Cant Get Quad off the Ground

I am having some major problems and was hoping that someone can please help me determine what is wrong and give me more direction on what else to check. I have my quad setup setup with APM2.5 and ArduCopter 3.1.2. Trying to do my maiden flight but cannot get the quad off the ground. Not sure what the problem is. I have gone through all the normal calibrations (Radio, Accelerator, Compass, ESC, etc). I am able to arm my APM and apply throttle. Even at full throttle, the quad will not lift off the ground. Verified that all motors are spinning the correct way (while on ground I am able to confirm that roll, pitch and yaw is correct with stick inputs). Thing just doesnt want to lift off ground.  I believe that I have a good thrust to weight ratio with my Motor/Prop combo compared to weight.  I have not changed any of the default gains in Mission Planner.  Have not changed any of the default gains for the Autopilot.  My full power throttle PWM is approx 1891.  Thought that I should be getting lift at approx 50% power.

Here is my quad configuration:

Weight: 1700 kg

Frame: Carbon Fiber Talon V2

Motors: NTM 28-36 1000kV Brushless Motors

Props: 12in x 4.5

ESCs: 30A Afro w/ SimonK Firmware Update

Battery: 3s, 2700mA

Autopilot: APM 2.5 w/ Ardupilot 3.1.2

Any help and direction would be much appreciated.  Thank you in advance!


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  • Just ran a test:

    50% throttle current draw (1505 PWM): 9;06V @ 37A

    100% throttle current draw (1891 PWM): 8.3V @ 52A - 60A

    I see FAILSAFE on my HUD.   All my Failsafe is disabled. 


    • Wow. I know you said the props are correct but it really sounds like your bird is trying to drive itself into the ground.

      Here are the details on 'failsafe' -- also here -- anything look out of the ordinary?

      Any possibility you can place your quad on a scale -- even a bathroom scale?  That way you could at least see whether your thrust is positive or negative.

      • Crady,

          Clearly what I thought was the correct way to install the props was backwards.  I thought the "R" was for counter-clockwise side.  I swapped the props and am getting thrust!!  Thank you SO much.  Time to continue testing.

  • Any possibility of submitting a video clip?  When you calibrated your ESCs did you do them individually or via the all at once method?  I understand your motors are turning in the correct directions (RF CCW, LF CW, RR CW, LR CCW) but is there any possibility you have the pusher and tractor props mixed up?  With those motors and those props at that weight the thing should be a borderline thrust monster.

    • What should I submit a video of (HUD, any status variables, the actual quad)?  I can take one on my cell phone and upload it.  I completed the all at once method for my ESC calibration.  I had previously done them individually via the manual process and was getting the same results.  Will try and re-run the ESC calibration to see if that helps.  Do the 30A Afro ESCS w/ Simon K firmware have any calibration issues with the APM/Arducopter config?

      Yes.. I confirmed that the "R" props (dont know if those are the pusher or the tractor) were at the correct corners.  Will double check again.

      I was previously using a 3s 5300 mA battery and 10" props but due to thinking that it may be a weight to thrust problem, i switched over to the lighter 2700mA battery and 12" props to get more thrust.  However, I get the same results. =(



      • Very strange. Instead of verifying the direction by position, see if it's going the right way considering its pitch. It basically works like a corkscrew. Each prop should spin in the direction of the highest edge, looking from the top.

        1000kV and 12" should be enough to even lift a little bit off the ground, so I'm really considering the props are on wrong.

      • Sorry, I missed that you were using 3S batteries and not 4S, but even then you should have more than adequate thrust. When connected to MP, can you see in the HUD what kind current you're drawing? That should give you a clue as to whether your getting 100% from your motors.

        eCalc estimates that when hovering, your setup should draw about 5A at 46% throttle and roughly 19A at 100% throttle. 

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Shivchand Jaysaval liked Shivchand Jaysaval's profile
Aug 25