Some servos (such as Futaba servo models 9241, 9251, 9253, 9254, 9255, 9256 and other digital servos) are not capable of handling 6V. In this case, connecting a 5.1V step-down voltage regulator to the rudder servo, or connecting it between BEC (ex. RCE-B6X) and the receiver for all servos could stop the servos overloading and being damaged.
Specification:
Max continuous current: 5A
Length:104mm
Weight:4.2g