Turbo Commander 690B: center of gravity/pitch trim issue

[expat]

This is a follow on to the recent thread on getting the Veneaviones Turbo Commander 690B to work reasonably well in FSX.

http://www.sim-outhouse.com/sohforums/showthread.php?t=21381

Thanks again to all that helped to resolve some of the remaining issues. Playing around with the alpha channel value I now have just the right amount of screen reflection in the VC.

Despite some air.cfg tinkering, the aircraft still needs 6 notches or so (that's a lot!) of DOWN pitch trim almost at all times. Otherwise the plane on take off leaps off the runway and wants to fly straight up until she stalls and also when you switch or reload into the plane it will do the same in flight. A bit of a nuisance to have to use so much trim + would think that must have to create some unwanted aerodynamic drag.

I tried moving the CG by moving the longtitudinal position of the fuel tanks substantially forward (e.g. 12 vs 1 in the air.cfg - funny most plane this value is 0). That helped by about 40-50% but the problem clearly remained. The CG however was outside the correct parameters and the nose wheel was sunk into the ground so I have reset this to the default value.

Is there a line one can add to the [flight tuning] section of the air.cfg that can adjust pitch trim. Any aeronautical engineers out there have thoughts on the root cause? Is there something in the FM that needs to be adjusted?


Here is a link to the original (freeware) aircraft:

http://avsim.com/veneaviones/ (http://avsim.com/veneaviones/)

Thanks and regards,

expat

[pogo01]

Did you ever find a way to change the aircraft.cfg file to fix that pitch issue?
I can not find any place in the cockpit to adjust trim on my version.
Is there a trim wheel somewhere that I might be missing?
Glen

[Henry]

This is a follow on to the recent thread on getting the Veneaviones Turbo Commander 690B to work reasonably well in FSX.

http://www.sim-outhouse.com/sohforums/showthread.php?t=21381

Thanks again to all that helped to resolve some of the remaining issues. Playing around with the alpha channel value I now have just the right amount of screen reflection in the VC.

Despite some air.cfg tinkering, the aircraft still needs 6 notches or so (that's a lot!) of DOWN pitch trim almost at all times. Otherwise the plane on take off leaps off the runway and wants to fly straight up until she stalls and also when you switch or reload into the plane it will do the same in flight. A bit of a nuisance to have to use so much trim + would think that must have to create some unwanted aerodynamic drag.

I tried moving the CG by moving the longtitudinal position of the fuel tanks substantially forward (e.g. 12 vs 1 in the air.cfg - funny most plane this value is 0). That helped by about 40-50% but the problem clearly remained. The CG however was outside the correct parameters and the nose wheel was sunk into the ground so I have reset this to the default value.

Is there a line one can add to the [flight tuning] section of the air.cfg that can adjust pitch trim. Any aeronautical engineers out there have thoughts on the root cause? Is there something in the FM that needs to be adjusted?


Here is a link to the original (freeware) aircraft:

http://avsim.com/veneaviones/ (http://avsim.com/veneaviones/)

Thanks and regards,

expat
ill take a look
H

[expat]

Thanks for your replies. This helped quite a bit.

http://forums1.avsim.net/index.php?showtopic=51179&hl=Veneaviones (http://forums1.avsim.net/index.php?showtopic=51179&hl=Veneaviones)

The key entry for stopping the pitching up I think is "htail_incidence", though I found that a value 0.500 worked even better in approaching a neutral pitch position. Let me know what you find. This is a great bit of freeware and Sean Doran's paints are superb.

expat

[pogo01]

Thanks a bunch!
Dumb me, never thought about checking FS9 forums!
Those aircraft.cfg changes are truly appreciated.
Still wonder why there isn't any trim wheel in the cockpit?
I used to love the AC500, but the props are messed up in FSX w/SP2.
Now, I much prefer the 690B anyway.
So, getting it to fly straight & level will make it much more enjoyable.
Also, like the VC, the winglets & the NOAA repaint.
Keep the glass side up y'all.
Glen