That's my first post, although I'm reading this forum for years now. Hello to everybody!
I'm struggling with a big coax X8 machine with 29" props, based on the Pixhawk. It's flying nicely, but from what I can tell from the telemetry data, I think it would be possible to get it a bit more efficient by running the bottom four engines a bit faster.
With a coax octo you should use props with bigger pitch on the lower engines, since the air coming from the top props is already moving quite fast. Since there are not too many 29" props available and I'm therefore using the same props on all engines, I would like to increase the rotations of the lower engines instead. But I can't find a mixer table or something similar in the latest firmware.
It would be possible to flash the bottom escapes with a firmware with a different signal-speed-characteristic, but it would be easier to do that in the main controller instead.