Performance & Limitations/Aerodynamics

Question 1

What are the 2 types of drag?

Answer 1

Induced drag: Is the total drag created by the production of lift.
- Lower airspeed, higher AoA required; higher induced drag

Parasite drag: Caused by the friction of air moving over the aircraft structure/surface
- 3 Types: Form, Interference and skin friction drag

Question 2

What are some of the dangers of ground effect?

Answer 2

Landing: More floating due to the reduce of induced drag

Takeoff: Feeling like the airplane can climb at a slower airspeed resulting in a higher pitch angle and the loss of power

Question 3

What is form drag?

Answer 3

• Drag created by the shape of different objects of the airplane (i.e. antenna, )
• Air separates to move around it. The less the aerodynamically shaped, the more drag is created behind it

Question 4

What is interference drag?

Answer 4

• Drag from intersecting airstreams that create eddies, turbulence, or restricts smooth airflow
• For example, the intersection of the wing, and the fuselage

Question 5

What’s skin friction drag?

Answer 5

• The drag created by the air moving over the surface
• No matter how smooth it looks, it’s rough under a microscope

Question 6

What is the opposite reaction of the horizontal lift component?

Answer 6

Centrifugal Force

Question 7

What is adverse yaw?

Answer 7

When initiating a turn, the increase in lift produced by the downward deflection of the outer wing also increasing drag

• This is the adverse yaw

Question 8

How does manufacturers compensate for adverse yaw?

Answer 8

Differential Ailerons: One aileron is raised a greater distance than the other aileron, and is lowered a little on the lowered wing. This adds an increase in drag. The greater the bank the greater the drag

Frise-Type Ailerons: The aileron that’s being raised pivots on an offset hinge. This projects the leading edge of the aileron into the airflow and creates drag

Coupled Ailerons and Rudder: The rudder is coupled into the controls when he airplane is banked to correct for the adverse yaw.

Flaperons: A combination of flaps and aileron

Question 9

What happens to velocity in order to main the same AoA at altitude, compared to sea level?

Answer 9

• IAS remains the same
• TAS is faster

Because air is less dense at altitude, in order to maintain the same AoA, velocity needs to be increased. Although the IAS will show the same, the TAS will be faster.

Question 10

What would be the first sign of a rapid decompression?

Answer 10

• Cabin fog because of the drop in temperature and change in relative humidity
• Air will escape through the nose and mouth from the lungs because the sudden lower pressure outside the lungs