A whole lotta shaking goin' on.........

[kelticheart]

A good weekend to everybody! :wavey:

I know this was discussed extensively before, and I duly downloaded the forum page to keep as reference, but I do not remember what makes an aircraft shake while resting on the ground.

I searched thorugh my saved pages and I can't seem to find it, I am sorry. :redface:

It usually happens with converted aircrafts when using aircraft.cfg, *.air and *.dp file from similar models built for CFS2, so the problem must sit in one of those files. But which one and what needs to be adjusted?

I normally copy contact points from the original FS2002 or 2004 aircraft.cfg to keep the aircraft from blowing up or dancing a spirited rock n' roll on the runway. This time it ain't working and the subject is Da Silva/Presley's beautiful North American LT-6G "Mosquito", the Korean conflict version of the famed AT-6 Texan/SNJ, available here:

http://www.simviation.com/fs2004vintage42.htm

Thank you for your help!
KH :ernae:

[OBIO]

I have found that if the contact points are too close to being under the COG that the plane will shake while on the ground. Try moving the contact points forward a bit...even if it means that the contact points are not under the wheels. This usually fixes the ground shaking.

OBIO

[Bill Kestell]

Yeah ... that's a good answer ... but did either of you ever consider:

1. The aircraft is scared.

2. The aircraft is cold.

3. The aircraft is excited.

Just wondering, that's all.:isadizzy:

[Milton Shupe]

I downloaded this aircraft to check out the issues.

The aircraft as it loads is 700+ pounds overweight with all tanks 100% full. If you eliminate excess fuel:

CoG with allowable takeoff weight is -7% MAC, i.e. ahead of the wing by about 6".

I corrected the CoG to 25% MAC and made a few other minor corrections.

If you wish to try these changes to the aircraft.cfg:

In the Airplane Geometry section, replace:

wing_pos_apex_lon=-14.7 // corrects CoG

Contact Point Section:
Replace the two main gear contact points to correct the tire diameter:

point.1=1.000, 7.833, -4.500,-5.300, 1574.803, 1.000, 1.242, 0.000, 0.428, 2.500, 0.701, 5.000, 5.000, 2.000, 0.000, 0.000 //L Main tire orig. 1st three: 2.833, -4.500,-4.333
point.2=1.000, 7.833, 4.500,-5.300, 1574.803, 2.000, 1.242, 0.000, 0.428, 2.500, 0.701, 5.000, 5.000, 3.000, 0.000, 0.000 //R Main tire orig. 1st three: 2.833, 4.500,-4.333

If you do not have autopilot installed, change the following:

[autopilot]
autopilot_available=0

With these changes, the aircraft seems to fly, taxi, brake, and land well.

[Milton Shupe]

One other change I failed to post above is a correction to the Engine location statement.

Originally in the aircraft.cfg the engine is placed 2' above the CoG which made changes in power create some strong pitching moments. Not what you want on a landing approach. Try this one to smooth out takeoff and landing.

In this section: [GeneralEngineData]

Engine.0=8.333, 0.000, 0.000

[kelticheart]

Thank you all and particularly you, Milton, for your detailed explanation! :jump:

I am going to save and print immediately this thread for my huge CFS2/SOH manual!

Cheers!
KH :ernae: