iNavFlight
The default PID parameters of INAV's fixed-wing design are unreasonable, which affects the success rate of the maiden flight.
Current Behavior
The usability of INAV is much better than that of ArduPilot. However, the default PID settings of INAV have received a lot of criticism. During the first flight using the default PID settings of INAV, the aircraft often experiences oscillations and crashes, which is a common problem. Many people have reported that the fixed-wing aircraft using the ArduPilot firmware has a much smoother first flight. As a result, there is a saying that "If you want to survive, please stay away from INAV."
Desired Behavior
Is there any way to solve this problem so that INAV does not crash during its first flight due to inappropriate PID parameters, thereby significantly improving the usability of INAV?
Suggested Solution
My personal flight experience leads me to believe that in the default PID of the INAV fixed-wing, the value of I is too large, which can cause the aircraft to experience oscillations. Therefore, during the first flight, I usually reduce the value of I and also reduce the value of FF to avoid oscillations. Because feedback is much better than oscillations
Who does this impact? Who is this for?
From a user of INAV and Ardupilot，Regarding the above suggestions, if you need any assistance, such as for the flight test, please feel free to contact me. I am willing to contribute to the improvement of INAV.
Additional context
This sounds more like a setup issue and you have excessive throws on your control surfaces. If anything, when the airplane is setup physically correctly. The default settings are sluggish and slow. This is done purposely so that large aircraft are not over-tuned by default.
How does your airplane fly in manual?
The aircraft hardware is completely normal. I have flown it many times. Recently, I replaced the flight control of the aircraft with a new one and used the default PID for flight. However, there was a severe and large-amplitude low-frequency oscillation in the pitch angle.
What version of INAV are you using ? And I assume if it's the first flight you aren't trying to use Nav modes, just Manual and Acro/Angle ?
The first flight used the angle mode and the firmware version was inav7.0.
The first flight used the angle mode and the firmware version was inav7.0.
OK well that rules out the pitch oscillation issue during Althold that affects 8.0. A Diff would be most useful in this case and perhaps you need to read the following to see if it helps if you haven't already done so:
https://github.com/iNavFlight/inav/blob/master/docs/INAV_Wing_Tuning_Masterclass.pdf