Question.<br><br>
How do I control the Throttle Jockey on my JR helicopter with the flight mode switch on my PCM9X transmitter?.  I want to plug the Throttle Jockey into the AUX3 channel, have 0% travel with the switch in Flight Mode N, 42% travel in Flight Mode 1 and 68% travel in Flight Mode 2.<br><br>

Answer.<br>
Selecting the Flight Mode switch to operate the AUX3 channel is easy.  Simply use the system mode menu "Device Select" function to pick the Flight Mode switch as the operating switch for the AUX3 channel.<br><br>

The problem is that when using a 3 position switch to control the AUX3 channel the 0% travel is in the central or Flight Mode 1 position.  The requirement is to have the 0% travel with the switch in the Flight Mode N position.<br><br>

Fortunately, there is an answer!&nbsp;&nbsp; Sub Trim.&nbsp;&nbsp;  The 9X enjoys an unusually wide range of sub trim and can accommodate up to approximately 75% travel.  The procedure is made easier by the use of the servo monitor facility of the 9X.  Proceed as follows:<br><br>

1. Set the travel (TRVL ADJ) to + 42% with the Flight Mode switch in the Flight Mode N position.<br><br>

2. Set the sub trim to about - 140 (as required) to bring the servo travel back to neutral as indicated on the servo monitor.  Use trial and error to find the right sub trim needed to do this.  The servo (or monitor) moves 42% from neutral when the Flight Mode switch is set to Flight Mode 1. <br><br>

3. Set - 26% travel (TRVL ADJ) with the Flight Mode switch in the Flight Mode 2 position.  The servo (monitor) moves to 68% from neutral when the Flight Mode switch is set to Flight Mode 2.<br><br>

Its done.<br><br>

In summary, set the lower speed "travel volume" to the required figure.  Use sub trim to offset this travel to neutral.  Set the high speed "travel volume" to the difference between the high and low required.<br><br>