Atpl Aerodynamics

Front 1

In supersonic flight, unlike subsonic flight, supersonic flow has fixed or variable density?

Back 1

Variable.

Front 2

In supersonic flow through a convergent duct, what happens to velocity / pressure / density?

Back 2

Decrease Velocity
Increase Pressure
Increase Density

Front 3

In supersonic flow through a divergent duct, what happens to velocity / pressure / density?

Back 3

Increase Velocity
Decrease Pressure
Decrease Density

Front 4

What does Mach Number represent?

Back 4

The percentage of the current speed of sound.

Front 5

What is the formula for calculating the TAS for a given Mach Number?

Back 5

TAS = 39 x √K

0 degress C = 273K

Front 6

Define the following terms:

M (fs)

Local Mach Number

M (crit)

Back 6

1. Free stream mach number - the mach number of the whole aircraft thru the air.

2. The mach number of the flow at a particular aircraft point.

3. The mach number that produces the first evidence of local sonic flow.

Front 7

M (cdr)

M (det)

M (mo)

Back 7

1. Slightly above M (crit) where significant shockwave drag problems develop.

2. The number at which the bow wave attaches to the leading edge of the aerofoil or A/C nose.

3. Maximum Operating Mach Number.

Front 8

What are the speed ranges for the following phases of flight;

Subsonic

Transonic

Supersonic

Back 8

Subsonic = 0 - 0.75M

Transonic = 0.75 - 1.20M

Supersonic = 1.20 - 5.00M

Front 9

Mach Tuck is a result of what moving rearwards as the aircraft accelerates?

Back 9

Center of Pressure

Front 10

How does a swept wing reduce the onset of compressibility effects?

Back 10

A swept wing is presented to the airflow at a less than perpendicular angle. More perpendicular = quicker onset of effects.

Front 11

List 5 advantages of a sweep back design.

Back 11

1. Delayed onset of compressibility effects.

2. Increased M (crit) & M (cdr)

3. Increased Force Divergent Number.

4. Reduced magnitude of CL changes.

5. Improved lateral stability and slight improvement in directional stability.

Front 12

List 6 disadvantages of a sweep back design.

Back 12

1. Increased chance of tip stall.

2. Reduced CL Max.

3. Reduced trailing edge effectiveness.

4. Structural complexity.

5. Possible dutch roll tendencies.

6. High induced drag at high AoA.

Front 13

Explain Dutch Roll.

Back 13

The increasing dominance of lateral stability over directional stability.

Front 14

Describe the 2 types of Yaw Dampers.

Back 14

1. Parallel - moves rudder pedals and must be off for T/O & LDG.

2. Series - doesn't move pedals and can be on for all stages of flight.

Front 15

What happens to the stalling EAS & IAS as altitude increases?

Back 15

They both increase, but IAS increases by the greater margin.

Front 16

What does the speed V imd represent?

Back 16

Speed of minimum total drag.

Front 17

V imd is also representative of what scenarios?

Back 17

1. Best Lift/Drag ratio
2. Best Endurance (Minimum Fuel Flow)
3. Max Excess Thrust, ie Best Angle of Climb

Front 18

Maximum still air range occurs at what speed?

Back 18

1.32 x V imd

Front 19

In a strong headwind, fly _______than V imd to achieve max range.
In a strong tailwind, fly _______than V imd to achieve max range.

Back 19

Faster................Slower.

Front 20

Best Endurance is flown at what speed?

Back 20

V imd

Front 21

As fuel is burnt during the cruise, the drag curve moves which direction?

Back 21

Down and to the Left.