Hi Robert, a few comments:
- Did you try powering on your plane on the ground (with all props removed, of course) and test the fixed-wing control surfaces to see if they respond? If they don’t then it’s probably a connection or servo problem.
- If you have a .bin log of your test flight, look through it to see whether there is any elevator response when you pull on the sticks. If there is, it may be that the controls are working but it isn’t responding quickly enough, which would point to a PID tuning issue.
- Also, posting the .bin log here would be very helpful.
- The issue where your plane noses down seems vaguely similar to a problem that I experienced in the past, where our quadplane would lose a lot of altitude when transitioning from VTOL to fixed-wing. We opened a discussion thread previously here, but have yet to solve the problem.