Quad wont lift off...

Discussion in 'General Discussion' started by hug_dealer :D, Aug 8, 2018.

  1. hug_dealer :D

    hug_dealer :D Active Member

    Hey guys... first time i fired the quad up all is well.... but it wont lift off...

    Using emax 935 kv motors with 10x45 props. (Yes they are mounted in the right direction!).

    My battery is the 3s tattu 5100mah 10c lipo. Could it be the c rating (so there isnt enough current) i have 4x20A esc's so i assume i need 80a... whereas with this i have 51 amps... any battery reccomendations? Want one to have good flight time
     
  2. mozquito1

    mozquito1 Well-Known Member

    Are you bound to rx & have Aux switches setup eg. Arm & modes.
    Are endpoints set on both config tab in betaflight & in blheli config on the esc's.
    Do the inputs work in the rx tab in betaflight. When move sticks do the ranges move.
     
  3. hug_dealer :D

    hug_dealer :D Active Member

    In english plz? Drone noob here.
    Using pixhawk and main outputs not the aux ones if that helps? As well as ardu pilot
     
  4. Jackson

    Jackson USA member at large

    You use the motors, not the ESCs for your calculation. 51 / 4 = 12.75A each.

    [​IMG]

    Looks like plenty. What is the total weight of the quad?
     
  5. hug_dealer :D

    hug_dealer :D Active Member

    With battery it is 1.236 kg
     
  6. mozquito1

    mozquito1 Well-Known Member

    20amp Is fine 30 would be safer.
     
  7. mozquito1

    mozquito1 Well-Known Member

    Do the props actually spin & you just can't get it up? I'd check prop direction again it maybe pushing into the floor.
    4 emax 2205 can pull a kg easy.
    Just one lifts my 600g wing easy.
    So should your setup. try a higher c rate but I use some 20C compared to 40-75 there is not a major difference.
    Just a bit less bite.
     
    Last edited: Aug 8, 2018
  8. Jackson

    Jackson USA member at large

    Why??? Didya look at the chart? For his combo it shows 9.5A. 20A is more than enough.
    That's cutting it close, but it will work. That said, the low amp draw on those motors should provide decent flight times.
     
  9. LoneRCRanger

    LoneRCRanger Well-Known Member

    Here's a simple test, set the quad on a flat surface, put some corn starch under each motor, run the quad. If the corn starch blows out and around, you've got the props in the right direction. If the powder blows up or not at all, you've got the props on wrong. My granny taught me that for some reason or other.
     
    Jackson likes this.
  10. mdm

    mdm Member

    Props may be mounted right, but are the motors turning the right direction?
     
    mozquito1 likes this.
  11. LoneRCRanger

    LoneRCRanger Well-Known Member

    Can the polarity to the motors switch? Something wired incorrectly, with the ESC getting the right flow but the motors not?
     
  12. mozquito1

    mozquito1 Well-Known Member

    Yeeeaaahhh Cowboy.
    What if he wants or needs bigger esc's in future.
    I got loads of spares but if I was going to buy any more I'd get 30amp as I'm wanting to try some 2306 soon.
    640g per motor on a 1.2kg quad
    Maybe the chart got lost in translation in Chinese & it wrong. Is that 640g at full throttle , mid stick is half of all 4 motors thrust, which about equals the weight.
    Did the op get to full stick.
    Somthing is fishy.
     
    Last edited: Aug 8, 2018
  13. wafflejock

    wafflejock Well-Known Member

    Yeah if you flip any two of the three phase wires you will flip the direction the motors spin, it could be all of them are going backwards relative to what they should be, seems pretty unlikely but there's a 1/8 chance of having all 4 going the wrong way so it can happen. You can either swap two out of three of each motors phase wires or switch reverse the direction with the ESCs configuration tool (know it can be done with BLHeli configurator and the suite has more I don't know anything about KISS but imagine they have something similar to reverse direction).

    Would just feel for if the breeze is in the air or on the ground like LoneRC said basically.
     
  14. hug_dealer :D

    hug_dealer :D Active Member

    Managed to get to full stick and quad started shaking. Motors are spinning righy directiom do maybe props? Also what c rsting do u reccomend?
     
  15. mozquito1

    mozquito1 Well-Known Member

    Acro flying 40C or higher.
    I got a few 20C I use for milling about.
     
  16. hug_dealer :D

    hug_dealer :D Active Member

    any high capacity 40c 3s lipos you could reccomend?
     
  17. RENOV8R

    RENOV8R Well-Known Member

    You don't need high C rating to swing larger props. The battery isn't your problem. If it's just shaking, it's either 1 or more motors are rotating in the wrong direction or your props are on wrong. Can you post a pic of your setup
    motor.jpg prop.jpg
     
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  18. mozquito1

    mozquito1 Well-Known Member

    Turnigy or turnigy nano & tattu is all I buy.
     
  19. mozquito1

    mozquito1 Well-Known Member

    Bad pid setting cause oscillation or shaking. Higher C rating does give more bite.
    I can tell & feel the difference on a turnigy 20C to a 40-75C.
    Like Renov8r say not really needed but will provide extra power if needed.
    I only use 3S now for groundstation equipment
     
  20. wafflejock

    wafflejock Well-Known Member

    The C rating shouldn't be much of an issue just for lift off. The amount of torque or force the motor can drive with will depend on how much current can be delivered from the batteries when you get to that limit but unless you are already drawing 100A+ or whatever your batteries support they aren't the limiting factor. If the batteries are too low C rating you would basically cook them by drawing more out of them than their internal resistance is rated to supply. Drawing more from the batteries than they are designed for will cause them to overheat and possibly puff, if these aren't things you're seeing wouldn't suspect the battery.
     
    Last edited: Aug 9, 2018

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