But why do helicopter captains sit on the right?
Simply because the helicopter is easier to control from the right side. Well, all the buttons/controls are in the center, and if your holding the stick with your right hand (like most people do), u can easily take off the left hand from the collective and push those buttons. If you were sitting on the left side, you'd have to reach across quite a bit, with some body twist, and your hand gets further from the collective - not really a problem, but annoying nonetheless, and if the collective creeps up on you while you are busy pushing some buttons, it can be 'distracting'.
Interestingly enough, the first certified civil helicopter (BH-47) has the pilot seat on the left side. Aside from 2 controls (fuel shut off valve and the starter, which is foot operated), i'd rather fly it from the right side too if it has dual controls
. I often found myself clutching the stick between my knees so i'd have a hand free to set some knobs with out having to let go of the collective, considering its friction lock isn't that good and if you got turbulence, its less than ideal. Doing that means taking the feet off of the rudder pedals though, also not really optimal. ANd if your hoving, unless u got monkey arms, you are better off putting it on the ground first before making prolonged frequency changes.