A good day.
I finally found my bug
It wasn't anything to do with the FM, it was in the display code. The display code assumed that the output quaternion returned euler angles in degrees. It returned radians.
Fixing that and my F4 flew!
Well for a little while. As soon as the gear left the ground, the right wing tip dropped. I tried to compensate with the ailerons, but that just made it worse. So I pulled up to grab some sky while I tried to figure out what was going on, but by the time I realized I had the keyboard mapping wrong (roll left is roll right, roll right is roll left) I was in a spin. Before I could remember which keys I had mapped to the rudder, I had totally lost control and she augured in.
Still,
SHE FLEW! So more work to do, but real progress.
Also I have had a slow week at work, I had a lot of jobs to do which involved building the entire game from scratch (takes about three hours ??? ) and then doing some tests. This gave me a lot of free time.
I came across a flight dynamics model called Yasim. The code is a hell of a lot simpler than my code, no where near as detailed, but also a hell of a lot faster. So I have started to port that to C# as well. This will give you a choice of flight models to play with and also reduce CPU load on lower end machines.
A good week.