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And then there were two!

Discussion in 'Cinestar 8' started by Josh Lambeth, May 17, 2013.

  1. Josh Lambeth

    Josh Lambeth Well-Known Member

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    We just finished building our second CS8! This will be our backup and heavier wind flying copter. We built it in an X8 form and will be flying 5s. We have the new AH sensor onboard as well! Im hoping to maiden it this afternoon! Can't wait to see how she handles in the wind!

    Josh

    [​IMG]
     
  2. Dave King

    Dave King Well-Known Member

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    DAMN DUDE!!!
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Interesting build Josh.
    What are curved things above and below the booms? Sheathing for motor wires?

    Also, what electronics did you put on it in the way of MK boards, Abusemark converter, and ESC?

    Andy.
     
  4. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Andy,
    Yes those are sheathing for the motor wires. I ran all the wires outside the motors this time. Not as clean looking but will be WAY easier to take apart and assemble.

    I am flying the default MK setup on this copter. Maybe down the road it will get upgraded to the HL version... We will see and I have to convince my GirlFriend we should do it. ;)

    josh
     
  5. Katya Nelhams-Wright

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    Nice Josh. I only have a flat 8, what kind of differences in flight are you expecting to get with your new build:)
    Looking forward to flight postings.
    Katya
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Josh:
    Thanks....what was the thinking re: the Quad config? More lifting power?

    Andy.
     
  7. Katya Nelhams-Wright

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    and by the way, those are some very bright leds, where are they from, mine pale in comparison:)
    Katya
     
  8. Brad McGiveron

    Brad McGiveron Active Member

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    Nice!... Welcome to the dark side:D
     
  9. Josh Lambeth

    Josh Lambeth Well-Known Member

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    LEDs are from gothelirc.com. yes they are really bright! I'm hoping this will fly better in heavier winds.

    Josh
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Nah. The bright LEDs will not affect the aerodynamic performance Josh... :rolleyes:
     
  11. Shaun Stanton

    Shaun Stanton Active Member

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    Did you change the mixer setup for the bottom motors to be higher than 64 like 71 in the MK example? Are you using the same length props?
     
  12. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Nope. I am on 64 all around. I am also using the same props, 14x4.7APCs top and bottom.

    I had the first maiden tonight! She flies great! Did some minor tunes and she is flying even better! At times there was a 10+mph wind and it felt very steady. Needs a bit more tuning but overall I am very happy with how it flew.

    I am using 5s batteries and the QC motors were REALLY hot after a 9 min flight. Can anyone else confirm that the motors will be really hot (almost to the point of not being able to touch them)? BL temps were mid 80s*C and ambient temp outside was around 90*F. I can tell that it isn't nearly as efficient as the original was. 9 1/2min on dual 8000mAh 5s with 5DMKII onboard. Hover was around 88amps. I forgot the SD card so I wasn't able to log any data but I will be flying it tomorrow again.

    Oh and the new ACC for AH is AMAZING!!!

    Josh
     
  13. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Quick shot from tonight.

    21293_10151552772697752_1230540119_n.jpg

    BTW... these new LEDs are amazing!
     
    MIke Magee likes this.
  14. Tim Joy

    Tim Joy Active Member

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    Nice job. About to do the same myself. When I used to have a Y6 I found better performance with graupner props, but the apc's are good for testing :). I imagine xoar will also work well.
     
  15. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Ugh... Well guys im not off to a good start with this new setup. I just did some flights this morning and am having all sorts of temp issues and also blew up a capacitor on the copter (I heard it pop right as I was plugging it in before the last flight!) Im glad it didn't go when it was in the air.

    BL temps are hitting the high limit of 115*C. It was only 85*F outside for ambient temp. I have heat sinks on the top and bottom of the BLs but it doesn't seem to be helping much. Also the motors themselves are so hot after 3-4 minutes in the air that you can't touch them and you can smell them. I am running on 5s batteries.

    I am going to go through and figure out what cap blew up and will report back on that.

    The other odd issue im having is the FC is resetting all the settings randomly... It's happened to me twice now. The reason I know is when I plug in the copter normally the two blue lights stay solid unless the battery is below the min. voltage. Twice now when i have plugged it in the lights are doing the random flashing. I plug into MKTools and what do you no, Everything except for the mixer setting has been reset back to default. I am on the 90h firmware and 30h for NaviCtrl. I do have the AH sensor installed as well which is working beautifully! Any ideas on this? Thanks.

    Im thinking about fixing the BLs, selling it, then going with individual ESCs. I just don't trust the MK BLs at all.

    Josh

    P.S. I will post GPX files shortly.
     
  16. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Here are the log files from today.

    Josh
     

    Attached Files:

  17. Josh Lambeth

    Josh Lambeth Well-Known Member

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    After looking at my logs again... it looks like motor 3 is the motor causing most of the issues. Im going to replace that motor and see if it fixes it... once I fix the BL. Who wants to put money on BL3 is the one the cap blew on?

    josh
     
  18. Howard Dapp

    Howard Dapp Active Member

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    Josh, what's your throttle stick position when fully loaded? Also, from my own testing, I've found that using the 64/71 motor speed mixer results in slightly better performance and a bit more thrust power. You may also have better results using stiffer xoar 13x6.5. APC slowfly 14" are not so rigid and sturdy against airflow hitting them from the top with the upper motor dumping all of that airflow...you may have to retune after swapping out those 14"
     
  19. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yeah. Motor 3's temperature is way high, isn't it?
    Other motors are pulling similar currents though -- but the BL's not as hot.

    So was it the cap on BL Motor #3 that blew up?

    In the terms of the quad do you have:
    Boom 1 : motors 1 and 2
    Boom 2 : motors 3 and 4
    and so on?

    I'm not sure how to see if there's a larger pattern in terms of the motors working too hard to counteract yaw imbalance.

    I don't know what your payload was, but all of those motors look to be working way too hard.

    Andy.
     
  20. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Howard,
    Throttle was at zero when I was on the ground. I always check throttle/switches prior to plugging things in.

    Andy, The motors are like the following diagram:
    [​IMG]

    I haven't had a chance to take it apart yet. Starting that now.

    josh
     

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