Mornin' flight simmers! My name is Robert Dixson, a virtual bush pilot for Timberwolf Airways. I have just upgraded to FS2002 and at first glance it looked good. The autogen is a nice touch. Too bad the FS design team didn't pay more attention to the basics of flight - like the autopilot. Well, I have found a work-around for us.

The problem seems to be that the autopilot responds too slowly to changes. There are two ways around this. Make the autopilot more responsive (sorry I haven't figured out how yet) or make the control surfaces more responsive to the autopilot. This is the direction I took.

As an example, let's look inside the Cessna172SP.air file for a moment. You'll need a utility called AirEd (available in the download area). The default values for section 300 'Control Effectiveness' read as follows:

300 Control Effectiveness

	Elevator 1/4 Effectiveness Speed = 100
	Elevator 1/2 Effectiveness Speed = 180
	Aileron 1/4 Effectiveness Speed = 200
	Aileron 1/2 Effectiveness Speed = 1000
	Rudder 1/4 Effectiveness Speed = 200
	Rudder 1/2 Effectiveness Speed = 1000

Now the airfile Performance Specs say cruise speed is 140 kts. (Extremely generous but let's use that number anyway). Now let's treat the Control Effectiveness Speeds as being listed in kts IAS. See the problem? Even at full throttle, you never get above 1/4 of the designed control sensitivity.

Here are the values I put in...

300 Control Effectiveness

	Elevator 1/4 Effectiveness Speed = 27
	Elevator 1/2 Effectiveness Speed = 54
	Aileron 1/4 Effectiveness Speed = 27
	Aileron 1/2 Effectiveness Speed = 54
	Rudder 1/4 Effectiveness Speed = 27
	Rudder 1/2 Effectiveness Speed = 54

The aircraft now follows the glidescope without problems. My general rule of thumb is to set the 1/2 values to clean stall speed. Make the 1/4 values half of the clean stall speed.

Don't bother looking in the .PDF manuals for the stall speeds of default aircraft. That's another one of the basics the FS design team overlooked. Check the aircraft.cfg file under the section 'Reference Speeds' for a ballpark value.

While I make no guarantees, I have tested this tweek on both default and third party singles and twins, and found it to improve the autpilot's handling. As always, make a copy of the airfile before tweeking just in case.

This tweek will not change the weaving around that FS2002 does when capturing an ILS beam, it only changes the descent portion. I will continue to poke at this bug (ILS capture) until I figure it out and I'll let you know.

Unlike Bill's FS2002 fix (aka FS-ACOF), this one's free.

Robert 'Grizzly Bear' Dixson
Timberwolf Airways VA (TWF-172)
grizzlybear@neonramp.com