Something I have noticed recently....

[twentyafter]

After my timer goes off and it's time to land I pick up my 120 to disconnect the lipo and notice that every once in a while the servos will move and I was wondering if this is normal. Why would the gryo be adjusting the servos when the motors are not running? I also noticed that if I put light pressure on the swash or link to the servos they will adjust also. Seems a little odd to me and wanted to make sure my 5 in 1 wasn't about to fry or something like that. I don't have any problems in flight, can pretty much hover hands off.
Thanks for the replies!

[Eldaren513]

Originally Posted by twentyafter

After my timer goes off and it's time to land I pick up my 120 to disconnect the lipo and notice that every once in a while the servos will move and I was wondering if this is normal. Why would the gryo be adjusting the servos when the motors are not running? I also noticed that if I put light pressure on the swash or link to the servos they will adjust also. Seems a little odd to me and wanted to make sure my 5 in 1 wasn't about to fry or something like that. I don't have any problems in flight, can pretty much hover hands off.
Thanks for the replies!

From what I've seen on my two 120's, that is normal. The gyro and servos are very sensitive.

[RoundWing]

The gyro on the 120SR is 1-axis which only controls tail thrust and yaw, not cyclic but there may be some built-in rudder > cyclic mixing being done by the 5-in-1 board. But more than likely its pressure the blades or flybar moving the servo link and the servo controller moving it back.

Servos work via a feedback loop. Fingers under the link run across a resistor strip. The Tx relays stick position via the pulse width of the FM signal, the motor moves link until the resistance corresponds to that position.

Normally servos move swash, swash moves flybar, and flybar moves blades. But the opposite can also happen. When you pick it up and the rotor or flybar flop around it will put pressure in the swash arms and may move the servo links slightly. The controller, detecting it is out of position because the resistance has changed will then activate the servo to move it back to where it was.

[twentyafter]

Thanks for the replies. Roundwing, that's pretty much exactly what I was thinking, just not as technical, LOL. Glad to know it's normal operation, I just don't remember it doing that when it was new.