Center of Gravity

[Rubicon]

I am flying a wonderful rendition of a PA-31-350 by Fred Choate but am having trouble with the center of gravity.
Everytime I use the flaps, the nose pitches down quite a bit.  I have tried adjusting the aircraft.cfg file using trial and error as well as suggestions found on this forum, but to no avail.
I have a copy of AirEdit to edit the .air files but need lots of help to know which settings to adjust.  I understand that several may need to be adjusted at one time to get the desired result.
Any help would be appreciated.
Also, is there some place on the internet that explains what the different settings in the .air file are.
Thanks

[Fozzer]

...are you sure that you have the aircraft trimmed correctly in flight, (Trim Wheel)...?
It should fly "hands off"......!

When the the power is reduced and the flaps are deployed, the aircraft needs to be re-trimmed again.

Cheers...!

Paul.... ..!

[Jimbo]

And welcome to the Simviation Forums Rubicon!

Cheers

James

[C]

...are you sure that you have the aircraft trimmed correctly in flight, (Trim Wheel)...?
It should fly "hands off"......!

When the the power is reduced and the flaps are deployed, the aircraft needs to be re-trimmed again.

Cheers...!

Paul.... ..!

Indeed Paul. On most aircraft the operation of flaps (particularly high flap settings) will/may initially cause a slight nose up pitch but as then the nose will drop (particularly if speed is not maintained). The key, as Foz says, is to trim the aircraft (up in this case) as the change occurs during and after to operation of the flaps.

And welcome to the Simviation Forums Rubicon!

Well spotted Jimbo. Welcome to SimV Rubicon...

[Fozzer]

Hi Charlie*...!

It is a fact that you spend as much time, (or even more), re-trimming the aircraft to cope with changing conditions, as you do with yanking on the yoke... ...!

It's generally left-hand on the yoke, right-hand on the trim wheel...LOL... ...!

Cheers...!

Paul.... ...!

*...need more smilies... ...!
LOL...!

[C]

Hi Charlie*...!

It is a fact that you spend as much time, (or even more), re-trimming the aircraft to cope with changing conditions, as you do with yanking on the yoke... ...!

It's generally left-hand on the yoke, right-hand on the trim wheel...LOL... ...!

Cheers...!

Paul.... ...!

*...need more smilies... ...!
LOL...!

LOL;D Tell me about it Paul! I spent all morning doing the very same exercise - trimming tastic (elevator, rudder and aileron) whilst doing large power changes - very noticable on an 1100hp aeroplane, and doing simulated downwind legs (airbrake, gear, flaps = lots of trim changes!!! )

[Staiduk]

I've tried out the Cheiftain that Rubicon was flying (It's the Montana Air one, right?)

Looking at the fuel/loading panel; the CG appears to be stuck somewhere over the nose which is undoubtedly what Rubicon is talking about - it looks very odd.

However; trial flights out of Comox showed no problems with the aircraft. Flies very sweetly - I'd keep it if it had a VC.
I tried adjusting the CG backwards in the .cfg file; it just made the aircraft unflyably unstable (as you'd expect for an aft CG), with the CG indicator somewhere forward of the windscreen.

Rubicon: Can you tell us how you've got your aircraft configured? i.e. how it's loaded? That might be able to help us narrow down the problem; if problem there is.

Cheers!

[Rubicon]

The configuration is just a pilot (170 lbs) and copilot (140 lbs) with 300 lbs in the rear storage.

The CG is definately well out over the nose and I've tried to adjust the aircraft.cfg and .air files unsuccessfully.

I can land it without flaps but I need a little extra rwy.  The flaps force the nose down quite a bit and are pretty much useless.

Any tutorials on modifying the .air or do I need to edit the .mdl files?

Thanks for the help so far.