New to Quadcopter

Hi Folks,
I built my own quadcopter with Ardupilot 2.6 ,rc receiver, esc’s motors and a frame printed myself.

I got all the connections right and i can even arm it so all motors will spin in the corect directions.
all esc drivers are correctly calibrated
But now there comes my problem:

When I increase throttle, 3 motors start , but the 4th motor does only start, when throttle raised about 50%
This is not acceptable because my quadcopter does not hover but just rotate to sit on the propellers.

The reason is this:

If I put it onto the ground and connect it to APM Planner I see a pitch and a roll shift/offset and I dont know how to compensate for this.

I cannot successfully perform compass calibration. it just does not work eventhough i follow the youtube video.

How can I manually set the roll and pitch offsets ?

Thank you

@gsohler,
Please provide tlogs and/or data flash logs to help troubleshoot your issue.
Regards,
TCIII GM

maybe a sync issue, you can try performing ESC Calibration again, 1 motor at a time, or start with the motor with longest delay first. after which, you can try testing all motors to check if there is sync issue still.

[quote=“TCIII”]@gsohler,
Please provide tlogs and/or data flash logs to help troubleshoot your issue.
Regards,
TCIII GM[/quote]

Thank you for answering.
How can I get tlogs or data flash logs ?

Hi, Thank you for your input.

I am quite confident, that the ESC’s are calibrated correctly, but I will redo.

The interesting thing is this:
If I increase throttle 3 motors spin immediately and one spins later.

Then If i turn the copter in such a way, that the lagging motor is in the bottom most position and repeat
the test again, the motor on the opposite side has the same problem.
I think I should measure, if the board creates equals pwm signals for all the motors.

Hi, Thank you for your input.

I am quite confident, that the ESC’s are calibrated correctly, but I will redo.

The interesting thing is this:
If I increase throttle 3 motors spin immediately and one spins later.

Then If i turn the copter in such a way, that the lagging motor is in the bottom most position and repeat
the test again, the motor on the opposite side has the same problem.
I think I should measure, if the board creates equals pwm signals for all the motors.[/quote]

I did some further tests:

  • Accelometer is perfectly balanced. If I put the quadcopter to my table. I see in the program, that its completely horizontal.
  • I still see the problem, that one motor starts much later to spin, if i increase throttle.
  • When I leave my quadcopter exact in the same position and swap the lagging esc cable with another one, the other motor
    has the same problem, but the orginal motor is fine then.

This means, the problem is with the APM not with the motors or with the ESC

What could APM make the front left motor port spin up later ?

“This means, the problem is with the APM not with the motors or with the ESC” ???

It seams your problem follows with a particular cable from the ECS; so why couldn’t it be an ESC problem?

Or have you tried replacing the wire in case you have bad wiring?