Thanks Bruce,

I understand the decalage perfectly. I guess I just had trouble with the concept of "arbitrary" fuselage reference line. Maybe it was just a philosophical point, but it must be arbitrary only for the designer. I, for example, cannot decide arbitrarily where that line is. I can guess, but I can't, for example, arbitrarily decide it goes from the cockpit to the landing gear (exaggeration to illustrate a point). Then the wings and stab would be about 90 degrees to the direction of flight.

Marl