KDE 5215 435kv Coax MK Octo

Discussion in 'Cinestar 8' started by Ryan McMaster, Feb 15, 2015.

  1. Bo Tornvig

    Bo Tornvig Member

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    I believe you need to have some quite long booms to get the camera out of the wash, with that prop size..?
     
  2. Ozkan Erden

    Ozkan Erden Distributor

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    I would suggest you to use carbon booms with 2mm wall thickness in size. It will make the frame much more rigid. And will get rid off resonance created by weak long arms.

    I'm using 550mm lenght boom to clear the gimbal from prop wash.
     
  3. Bo Tornvig

    Bo Tornvig Member

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    @ Ozkan
    I'm on 1,5mm wall thickness already on 500 booms - Maybe not enough...? What size props are you swinging?
     
  4. Ozkan Erden

    Ozkan Erden Distributor

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    I'm using 18" props with 5215-435KV.
     
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  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hmm. Wanted to try some tests with the 5215-435's but none of the motor mounts I've got have a large enough hole to accommodate that lower central bearing....not even the metal mount from KDEDirect (which came from another motor, but...)

    What mounts are you guys using? Need to order some up...so a URL would be cool, thanks.
    Andy
     
  6. Howard Dapp

    Howard Dapp Active Member

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    Andy, I use square tubing therefor my mounts will not work with your setup but these will: https://aerialpixels.com/fx8-4mm-carbon-fiber-motor-mounts-for-t-motor-u7-u8-u10-u11/
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Excellent, Howard. Thanks for a response so rapid that it made my eyes water! :)

    Andy.
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Bummer. The guys at aerialpixels.com are out of stock and their web site does not even accept an order if there's no stock.

    Andy.
     
  9. Justin John

    Justin John Member

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    Has anybody tried anything larger than 18 inch props with the KDE 5215 435s?
     
  10. Sam Fleishman

    Sam Fleishman Member

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    forums have been pretty barren lately, must mean there's going to be big boom soon.
    I'm running the aerial pixels fxpro frame the first one in coax, 5215-435s 18''props 75amp KDE escs wookong power hungry 10 board. my AUW is about 36 pounds i think, and i'm hovering at 120 amps. Camera payload is an m10 (we usually fly the dragon on m15 which is a lot heavier) with dummy red and extra weight added to equal 16.2 pounds to simulate a dragon with ultra primes, and maybe follow focus. flight times are too short on 6s. I went to 8s on just the escs and motors and had a separate lipo for the FC and accessories. I think i had 8s 8500mah on four 4s packs in series. I definitely noticed all the components and wires were ice cold where as the esc heat sinks could cook eggs before. it was very obvious in terms of power that something had awoken from within the beast during the 6s-8s conversion. I flew in manual mode for a second from take off to get an idea of my hover throttle. Cant tell you exact numbers but it was way under 50% stick. flight time wasn't where it needed to be about 4 minutes...but the climb outs were nuts. I think when I go down in prop size I'm going to hit the sweet spot for flight time and lift. You guys tell me what direction should I go with this?
     
  11. Thijm le Grand

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    120A @ hoover equals 2A a minute. So with 17.000mAh you should get about 7 minutes.
    If it’s allot less something is wrong.
    I think you can get better hoover point and efficiency with a smaller prop.
     
  12. Sam Fleishman

    Sam Fleishman Member

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    I am getting a lot less than 7 minutes. I feel it might be the batteries. running tattuu 6s 10amp. so a total of 20amps per flight.
     
  13. Sam Fleishman

    Sam Fleishman Member

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    when I first built it I feel like i was getting more flight time on 6s
     
  14. Thijm le Grand

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    A reason could be that the esc's are holding back on output and getting allot hotter then with 6s. Smaller props on 8s will give better efficiency. Best efficiency on motors and esc's are around 80% (but less ideal for multirotors)
    How are measuring amps?
     
  15. Steve Maller

    Steve Maller UAV Grief Counselor

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    I think the opposite is true. The reason to go higher voltage is to swing larger props, right? The 8S and 12S super heavy lifters are swinging 26-29" props from what I've seen.
    IMHO the problem he's having may just be not enough pipeline to handle the current demands (ESCs, wiring, etc).
     
  16. Sam Fleishman

    Sam Fleishman Member

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    Thats where the motors KV comes into play.The higher the kv the smaller the prop you want to spin. All those 12s motors with 27" props are about 110-150 kv. My motors are 435kv. at 8s everything was cooler but I could tell I was overpropped because I was still drawing too many amps. my hover throttle was too low as well. I just want to fly our dragon at the same weight longer.
     
  17. Sam Fleishman

    Sam Fleishman Member

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    I'm measuring amps using the eagletree elogger v4. it connects in line between one lipo and pdb. theres 2 ways to take the readings. plug both lipos in and take readings from one of them and double the numbers. or plug 1 lipo in so all the power to the motors goes through the elogger. It was its rated to 150amps I saw max amps at 183 on climb outs. Aerial pixels guy tells me these motors are not really made for 6s and 8s and 12s is a no brainer because of the benefits of lower amp draw with higher current.


     
  18. Thijm le Grand

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    Yes you are correct. But then you also need to change the motor to lower kv.
    U can easily ramp up voltage on any setup. But that only gives lower hoover point and less efficiency

    Can’t comment on the wiring. Don’t know the build
     
  19. Sam Fleishman

    Sam Fleishman Member

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    So you don't think going to 8s and 16" props is going to be a good choice?
     
  20. Sam Fleishman

    Sam Fleishman Member

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    from 6s and 18"
     

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