New MK redundant test copter project

Discussion in 'Cinestar 8' started by Dave King, Jan 14, 2015.

  1. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    Yeah I sent Holger a U5 to test this past summer and it said it was fine under lighter loads. I probably had 300 flights with those motors this year. This is the first time I used the U5's since I had the incident where the one board caught on fire. It could have hurt the motor in the process. Nevertheless I think I'm going to replace all 8 with 4120's that way I have 2 identical copters.
     
  2. Jose Luis Ocejo

    Jose Luis Ocejo Active Member

    Joined:
    Sep 20, 2012
    Messages:
    581
    Likes Received:
    44
    hi Dave could the u5 failure be bad bearing?
     
  3. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    HI Jose

    Not sure yet. I"ll have to take it apart.
     
  4. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    Looks like bad bearing was eating itself up. I ran the hell of the motors with the Red camera this year and then the motors sat for about 4 months. Check out the picture here you can see metal shavings in the bell. It was even worst as I cleaned some of it up.

    U5bearings.jpg
     
  5. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    I decided to take the rest of the U5 motors apart and its a good thing I did. Here's another motor. :eek: :eek: :eek:

    Looks like I will be ordering up a new of 4120's tomorrow.

    U5-2a.jpg

    U52b.jpg
     
  6. Jason Smoker

    Jason Smoker Active Member

    Joined:
    Oct 23, 2012
    Messages:
    842
    Likes Received:
    67
    Are those windings melted together Dave?
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,357
    Likes Received:
    1,161
    Yup. A U5 "tuna melt."

    Andy.
     
    Steve Maller likes this.
  8. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    Yes!
     
  9. Gary Haynes

    Gary Haynes Administrator
    Staff Member

    Joined:
    Jul 6, 2012
    Messages:
    5,211
    Likes Received:
    460
    There is melted and melted. It looks more like the coating, like a resin, from the wires. If it is copper that has gone into a liquid state and solidified, well, holy cow Batman!!
     
  10. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    HI Gary

    I really can't tell to be honest. I think you might be right that there is a coating on the copper and that when the motor got hot that resin started to melt. I would think that if the windings were really melted that it would probably damage the BL upon load but the board is fine. I can tell you that this is the only motor out of all 8 that's like this and the motors were involved in a pretty bad melt down when I tried to use the U5's to lift 28 pounds (this was several months ago) When I tried to lift 28 pounds, As soon as I gave the copter to get off the ground the power board caught on fire. We are talking a really big fire not just a little bic lighter flame. 3 BL's were melted down to the copper of the board. When I dissembled the motors I didn't mark which one was which (that would have made sense to do that) :rolleyes: The motors have just been sitting idle ever since until this past week.

    When I assembled this new build I did a motor check and ran each motor one at a time and everything seem looked good. It was only when I started doing yaws with the copter after about 2 minutes in air did the motor stop spinning. When I got the copter down I could smell the motor burning and it was super hot.

    Time for all new motors.
     
  11. Steve Maller

    Steve Maller UAV Grief Counselor

    Joined:
    Oct 30, 2012
    Messages:
    3,979
    Likes Received:
    807
    Here's to the reason one shouldn't trust an expensive camera payload to anything less than an octocopter! :eek:
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,357
    Likes Received:
    1,161
    You could check the resistance readings you get between each pair of the three wires -- they correspond the three coil sets. The problem is that usually the readings are quite low and so your VOM might not read that low. But if it can, you can probably tell whether one set of coils is shorted or open.

    Andy.
     
  13. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    Just got my hands on a new set of Tiger 4120 motors. As I documented before, these are the biggest motors you can run reliably on the MK power boards. They draw a max of 30 amps, and even at 28 pounds I didn't hit 30 amps so I'm running on this new rig too.

    Thanks to the folks at Quadrocopter I"m trying their new HL motor plates. Here's a side by side comparison of the new Quadrocopter plates on the right and the famous hobby ones on the left. With my first set of 4120's I had to open up the center hole all the way till it just about drilled into the slotted area for the screws. With the QC plates on the right you can see how big the motor bearing opening is. BTW: The famous plate on the left looks worst than it actually is, its just dried up loctite you see.

    DSC_0096.jpg

    BTW: If you order these plates on their site, you will see they come in singles and pairs. I didn't read the text very well and didn't see that they are made for a X8 pair with no press nuts on one plate. Karsten sent me 4 more plates super fast, these guys rock.

    With the 4120's you have to use 4mm bolts which don't come with the motor. To accommodate the bigger screws I have to route out the slot a bit using a 4mm drill bit. You can see the the c clip in the middle needs that extra space QC provides.
    DSC_0108.jpg


    Size comparison of the 4120's to the U5's.
    DSC_0109.jpg
     
    Ozkan Erden likes this.
  14. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    Copters all ready to back up in the air for more testing. WE just got a lot of snow though, might not test to the weekend.
     
  15. Jason Smoker

    Jason Smoker Active Member

    Joined:
    Oct 23, 2012
    Messages:
    842
    Likes Received:
    67
    any update Dave?
     
  16. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    Haven't been able to fly because the weather here has been really bad, either very cold or snowing, or very windy that blows snow. There might be a chance to test this coming weekend.
     
  17. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    Finally some good weather to test. Everything flew as expected.

    <edit> I removed the video and posted a new one below with more screen shots and a better explanation of how the testing went.
     
    Michael McVay likes this.
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,357
    Likes Received:
    1,161
    How did you "jam" the I2C bus, Dave? Short it to "ground?"
    Why the altitude change? Did you figure that out?
    (Brave dude, testing over concrete/asphalt/ice!)

    Andy.
     
    Steve Maller likes this.
  19. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    Hi Andy and everyone

    I redid the video I posted yesterday. I added screen shots and a better explanation of how it works.


    Andy: The flight you see filmed wasn't the first test of the day it was actually the 3rd. The first ones were over snow covered grass :)
     
  20. Dave King

    Dave King Well-Known Member

    Joined:
    Dec 24, 2012
    Messages:
    2,711
    Likes Received:
    311
    Hey all

    Just a couple quick clarifications. When I assign the switch to user 7 its not actually jamming the data buss but more less simulating the failure. I also discovered that the jump in altitude was because AH on the slave board was disabled and with the very little load on the copter during the test combined with the beefy motors I use the copter hovers less than 50% throttle.

    Here's a screen shot of the GPX file and I also attached the GPX file as well for anyone that wants to take a look at it.

    redundant1.jpg
     

    Attached Files:

    Jason Smoker likes this.

Share This Page