Aerodynamics 1

Question 1

What effect does weight have on glide range?

Answer 1

No effect - glide perf is based on lift-drag ratio.

Question 2

What effect does weight have on rate of descent?

Answer 2

The heavier the ac, the greater its ROD. Due to ac having a higher speed for a given rate of descent.

Question 3

What is the aerofoil chord line?

Answer 3

A straight line from leading edge to the trailing edge of the aerofoil

Question 4

What is the mean chord line?

Answer 4

Wing area divided by wing span.

Question 5

What is the angle of attack?

Answer 5

Angle between the chord line and relative airflow.

Question 6

What is the coefficient of lift?

Answer 6

The lifting ability of a particular wing

Question 7

What 2 things does the coefficient of lift depend on?

Answer 7

Shape of the wing and the angle of attack

Question 8

Where does the centre of pressure move with a higher angle of attack?

Answer 8

Closer to the leading edge

Question 9

Describe aspect ratio?

Answer 9

Aspect ratio is the ratios of the wing’s span to its geometric chord.

Question 10

What are the two types of drag?

Answer 10

Profile drag

Induced Drag

Question 11

What is profile drag also known as?

Answer 11

Zero-lift drag

Question 12

What is profile drag comprised of?

Answer 12

1. Form or pressure drag
2. Skin-friction drag
3. Interference drag

Question 13

What is VIMD?

Answer 13

The speed at which induced and profile drag are equal.

Question 14

What causes wingtip vortices?

Answer 14

Spanwise airflow over the upper and lower surface of the wing.

Question 15

What are the effects of span wise airflow over a wing?

Answer 15

Creates wing-tip vortices
Reduced aileron efficiency
Reversed span wise airflow increases disturbed airflow on the upper surface at the tip - contributes to wingtip stall.

Question 16

What is the purpose of vortex generators/fences?

Answer 16

To reduce span wise flow.

Question 17

What are winglets designed to do?

Answer 17

Reduce induced drag

Question 18

What limits an ac CG?

Answer 18

The ability of the tailplane to generate lift.

Question 19

How does weight effect the descent point?

Answer 19

The heavier the aircraft the earlier its descent point due to momentum.

Question 20

What are the 2 main advantages for jet aircraft having swept wings?

Answer 20

1. High mach cruise speeds

2. Stability in turb

Question 21

What are the four disadvantages of a swept wing?

Answer 21

1. Poor lift qualities
2. Higher stall speeds
3. Speed Instability
4. A wing tip stalling tendency.