KA 50 3 Randomly Turns during Autohover

[Keta]

I've been flying the KA 50 3 for a bit now. A good 90% of the time I go into an auto-hover and everything is smooth. The other 10% of the time and it quite wildly starts swinging to the right about 180 degrees before stopping. I'm pulling my hair out trying to figure out why it does this. I'll go over the various things I have tried and hopefully somebody else has an idea.

Start-up has been done in accordance of Chuck's Guide. I've done both the quick alignment and precise 20 minute alignment. It made no difference.

Pedal Trimmer is off. As well I have the input window open on the bottom left and it shows the rudder being neutral. It is not random input from another controller or drift as not only do I have deadzones on but after about a 180 degree spin, it stops turning right.

No waypoints are on on the PVI-800. I have tried with it both in Operation Mode and Off. As such, Route Mode is not engaged or used.

Trimmer is set directly on the nose before going into auto-hover. Like I said, 90% of the time I hit into auto-hover no problem.

Auto-turn is not engaged. I have reset the Shkval multiple times and disengaged and reengaged all auto-pilots, including the heading hold multiple times.

Probably a coincidence but I usually fix it by flying away from danger and continually do hard loops in any direction. I've flown in bad weather before and it sometimes sways but when this thing is doing its thing and turning randomly, it turns HARD. That is not the wind unless its a tornado.

Please help...I'll try to answer any questions and recreate anything, though its completely random when it does it. Was just flying, engaged auto-hover. Rose above trees, descended back down. Undid Auto-hover, moved about 50 meters to the left to see around a tree. Suddenly it turns 180 degrees to the right after auto-hover is engaged.  As a note, after it starts doing it in auto-hover, it will start doing it out of auto-hover when below 50 KPH as well but only after it starts doing it in auto-hover.

[Amarok_73]

The yaw stabilisation is INS dependent, so if the INS is not stable, the heli will have tendency to oscilate.
Similar behaviour can be observed when enabling the route following mode, while the INS is still not stabilized, so the heli flies in slalom that eventually straightens up.

[primus_TR]

It could be a heading alignment mishap. You're not inadvertently flipping the mh/gyro/man switch while hovering by any chance, are you? 

[Keta]

Hey, thanks for the replies I appreciate it.

In terms of INS, this happened both after the 3 minute quick INU and the 20 minute precise INU. I'm not sure what else I could do if it was an INS problem. I shouldn't have to in flight course correct via way points just after takeoff.

And no, I do not flip that switch. Only started messing with it AFTER it started turning hard to try and align mid flight.

I'm not having any problems with other aircrafts. Only the KA 50 3. Still trying to figure it out. Flew it again last night and no problems. Flew it again later that night and it did it once. Just so random.

[Hobel]

vor 52 Minuten schrieb Keta:

Hey, thanks for the replies I appreciate it.

In terms of INS, this happened both after the 3 minute quick INU and the 20 minute precise INU. I'm not sure what else I could do if it was an INS problem. I shouldn't have to in flight course correct via way points just after takeoff.

And no, I do not flip that switch. Only started messing with it AFTER it started turning hard to try and align mid flight.

I'm not having any problems with other aircrafts. Only the KA 50 3. Still trying to figure it out. Flew it again last night and no problems. Flew it again later that night and it did it once. Just so random.

Send a track of it when that happens.

[Amarok_73]

12 hours ago, Keta said:

In terms of INS, this happened both after the 3 minute quick INU and the 20 minute precise INU.

It doesn't matter, there's still some inertia on this subsystem, causing dependent systems to follow it, but eventually it fades away when the heli stabilizes on the course.
Only thing that makes me wonder is this 180 degree. I couldn't force my heli to oscilate so wildly, no matter how sharp turns I made.

EDIT: observe one more thing - when it happens, check if the Doppler sensor located on the tail have line of sight with the ground. You can recognize it by digital speedometer on the HUD, that gets stuck on the speed You've had at the moment the sensor lost the contact.

Edited May 27, 2023 by Amarok_73