Need help with Gmax model of FSX gyroplane, Catapults into ground at start

[gorlosky]

Hi - I wonder if there are any designers that could help me through a snag in getting my gyroplane moving along

I built it in Gmax and my biggest problem right now is that it catapults around while just sitting there. Also my Center of Gravity (looking at FSX Fuel and Payload) is clear back at the tail.

So I'm looking for help in this particular area:
Getting the basic aircraft.cfg and/or .air files stable.

(Maybe someone that owns AirWrench and understands the basics.)

Thanks

[Felix/FFDS]

First - did you make your model with your estimated empty Center of Gravity (COG) =  to your model's reference 0,0,0 point?

(CAveat:  This is NOT an absolute necessity, but it is a convenient rule of thumb to follow.)

What aircraft.cfg / .ini files are you using, and did you change your reference files'  contact points, cof, etc etc to match your model?

[gorlosky]

CoG is now set to the following and it is sitting okay. Not sure if that is right yet, but at least the aircraft isn't jumping all over. I didn't have any ini files, but borrowed an ultralights air and then combined a helicopter and ultralight cfgs. Regardless, it seems to have come down to the CoG. Thanks.

reference_datum_position =  8.33,  0.0, 0.0   // (feet) distance from FlightSim Reference position: (1/4 chord, centerline, waterline)
empty_weight_CG_position = -2.0,  0.0, 0.0   // (feet) longitudinal, lateral, vertical distance from specified datum

[JakesF14]

Is your problem solved now?