Aerodynamics

Question 1

Mach tuck

Answer 1

Aircraft pitches down due to supersonic airflow over the wings. Center of pressure continues to move aft thus affecting the elevator control, making inputs useless and leads to uncontrollable dive

Question 2

Critical Mach

Answer 2

When airflow over the wings reach Mach 1.0

Question 3

Coffin Corner, how to avoid?

Answer 3

The point at which stall speed and max operating speed meet. Only way to avoid is reduce altitude

Question 4

Dutch Roll

Answer 4

Combo of yaw/roll oscillations when dihedral effects are more powerful than directional stability

Question 5

Purpose of Swept wings (pros and cons)

Answer 5

Delays crit mach by dividing/separating relative wind component over the airfoil.
Pros: Allows aircraft to go faster at higher altitudes.
Cons: stall occur at wing tip, reduced lift, poor low speed characteristics

Question 6

Yaw Dampner

Answer 6

Gyro operated stability feature to provide rudder input when needed to counteract yawing tendencies

Question 7

Mach Buffet

Answer 7

Flow separation over the wing when at crit Mach or too high AOA

Question 8

What is a critical engine

Answer 8

Engine with most adverse effect on aircraft if it were to fail

Question 9

Critical engine factors?

Answer 9

Pfactor (defending blade faster than ascending)
Accelerated Slip stream (more airflow due to P)
Spiraling slip stream (left yaw tendency rudder)
Torque (offsets rolling action)

Question 10

Vspeeds (Vmc, V1, V2)

Answer 10

Vmc: minimum control speed with critical engine inop
V1: rotation speed for takeoff
V2: takeoff safety speed for require climb gradient

Question 11

What is the purpose of a winglet

Answer 11

Directs airflow up and away from the wing reducing induced drag