :lol: I will knock 50g off this when I stop using the extra little battery and I fly down to unloaded 11.1-11v on my OSD. Loaded will be 10.3 at high rpm or about 10.6v when just hovering around.

    Gain settings though all depend on the props your using and weight, there is no magic number best to adjust them in flight if you can with a 3rd party radio. Keep upping gain 10% at a time until it starts to oscillate then go back 10% from that point is a good way to go about it. If you cant do it in flight do the same just connecting to the computer and test flying each setting til you get to the point of oscillation and then back off 10-15%. Best to do pitch and roll together then do yaw and altitude seperatly once you have found settings for pitch and roll. With yaw just set it so it holds nose direction and same with altitude only adjust if your having trouble holding altitude or reaction is a bit too slow to throttle changes.

    Do this in calm conditions to get the best results but mine still fly's ok at stock phantom gains at max weight. I do adjust them up a little in flight sometimes but not much and I honestly dont even know the figure just the number of clicks on my futaba dial.
     
  7. Miika

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    There's something wrong with your Phantom, if this commentary is based on actual experience.... 1.3kg isnt a problem, and you should get 6-8 minutes of flight time with that setup.
     
  8. Peter Patricelli

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    The more of these I read the more I am drawn to the conclusion that there are some major differences between how some Ph's perform, and I mean flight times carrying weight, than others. There almost seem to be two different camps, those that can fully load a bird and with tweaked props, etc. can get much longer flight times and others that are lucky to get around 5 minutes. I am unfortunately in the latter group, no matter how much I try and emulate the exact setup, props, etc. that long flyers have.

    It is certainly possible that, right out of the box, all PH's are not equal. And the list of possible reasons, most likely hardware components, is really quite long.
     
  9. The Editor

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    Don't forget where people live/fly is a factor as well. High altitude means much thinner air and since multirotors do not benefit from collective pitch the motors have to spin faster just to maintain lift. This means far more mAh being consumed.
    Bet you're going to tell me you like 500m below sea level now.... :lol:
     
  10. fizzviic

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    For what it might be worth, I too have flown my Phantom in excess of 1200 grams. I found that sink rates could be high due of course to the added weight and directional changes could be quite dramatic due to "tossing" a whole lot of mass around and inertial resistance to directional changes, etc,

    One thing I haven't heard mention in all this, is at what density altitude are you flying. Props bite a whole lot harder ie are more efficient in the heavy atmosphere at sea level than they are in thin mountain air.

    At 1270 grams all up T/O weight and at sea level, I got a consistent 12 minutes of flight time on standard batteries and tri-bladed props. I have since gone back to a single battery setup because I felt the marginal gains in flight time were just not very efficient. I could get a whole lot more overall stick time by using those two battery separately and flying for 16 minutes instead of 12...more play time, as it were! And besides, my Phantom liked it better, too. :)
     
  11. Peter Patricelli

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    No, I'm not at altitude. Less than 500 feet above MSL....that is RISING!! And this is heavy, relatively saturated air.....which should give a good bite.