Rafael E

I am using the HiTec HS77BB proportional servo along with a servo rate reducing unit for the retracts. The servo end points are adjusted via the DX7 travel adjusment. I am getting a continuous hum both when the gear is fully extended and retracted. I can cancel the hum by reducing the travel but eventually after recycling the gear several times the travel is reduced and the gear hangs. Has anyone had a similar experience with this servo?

Thanks,

A.T.

The Hitec HS-77BB servo works very well when used as is intended as an aileron servo. Perhaps you have a faulty rate reducing unit or you have a problem with mixing the reduction unit and EPA of your TX - all retract set ups are best done mechanically. You do not mention the size of model/retracts/wheels etc - note the spec diference between the aileron servo and the same cased retract servo
Hitec HS-77BB Low Profile Servo - ailerons specifications
4.4kg.cm(61.1oz.in) at 4.8v - 5.5kg.cm(76.3oz.in)
HS-75BB Retract Servo specifications
6.6kg.cm(91.65oz.in) at 4.8v - 8.2kg.cm(113.87oz.in) at 6.0v
perhaps E.P.A - A.T.V - Dual Rates differences will also assist.
Regards
Alan T.
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