ORIGINAL: piper_chuck
ORIGINAL: carrellh
Advantage to using two channels - you can use flaperons if you want
Disadvantage - takes longer to set up the controls because you have to set servo travel end points on two channels rather than one
If you can setup 2 servo ailerons using a y-harness, and without endpoint adjustment, you sure as heck can do the same with a two channel setup. Far too often people think that because the computer radio lets one do something, that they must do it. Spend the time getting the control right mechanically. Endpoint adjustments should be used as a last resort for small fine tuning or in case there's a mechanical issue that prevents using the full range of the servo. The only thing that I've found takes longer when setting up up two channel ailerons is to learn or remember how to do the radio programming.
Chuck said a mouthful with this one. Too many people try to rely on the radio to fix mechanical problems. If you try to adjust your controls with the radio before you have them mechanically correct you will just make more problems for yourself. This is one reason why I don't prefer for students to have computer radios while they are learning. For may that don't understand what is involved in mechanical adjustments they will use the radio to try and fix the problem instead, thus causing more problems. With basic radios all adjustments need to be made mechanically in order to get the plane to fly correctly, and the student learns these skills because of that. Anyway, I'll get off my soapbox now.
Make sure that the throws, as well as the endpoints, are mechanically correct before you start adjusting with the radio. I own several computer radios, but this is what I do with ALL of my radios (computer as well as standard). I will assemble the plane and put all the control surfaces in the neutral position. I then will fly the plane and trim it out. Then I will take the plane back to the bench and mechanically adjust the control surfaces so that when the radio is in the neutral center position they are in the same position as when I trimmed them in flight. This way all of my trim tabs should always be in the center position (or very very close). If you do this then you won't have to fear accidentally "bumping" a trim tab because you only need to put the tab back in the center position to be back in trim.
You can do the same thing with your end points, but not to the same level as with the center points. Try using the different holes in the control arms on your control surface, as well as on the servo, to get your control throws as close as you can. In some cases you will need to use the EPA (End Point Adjustment) to get the control throw correct. Now with that said I'll add that you should RARELY need to use EPA on a trainer, or even a 2nd intermediate plane. Also, the control surface where you will probably use EPA the most is on the rudder. This is because you don't want the rudder servo driving the rudder so far that it hits the elevators, and you can use the EPA to adjust it so this wont happen.
Anyway, to wrap up, make sure that all of your control surfaces are mechanically correct before you ever try to make any adjustments with a radio. If they aren't mechanically correct you will more than likely make things worse by using the radio. If you're not sure what do to on mechanical adjustments please don't hesitate to ask here in this forum. Of ask your instructors, or other members at your club, for help. I'm pretty sure they will be more than happy to help.
Hope this helps
Ken