Need Help with Tail Twitch

[Speedz]

I have a 401 connected to a 9650 on my trex 450 everything seems fine till the voltage drops then the tail on the bird will twitch. Is this common when the voltage drops or do I have another problem.

[900steve]

this seems common. when flying my nitro heli, as the receiver's battery dropped towards critical, the tail starts to twitch.

[Steve1953]

Speedz,
I also have 401 mated w/S9650. But my Align esc is set up to lower the power when any cell reaches 3.2 When this happens the tail will wag, but it is do to pulsating in the power or the "low voltage" warning.