ORIGINAL: joco1
ive got a nexstar also how much of a job is it to add the second servo and what is the advantage of doing this will the plane have a extra control if you do this?
Not much effort. You've placed one servo so know how much that was. This is placing two. You will have to place aileron horns, and make pushrods. And you'll probably need two extensions for the connections to the "Y" harness. You'll need the "Y" to plug into the receiver and to bring the two servo leads to one lead in to the receiver.
You will only get "extra control" out of the arrangement if the single servo wasn't powerful enough to drive two ailerons. Probably not the case if you were using a standard in that airplane for the ailerons.