[taxcontrol]

Ok you air craft design engineers, help me understand something. Why the double deck? Why not a wider body instead?

It is my understanding that an airplane with wings below the fuselage is less stable than when the body of the plane is 'slung' below the wing. So it would seem to me that a double decker would be even more unstable. Lastly, a wider body could be used to create a lifting frame but I would not see it impacting the stability of the aircraft.

Since I see that others are going with the double deck, I must be missing something.

[puppypusher]

The Plane can't have an overly-wide body because they have to use airports that are designed for todays jets. Thats why Airbus will have a problem with the A380 it's wider than the 747 derivitive. Thats what I have heard.

[steve86]

It is my understanding that an airplane with wings below the fuselage is less stable than when the body of the plane is 'slung' below the wing.

Not an AE but as a former private pilot I can say it is really difficult to tell the difference in stability between a high wing and low wing plane, if both aircraft are the same type (e.g. trainer). Switching between the two, it was really not a factor you needed to be aware of except for the difference in visibility.

In the realm of R/C models, other factors, such as wing dihedral, make much more difference.