Severe Pitch Oscilation AR Wing 900

I have observed a problem during maiden flight. The model is AR Wing 900 with two elevons.

Takeoff was hand launch in TAKEOFF mode, I immediately noticed oscillation in pitch. which disappeared after few seconds. Next I tried autotune which resulted in extreme pitch oscillation… Can anyone help me resolve the oscillation problem?

Assume you’ve checked the CG? Any excess slop in control surface linkages?

Have you tried flying it manually? How did it handle?

I also had severe pitch oscillations when I started with the smaller AR Wing 600. I solved it by starting off with some else’s PIDs for that plane (which were by far lower than the defaults), then Autotuned it, and it has been flying perfectly ever since.

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Without log file or video … Difficult to state
I have also zohd orbit which is similar and for me it was not enough throttle

Cg is as per manual. There is some flex in elevons and small play. In manual mode it flys okay.

I have halved the P gain on pitch axis and it helped alot

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For second flight i have adjusted pids manually. Could you share your pids? For ar wing

I don’t have the numbers handy, but I just went through exactly the same problem. I tried to cheat and didn’t fully reset the controller after moving it from another plane. The oscillations were so aggressive I could hear it as it went past me and I thought my servos were going to fail.

Lower the pitch PIDs, not just P but I and D as well. I reset the pitch PIDs to stock and I think I spent 10 minutes in auto tune just going up and down, and that made a ton of difference. The stock pitch PIDs for the AR900 are too high (and for all my other planes they’ve been very low so I guess that makes them a good starting point).

If I get a chance to look the numbers today from mine I’ll post them here for you.

I took them from this video:

But note that they’re for the 600mm version.

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I don’t consider this to be my final tune, but it’s flyable and I didn’t notice the pitch oscillations. Hopefully this gives you a good starting point. My AUTOTUNE_LEVEL is still at 6, but I may try it at 7 to see if that makes it a bit more snappy.

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