Hi Jimi,
after my fruitless excursion with the AOA limiters I have been experimenting with the cg's (empty weight, stations & fuel) and have been somewhat successful in setting up a hornet configuration (.air & .cfg) with RL cg's that seems to be ok, apart from the pitch auto trim behaviour - but that was to be expected.
When moving all cg's (empty weight, stations & fuel) to their RL positions, mostly further backwards, I had to make the following adjustments in order to get to an aircaft that is stable on the runway and in the air:
a) moving cg's backwards makes the stationary plane on the runway pitch its nose down, so nose gear cp's (static and max/static compression needed to be adjusted). Result: stable plane on runway.
b) moving cg's backwards makes aircraft unstable around the yaw axis, so Cn_R (yaw rate) dampening has to be decreased (inverted/negative), and Cn_beta (sideslip) has to be increased in order to compensate (normal/positive) too. Result: stable flight envelope, similar to what it was before.
c) moving cg's backwards negatively effects pitch behaviour, in order to compensate elevator effectiveness needs to be increased. Result: same pitch behaviour as before.
I have done these changes in order to better understand how it all works, so in the future it might be easier to change certain parameters to get to a certain result - to improve flight dynamics.
1) What puzzled me before and now again: Whenever the cg's are moved backwards the stationary model on the runway moves its nose downwards although one (I) might expect the opposite. Do you have an explanation resp. do you understand why it works this way?
2) When I understand NATOPS correctly the FCS will compensate for cg variations due to fuel transfer and weapons release. Since we cannot implement this easily, it seems be the best way move all cg's close together around the longitudinal axis - as you have already done with you current versions. Is there a specific reasoning (some rough calculations) behind it for moving empty_weight cg to -27.0 and all other stations & fuel to -28.5 around the lon. axis. I understand that it has to do with pitch_auto_trim, and that it functions best around the center of the aircraft, but why is that so?
3) When cg's were moved backwards to their RL positions, pitch auto trim kicks in at around 7deg attitude, above that it does not seem to work. I.e. when you pull pull up the nose to 15 or 20deg. - although the g's are below 1.0 the plane will gradually pitch down until it reaches roughly 7deg. attitude and the movement stops. I have tried several changes in the coding, but none seem to effect this behaviour. Do you understand why it behaves this way in combination with the cg's moved backwards?
These are the questions that have been bugging me for the last few days, and I understand they might not be easy to answer, so please take your time - I will be on a short holiday the next two days anyway, where I hope some enlightenment will strike me.
Best regards, Peter