Motors not in sync when RC is used (after ESC calibration with Cleanflight)

I built my own quadcopter and I calibrated my ESCs all at once (with Cleanflight) and it worked. The motors are in sync when I let them spin using the Cleanflight interface (there is a throttle bar that you can pull up and down under the tab "motors"). But when I use my radio control to throttle up, the motors are not in sync at all (some motors spin more slowly than others) so my quad never takes off smoothly and can't hover stably.

What could cause the motors to behave differently when I throttle up using my RC instead of the Cleanflight interface?
How could I fix this?

Here's some information in case that helps:
- I already made sure that all my stick inputs go from 1000us to 2000us and that the stick centers are at 1500us
- RC transmitter: Flysky FS i6s
- RC receiver: Flysky FS-iA6B
- flight controller: Cleanflight SP Racing F3

Oaksl said:

I built my own quadcopter and I calibrated my ESCs all at once (with Cleanflight) and it worked. The motors are in sync when I let them spin using the Cleanflight interface (there is a throttle bar that you can pull up and down under the tab "motors"). But when I use my radio control to throttle up, the motors are not in sync at all (some motors spin more slowly than others) so my quad never takes off smoothly and can't hover stably.

What could cause the motors to behave differently when I throttle up using my RC instead of the Cleanflight interface?
How could I fix this?

Here's some information in case that helps:
- I already made sure that all my stick inputs go from 1000us to 2000us and that the stick centers are at 1500us
- RC transmitter: Flysky FS i6s
- RC receiver: Flysky FS-iA6B
- flight controller: Cleanflight SP Racing F3

Click to expand...

They aren't spinning the same speed because the quadcopter is trying to stabilize. If you hover too close to the ground the air you are pushing down reflects off the ground and comes back up at you. You may need to adjust your PIDs to get better stabilization if you don't hover very well when around 1 - 2 meters off the ground. If they spin up about the same time when you use the master slider then they are fine, so don't worry about them looking like they are in sync. Your main concern will be to make sure it is stable (note that it won't hover in one spot). When you try to hover you will still be making minor adjustments with the sticks to keep it in the same spot, but you want to get rid of any oscillations. If it is not too bad you can probably get away with learning to fly a bit before worrying about PIDs.

What are PIDs?


Tuning PIDs


In-flight adjustments (If you have to tune I'd suggest starting out with in-flight tuning as it is much easier)


General PIDs, related to Cars (if you are still interested in PID theory)