BASIC AERODYNAMICS

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SUBCOURSE OVERVIEW
This subcourse is to be completed on a self-study basis. You will grade the practice exercise when you
complete it using the answer key which is enclosed. If you have answered any question incorrectly,
study the question reference shown on the answer key and evaluate all possible solutions.
There are no prerequisites for this subcourse.
This subcourse reflects the doctrine which was current at the time it was prepared. In your own work
situation, always refer to the latest official publications.
Unless otherwise stated, the masculine gender of singular pronouns is used to refer to both men and
women.


GRADING AND CERTIFICATION INSTRUCTIONS
Examination: This subcourse contains a multiple-choice examination covering the material in the
three lessons. After studying the lessons and working through the practice exercises, complete the
examination. Mark your answers in the subcourse booklet, then transfer them to the ACCP examination
response sheet. Completely black out the lettered oval which corresponds to your selection (A, B, C, or
D). Use a number 2 lead pencil to mark your responses. When you complete the ACCP examination
response sheet, mail it in the preaddressed envelope you received with this subcourse. You will receive
an examination score in the mail. You will receive two credit hours for successful completion of this
examination.



GENERAL
The atmosphere is the envelope of air that surrounds the earth. Over one-half of the air, by weight, is
within the lower 18,000 feet of the atmosphere; the remainder is spread out over a vertical distance in
excess of 1,000 miles. No definite outer atmospheric boundary exists: the air particles become fewer
with increasing altitude until they gradually overcome the earth's gravitational force and escape into
space. The atmosphere rotates with the earth as a gaseous outer cover. Within the atmosphere, other air
movement occurs. Differences in the temperature of the earth's surface affect the density of the
atmosphere and cause a continuous internal air movement called circulation. The force of this
circulation varies between breezes and winds. The latter can have forces that range from mild to gales,
hurricanes, and typhoons.

1.2 COMPOSITION OF THE ATMOSPHERE
As shown in figure 1.1. a given volume of dry air contains approximately 78 percent nitrogen; 21
percent oxygen; and 1 percent argon, carbon dioxide, and minute amounts of other gases. Air contains,
in addition to the gases just mentioned a variable amount of water vapor, most of which is concentrated
below 30,000 feet. The maximum amount of water vapor the air can hold depends primarily upon the
temperature of the air; the higher the temperature, the more water vapor the air can hold. Water vapor in
the atmosphere varies from insignificant amounts to 4 percent by volume (100 percent humidity).