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Flashcards in Drag Deck (30)
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1
Q

What is Drag?

A

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

2
Q

Which direction does it act in?

A

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

3
Q

What force does drag oppose?

A

Thrust?

4
Q

What are the 2 groups of drag?

A

1) Parasite Drag

2) Induced Drag

5
Q

What is induced Drag?

A

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

6
Q

The lower the ______, the less______ required to balance it

A

Drag

Thrust

7
Q

Is parasite Drag associated with the development of lift?

A

No

8
Q

What are the 2 sub groups of parasite drag?

A

1) Profile drag

2) Interference Drag

9
Q

What does Form drag result from?

A

Results from the airflow separating from the surface.

10
Q

What is the separation point?

A

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

11
Q

When is a wing said to be stalled?

A

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

12
Q

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

True or False?

A

True.

13
Q

What helps to delay the separation if the boundary layer?

A

Streamlining

14
Q

What is skin friction?

A

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

15
Q

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

A

True.

16
Q

What 5 factors effect skin drag?

A

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

17
Q

Where does Interference Drag occur?

A

At the junction of aircraft surface (wings joining fuselage)

18
Q

How can Interference drag be reduced?

A

With Filleting/ fairings

19
Q

What is Induced Drag?

A

A by-product of the production of lift

20
Q

What is an example of induced drag?

A

Vortices at the end of wing tips

21
Q

What is a spillover?

A

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

22
Q

When is the pressure differential/ vortices at their strongest?

A

Approach phase

High AoA and low speed

23
Q

Which wing is less affected by induced drag?

A

Long narrow wings (high aspect ratio wings)

24
Q

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

A

True

25
Q

When are vortexes greatest (induced drag)

A

When heavy, clean configuration and flying slowly.

26
Q

What are another means of reducing wing tip vortices?

A

Wing lets

27
Q

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

A

Parasite drag

28
Q

When is induced drag at its greatest?

A

During high angles of a attack (climbing)

29
Q

What are the two types of profile drag?

A

Form drag

Skin drag

30
Q

What is a consequence of form drag?

A

Eddies are formed and streamlined flow is disturbed