blaplante
Well Known Member
I'm currently working on installing used TruTrak autopilots in two planes.
On one of them the servo motor seemed to be loose. It turns out that the servo motor is mounted to a steel web which serves as a rotary spring. It allows the motor to twist slightly with applied torque. This movement is sensed, so when sufficient torque is applied a sensor will indicate that pitch trim is needed.
Upon opening the gearbox, the steel web was found to have two of the four legs cracked.
I subsequently got curious... and opened the 'good' DSP-C servo. And found that it also has a cracked leg, but just one of the four.
https://photos.app.goo.gl/sXBvA5rLLdoA9wpM9
So in looking at two used DSP-C servos... 100% of them have issues.
I'm thinking the symptom would be that it gets very sensitive about pitch trim.
On one of them the servo motor seemed to be loose. It turns out that the servo motor is mounted to a steel web which serves as a rotary spring. It allows the motor to twist slightly with applied torque. This movement is sensed, so when sufficient torque is applied a sensor will indicate that pitch trim is needed.
Upon opening the gearbox, the steel web was found to have two of the four legs cracked.
I subsequently got curious... and opened the 'good' DSP-C servo. And found that it also has a cracked leg, but just one of the four.
https://photos.app.goo.gl/sXBvA5rLLdoA9wpM9
So in looking at two used DSP-C servos... 100% of them have issues.
I'm thinking the symptom would be that it gets very sensitive about pitch trim.
Last edited:
