Principles of flight

Question 1

Aircraft can only remain airborne whilst…

Answer 1

Moving

Question 2

How is lift generated?

Answer 2

By the aircraft’s wing

Question 3

How is the top surface of the wing shaped?

Answer 3

Such that air which flows over the wing increases speed and reduces pressure

Question 4

How is the bottom surface of the wing shaped?

Answer 4

Such that air which flows under the wing reduces speed and increases pressure

Question 5

At what angle does lift act to the direction of air flow on the wing?

Answer 5

90 degrees

Question 6

What is the point at which lift acts called?

Answer 6

The centre of pressure

Question 7

Factors affecting lift:

Answer 7

• An increase in airspeed results in an increase in lift
• An increase in angle of attack results in an increase in lift

Question 8

Airspeed is direction proportional to…

Answer 8

Lift squared

Question 9

What is the critical angle for stalling?

Answer 9

15 degrees

Question 10

Decreased air density leads to…

Answer 10

Decreased lift (this can be due to an increase in altitude, temperature or humidity)

Question 11

What happens if lift is greater than weight?

Answer 11

The aircraft ascends

Question 12

What happens if lift is less than weight?

Answer 12

The aircraft descends

Question 13

What happens if lift is equal to weight?

Answer 13

The aircraft remains at level flight

Question 14

What happens if thrust is greater than drag?

Answer 14

The aircraft accelerates

Question 15

What happens if thrust is less than drag?

Answer 15

The aircraft decelerates

Question 16

What happens if thrust is equal to drag?

Answer 16

The aircraft’s speed remains constant

Question 17

Aircraft speed is directly proportional to…

Answer 17

Drag squared

Question 18

What are the 3 axis through the centre of gravity?

Answer 18

1. Lateral axis through wings
2. Longitudinal axis along the aircraft
3. Normal axis, up and down

Question 19

What is pitching?

Answer 19

Nose of the plane up and down (elevators)

Question 20

What is rolling?

Answer 20

Whole plane to one side (ailerons)

Question 21

What is yawing?

Answer 21

Nose of the plane side to side (fin/rudder)

Question 22

What is stability?

Answer 22

The ability of an aircraft to return to level flight of its own accord without the pilot having to intervene, a result of good design

Question 23

Turbulence

Answer 23

Bumpy air can cause a wing to drop or nose to rise or fall

Question 24

What are dihedral wings?

Answer 24

Those with their lowest points at attachment to the body

Question 25

What are anhedral wings?

Answer 25

Those with their highest points at attachment to the body

Question 26

What are trimming tabs?

Answer 26

Extensions on the elevator, aileron and rudder to help to cancel out unwanted forces on the pilots joystick

Question 27

Airbrakes

Answer 27

- Reduces lift and increases drag - Used when approaching landing

Question 28

Gliding angle

Answer 28

How far a glider can glide from a given height e.g. Viking is roughly 15km for 1km (weather dependent)

Question 29

What does spinning rotor blades in one direction cause?

Answer 29

Torque in the other direction

Question 30

What does the tail rotor do?

Answer 30

Counteracts force, preventing the helicopter from spinning out of control

Question 31

What is the rotor disk?

Answer 31

The area covered by the blades

Question 32

How can lift be increased in a helicopter?

Answer 32

By increasing the angle of attack

Question 33

How is lift generated?

Answer 33

By the Bernoulli principle

Question 34

How is lift distributed around the wing?

Answer 34

Uneven

Question 35

What accompanies an object when it moves through the air?

Answer 35

A "wake" of eddies and vortices which wastes energy

Question 36

How can we minimise drag?

Answer 36

- Reduce protruding parts - Streamlining - Streamlining shapes to have a "finesse ratio" of between 3 and 4:1

Question 37

What are elevators controlled by?

Answer 37

Moving the joystick back and forth

Question 38

What are ailerons controlled by?

Answer 38

Moving the joystick left and right

Question 39

What is the rudder controlled by?

Answer 39

Rudder pedals

Question 40

What happens when the angle of attack is too great?

Answer 40

The airflow over the wing cannot meet the airflow under the wing

Question 41

What do flaps do?

Answer 41

Allow you to generate lift at lower speeds

Question 42

Lower stalling speed is...

Answer 42

Better

Question 43

Factors increasing stalling speed

Answer 43

- More weight - Less power - Manoeuvres and steeper turns - Wind

Question 44

The gliding angle

Answer 44

How steep your descent is

Question 45

What does increasing or decreasing rotor speed affect?

Answer 45

Lift production

Question 46

What does the collective pitch lever do?

Answer 46

Changes the angle of the rotor blades

Question 47

What do the yaw pedals do?

Answer 47

Control the angle of the tail rotor blades