I've downloaded your 787V2, tested it and propose you some remarks and modifications.
- In "Altitude Hold" mode, your autopilot reacts the right way, just a bit nervous. It regulates well, holds its altitude, decides and reaches its targets (target-climb-rate, vertical-speed-fps, then altitude). It becomes temporarily crazy when you change flaps.
- In NAV1 CDI Course, when seriously disturbed, the heading can go to roll oscillations which don't stop.
- Drag from flaps is way too strong: with full flaps (30 deg), you can't even hold an altitude at full thrust because the speed falls until stall. Moreover, for landing, you have to keep strong thrust almost until touching down, otherwise you fall like a stone. This is a remnant from the old model.
On this version (787V2-01 http://www.datafilehost.com/download-a7aadad6.html
), I've made the following modifications:
- 787.xml: (modifs marked "modif dany 11 oct 2010")
- decreased lift and drag on <wing> <flap0>
- decreased "effectiveness" on hstab. In fact, I've read such high effectiveness is a kind of cheat, maybe a trick to stabilize the aircraft or make iterations convergence possible. I'm not sure to understand. But it works, and that's probably better.
- deleted the negative ballast at the tail. It seemed weird to me, and in fact I see no CG problem. After this, the aircraft is more prone to spontaneously raise its nose before takeoff and it seems to me it's more stable in shift with the autopilot (greater moment of inertia around Y axis?)
I've inserted "my" whole version (smoother, which of course is the old one modified). You are right, it's sometimes a bit long to change pitch from climbing to descent. I've slightly increased my Kp gain (from 0.003 to 0.0035, you were at 0.01) in Altitude Hold, stage2. I feel the compromise is between 0.03 and 0.05, but I don't know what to do. To refine... It's stable in normal transient conditions, when you change the altitude on autopilt from higher to lower and vice-versa, but it doesn't like a lower altitude setting when the aircraft is climbing at (manuallly) very high shift angle (due to the difference between target and present vertical speeds). A servo motor may solve this roughness, but I ignore all of this (I just learned to tune an autopilot 2 weeks ago).
With all of that, the aircraft seems correct and pleasant, down to landing (approach 170 kts flaps 30 deg, touchdown 125 - 135 kts). Its max speed is 495 - 500 kts.
Here I am presently. I hope it can help you to choose the best of all that.
PS: I sometimes have a sudden cutoff (instruments, engines) just after a seemingly good start of the game, I think when the engines are slowing down. I had already seen this with the sept 2009 version, not on yours. I hope that's not something in the autopilot. I'll try to investigate it.