NEW U7 motor tmotor

Discussion in 'Cinestar 8' started by kjetil tønnesen, Nov 22, 2013.

  1. Dave King

    Dave King Well-Known Member

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    What motor brackets did you use? IF you used the generic ones from China did you enlarge the center openings?
     
  2. Chakradhar Raju

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    U7 not ready to fly...
     
  3. Bryan Harvey

    Bryan Harvey Member

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    I know someone who has complained to Tmotor, and are in email talks with them right now. At least with the U7 490kv motor, I think there may be an issue. We tested them out of the box and with both the CC Edge 75A and Hobbywing Platinum Pro 70A ESC, the ESC's got too hot (over 200F) with the U7 490kv. We did not wish to test every single ESC on the market, and decided against using the U7 490kv for various reasons. I sold the motors and the guy that bought them flew with a RED and 3 of his ESC's burst into flames in mid-air after only a few flights, resulting in a crash.
     
  4. Dave King

    Dave King Well-Known Member

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    Bryan that's crazy! I"m glad I switched instead of trying them again.
     
  5. Kari Ylitalo

    Kari Ylitalo Member

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    Just ordered bunch of castle 75A:s after hearing few had succeed with them. Well, castles are quality escs and i'll go with them anyway but i'll to contact t-motor as well about these issues.
     
  6. Bryan Harvey

    Bryan Harvey Member

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    do you have the 490kv or 420kv U7's? Many people are using the 420kv with no problems.
     
  7. Kari Ylitalo

    Kari Ylitalo Member

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    I have 490kv.
     
  8. Howard Dapp

    Howard Dapp Active Member

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    With my test setup running the 490s I did not gain any real flight time numbers compared to my lighter 4s and 5s setup carrying the same payload. The added weight of the U7, mounts, additional frame strengthening weight, heavier 6s packs in conjunction with the 490kv produced an extremely power hungry copter.

    I've drop down to the U5, which are somewhat lighter in weight than my Axi motors and will not need all the added weight from heavy duty mounts and frame components plus the lower 400kv will be more efficient.
     
    Jason Herring and Bryan Harvey like this.
  9. Kari Ylitalo

    Kari Ylitalo Member

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    Yes there's 800g difference in weight already in motors which obviously affects flight time.

    With 17X6 props and 2X 10Ah 5s Ecalc calculations with U5 400kv, AUW 9200g gives 15min flight time, U7 490kv 10000g 12.1 min. Ok U7 hovers then at 29% and U5 at 46%.
     
  10. theo van Niekerk

    theo van Niekerk New Member

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    Hey Guys,

    this thread was brought to my attention by Chakradhar Raju, I supply Tigermotor in NZ and have a customer who has built 2 machines using U7 (490) Tmotor 16" props and Tmotor 60amp ESC using the DJI A2 - all tests flights and testing was 100% and the machines would even "hold" position 100% indoors with no GPS (the Default alignment check)

    The one test was with a Fully loaded machine AUW at about 13 kg and she flew like the weight was not even there I'm told. I will see if i can get some video.

    both machines have however been shipped to their final destinations.


    Im begining to wonder if the current "generation of frames" may have something to to with the "vibrations" that are being blamed but Chakradhar Raju for his Xerolfy Flight controller giving him white flashes.

    do these big motors and big props not maybe need a much stiffer frame?

    Just a thought,

    as i mentioned i will see what i can find re videos' and settings for the successful setups i mention.

    cheers
    Theo
     
  11. Lance Robb

    Lance Robb New Member

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    My motors are the U7 420Kv and I'm running 18x6 carbon props.

    I'm using MK flight control and not getting any issues with vibrations......Just this screeching noise when it's right at the hovering point. More testing this weekend and I'll report back what I find
     
  12. theo van Niekerk

    theo van Niekerk New Member

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    Hey guys

    Please have a look at this video, this is with 490KV motors DJI A2, 16" tiger props and 60amp tiger esc,



    would like to hear your thoughts....

    video will be ready in 42 min.
     
  13. Howard Dapp

    Howard Dapp Active Member

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    What are you showing is here? That the U7 motors can fly with a heavy payload? Obviously not everyone will have the same issues some here have encountered. The motors in that video do however screech and squeal a great deal same as a few of the U7 motors I've tested. It's strange that not all of the motors I've tested have this loud annoying sound.
     
  14. Lance Robb

    Lance Robb New Member

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    Theo I agree with Howard it sounds like you have the screeching sound coming from your motors too
     
  15. Steve Maller

    Steve Maller UAV Grief Counselor

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    My thoughts? If my coax Cinestar sounded like that and wobbled that badly, I’d bring her down in a big hurry. Somebody in the video remarked that it was windy, so maybe that’s the A2 fighting the wind, but given the horsepower and weight you’ve got up there, I’d expect a smoother ride. Or maybe I’m just used to my X8 being more stable than that.
     
  16. Dave King

    Dave King Well-Known Member

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    The copter in the video provided is behaving in a manner that I would not put any camera on it. It looks like its struggling a lot and I"m hearing a lot of change in motor RPM.
     
  17. Chakradhar Raju

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    Iam able to notice intermittent white light on the LED which is mounted in the front while landing....abnormal IMU behaviour...probably need to double check on this...
     
  18. Chris Newman

    Chris Newman Member

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    I've been flying the U7 490's with castle 75amps, 18" tiger props, wookong M for 4 weeks. Flew it for 2 weeks in Iceland and just finished a week long car commercial shoot. Temperatures in both places have been from 15-40F. It's flown very well and I really like the motors. Only had one instance in Iceland when flying in extreme cold, (or possibly magnetic rocks or solar flare)? The real test will be when the weather gets warmer I will keep an eye on the ESC temps.

    My friends have the U7 420's and within 2 minutes an 50amp ESC burned out. They switched to castle 75amps and haven't had any problems since.

    How tight do you guys tighten down the bearing screw on your motors? I've found if you crank it tight then the motors doesn't spin freely??
     
  19. Michael Braun

    Michael Braun Member

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    Did anyone had any problems with U7 and Tiger ESCs?
     
  20. Chakradhar Raju

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    We'll I read in the same thread that U7 do not work well with Simon flashed ESC...
     

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