Wiring an On/Off Switch

[BrianG]

I too think the Spektrum is part of the problem, that's why I mentioned it. Binding position would be an easy thing to overlook and rectify. I always like to start with the easy (and free) solutions. Sorry to make it seem like I was going off on a tangeant. :)

A UBEC is a switching regulator and might be prone to start up noise until the regulator circuitry can settle down and provide relatively clean DC (switching regulators generally use current feedback to regulate the voltage). It is possible the Spektrum receiver does not like the startup noise and gets a little crazy. A switch is probably the easiest solution. Another may be to add a capacitor to the output of the BEC; it would filter the DC output and would also help beef up current pulses for better servo response.