Autopilot cfg adjusting

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Autopilot cfg adjusting

Postby Staiduk » Tue Jan 03, 2006 10:02 pm

'Lo!

I've a Mohawk I've been tweaking a bit; it was already great I just added weight to the controls. Now I have one little problem: the autopilot overcorrects on the rolling axis. This is due to the decreased aileron size and increased roll inertia required to 'heavy' up the airplane. The result is that until the aircraft reaches around 250kts; she rolls continually through approx. 40 deg. total.
I'd like to eliminate this roll. I can do it by increasing stability or aileron effectiveness; but then that affects aircraft control, of course.

Is there a way to tweak the autopilot settings in the aircraft.cfg so that it compensates for the increased inertia?
Thanks. :)
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Re: Autopilot cfg adjusting

Postby Milton » Tue Jan 03, 2006 10:35 pm

From looking at the Mohawk 3-views and pictures, it seems to me it has sizeable aileron control surfaces.  You really need to specify all the surface areas correctly to get a proper response.

By understating, you have asked the AP to do the impossible.  Looks like to me the large percentage of mass is near the center of the aircraft and it should be more responsive in roll than in pitch.    With twin engines, yaw should be very stable.

Properly defined control surface areas and distances, well placed engine thrust, fuel weights and CoG, and calculated MOI's should yield reasonable responses.  The AP should be able then to do what it is asked.
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