chemie: For the servos with arms, well, first you have to center the servo using the receiver, a battery, and your TX. Here's how:

1. Center the control you intend to use that servo for. Meaning, if it is for the aileron, for instance, center both the stick and the trim.

2. Plug the servo into the aileron slot on the RX.

3. Power up the RX.

4. Take one of the servo control arms and push it on the servo shaft. Don't screw it down. See if it is perpendicular to the sides of the servo. If it is slightly off, then remove the servo arm and rotate it to the next position (the next arm) and see if THAT one is perpendicular. One of the four will be perpendicular. When you find the one that is, well, mark it or cut the other arms off, and keep that combination servo and servo arm together as a matched pair.

For the round ones, well, those can be used pretty much however you want, pretty much using the holes as guides as to the position you want them to be in, and centering, if necessary, on that hole.

There was a thread here on RCU about setting up a throttle servo and it pretty much describes that setup, as it is somewhat different than it is for other applications in that it is easy to over-rotate the servo arm and put the servo into a binding situation. If you want that information, well, either you can look it up or let me know or one of us know here on RCU and we can re-post that information.

CGr