using a channel in rf transmitter and receiver to control 12v dc motor

hi everyone,
i use five channel in the RF tx and rx for controlling a drone and i want to use the sixth channel for controlling a dc motor present in the drone in both clockwise and anticlockwise direction but the PPM values for the 6th channel is not constant
how can i do this?

start by reading How to use this forum

paying particular attention to

  1. If you are posting code or error messages, use "code" tags

we can not help you if you don't help us help you

i dont understand what u r asking me to do

Read the posting guidelines, so you know what information you need to provide for us to help you.
And don't spread your APM 2.8/drone project across several posts.

I am asking you to post your code, in the code tags provided by the host, so we can see all the code, because frequently the problem is somewhere you don't expect to find it.