Engine Speed Problem

Hello. I’m trying to build a new f450 frame, pixhawk2.4.8 quad.

When I try to accelerate the motors there are only 3 speed levels.
Slow, Medium and Fast. There is no in between.
To explain in more detail, we gave power to the engines, they started to spin at idle, there is no change until we bring the speed bar to half, when the speed bar comes to half, the engines suddenly start spinning at medium speed, we constantly raise the speed bar still does not change, when the speed bar is at the top, it suddenly starts to spin at full throttle. Then we start to lower the speed bar, there is no change until it reaches medium speed, it continues to work at full throttle, when the bar comes to the middle, it suddenly drops to medium speed, then it comes to medium speed. at the bottom, it suddenly drops to idle speed, so I can only get 3 levels of speed.
The Remote Speed bar normally increments millimeter by millimeter in Radio Calibration in the Mission Planer program. But the motors only give me 3 speeds. What should I do so that the speed gradually increases and decreases gradually according to my bar movement? ,

Please Volume Up and Watch:

It’s pointless to test on the bench as you are doing. It means nothing. There are countless posts on the forum explaining why this is. Move along with the configuration, calibration, Initial Tuning Parameters and then follow with tuning as per the documentation.
All you should be doing with the craft at that stage is running Motor Test in Mission Planner to confirm proper motor order and direction, turn off the Transmitter.

Thank you so much.
“the problem may be fixed when I install the propellers”. Do I understand correctly?

Only use MissionPlanner motor test for pre-flight testing.
With the way motor control works any other method gives crazy results, because the flight controller wants to be flying and cannot know why it isnt.

Maybe if things are correct when you run Motor Test. Or if you have the order and direction wrong it will flip on take-off.

Thanks bro.
But I had this problem already during the first flight.
I had a lot of trouble landing.
Since I couldn’t reduce the speed gradually, I had a sharp drop as the speed suddenly decreased after approaching the ground.