In connection with the following blog and post, I am interested in converting a k110s micro heli to Ardupilot traditional helicopter with GPS, lidar and optical flow.
Although these projects are old, it would be interesting to modify k110s instead of k120 and V922 with minimum replacement parts and for a 1s battery instead of 2s.
I think it is doable without replacing the k110s ESC and brushless main motor. I am not sure what is the output voltage of ESC being fed to the stock FC board, but whatever it is, connecting it to a mini boost converter to step-up to 5V for powering a F4V3S flight controller and other boards such as AC900 Mini S-FHSS Rx (which will work with the XK Tx), a micro brushed ESC for tail motor, GPS, VL53L1X lidar and GL9306 optical flow sensor. In this way, no need for additional BEC and the stock ESC will cut the power once 1s battery voltage drops to minimum.
I think the biggest advantage of k110s is the 1s battery and it is still very popular and durable with most of the parts available. The k120 is phasing out and I am not able to find much for it.