As you may know the FS9 default Ford Tri-motor is not equiped with autopilot. I have tried to install an autopilot in this aircraft but with no success. I copied the autopilot section from another aircraft into the Tri-Motor's aircraft.cfg file. The plane will hold altitude but will not hold heading. It banks from left to right and gradually goes into a spin. I've tried tweeking the autopilot section a bit but no improvement. Any sugguestions out there?

As for elevator trim, yes. the plane climbs and descends just fine, it  just won't hold heading. I don't think the Tri-Motor has a rudder trim, maybe that's the problem. Thank's for your reply, Ozzy72.

Thanks again Ozzy, I wish you could try this experiment yourself because it's becoming apparent that the Tri-Motor is a "hands on" flying machine. It banks over and eventually spins and crashes even with the autopilot off. I'm looking to see if there is a way to edit something to allow this plane to fly in autopilot mode. The autopilot section has been copied from the DC-3 in the aircraft.cfg file but it obviously needs other changes. I have had success adding autopilot to other planes without autopilot but I can't get this aircraft to do it.

Jaypee Dippel wrote on Dec 11^th, 2009 at 10:03pm:


Have you installed an autopilot gauge in this plane in addition to the aircraft.cfg mods?

If so, which one?

cheers,
Joe

Jaypee Dippel wrote on Dec 12^th, 2009 at 4:41pm:

Gives you a lot of respect for the pilots who did this back in the day.

For the autopilot to hold a heading it has to receive some heading input. This usually comes from a DG or HSI. Did you install anything like that?

Without some instrument to manage heading I can't imagine you will get heading hold with an autopilot.

You might also need a NAV/GPS switch too.

As I am in the middle of some PC maintenance I do not have FS installed right now, so I can't test this.

cheers,
Joe

I copied this from the
tri-motor's aircraft.cfg

[direction_indicators]
//1 Type: 0=None, 1=Vacuum Gyro, 2=Electric Gyro, 3=Electro-Mag Slaved Compass, 4=Slaved to another
//2 Indicator number of slaving indicator if Type = 4
direction_indicator.0=0,0

Edit yours to read -
[direction_indicators]
//1 Type: 0=None, 1=Vacuum Gyro, 2=Electric Gyro, 3=Electro-Mag Slaved Compass, 4=Slaved to another
//2 Indicator number of slaving indicator if Type = 4
direction_indicator.0=,0


and see if that helps.

cheers,
Joe

SUCCESS!
Jobee's idea about the Directional Indicator was a good clue. I copied these sections below from Jens B. Kristensen's DH-91 Albatross into my tri-motor's aircraft.cfg and I'm not sure why but the Autopilot works superbly now. It works on manual heading and GPS navigation, not very historically correct but it makes the Tri-Motor a lot more useful. Thank's JoBee and Ozzy for all your help, I would have given up without you.
Here you are:

[direction_indicators] //DH-91
//1 Type: 0=None, 1=Vacuum Gyro, 2=Electric Gyro, 3=Electro-Mag Slaved Compass, 4=Slaved to another
//2 Indicator number of slaving indicator if Type = 4
direction_indicator.0=1,0
direction_indicator.1=1,0

[attitude_indicators] //DH-91
//Type: 0=None, 1=Vacuum Gyro, 2=Electric Gyro
attitude_indicator.0 = 1
attitude_indicator.1 = 1

[turn_indicators] //DH-91
//Type: 0=None, 1=Electric Gyro, 2=Vacuum Gyro
turn_indicator.0=2,0

[autopilot] //Original no autopilot available
autopilot_available=1
flight_director_available=0
default_vertical_speed=500.000000
autothrottle_available=0
direction_indicator=1
pitch_takeoff_ga=8.000000
use_no_default_pitch=0         
use_no_default_bank=1 
default_bank_mode=0   
max_pitch=10.000000
max_pitch_acceleration=1.000000
max_pitch_velocity_lo_alt=2.000000
max_pitch_velocity_hi_alt=1.500000
max_pitch_velocity_lo_alt_breakpoint=20000.000000
max_pitch_velocity_hi_alt_breakpoint=28000.000000
max_bank=12.000000
max_bank_acceleration=1.200000 //Original 1.8
max_bank_velocity=2.20000      //Original 3.0
max_throttle_rate=0.100000
nav_proportional_control=9.000000
nav_integrator_control=0.250000
nav_derivative_control=0.000000
nav_integrator_boundary=2.500000
nav_derivative_boundary=0.000000
gs_proportional_control=9.520000
gs_integrator_control=0.260000
gs_derivative_control=0.000000
gs_integrator_boundary=0.700000
gs_derivative_boundary=0.000000
yaw_damper_gain=0.000000