Doesn't speak well for their optimism now does it.....


Modeone, if you have not figured it out by now there is NOline that can be used for a reference forflying straight and level. Why you ask? Because straight and level at max airspeed and straight and level at near stall speeds involves a change in the angle of attack of the wing and by connection the fuselage of a good 7 to 8 degrees. So you can't pin it down to any sort of reference line be it the thrust line, datum line, center line or any other line. In flight the line of flight of the fuselage as well as all those rather important parts connected to it is fluid, very fluid. At best you can find the best angle at any one given speed. This is what airliner designers do. They know the plane will fly at X speed at Y altitude for most of the flight and they choose wing incidence angles such that the fuselage will fly at the least drag aspect for this portion of the flying time. The rest is not a big deal.