Principles of Aerodynamics

Question 1

The science of action of air on an object.

Answer 1

Aerodynamics

Question 2

Air is a ___ because it is a substance that may be made to flow or change its shape by the application of pressure.

Answer 2

Fluid

Question 3

Atmospheric pressure ate mean sea level when the temperature is 59°F.

Answer 3

14.7 p.s.i. / 29.92 in Hg

Question 4

As altitude increases, air pressure ___.

Answer 4

Decreases

Question 5

As altitude increases, air density ___.

Answer 5

Decreases

Question 6

Would an aircraft fly faster in air that is high in density or low in density?

Answer 6

Low Density (With the same horsepower, an aircraft can fly faster at high altitude, where the density is low, than at low altitude, where the density is great.)

Question 7

Which is heavier, water vapor or dry air?

Answer 7

Dry Air

Question 8

Which would weigh more, (A) an air mixture with 55 parts dry air and 45 parts water vapor, or (B) an air mixture with 45 parts dry air and 55 parts water vapor?

Answer 8

A. (Dry air weighs more than water vapor - recall that steam rises.)

Question 9

What happens to energy as it is used?

Answer 9

It is converted to another type of energy, but never destroyed.

Question 10

The aerodynamic force that opposes gravity/weight.

Answer 10

Lift

Question 11

The aerodynamic force that opposes drag.

Answer 11

Thrust

Question 12

The aerodynamic force that opposes lift.

Answer 12

Gravity/Weight

Question 13

The aerodynamic force that opposes thrust.

Answer 13

Drag

Question 14

What happens to the center of pressure on an airfoil as the angle of attack is increased?

Answer 14

It moves forward.

Question 15

What happens to the center of pressure on an airfoil as the angle of attack is decreased?

Answer 15

It moves rearward.

Question 16

The term for the event that occurs when the angle of attack is increased beyond the critical angle, or the burble point, where the boundary layer breaks away from the upper camber of an airfoil and lift is lost.

Answer 16

Stall

Question 17

What happens to lift as camber is increased?

Answer 17

It increases.

Question 18

What aerodynamic force is created by an aircraft’s engine(s)?

Answer 18

Thrust

Question 19

What aerodynamic force is created by the disruption of airflow by the wings, fuselage, and protruding objects?

Answer 19

Drag

Question 20

In addition to Bernoulli’s Principle, what produces lift on an airfoil.

Answer 20

Downwash. (Newton’s Third Law of Motion, “For every action, there is an equal and opposite reaction.”)

Question 21

A rowboat is an example of what law?

Answer 21

Newton’s Third Law of Motion (For every action there is an equal and opposite reaction.)