Big eror between Desroll and roll

I’m trying to fly a Heli 500. In stabilize mode, it seems to fly all right. But when I look to the log file, I’ve found that in attitude log, there is quite a big error between Desroll and roll, about 9 degrees. There is also an error between Despitch and pitch but not so big. Regarding the Desyaw and yaw, thay are almost the same. The problem is that I can’t explain the question, can anyone explain it to me, please.

I tried many times to find the reason with no success. So here I include the DF log file with the hope that someone would look into it then give me a break in the clouds

The reason is much simpler then I thought. Because the heli leaned on one side I trimmed the RC transmitter. But after that I didn’t do radio calibration again, that’s why the DesRoll was shifted away and there was a big error between DesRoll and Roll. After redoing the radio calibration, everything works fine.

Hi minhtq98,

I am really sorry to ask question in your post, but I really need your help.

Since your heli now flies very well, may I ask you a question about the tail rotor?

It seems that the recommended helicopter frame has a tail servo which should bu connected to ch4 of the APM output, but my helicopter does not have a tail servo. It only has a tail rotor. So could you please give me some advice on how I can connect this tail rotor? I would appreciate you advice.



Hi ylwhello,
I think that you have a direct drive tail which is not my case. I haven’t tried with dd tail but in your case I’d connect ch 4 to an ESC then connect to tail rotor. Then I can see how the tail moves and decide the next steps.

Hi minhtq98
Thanks so much.
I’ll try you advice.