Motor RPM not increasing smoothly when through Pixhawk

A friend and I are building a Flamewheel F450 Quad and we both have Pixhawk 2.4.8 controllers. We both purchased a kit off Amazon which included HobbyPower motors and SimonK firmware ESCs. We are both having issues with motor control through the Pixhawk. On both copters during the calibration phase of the ESCs (not through the software but doing manually by connecting power with throttle high) we get smooth RPM increase from bottom to top of range. When we arm the motors through the pixhawk either with the motor spin at idle or no spin at idle we get erratic results when increasing throttle on the stick.

On mine it increases smoothly up to about 50% and then there is no more increase from 50 to 100%. On his he clicks in one ratchet notch of throttle and it starts to increase and the second ratchet notch of throttle sends his to max RPM and then no increase for the remainder of the stick.

Due to the fact that both have smooth operation in calibration mode tells me that this must be a pixhawk configuration issue but I am at a loss as to how or where to adjust this so that it is smooth.

I was able to test fly mine and it seems stable but the throttle is way too sensitive and I have to constantly click one notch up then it will climb … then one notch back down and it will descend… no easy way to get it to have hands off sticks hovering.

Any help is greatly appreciated here!

Have you been through “Arducopter Documentation” First time set up ?

Yes… and I have now discovered that this is only in stabilize mode. If I go to PosHold or AltHold it operates more as I would expect. Although now the entire throttle response is between 50 and 100% but it doesn’t seem as sensitive. I can hover much easier with hands off the sticks. I cannot in stabilize mode.

His straightened out when he got new higher quality ESCs. The ones in the kits we bought were not good quality. I had to recalibrate mine a few times to get them to operate properly. I’m debating if I should just calibrate them one at a time rather than doing all at once.

I think we just need to get more acquainted with the controller and the flight modes. It’s likely operating as designed.


It sounds normal to me. In assisted modes (Alt Hold, Loiter, Pos Hold) hover will be at center throttle so this is likely why you say 50-100%. And of course it’s not as sensitive because it’s being altitude controlled and there are separate parameters for that. In Stabilize there is no expectation of control other than attitude stabilization, you have to control the craft with the sticks. How sensitive it is depends on your craft.

It´s a closed loop control system. you are NOT supposed to get a nice smooth response while on a desk testbench. Let it loose in the air and you will see that it responds fine.

Yes, that makes sense. Still learning. It’s just a little scary taking it up for the first time when it doesn’t seem like it’s operating properly on the bench.

We’ve had a couple successful flights now. Although we’ve got some wobble happening on and off… this may be the props but I’m not sure. I ordered new DJI motors and the screw on props. I’m betting it will fly much better with those.

Now I’m just trying to figure out what and how all the flight modes work and which ones I want on my radio. Everywhere I look it says you definitely want stabilize mode but Alt-Hold (also not requiring a GPS lock) seems much more stable. Why is it a requirement to have stabilize? (and I say requirement loosely because obviously you can put what you want into your flight modes)

it is a safe mode with little automation.