overtaxed my digital rudder servo

[s vernon]

I sailed my boat today in winds of mostly about 10 to 20 with lots of gusts to probably almost 30. Wanted to see what would hold together and also tune the B rig. I probably sailed long 1000 foot windward/leeward legs for a bit longer time than a normal race. The boat got squirrely downwind several times, of course, and I fought to get it back under control with the rudder over at about 30 degrees for several seconds at a time (dual rate was at 80% I believe).

Servo is a coreless digital Futaba S5381 beauty with 192 inoz at 6V. When I brought the boat back in the house (short walk), I noticed that the servo was making a constant growling noise that would not stop even with the radio off and the boat battery still on. It was not twitching, just making the noise. It would still function normally when I moved the stick, but with that constant unhappy noise.

I did put my finger on the servo and it was not hot. That was the only way I could tell which servo was unhappy. I could feel the case vibrating.

I shut the boat off and later turned the radio and then boat on and the servo seems to have recovered. I worked the rudder stick and put a little finger pressure against the rudder and the servo did its best and made the usual grunting sounds that it makes when challenged.

I wonder if anyone knows if the servo has been permantently damaged or not. Like I say it seems okay, but I know nothing about the results of apparent mistreatment of digital servos.

Thanks

Scott

[Chuck Luscomb]

Hi Scott,

I am not sure I have ever abused a digital servo to the extent you did today but they are noisy buggers. I used to have a digital rudder servo in my boat but replaced it with the highest torque analog servo I could get. The reason for the replacement was the constant high pitch whine coming out of it and the abrupt jerkiness to the rudder. The analog seems to have the power to do the job and makes no noise.

Has anyone ever determined the what the rudder tourqe is on one of these boats at full lock?

Chuck #84

[tharmer]

The digital servos have a tendency to growl around center. If you have Hitech and the Hitech programmer you can widen the dead band a bit to get rid of it. Usually it just costs a bit of battery life and doesn't hurt anything else.
-terry