Trims and Forcefeedback

[Furio]

Originally Posted by zipper

That was because when the fuselage tank was full the CG was AFT of the aft limit - not AT the aft limit.

The P51 was just an example. Stability is reduced while the cg goes aft and, beyond aft limit, we cannot talk anymore of reducing stability but of increasing instability. All of this to say that playing with cg for obtaining more speed is something acceptable for racing, but I doubt it can be a wise choice – or a realistic one – in an operational plane loaded for war.

Originally Posted by zipper

Again, different aircraft behave ... differently. The flaps by themselves cause a severe nose down force that is countered by the downwash behind the wing (created by the flaps) landing on the stab. The size of the stab and its position in the downwash are major factors in trim settings. I've flown planes that I've trimmed in the downwind leg and not had to retrim before touchdown. As the planes slowed on base and final rather than retrim noseup I simply fed the flaps down and maintained neutral trim. Not all planes are like this.

You’re right, different planes behave differently, and I also flew with planes that showed pitch-up at flaps lowering. But generally speaking, the effect of flaps in landing position is to generate more drag than lift and – again, generally speaking – planes steepen their approach with flaps down.

Returning on topic, trim is presently simulated with moderate realism, and this is perfectly understandable and acceptable. Any attempt to simulate it with force feedback should try to simulate stick force variation with trim changes. It's no easy task, and I sincerely wish good look to anyone attempting it!