New Project: MK X8 coaxial heavy lifter

Discussion in 'Cinestar 8' started by Dave King, May 3, 2014.

  1. Dave King

    Dave King Well-Known Member

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    Now that my main rig (flat 8 with Tiger U5's) is flying great I am starting a new project. At the very least this will be my backup copter. I"m hoping that this copter performs a little better and becomes my main rig. Here's what I am hoping out of this copter.
    1. Improved PH on tighter shots, looking for the copter to be a little more planted.
    2. Ability to shoot in higher winds (20-25 mph)
    3. Get rid of front boom so its not in the camera frame as much.

    Here's the Equipment I'm planning on using.
    *All MK electronics with external compass
    *KDE 4014 motors with 18 inch props
    *Cinestar frame with outboard battery plates just like my current rig. Using all metal clamps for the frame and motors.

    My payload is between 11.5 to 12.5 pounds.

    To compensate for the shorter flight times I plan on testing the QC 16,000 batteries. This will put my copter about 4.5 pounds heavier than my rig with the 10,000 batteries putting my total flying GAW at 29.5 to 30 pounds. I am pretty confident that the motors and electronics can handle the weight my main questions will be is there enough flight time to be gained from the bigger batteries despite the extra 4 pounds. I would love to see a X8 setup get 18 minutes flight time.

    I'm still waiting on the motors and the updated power board from Holger, hopefully I'll be assembling sometime in the next 10 days.
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    All the cool kids are doing it. :) Can't wait to see her come together, Dave!
     
    Shaun Stanton likes this.
  3. Jason Smoker

    Jason Smoker Active Member

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    interesting big rig!!
     
  4. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    Hi Dave Q I check KDE website and I notice that the 4014 motors are a preorder to a aprox ETA of 05/15 is this right and yours are from a limited batch, I guess I should call them
    by the way what is your progress on this new build
    Thanks
     
  5. Dave King

    Dave King Well-Known Member

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    I got my motors on Tuesday. I think they are the best selling motor out of their lineup and they can't keep up. I have all my parts except props and I'm working on it this weekend assembly the motors and wiring them up.
     
  6. Dave King

    Dave King Well-Known Member

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    Worked all weekend assembling the X8. Thanks to Quadrocopter for the last minute parts and to Steve Maller for getting Tiger props. My combo consists of MK electronics, KDE 4014 motors with 18" Tiger props. I tested the new combination using a mixer setting of 64 up and 67 down. I tested the combination with 10 pounds of weight and a flying weight of 24.75 pounds. Hover throttle was 58% (5% better than the U5 motors at this weight). Flight time was 15 minutes (about a minute and a half less than my flat 8 U5 combo). Next flight I tested the rig with flying weight of 27.25 pounds. Hover throttle was 62% and flight time was 13 minutes. All tests I used 2 QC 10,000 batteries. With the Flat 8 U5 combination my hover throttle is 70%.

    Overall impressions - It flew very smooth and was very stable. I noticed a small amount of improvement in PH overall but I contribute that to my flat 8 being very smooth and dialed in. I would like to see what flight times are like with the bigger QC 16000 batteries. There was a noticable difference in motor temperature between the bottom and top motors. The top motors felt hot compared to the bottom motors felt warm. Not sure if the bottom motors are being cooled by the top motors.



    _MG_1144 pool-1252.jpg

    _MG_1144 pool-1254.jpg

    _MG_1251.jpg
    24.75 pound flight
    MK Version: FC HW:2.5 SW:2.06a + NC HW:2.0 SW:2.06a BL:V3
    Flight date: 5/18/2014 5:30:16 PM
    Flight time: 5:30:16 PM.6 - 5:45:23 PM.0 (906 secs, 00:15:06)
    Batt. time : 900 secs, 00:15:00

    Start Lat./Lon. : 40.38463 / -80.0875258
    Elevation(GPS) : 0 20.66 42.616 m (min/avg/max)
    Altitude(Barom.): 3.65 35.95 58.35 m
    Vertical speed : -2.48 -0.02 1.69 m/s
    Max speed : 39.9 km/h
    Max target dist.: 17.8 m
    Max distance/LOS: 148.6 m / 158.9 m

    Sats : 9 12 13

    Voltage : min. 21.2, max. 24.2 V
    Current : 0.5 79 101.9 A
    Wattage : 11 1770 2201.92 W
    Capacity: 18088 mAh

    Motor1: 0.1 10.5 16.0 A Temp: 22 30 36 °C
    Motor2: 0.0 10.7 16.1 A Temp: 20 29 39 °C
    Motor3: 0.0 10.4 17.0 A Temp: 22 31 39 °C
    Motor4: 0.0 9.8 14.4 A Temp: 24 32 38 °C
    Motor5: 0.0 9.8 19.5 A Temp: 25 32 40 °C
    Motor6: 0.0 9.1 15.9 A Temp: 26 34 42 °C
    Motor7: 0.0 6.1 9.7 A Temp: 26 32 39 °C
    Motor8: 0.0 10.4 16.4 A Temp: 23 30 37 °C

    Magnet Field: 97 101 106 % (ok)
    Magnet Inclination: 57 65 80 deg

    Errors / warnings:
    FC-Flag "LowBat" (5) occured 527 times!


    27.25 pound flight
    MK Version: FC HW:2.5 SW:2.06a + NC HW:2.0 SW:2.06a BL:V3
    Flight date: 5/18/2014 5:10:04 PM
    Flight time: 5:10:04 PM.0 - 5:23:11 PM.4 (787 secs, 00:13:07)
    Batt. time : 782 secs, 00:13:02

    Start Lat./Lon. : 40.3846419 / -80.0875386
    Elevation(GPS) : 0 7.17 22.647 m (min/avg/max)
    Altitude(Barom.): 2.05 16.6 36.7 m
    Vertical speed : -1.24 -0.02 1.52 m/s
    Max speed : 18.9 km/h
    Max target dist.: 14.8 m
    Max distance/LOS: 73.9 m / 81.2 m

    Sats : 11 10 12

    Voltage : min. 21.1, max. 24 V
    Current : 0.5 92 111.4 A
    Wattage : 11 2061 2414.72 W
    Capacity: 18502 mAh

    Motor1: 0.0 11.4 16.4 A Temp: 24 33 38 °C
    Motor2: 0.0 13.1 17.9 A Temp: 21 31 38 °C
    Motor3: 0.0 11.4 18.1 A Temp: 22 31 38 °C
    Motor4: 0.0 12.6 17.5 A Temp: 27 36 42 °C
    Motor5: 0.1 10.8 15.9 A Temp: 28 34 41 °C
    Motor6: 0.0 11.4 15.6 A Temp: 28 39 46 °C
    Motor7: 0.0 6.4 11.2 A Temp: 32 36 43 °C
    Motor8: 0.0 13.1 18.2 A Temp: 22 33 40 °C

    Magnet Field: 97 99 104 % (ok)
    Magnet Inclination: 60 69 80 deg

    Errors / warnings:
    FC-Flag "LowBat" (5) occured 474 times!

    Thanks to all those that helped on the tech X8 stuff. It was a painless transition thanks to all the help from everyone here.
     
    Ruben likes this.
  7. Michael McVay

    Michael McVay Active Member

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    Just watched your video but have not studied the data yet. In reading your post I am a little surprised about the hover throttle percentages. I thought they would be lower at those weights. Maybe the KDE specs are a little "loose" in their accuracy. For example:

    On your second flight you hover 27 pounds at 62% throttle.

    KDE says 62% throttle would put out 2520 grams per motor (18 inch props right??)

    2520 * 8 (then x .85 for X8) is 17136 grams which equates to 37.7 pounds. Something seems a little off. You should have had 10 more pounds of thrust or the KDE specs are way off. If we were to blame it more on the X8 config and go 25% efficiency loss we would still get 33.3 pounds of thrust. If there is more than a 25% efficiency loss you might as well fly a flat hexacopter at that point in a much smaller footprint than a large X8. Obviously more reason to fly an X8 than that, but if we are saying all 8 motors together lose more than 25% or their power something seems wrong to me.

    Interesting, your amp draw is in line with the 62% hover throttle numbers on the KDE specs (chart attached) but the thrust does not appear to be very close.

    I also just built a KDE 4014 X8 with 18 inch tiger props but have only flown it around 21 pounds...did not even measure the hover throttle (and this one is on DJI so the data is not very good from the iOSD anyway). I will certainly test mine too to see if my numbers are close to the published specs or not and report back when I do that.

    Anyone else flying KDEs try to determine how close the specs below are to your real world examples?

    KDE 4014 Specs.png
     
  8. Michael McVay

    Michael McVay Active Member

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  9. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

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    Nice work Dave Q, how hi is your GPS hat in relation to the to side to side lipos do you have any concern for a strong magnetic field around your GPS I know you are very careful on that subject
     
  10. Dave King

    Dave King Well-Known Member

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    I use the external compass and put it on boom 1 so its really not a factor. I tried testing flights with internal compass versus external compass and my deviation % is very close to 100 with the external compass. With the internal compass on the NAV board I can see it as a high as 115-116 but not high enough to throw errors.
     
  11. Tim Sessler

    Tim Sessler Active Member

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    Curious to hear why you used those mixer settings. How is it different from the 64 up and 71 down standard X8 settings?
     
  12. Dave King

    Dave King Well-Known Member

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    I was luckily enough to have a friend with HL KDE motors who experimented through trial and error to get to these settings.
     
  13. Tim Sessler

    Tim Sessler Active Member

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    Interesting! Can you describe how its different form the 64/71 settings? Better stability, more responsive, better efficiency?
     
  14. Dave King

    Dave King Well-Known Member

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    From what I understand, the current numbers for each BL are more consistent with this mixer setting. At least for these motors.
     
  15. Steve Maller

    Steve Maller UAV Grief Counselor

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    I was the one who came up with the 64/67 numbers. I did some testing on my copter (a little different than Dave’s but close enough) and found the 71 number to be unnecessary. I think it might have to do with the difference in newer motors and CF props vs. older motors and nylon props. But I’m not sure it really matters that much. My copter flies great, and it sounds like Dave’s off to a great start, too. I suggest doing some measurements (both objective and subjective) and deciding for yourself.
     
  16. Bryan Harvey

    Bryan Harvey Member

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    Hi Mike, I posted the following over a month ago on the U7 thread:


    We have built and tested the KDE 4014XF motors on a Gryphon X8 frame with MoVI MR gimbal at 27lbs and 33lbs.

    specs:
    6S
    Castle Creations Edge Light 75A ESC's
    Xoar 17x5 props
    DJI A2 controller

    Based on KDE printed specs I was excited to test them as an alternative to the U7. But during bench testing we found the KDE motors had slightly more efficiency, but even less power than the Tmotor 4014, (similar in class to the U5).
    As there were no U7's available during this time, we went ahead with the build, hoping they would work for a RED payload.

    Testing:
    Carrying 20,000mah at 27lbs AUW, flight time was 12-13 minutes and the craft flew very nicely. Great for DSLR sized loads.
    At 33lbs. AUW (this is what it would be with a RED) flight time was 9 minutes, but yaw stability was compromised because the motors were operating near their limit. Any aggressive throttle inputs yielded adverse yaw effects.

    Motors and ESC's only slightly warm after all test flights.

    Now we are thinking about just getting an extra set of Gryphon folding boom arms and building them up with the U7 420 motors. We are using bullet connectors at the fold. We could switch arms depending on the load.
     
  17. Michael McVay

    Michael McVay Active Member

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    Bryan: Thanks for posting this. I do remember reading it on the U7 thread. How do you bench test your motor and prop combos? I am interested in getting the equipment to do this but am not sure where to start.
     
  18. Dave King

    Dave King Well-Known Member

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    I have a problem. Need help from those that use Alexmos. My 3rd axis (pan) board is bad. The unit doesn't initialize if I go through it but its fine if I bypass it. Where can you get the 3rd axis pan boards? Also where do you get replacement IMU cables?
     
  19. Michael McVay

    Michael McVay Active Member

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    Dave, look at the board and see who made it. I'm not sure if all the 3rd axis boards are interchangeable or not, but if we know who made it we can point you to getting an new one and some IMU cables.
     
  20. Dave King

    Dave King Well-Known Member

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    Here it is. No markings on it.

    pan board1.jpg

    pan board2.jpg
     

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