HL X Flight times

Discussion in 'Cinestar 8' started by Jose Luis Ocejo, Jan 6, 2015.

  1. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    Guys I wanted to cross reference the flight times some of you guys are getting with your setups
    Dave King mention that with the same motors but with MK BL3 and MK FC he was getting way more time in the air
    Im currently flying a CS8 coax frame with T- Motor U5 motors, DJI A2 controller, T-motor 40A Pro Esc, TM 16 CF props, 2x 10K 6S lipos, Power Hungry Dist, Gimbal M5 and a AUW of about 23.5 lbs, I'm getting about 8.5minute flight time with 20% left
    what do you guys think I suspect the difference could be the MK BL3 vs individual ESC
    any sugestions
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    Same frame with 500mm booms, all MK, KDE 4012 16" props, 2x10a Tattu or Pulse. AUW 22-23lbs. 12-14 minutes with 25% reserve.
     
  3. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    This question of flight time revisits the idea or perhaps a fact that the MK Bl-3 utilizes the power more efficiently vs individual Esc,
    other theory is that motors efficiency performance decreases after crossing a particular weight 1 pound could be the difference, Dave King mention some thing like this before, Im going to make some tests at 20,21,22,23,24 Lbs with my set up and see the time ratio differences put them in a graph and check if the curve is gradual or not hmmmm!!!
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    One thing you guys might be interested in is that, based on my ESC/Motor/Prop testing, the MK BL-Ctrl v3 uses "active" braking -- that is, if you are running a motor at X% throttle, and you (or the flight controller) decide to reduce the throttle, what I'm seeing is a large voltage spike come back from the motor down into the LiPo. That voltage spike is also accompanied by a back-flow of current, of course -- in effect recharging the LiPo with recovered energy.

    In one case, where I happened to be testing a 16 volts (simulating 4S), the voltage spike represented about 32 volts -- the Bl-Ctrl is apparently "dumping" excess charge caused by the the motor slowing down and acting like a generator, back into the LiPo.

    I see the same voltage spike at 6S too.

    Andy
     
  5. Steve Overstreet

    Steve Overstreet New Member

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    My latest iteration of a HL copter is as follows:
    CS 8 Frame
    Maytech 40 Amp ESCs
    Tiger 4120
    RCTimer 16x5.5
    WKM Flight Control
    2 x 10000 Mah Pulse batteries
    Copter weight = 15.5lbs
    test flight with 10 lb weight added
    AUW 25.6 lbs

    My flights (averaged over 10 tests, and watching only voltage not Mah used) provided me a very predictable and reliable 13 min of Hover time in Attitude only flight. A slight reduction of 30 sec in Att/GPS mode and again a very consistent average of 80 amps usage as measured through the Eagle tree system.

    I am currently testing the same set up with 20 lbs. of payload (AUW 35.5). So far I am able to get approx. 7.5 minutes if I bring the battery down to 3.3669 volts per cell under load. I have been very happy with the Pulse batteries as there has not been any sign of degradation and the internal resistance is still only 1.5 per cell upon each recharge.

    My personal opinion is that we are all (and I was was this way for over a year) very afraid of damaging the batteries. We are playing very safe with them, and rightfully so. In my limited experience I have found that the Voltage safety (of not bellow 3.3 under load) is far more important than the percentage of Milliamps used and allows me to use the power more completely, or, at least so far.
     
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  6. Aj White

    Aj White Member

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    This has been touched on a few other places but I am spurred on by Steves flight times.. I also am running X8 with U5 motors and want to try 17" props on it... has anyone done this already? Should I just stick with 16's?
     
  7. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    Hi Aj my x8 with U5 get warm with 16' props at 23 AUW after 8.5 minutes with 20% left, Hmmm? so 17" props at the same 8.5 minutes at the same 23 AUW motors would be hotter??? battery would be at 20%??
     
  8. Dave King

    Dave King Well-Known Member

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    HI Jose

    With my X8 copter I was using KDE 4014's with 2 QC10,000 batteries and lifting 25 pounds. I was getting about 12-13 minutes with about 15% left. Converted it back to flat 8 with the same 4014's and flight time jumped up to 16 minutes with the same motors. I was getting 18 minutes with the U5's at that same weight.
     
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  9. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    I guess then the benefit of the MK BL3 is the reason you are getting those better flight numbers
     
  10. Aj White

    Aj White Member

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    This is amazing to me, what prop size? U5 setup was flat 8? And running dual 10000maH right?

    Sorry I'm just really trying to bump up my flight times and if I can use my current U5's then I'll be stoked.
     
  11. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    Hi Andy are this findings conclusive, is this a strong theory back by MK as a intended or un intended feature of the MK BL3, I know I should send this Q to MK, I wonder if Herkules 3 boards have a similar advantage ?
    this feature alone justify the extra cost of the boards vs individual ESC.......I guess!!
     
  12. MIke Magee

    MIke Magee Active Member

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    Hi Jose. I'm experimenting with the Herk now, and it does have"active breaking with energy recuperation"

    http://kopterworx.com/shop/powerboa...ules-iii-3-6s-brushless-esc-okto-xl-1053.html


     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I'm pretty sure it is an intended feature of the MK BL-Ctrl v3, Jose.

    Andy.
     
  14. Dave King

    Dave King Well-Known Member

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    U5's with Tiger 16 inch props, 25 pounds running 2 QC 10,000 batteries.
     

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