My new MK heavy lift copter project

Discussion in 'Cinestar 8' started by Dave King, Jan 4, 2014.

  1. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Cedar: Does Holger know that you had a MOSFET blow its brains out?

    I'm a bit suspicious of whether there is an underlying commonality between what you had happen and what Steve had happen and that it would be helpful for Holger to know of MOSFET's that join the choir eternal, etc.

    Andy.
     
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  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    ...almost forever. I had one BL 2.0 transit to the other side in my OctoXL board a few months ago after nearly a year of flawless operation. The copter was out over the ocean in clear skies with no noticeable moisture in the air, and I have no idea what might have happened. The good news is that the copter did what it was supposed to do, and I landed it without incident.
     
  3. Dave King

    Dave King Well-Known Member

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    Update: I have the copter all back together with the larger 550 booms and the U5 motors. I had to extend the motor wires which was a real pain in the neck. I have 16X5 Xoars to test and then will install Tiger props after I do about 6 flights. I fired it all back up and I have one small problem. I have a bad U5 motor. It doesn't sound all that great and as luck would have it just about everyone in the country is out of stock. I found one small dealer that had it so I should have it tomorrow and hopefully if the weather holds I'll be back up in the air this weekend.
     
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  4. Howard Dapp

    Howard Dapp Active Member

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    Soon enough Dave, you'll be there.

    One thing I'm not happy about with this new line of U-motors is the use of a 4mm motor shaft. I think at minimum these hefty motors should have 5mm shafts installed. A single prop strike could end with a bent shaft.
     
  5. Ozkan Erden

    Ozkan Erden Distributor

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    Dave, can it be a bearing problem?

    Howard, foxtech has a quick propeller detach kit. I ordered it and has not arrived yet but, it can be a good solution for keeping the props away from thecrashes while transporting and storing.

    http://www.foxtechfpv.com/propeller-quick-detach-cwccw-p-1303.html

    My only concern is if they will unbalance the motors or not.
     
  6. Chris Fox

    Chris Fox Active Member

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    G'Day Ozkan,

    What goes on easily comes off easily, if you run the MK BL 3 with the regen/active braking feature, the motors will be unscrewing themselves from the propellers. For V2 BL controls, or standard ESCs the quick connects should work as advertised.

    Just my 2 cents, milage may vary :)
     
  7. Howard Dapp

    Howard Dapp Active Member

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    Thanks Ozkan, they look good but I wouldn't consider installing quick disconnects on any of my filming birds...I would drive myself insane with worry.
     
  8. Ozkan Erden

    Ozkan Erden Distributor

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    Good point Chris.

    Howard, I agree with you about being cautious. I will give them a try on a small bird to see how they can be trustful.
     
  9. Steve Maller

    Steve Maller UAV Grief Counselor

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    If you're that worried about this stuff, I'd look into the foldable props like DJI are using on their newer big copters. But at the end of the day, I'd be really wary of those, too.
     
  10. Dave King

    Dave King Well-Known Member

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    I got the new U5 motor this morning and was able to do some testing this afternoon. The results are a little better than I expected and I believe I will be right on the money with my expected flight weight with the red and the brushless motor gimbal.

    As a recap, previously with the U5 motors and the Xoar 15X5 props/500mm booms at about 23.5 pounds (106k grams) I got these results
    XOAR 15X5 props at 23.5 pounds
    Hover throttle - 68%
    Flight time: 1:41:08 PM - 2:01:09 PM (1201 secs, 00:20:01)
    Batt. time : 1194 secs, 00:19:54
    Elevation(GPS) : 0 22.28 53.88 m (min/avg/max)
    Altitude(Barom.): 0.2 26.87 58.55 m
    Vertical speed : -2.78 -0.02 2.49 m/s
    Max speed : 45.8 km/h
    Max target dist.: 16.6 m

    Sats : 7 9 12
    Voltage : min. 21.2, max. 24.8 V
    Current : 0.5 63 87.1 A
    Wattage : 11 1445 2072.98 W
    Capacity: 20983 mAh

    Motor1: 0.0 8.6 14.5 A Temp: 5 12 21 °C
    Motor2: 0.0 8.5 14.0 A Temp: 7 13 23 °C
    Motor3: 0.0 7.1 11.9 A Temp: 6 11 20 °C
    Motor4: 0.0 6.8 12.1 A Temp: 4 9 21 °C
    Motor5: 0.0 6.4 12.0 A Temp: 5 9 19 °C
    Motor6: 0.0 7.6 12.2 A Temp: 1 9 21 °C
    Motor7: 0.0 6.3 10.4 A Temp: 4 9 16 °C
    Motor8: 0.0 9.8 15.6 A Temp: 4 13 22 °C

    Today with a 10 pound payload and a total GAW of 24.25 pounds (11k GRAMS) I made one flight and landed with plenty of juice to spare so I could test with 12.5 payload after this test. To keep things consistent I used the Xoar 16.5 props but will test soon with the Tiger props.
    XOAR 16X5 props at 24.25 pounds
    Hover throttle - 60-61%
    Hover current - 65 amps

    Flight date: 2/1/2014 1:13:25 PM
    Flight time: 1:13:25 PM - 1:27:16 PM (831 secs, 00:13:51)
    Batt. time : 826 secs, 00:13:46
    Elevation(GPS) : 0 6.51 15.732 m (min/avg/max)
    Altitude(Barom.): 2.8 11.94 17.5 m
    Vertical speed : -2.32 -0.02 1.93 m/s
    Max speed : 17.6 km/h
    Max target dist.: 16.6 m

    Sats : 9 9 12
    Voltage : min. 21.9, max. 24.5 V
    Current : 0.5 65 83.5 A
    Wattage : 11 1512 1858.2 W
    Capacity: 14978 mAh

    Motor1: 0.0 7.6 10.8 A Temp: 10 22 30 °C
    Motor2: 0.0 8.5 13.2 A Temp: 9 20 28 °C
    Motor3: 0.0 6.3 9.1 A Temp: 12 19 25 °C
    Motor4: 0.0 8.1 12.4 A Temp: 9 21 31 °C
    Motor5: 0.0 6.4 8.8 A Temp: 12 21 30 °C
    Motor6: 0.0 9.1 11.6 A Temp: 13 32 37 °C
    Motor7: 0.0 6.2 8.3 A Temp: 14 24 31 °C
    Motor8: 0.0 10.7 14.6 A Temp: 13 31 38 °C
    Magnet Field: 98 101 108 % (ok)
    Magnet Inclination: 62 68 73 deg

    Calculating the mah/second consumed I would have gotten 19.5 minutes flight time on a set of fully charged batteries. So even though I added about 3/4 of a pound compared to the tests with the 15 inch props my numbers are very reasonable and the hover throttle is better than expected.

    I then added another 2.5 pounds to make the payload 12.5 pounds with a full up weight GAW of 26.75 pounds (12.2K grams)
    It was definitely too much and made a drastic difference with the hover throttle taking it from 60-61% to 75-76%. Hover current was about 78-81%. Here's the numbers.
    XOAR 16X5 props at 26.75 pounds
    Flight date: 2/1/2014 1:31:06 PM
    Flight time: 1:31:06 PM - 1:34:55 PM (229 secs, 00:03:49)
    Batt. time : 227 secs, 00:03:47
    Elevation(GPS) : 0 5.73 16.913 m (min/avg/max)
    Altitude(Barom.): -0.05 8.77 20.9 m
    Vertical speed : -2.52 -0.02 1.75 m/s
    Max speed : 11.4 km/h
    Max target dist.: 16.6 m

    Sats : 7 7 10
    Voltage : min. 21.1, max. 22.5 V
    Current : 0.5 78 111.1 A
    Wattage : 11 1730 2399.76 W
    Capacity: 4980 mAh

    Motor1: 0.0 9.5 13.4 A Temp: 13 29 37 °C
    Motor2: 0.2 11.5 17.1 A Temp: 11 30 38 °C
    Motor3: 0.0 7.8 11.8 A Temp: 13 26 32 °C
    Motor4: 0.0 9.5 13.1 A Temp: 9 24 31 °C
    Motor5: 0.0 6.9 8.7 A Temp: 12 21 27 °C
    Motor6: 0.0 10.3 12.7 A Temp: 13 34 41 °C
    Motor7: 0.0 7.5 9.2 A Temp: 15 26 31 °C
    Motor8: 0.0 13.6 18.2 A Temp: 15 36 45 °C

    Magnet Field: 99 98 102 % (ok)
    Magnet Inclination: 67 69 73 deg

    No errors found ;)

    I included both GPX files.

    Here's a crappy pic I took with my cell phone today.
    02012014.jpg
     

    Attached Files:

  11. Chris Fox

    Chris Fox Active Member

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    I see you got the weight lifting sorted ;)

    It's funny how when your at the edge of the curved the weight can be ok, but a bit more and it's then way off ... Glad you're airborne again
     
  12. Michael McVay

    Michael McVay Active Member

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    Glad to see the new numbers...looks like the 16 inch props were just what you needed. Looks great. How close together do the 16 inch props get on the 550mm booms?
     
  13. Dave King

    Dave King Well-Known Member

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    Thanks Michael - 2 inches
     
  14. Michael McVay

    Michael McVay Active Member

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    Nice, so you technically could squeeze 17 inch props on if you wanted to. I like having a little extra space between them, but at least you know you could do it if you had to. And since the Tiger prop you are going to change to has a little more pitch than the XOAR prop your hover throttle should take another small dip as well.
     
  15. Dave King

    Dave King Well-Known Member

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    Yeah huge difference between 10 pounds and 12.5 pounds. I think I can keep my RED and BL gimbal payload to 10.5 pounds which should be perfect with the Tiger props.
     
  16. Chris Fox

    Chris Fox Active Member

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    What sort of lens are you looking at running to keep it at that weight? 20mm f/2.8 or similar?

    Our follow focus has now arrived, so by the time that and the tomahawk goes on, we won't have a chance at keeping under those weights.
     
  17. Dave King

    Dave King Well-Known Member

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    20mm and 24mm IS prime lenses.
     
  18. Chris Fox

    Chris Fox Active Member

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    G'Day Dave,

    Just wondering how your upgrade is running now, working a treat?

    Cheers
    Chris
     
  19. Dave King

    Dave King Well-Known Member

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    The weather here has been so bad that I have not been able to fly. I have my new brushless motor gimbal together and I now trying to tune it up in my basement.
     
  20. Todd Livdahl

    Todd Livdahl New Member

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    Dave,

    I'm doing all the same type of tests but using a Vulcan X8 BW frame and DJI A2, with the U5 motors. I'm planning on using a Movi, with a Red Epic, I'm right now doing all the weight tests as well as modifying a bunch of things to get this to run with the right flight times. I'm on 15.5 T-motor props and am wondering if the 16 will be better for me as well. Instead of me trying to recap everything I have done, I have a thread here which documents everything. http://www.rcgroups.com/forums/showthread.php?t=2071124
     

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