Aerodynamics

Question 1

Density varies with _____ and _____.

Answer 1

Density varies with temperature and pressure.

Question 2

Viscosity varies with _____.

Answer 2

Viscosity varies with temperature.

Question 3

The standard atmosphere is defined from the perfect gas law. Write the equation for the perfect gas law.

Answer 3

Question 4

For our purposes, the atmosphere can be regarded as a _____ gas of _____ composition that satisfies the _____ _____ _____.

Answer 4

Question 5

How does water vapor affect the density of air?

Answer 5

Water vapor decreases the density of air (a very small amount).

Although the effect of water vapor on air density is very small, water vapor does have a significant effect on engine performance and supersonic aerodynamics.

Question 6

What are the standard sea level properties for gravity, pressure, temperature, and density?

Answer 6

Question 7

What are the regions of the atmosphere?

Answer 7

Question 8

What is the equation for temperature below 36,089 ft?

Answer 8

Question 9

Above 36,089 ft, the temperature is assumed to be _____.

Answer 9

Question 10

What is the equation for kinematic viscosity?

Answer 10

Question 11

What is the equation for Reynolds Number?

Answer 11

Question 12

What is indicated airspeed?

Answer 12

Question 13

What is calibrated airspeed?

Answer 13

Question 14

What is true airspeed?

Answer 14

Question 15

What information do we use in performance from aerodynamics?

Answer 15

Drag polar

Lift coefficient

Question 16

What information do we use in performance from propulsion?

Answer 16

Thrust or Power

SFC

Question 17

What are the four forces of flight?

Answer 17

Question 18

A body immersed in an airflow will experience an Aerodynamic Force due to…

Answer 18

Question 19

Pressure is affected by

Answer 19

Question 20

Shear stress is affected by…

Answer 20

Question 21

What assumptions does Euler’s Equation make to Bernoulli’s Equation?

Answer 21

Inviscid, steady flow

Question 22

What is Euler’s Equation?

Answer 22

Question 23

Is Bernoulli’s Equation valid for compressible flow?

Answer 23

No. It was derived from incompressible flow assumptions

Question 24

What is the moment convention on an airfoil?

Answer 24

Question 25

What is Buckingham Pi Theorem?

Answer 25

Question 26

What is the equation for dynamic pressure?

Answer 26

Question 27

Give the equation for Mach number

Answer 27

Question 28

Give the equation for Reynolds Number based on chord length

Answer 28

Question 29

What is the reference area, S, as wetted area?

Answer 29

Question 30

What is the reference area, S, as planform area?

Answer 30

Question 31

What is the reference area, S, as base area?

Answer 31

Question 32

What is the center of pressure of an airfoil?

Answer 32

The center of pressure is the centroid of the distributed load where the forces act.

Question 33

Why don’t we use the center of pressure as a reference point in aircraft dynamics?

Answer 33

Because the center of pressure changes with changes in angle of attack.

Question 34

What is the aerodynamic center of an airfoil?

Answer 34

Question 35

Draw and label the anatomy of an airfoil.

Answer 35

Question 36

What do each of the digits mean in a 4 digit airfoil? ex. NACA 2412

Answer 36

Question 37

What do each of the digits mean in a 5 digit airfoil? ex. 23012

Answer 37

Question 38

What do each of the digits mean in a 6 digit airfoil? ex. 64-212

Answer 38

Question 39

What is the design lift coefficient?

Answer 39

Question 40

Draw and label all the parts of a generic lift curve slope

Answer 40

Question 41

Answer 41

Question 42

All positively cambered airfoils have _____ zero-lift angles of attack.

Answer 42

All positively cambered airfoils have negative zero-lift angles of attack.

Question 43

How does Reynolds Number affect the lift-curve slope?

Answer 43