Aerodynamics

Question 1

What is Bernoulli’s law?

Answer 1

When a fluid like air moves through a venturi, air is compressed and forced to move faster, resulting in lower pressure.

This principle explains how lift is generated in aircraft.

Question 2

How is lift created in aircraft?

Answer 2

Lift is created when air passes over the wing, resulting in a pressure differential with lower pressure on top and higher pressure below.

The curved shape of the wing causes air to travel faster over the top.

Question 3

What does Newton’s third law state?

Answer 3

For every action, there is an equal and opposite reaction.

Question 4

What is the chord line

Answer 4

The chord line is the imaginary line from the leading edge to the trailing edge of the wing.

Question 5

What is relative wind?

Answer 5

The direction of airflow relative to the aircraft.

Question 6

What is the angle of attack?

Answer 6

The angle between the chord line and the relative wind.

A greater angle of attack can increase lift until a critical angle is reached.

Question 7

What happens when the aircraft reaches its critical angle of attack

Answer 7

Air no longer flows over the wing and aircraft will stall

Question 8

What is the critical angle of attack?

Answer 8

The angle at which airflow can no longer smoothly go over the wing, leading to a stall.

Question 9

Does weight affect the critical angle of attack?

Answer 9

No, weight has nothing to do with the critical angle of attack.

Question 10

What occurs during a stall?

Answer 10

Both wings of the aircraft stall, with one wing typically stalling more than the other.

Question 11

How do flaps affect lift?

Answer 11

Flaps increase the wing area, allowing for more lift at lower speeds.

Question 12

What is the purpose of flaps during landing?

Answer 12

To enable a steeper landing approach without increasing airspeed.

Question 13

What are the 4 forces in flight

Answer 13

Thrust, drag, lift and weight

Question 14

When are all forces in equilibrium

Answer 14

When thrust equals drag and lift equals weight

Question 15

What causes lift

Answer 15

Pressure differential. Low pressure on top of wing and high on the bottom

Question 16

What causes the airfoil to have low pressure on the top

Answer 16

Because the top of the airfoil is curved, it must travel at a faster velocity then the straight edge of the bottom of the wing. When fluid like air speeds up, pressure is decreased

Question 17

What are the three axes of rotation for stable aircraft?

Answer 17

Roll, pitch, yaw

Aircraft stability involves rotation about these three axes.

Question 18

What controls yaw, roll, and pitch in an aircraft?

Answer 18

Yaw is controlled by the rudder, roll by the ailerons, pitch by the elevator

These controls help maintain balance and maneuverability.

Question 19

What does the tail of an aircraft do?

Answer 19

The tail creates downforce to counteract the weight from the engine creating a nose down tendency

This helps maintain stability.

Question 20

How can the center of gravity be changed?

Answer 20

By shifting weight within the aircraft

This can affect the aircraft’s stability.

Question 21

What is the stability of an aircraft with an aft center of gravity?

Answer 21

Less stable at all speeds

Forward center of gravity increases stability.

Question 22

What happens when the center of gravity is forward?

Answer 22

There is more leverage and rudder authority

This enhances control during flight.

Question 23

What can happen when the CG is too aft past the limitations?

Answer 23

The aircraft may have a nose-up attitude and be hard to recover from a stall

This can lead to dangerous flight conditions.

Question 24

What happens to lift when an airplane is in a bank?

Answer 24

Lift shifts from vertical to horizontal

This affects the aircraft’s performance and handling.

Question 25

What is adverse yaw?

Answer 25

Aircraft's nose rotates in the opposite direction of the intended turn ## Footnote The rudder is used to counteract this effect.

Question 26

What happens to load factor in a bank?

Answer 26

Load factor increases, it’s as if airplane weight increases in turn ## Footnote More bank results in higher load factors.

Question 27

What can happen to stall speeds while in bank

Answer 27

The airplane can stall at higher speeds ## Footnote This is due to increased load factors and lift dynamics.

Question 28

What is center of gravity

Answer 28

It’s at what point the aircraft would balance on a fulcrum or if it was hung by an imaginary string

Question 29

What is the center of lift or pressure

Answer 29

Average location at which the most lift is acting upon

Question 30

What happens to elevator effectiveness when power is reduced

Answer 30

When in low power setting less of propeller slipstream gets to elevator which makes it less effective

Question 31

How is adverse yaw counteracted

Answer 31

Rudder

Question 32

Why does adverse yaw occur

Answer 32

When airplane is in a bank, one wing produces more lift and drag than the other

Question 33

Is a forward or aft CG more stable?

Answer 33

Forward is more stable and aft is less stable

Question 34

What determines the load or G's that are put on an aircraft's wings?

Answer 34

Speed ## Footnote Higher speed results in increased loads on the wings.

Question 35

What is the left turning tendency of an aircraft primarily caused by?

Answer 35

P-Factor ## Footnote P-Factor occurs due to the difference in thrust produced by the left and right propeller blades.

Question 36

What is thrust in the context of flight?

Answer 36

Forward lift ## Footnote Thrust is the force that propels the aircraft forward.

Question 37

What is the torque effect in flight?

Answer 37

A left turning tendency

Question 38

What is the significance of V speeds in aviation?

Answer 38

They are specific and critical speed limitations for different phases of flight ## Footnote V speeds are critical for safe aircraft operation.

Question 39

What does Vr stand for?

Answer 39

Rotate speed ## Footnote Vr is the speed at which the aircraft should be rotated during takeoff.

Question 40

What does Vx represent?

Answer 40

Best angle of climb (over distance) ## Footnote Vx provides the best altitude gain over a given horizontal distance.

Question 41

What does Vy indicate?

Answer 41

Best rate of climb over time ## Footnote Vy provides the highest altitude gain in the shortest amount of time.

Question 42

What is Vle?

Answer 42

Maximum landing gear extended speed ## Footnote Vle is the maximum speed at which the landing gear can be safely extended.

Question 43

What does VNE stand for?

Answer 43

Never exceed speed ## Footnote VNE is the maximum speed limit that should not be exceeded during flight.

Question 44

What is VNo?

Answer 44

Maximum structural cruising speed

Question 45

What does Va represent?

Answer 45

Maneuvering speed ## Footnote Va is the safest speed for making abrupt maneuvers without risking structural damage.

Question 46

What is Vsi?

Answer 46

Stall speed in clean configuration ## Footnote Vsi is the minimum speed at which the aircraft can maintain level flight without stalling.

Question 47

What does Vso indicate?

Answer 47

Stall speed in landing configuration (dirty) ## Footnote Vso is the stall speed when the aircraft is configured for landing.

Question 48

Where can V speeds be found?

Answer 48

In the Pilot's Operating Handbook (POH) ## Footnote The POH contains vital information regarding aircraft performance.

Question 49

What is p factor?

Answer 49

P factor occurs because the the right propeller blade takes a bigger bite of air than the left. More thrust is produced and makes aircraft want to turn left

Question 50

How is p factor counteracted

Answer 50

Right rudder

Question 51

When is torque affect at its greatest

Answer 51

High power, low airspeed and high angle of attack

Question 52

Why does torque affect occur

Answer 52

The propeller turns right resulting in the airplane wanting to turn left. Torque affect is most noticeable when in a high power setting

Question 53

Is Va shown on the airspeed indicator

Answer 53

No, but it can be found in the planes POH

Question 54

Explain Va

Answer 54

The fastest speed the aircraft can be at in which any abrupt manuveer is made with one flight control and airplane will stall before structural damage occurs

Question 55

In which airspeed is v speeds read

Answer 55

Indicated airspeed

Question 56

What is Vno used for

Answer 56

Maximum structural cruising speed is the fastest \ normal speed you would want to fly at in smooth air

Question 57

Explain how Va changes with weight

Answer 57

Va is calculated with max gross weight in mind. When you are lighter Va slows down, when heavier Va speed is higher. This is because heavy aircraft fly at a higher angle of attack this means the heavier you are the closer you are to stalling or the critical angle of attack.

Question 58

What are wing tip vorticies or wake turbulence

Answer 58

It’s trailing air behind any aircraft producing lift

Question 59

Why does wake turbulence occur

Answer 59

Wake turbulence occurs because the high pressure under the wing attempts to meet the low pressure on top of the wing

Question 60

How do wing tip vorticies move

Answer 60

Outward, upward, around each wing tip

Question 61

When is wake turbulence at its greatest

Answer 61

Heavy, clean and slow

Question 62

How do you avoid wake turbulence

Answer 62

In air, fly above other aircraft. Landing beyond other aircraft’s touchdown point. Take off before other aircraft rotates and fly upwind

Question 63

Explain ground effect

Answer 63

In normal flight some lift gets destroyed but when aircraft is a wings width of the ground that lift no longer gets destroyed resulting in aircraft to fly more efficiently

Question 64

When is ground effect most important to keep in mind

Answer 64

On takeoff it could cause plane to be airborne too quickly or float on landing if there is any excess speed