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Updates have made me somewhat nervous....

Discussion in 'Phantom FC40 Discussion' started by Bow Tie Mike, Nov 21, 2014.

  1. Bow Tie Mike

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    I have a never been flown FC40 and have added a dual battery bracket and prop guards and it seems to handle much different than the original phantom. I am flying it in a 12-15 mph wind. Seems to handle very loosely. I have made no corrections to the firmware.

    Is this normal?

    Terribly afraid of a fly away.

    Thanks bow tie
     
  2. darwin-t

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    Prop guards probably decrease performance some, as does extra weight. Do you know how much it weighs with dual batteries?

    I bought a kitchen scale at Walmart for less that 10 bucks.

    Have you crashed it?
     
  3. Beario

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    If you follow all of the pre flight preparation, you will never have a fly away. The prop guards affect performance slightly, but the 2 batteries on the side affect performance a bit more. You WILL notice the difference in that kind of wind.
     
  4. Molokai

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    Make sure you mount the batteries the narrow way instead of the wide way...it makes a HUGE difference in performance.
     
  5. zerodb

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    Prop guards definitely will have some effect in the wind, but I agree with the others; mounting dual batteries outboard of the fuselage not only has an effect on how efficiently the prop wash can clear the fuselage, it also dramatically changes the roll inertia (polar moment of inertia for those who are counting) by moving the most massive parts of the aircraft further away from the center of gravity. You're gaining battery capacity but adding weight and sacrificing maneuverability (maybe improving stability for video/photo use, though...)

    For what it's worth, you can get virtually identical flight time (maybe better, since the aircraft doesn't have to work so hard to maintain attitude) with a 4000maH Multistar battery for $25 and it fits in the battery compartment with just a little trimming behind the battery door, so it minimized any effect on the flight dynamics.

    That said, I'd really suggest you try ditching your double battery and prop guards and see if it flys more like you think it should... if there's something "off" in the NAZA tuning, you should probably figure that out.
     
  6. IflyinWY

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    I've done the dual batteries and prop guards in up to 20 mph winds. Yep, it flies like you don't want it to, loose and sluggish. :(

    I've also switched to the 4000 battery with better results because of less weight, reduced aerodynamic drag and more appropriate loading (the weight is closer to the center of lift). For 25 bucks, I think it's worth trying. :D I bought 4.
    FYI: The 4000 mAh 3S 11.1V MultiStar by Turnigy is a 10c vs the stock battery which is a 20c.
     
  7. G Tek Fab

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    Anyone try the multistar 3S 5200 mAh lipo, or the 6600 4S for that matter? :eek:
     
  8. zerodb

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    Those get significantly fatter and longer than the 4000maH, so it's gonna be a bigger project to get them to work. I don't think they'd actually fit INSIDE a P1 shell, unless you really carve up the cavity. Not sure. If so, you'll need an extended battery door, which means you're also pushing your CG even farther forward of center. If not, you've got to hang them outside (which may not be so bad, if you can tuck it behind your gimbal and balance the aircraft a little better)

    On the other hand, It literally took me about 30 seconds with a dremel to notch out my battery opening and door for the multistar 4000, it fits snugly and easily in the standard body cavity and with the stock battery door (cables outside), and it pretty easily gives me 12-14 minute flights with a gimbal and camera mounted, on stock props. Also that puts me at just barely over 1200g flying weight, so it seems like a pretty good sweet spot for my needs. And they're so cheap it's easy to have a few lined up and ready to swap out. I guess if i got into swapping to a P2 shell, I'd be interested in trying the bigger ones, but for now I just don't see the point.
     
  9. G Tek Fab

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    Thanks for the info, makes a lot of sence.

    I think I'll Give the 5200 a shot first and if it doesn't work out I'll put it in the classifieds and do a 4000.