Page 130 - Understanding Flight

CH05_Anderson 7/25/01 8:58 AM Page 117

5
CHAPTER

Airplane Propulsion

he propulsion system is one of the most complex systems on an
airplane, yet the principles behind airplane propulsion are not very
Tcomplicated. An airplane in flight requires power to provide lift
and to overcome the drag associated with the impact of the air on the
airplane. If it is climbing or making a turn, additional power is
needed. In Chapter 2, “How Airplanes Fly,” we showed that in pro-
ducing lift, work is done on the surrounding air. Here we use similar
arguments to describe how aircraft propulsion systems work.
The power required for climbing and turning is discussed in
Chapter 7, “Airplane Performance.” In this chapter, you will learn how
propulsion systems provide the necessary power for flight. You will
also learn how jet engines differ from piston engines in how they
deliver the needed power. Some of the differences, and similarities,
may surprise you.
With some exceptions, the gliders being the most notable, the
power needed for flight is provided by either a piston or a jet engine.
The energy produced in these engines must be transferred to the
surrounding environment to propel the aircraft. These propulsion
systems require some very complex engineering. But one need not
understand the details of those systems to understand what the
propulsion system is doing and why engines look the way they do.

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