autopilot and turns

[flyforever 0]

Somehow, if the aircraft is on autopilot and climbing, turning the aircraft sends the aircraft in a shallow dive. Only pulling back on the elevator will prevent the aircraft from crashing into the ground.

tc

[Michael2 236]

Can you tell me if this is in FSX or P3D? Also what version of the DC-8 are you using?  Is it the latest version with the 2D autopilot panel (shift-6)?  I would like to rule out the new version having introduced a bug of some kind.

 

Also, are you sure vertical speed is selected on the AP panel's pitch knob?  

[flyforever 0]

It's P3d and it's the latest version with the 2d autopilot pop up. I have not tested it, but I'd be curious to know at what point the rate of turn(10-45 degrees) starts to affect the rate of lift, thus the drop in vertical speed.

tc

[Michael2 236]

I wasn't able to duplicate this using the aircraft as set up for the tutorial. 

Did you touch the vertical pitch knob at all? Perhaps you inadvertently took it out of vertical speed mode. 

The other possibility is perhaps the aircraft ran out of available elevator trim.  The autopilot uses elevator trim for pitch control (a default behaviour). If you use the cargo version it is possible to set the centre of gravity too far forward to the point there might not be enough elevator trim available to maintain both a climb and high rate of turn.  If this happens again, please check the trim indicator to see if it is maxed out and also check the centre of gravity % of MAC (shift-3) and let me know your findings. 

Another possibility is too high a rate of climb and that the aircraft stalled, but I would expect the stick shaker to go off in those circumstances.