Hi Tal
Look at this link, it will give you some answers to your Question, and how to connect it all so it works correctly
Since you are using V-tail there is no YAW control, so: Ch-1 will be Ailerons, CH-2 Elevator, CH-3 throttle
in other words : you need a plane that has aillerons
http://plane.ardupilot.com/wiki/ardu...stick_channels