Page 70 - Understanding Flight

CH03_Anderson 7/25/01 8:56 AM Page 57

3
CHAPTER

Wings

n the last chapter you were introduced to the physical description of
flight. There the role of the shape of the wing to lift was downplayed
Iand modern airplane wings and barn doors were treated as equals. In
this chapter you will learn how the concepts used to understand flight
can help to understand the design of a wing. There are many factors
that go into the design of a wing. Should the wing be swept back and
tapered? What airfoil should be used? What high-lift devices should be
added to improve takeoff and landing performance? These are just some
of the questions that must be answered when designing a wing.
Besides aerodynamic considerations, the wing designer must
consider other tradeoffs such as structural weight and cost. Some
aerodynamically sound principles have fallen prey to the realities of
construction costs or structural weight. Understanding these tradeoffs
is more a function of experience than of formal training. Hopefully, by
reading this chapter you will gain an appreciation for the decisions
that must be made.

Airfoil Selection

Before a wing can be designed, a wing section, or airfoil, must be
selected. As stated in Chapter 1, the airfoil is a slice of a wing as viewed
from the side (see Figure 1.3). In the previous chapter it was emphasized

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