Aircraft losses altitude in turns (and attitude is way-off)

Hello all,

I am new to the this forum. I have been working with an Ardupilot APM 2.5 in a foam aircraft that roughly resembles a Mig-27. I am trying to get the aircraft to fly a series of waypoints in support of some work we are doing at NASA LaRC. We had a great flight last week, then we experienced a consistent problem. The problem we are seeing is that during turns, the aircraft will lose a lot of altitude (180-deg turn loses 75m). Inspecting the data revealed that the pitch attitude is way off when the aircraft turns. The actual attitude may be ~5 degrees nose-up, but the VFR-HUD attitude indicates values greater than 30. Any clues would be greatly appreciated.

Thanks, Lou.

Lou, do you have a log file you could share?

Mark