lamans terms- the rotary carb -rotates clockwise and counter clockwise,(like the hands on a clock) the slide carb slides open and shut (in and out)

the reason people use the rotary carb on 10th scales it because its more controlling not so fast as the slide. but if your radio had expo on it just adjust it on the slide carb so it doesnt open so fast. on 10th scale you dont want to be halls balls on the git go or it would be all over the track.