Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

M11 > 11.1 High Speed Flight > Flashcards

11.1 High Speed Flight Flashcards

1
Q

What are the two types of shock waves that are formed at supersonic flight?

A

Normal and oblique

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens to air temperature behind a shock wave?

A

The temperature rises

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does the area rule effect an aircraft’s transonic flight performance?

A

It reduces wave drag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In dry air at 20 degrees C what is the speed of sound?

A

343.2 metres per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Speed of sound varies depending on its substance, what does it travel the fastest an£ slowest through?

A

Fastest through a solid object
Slowest through a gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the three region of aircraft speeds?

A

. Subsonic
. Transonic
. Supersonic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define transonic

A

Some speeds around the aircraft are below the speed of sound and some are above the speed of sound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

As an aircraft approaches the speed of sound, what is formed after the leading edge?

A

A shock wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the Mach number for subsonic flight?

A

<0.8 Mach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the Mach number for transonic flight?

A

0.8-1.2 Mach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the Mach number for supersonic flight?

A

1.2-5.0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do you calculate the Mach number?

A

It’s aircraft’s speed divided by speed of sound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the critical Mach number?

A

The highest possible Mach number that you can reach without turning to supersonic flight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When does a normal shock wave take place?

A

At 1.2 Mach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is wave drag?

A

It is the portion of total drag that is caused by shock waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the two ways to reduce wave drag?

A

. Area rule
. Vortex generators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the disadvantage of a vortex generator?

A

It increases parasite drag

18
Q

How does area rule effect the aircraft transonic flight performance?

A

Decreases the amount of wave drag

19
Q

When speed is increased to 0.8 Mach, we get shock waves. Therefore for fast aircraft you must have a what profile?

A

Thin profile

20
Q

Most modern aircraft have a sweep back wing of what?

A

30 degrees

21
Q

What is the main advatange of having a movable swept wing?

A

High performance at both low and high speed flight

22
Q

What are the three characteristics for an aircraft that flies at transonic flights?

A

. Flatter upper surface
. More curved leading edge
. Thinner trailing edge

23
Q

What can a wing with a transonic profile also be called?

A

Rear loaded wing

24
Q

What is the main advatange of a transonic wing profile?

A

It uses the skin as the torque box, therefore lighter and has greater fuel capacity. Therefore reducing drag.

25
Q

What is a flow separation on a wing also called?

A

Shock stall

26
Q

When the aircraft passes critical Mach was is its reaction?

A

Nose down - tuck under effect

27
Q

How can the tuck under effect be corrected?

A

By the horizontal stabiliser as it has the Mach trim system

28
Q

When a supersonic airflow passes through a shock wave, what happens to temperature?

A

Temperature increases

29
Q

When a supersonic airflow passes through a shock wave, what happens to pressure and density?

A

They increase

30
Q

When a supersonic airflow passes through a shock wave, what happens to velocity?

A

Decrease

31
Q

What are the two main types of WAVES formed in supersonic flow?

A

. Shock waves
. Expansion waves

32
Q

What are the two types of shock waves?

A

. Normal
. Oblique

33
Q

Where is a normal wave formed in conjunction to the object?

A

In front of the object

34
Q

Where is a oblique wave formed in conjunction to the object?

A

Formed above and below the object

35
Q

When a supersonic airstream passes through a normal shockwave what happens?

A

The velocity of airflow is decreased to subsonic (but not direction change)

36
Q

When a supersonic airstream passes through a oblique shockwave what happens?

A

Change in airflow direction and speed decreases but Stays at supersonic.

37
Q

When is an expansion wave formed?

A

Where the supersonic air stream turns away from preceding flow direction

38
Q

When a supersonic airstream passes through an expansion shockwave what happens?

A

The velocity increases
Direction stays same as long as no flow separation

39
Q

What are the two typical supersonic profiles?

A

. Double wedge profile
. Circular arc profile

40
Q

When flying a supersonic flight, the air entering the engine inlets must be slowed to what?

A

Subsonic range without wasting energy

41
Q

What is the correlation between Mach number and temperature?

A

At Mach number increases so does temperature

M11 (41 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions