Page 89 - Understanding Flight

CH03_Anderson 7/25/01 8:56 AM Page 76

76 CHAPTER THREE

Fig. 3.17. The Boeing 737 noncircular engine inlets with the old engine as
insert.

Airplanes with wings positioned in the middle of the fuselage are
usually found only in military fighter or aerobatic airplanes. The
midposition offers the benefit of clearance for stores underneath the
wing, while maintaining visibility above. The configuration also has
the lowest drag. The primary disadvantage of a midwing configuration
is that the wing-fuselage joint occurs in the middle of the fuselage.
The structure must carry through the fuselage at a point where one
might want to put passengers, cargo, etc.

Wingtip Designs
The design of the wingtip has an effect on lift. A nice rounded wingtip
looks clean but actually results in lower performance than a square tip.
The design of the wingtip also affects the distribution of lift along a
wing and thus the wing’s efficiency. Thus the shape of the wingtip has
become an important design criterion.