Originally Posted by ES201
...........I wonder if there is a tx with more than 4 proportional ch and what their use is... ...
Rudder, 2x elevator, motor, 2x flaps, 2x aileron - each one controlled via a separate proportional channel operated from 2 sticks and 2 sliders on the Tx through mixers.
That's 8 proportional channels.
Scale models and some gliders might have even more options.