94 AMPS

Discussion in 'Cinestar 8' started by Nicholas Donnelly, Mar 17, 2015.

  1. Nicholas A Donnelly

    Nicholas A Donnelly New Member

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    Motor test complete: ran @ 95amps for approx 7mins. Results below, I put a line through the likely bad readings.
    image.jpg image.jpg image.jpg
     
  2. Thijm le Grand

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    Looks ok. Time to test one 16" prop and check the difference
     
  3. Dave King

    Dave King Well-Known Member

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    Here's some of the copters I built.
    Aerial X8.jpg

    DSC_0222.jpg

    Wookong01.jpg

    EXCOMPASS01.jpg
     

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  4. Nicholas A Donnelly

    Nicholas A Donnelly New Member

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    thijm-
    Is your suggestion to preform the same test with 7x 15" props and 1x 16" prop?

    David-
    Thanks for the photos. I ordered an external compass today. Proximity-wise, I wouldn't expect to see better results having the compass centrally located between two large batts but perhaps being 'above' the EMI is more important? I can see by the photos that youre a firm believer in lower battery placement!
     
  5. Thijm le Grand

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    Test only one motor with 16" Use the motortest in koptertool and verify that the motor does not get to hot after 5 min and 50/60% power.
    If all good you are left with the choice > new motors & 15" or 550booms and 16"
     
  6. Nicholas A Donnelly

    Nicholas A Donnelly New Member

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    Thijm
    While my specific Voltage/prop/motor combo isn't listed on the 4012 motor sheet, my test results show that I'm still w/in spec for tempurture. Unless I'm missing something, I think I'm safe to fly my current config. The cost of upgrading booms, motors, and props wouldn't be worth a marginal increase in flight time / efficiency.
     
  7. Thijm le Grand

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    Yeah you are correct. it isn't that far of. Gain is about 10 amps.
     
  8. Dave King

    Dave King Well-Known Member

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    Define safe? TO me safe is the ability to maintain control of a 27-28 pound $25,000 rig if you lose a motor? Would you have enough head room for 7 other motors that will allow you to safely land? I know for sure the U5's were not enough at that weight and the 4012's are not that much bigger than the U5's. I know I would feel a lot better with your combination if you were running Tiger 16's.

    Here's what I think you should use for a yard stick in regards to head room. What is the stick position at hover? Hover throttle around 65% is starting to go into the IFFY range. If you are at 68% or higher than you don't have enough head room IMO.

    As far as temperature goes I wouldn't worry about that too much unless its excessive and you don't need a heat gun or a data log temp number to tell you are you in trouble. I think BL temperature is much more important. IF you touch the motor and it doesn't burn your hand your ok IMO. These motors are meant to take higher temps and with them flying in the air they get cooled. Patrick at KDE told me that all his motors can handle a tremendous amount of temperature and I"m sure Tiger motors are not that different.
     
  9. Dave King

    Dave King Well-Known Member

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    I am a firm believer that the compass needs to be physically higher than any of the battery lipo wires. Lipo wires give off magnetic fields that usually stay at or below the lipo wiring. Using the external compass has confirmed that for me and I am 100% sold on that.
     
  10. Dave King

    Dave King Well-Known Member

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    Once you fly with a copter that is way too top heavy you immediately understand the relation of proper CG and good flight characteristics. I found that out with by trying 2 big batteries on top. In addition if your CG is off your motors have to work that much harder to maintain level and if you have borderline motors to begin with your asking for a whole lot of trouble. I also find that with the rather aggressive nature of the MK active breaking its not uncommon for a copter to tilt 45 degrees or more. If your vertical CG is off it really becomes apparent.
     

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