Originally Posted by dahawk
Something about matching up the trim settings though. Any magic to this?
The magic comes when you don't have a trainee trim your plane! J/K... My method is to first fly the plane alone on the master TX, and get it all trimmed out. Then, land and connect the slave TX. On the ground, switch back and forth from Master and Slave, and watch the trim settings. Get them as close visually as possible, and often that is enough. After you get it visually as close as possible, you get another pilot (or instruct the student on the trim) and take off. Ideally, when you switch back and forth, there should be no servo movement. Watch each control surface separately during the switching.
Once airborne, you go from master to slave momentarily , only to check trim. With the student radio only having the same throttle setting, you hold the trainer button (or switch) and watch the plane. You, the instructor then releases the trainer button, take control back, and tell the student what trim changes you want.
You go to the trainer box just long enough to see if it is trimmed. You take control back, then tell the other pilot, "one click up" or whatever you want. Then you momentarily hold the trainer button to check. If changes are needed to be made, you take control back, and tell them what to do on their box. They dont have to fly and trim, and you are still doing the thinking.