pixhawk hexacopter no lift on full throttle

hi all,

i am using the following setup on my hexacopter. i hav made the setup complete, calibrated accel,compass,radio. when i arm the hexacopter and raise the throttle, motors seem to spin, on full throttle it slightly moves backward but no lift.

frame: hexacopter

motors: 650 kv

props 12*3.8

i am using inverted motor setup on the frame.

i am using flysky 6 ch transmitter and rx with ppm encoder. i have had to power my receiver seperately.

i can hear motors spin faster when i am doing yaw or roll, pitch, but when evn on full throttle it just barely lifts and moves back

i have checked THR_MAX to 1000.

even tried installing different software platforms and coming back to hexacopter 3.2 but of no use

i would really appreciate if someone could help me find a solution

thanks in advance

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  • Do you have dataflash logs instead? I find them much easier to use.

  • If you post a log from that time  it would help diagnose it.

  • Agree. Need minimum 4s. That's what I have on mine. Takes at least 8000mah to get decent flight time
  • Moderator


  • your RCouts are pretty much getting to full throttle so its not the brain. Looks like you are running 3s. I don't know how heavy your hex is but 650kV on 3s with 12x3.8 props just sounds too under powered. If you motor/escs will accept 4s I'd say try 4s, and probably bigger props too if you have power full enough motors/escs. If you copter is light probably just need to try 4s if you can. Your props don't have that much pitch for their size either.

    Run you numbers using ecalc if you want to test my theory before buying anything.

    • out of curiosity I just ran some ecalc numbers on a setup similar to yours with a guess weight of 2.5kg, and it showed almost full throttle to take off, changing to 4s (although slightly cheating keeping the weight the same) hover throttle reduced to ~50%

  • for best help post logs

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