Hi im at final of my projet ! and i have some glue here  

in the aircraft config in [airplane geometry]

wing_sweep=2.3                   //Degrees, wing leading edge
wing_pos_apex_lon=1.12                 //Feet, longitudinal distance from reference point, negative going aft

??? my question is where is the apex of the wing  ??? in center of the wing or at is much far edge  ??? 

distance are taking from ref datum or cog position  ??? and what ( negative going aft )  ???


htail_pos_lon=-16.90                 //Feet, longitudinal
distance from reference point, negative going aft

same trouble here  

in center of the htail or at is much far edge  ??? 

distance are taking from ref datum or cog position  ??? and what ( negative going aft )  ???


htail_pos_vert=0.0                   //Feet, vertical distance

Thank very much milton 
i have not find where is the apex of the wing 

but i suspect the midle of the wing becose i have take a look on a  other aircraft.cfg plane  htail data and is look is at the cog of the wing  ???