Hey everyone,
Today when I went out to fly there were 20mph winds, I fly a trex 800 so it shouldn’t bother it too much and I wanted to see how it would handle.
It flew solid as a rock in stabilize, however, when I switched to altitude hold mode after a while the heli began to spin, the logs show that at that moment the Dalt terms and Alt terms match. Also, the ch4 input and output remain constant, however the helicopter knows that it is yawing, and it maintains the desired yaw following the yaw value it needs, rather than hold to the last input asked for.
I recently swapped out all of the servos with newer versions, and had to adjust the swash collective range (I raised it so that hover occurs at about 40-50% throttle, and that it doesn’t have the full negative pitch (it doesn’t need it and just risks binding). I also changed the tail servo out.
Is this similar to the issue in the thread below? My I value for yaw is low (.025) compared to my P (.25), the imax is also really low (200). So I believe this is why it behaves like a rate gyro, but this still doesn’t explain why it spun on its own without my input, there was no change in pitch or jump in motor power to correspond with it, and it turned from nose facing the wind toward a position that would align the helicopter (vector from tail to nose) with the wind.
I have included a log, I will tune up the yaw values next flight to match the recommendations below. But ideas for the other causes would be very appreciated.
Log file here: drive.google.com/file/d/0B30gog … sp=sharing
Thanks,
Seb