Drag

Question 1

What is Drag?

Answer 1

The air resistance experienced by aircraft as it moves relative to the air

Question 2

Which direction does it act in?

Answer 2

Opposite to the direction of thrust (motion through the air)

Question 3

What force does drag oppose?

Answer 3

Thrust?

Question 4

What are the 2 groups of drag?

Answer 4

1) Parasite Drag

2) Induced Drag

Question 5

What is induced Drag?

Answer 5

Unavoidable by product of lift and increases as the angle of attack increases.

Question 6

The lower the ______, the less______ required to balance it

Answer 6

Drag

Thrust

Question 7

Is parasite Drag associated with the development of lift?

Answer 7

No

Question 8

What are the 2 sub groups of parasite drag?

Answer 8

1) Profile drag

2) Interference Drag

Question 9

What does Form drag result from?

Answer 9

Results from the airflow separating from the surface.

Question 10

What is the separation point?

Answer 10

The point at which the streamline flow separates from the surface and becomes turbulent.

Question 11

When is a wing said to be stalled?

Answer 11

A very high angle of attack, the boundary layer cannot follow the upper surface and breaks away from the wing at the critical angle of attack

Question 12

To delay the separation of the boundary layer from the surface, reduce form drag.

True or False?

Answer 12

True.

Question 13

What helps to delay the separation if the boundary layer?

Answer 13

Streamlining

Question 14

What is skin friction?

Answer 14

Results from the friction forces existing between an object and the air through which it moving.

Question 15

An increase in airspeed increases skin friction drag. True or False?

Answer 15

True.

Question 16

What 5 factors effect skin drag?

Answer 16

1) Surface of A/C
2) boundary layer airflow near surface is laminar or turbulent
3) Roughness on a surface.
4) increases in airspeed
5) Thickness of Aerofoil

Question 17

Where does Interference Drag occur?

Answer 17

At the junction of aircraft surface (wings joining fuselage)

Question 18

How can Interference drag be reduced?

Answer 18

With Filleting/ fairings

Question 19

What is Induced Drag?

Answer 19

A by-product of the production of lift

Question 20

What is an example of induced drag?

Answer 20

Vortices at the end of wing tips

Question 21

What is a spillover?

Answer 21

Where the high and low pressure Air meet to create a vortex

Question 22

When is the pressure differential/ vortices at their strongest?

Answer 22

Approach phase

High AoA and low speed

Question 23

Which wing is less affected by induced drag?

Answer 23

Long narrow wings (high aspect ratio wings)

Question 24

Flaps and undercarriage act to reduce the effect of induced drag. True or False?

Answer 24

True

Question 25

When are vortexes greatest (induced drag)

Answer 25

When heavy, clean configuration and flying slowly.

Question 26

What are another means of reducing wing tip vortices?

Answer 26

Wing lets

Question 27

An aircraft accelerated along the runway with zero angle of attack. What drag exists?

Answer 27

Parasite drag

Question 28

When is induced drag at its greatest?

Answer 28

During high angles of a attack (climbing)

Question 29

What are the two types of profile drag?

Answer 29

Form drag

Skin drag

Question 30

What is a consequence of form drag?

Answer 30

Eddies are formed and streamlined flow is disturbed