Confusion on Negative Throttle in RC Calibration Documentation

ArduCopter
1

Hi,
I was looking at the RC calibration documentation (https://ardupilot.org/copter/docs/common-radio-control-calibration.html) to calibrate my RC to control a copter.

At the last point of the calibration section, it is written that " * If when testing your throttle stick you notice that the motor turns in a single direction, check in the full parameters list that RCx_TRIM for the throttle channel is set to the motor controller’s neutral value (usually about 1500 us). This should be detected and set automatically during calibration if you followed the procedure without forgetting to center your throttle in the last calibration step instead of the normal low position." I find it confusing since why the throttle motor should run in negative direction at all. It should run in one direction only. The throttle channel trim value should always be the minimum value that is 1000 and not 1500, right?

Can anyone please help me understand this?

Thanks,
Sayan

2

I am using FS- i6 rc transmitter.

3

That guide also includes content for Plane and Rover which can use bi-directional motors, not applicable to Multirotor.

1 Like
4

Thanks Dave, for the answer. For rover it is understandable that it needs to move both in forward and reverse direction on a path. Though I only have a multirotor and no plane, I wonder why throttle motors in plane should run in reverse direction. It is like flying the plane when trail becomes the front side of plane when flying.

5

https://ardupilot.org/plane/docs/reverse-thrust-setup.html

For shortening landing and approaches. Not all ESCs can manage it, and if it’s not set up properly the plane can stall.

1 Like
6

Thanks Allister, for the doc! It is now clear to me.