Theory Of Flight

Question 1

For an aircraft to remain in flight, 4 forces must be balanced. Name them.

Answer 1

Thrust, Drag, Lift, Weight

Question 2

Define thrust

Answer 2

The mechanical force, provided by a system of propulsion, which moves the aero foil through the air allowing the aero foil to produce lift.

In other words, propulsion from jets/ propellers that drives the plane forward

Question 3

Define drag

Answer 3

The aerodynamic force that opposes and aircrafts motion through the air and is generated by every part of the plane.

Question 4

Define lift

Answer 4

An aerodynamic force generated by the aerofoils motion through the air, to overcome the weight force.

Question 5

Define weight

Answer 5

The force generated by the gravitational attraction of the earth on the aeroplane. Always acts downwards towards the centre of the earth irrespective of the attitude of the aircraft.

Question 6

What is the fuselage of an aircraft?

Answer 6

The main body of the aircraft, containing the crew, passengers and cargo.

Question 7

Name some directional structural components of fixed wing aircraft?

Answer 7

Vertical stabiliser, rudder, elevator, ailerons, flaps

Question 8

The rudder, elevator, and vertical stabiliser can be found on which part of the plane?

Answer 8

The tail plane

Question 9

What is a chord line?

Answer 9

An imaginary straight line passing directly from the mid-point of the leading edge of the wing to the trailing edge. Any number of chord lines may be drawn along the length of a wing.

Question 10

What is a camber line?

Answer 10

An imaginary line that follows directly in the midpoint of thickness of a cambered wing from leading edge to trailing edge. Usually cured towards the upper surface.

Question 11

What is the angle of attack?

Answer 11

The angle between the chord line and the relative wind flow.

Question 12

Name some wing configurations you may find on a fixed wing plane?

Answer 12

Low wing, mid wing, high wing, gull wing, inverted gull, anhedral wing (sloping up) and dihedral wing (sloping down)are all wing configurations used by commercial air transport

Question 13

Explain the Bernoulli principle?

Answer 13

Air passing over an aero foil wing speeds up as it passes over the upper surface, causing a decrease in static pressure to account for the increase in dynamic pressure. This pressure gradient forces the air to move from high to low pressure, forcing the aircraft upwards.

Question 14

At smaller angles, lift is related to angle of attack. But as angle of attack increases beyond critical angle of attack, what happens?

Answer 14

The air flow can become too turbulent causing a stalled air flow.

Question 15

Aircraft ‘yaw’ around which axis?

Answer 15

Vertical or ‘Z’ axis. Aircraft remains stable but shifts slightly left or right.

Question 16

Aircraft ‘pitch’ around which axis?

Answer 16

The lateral or ‘Y’ axis. The nose will dip up or down

Question 17

Aircraft ‘roll’ around which axis?

Answer 17

The longitudinal ‘X’ axis. Aircraft bank left or right and aircraft tilts accordingly.

Question 18

What controls aircraft yaw?

Answer 18

The rudder

Question 19

What controls aircraft pitch?

Answer 19

The elevators. Allows a/c to climb or descend

Question 20

What controls aircraft roll?

Answer 20

The ailerons

Question 21

What are trim tabs?

Answer 21

Auxiliary flight control surfaces that enables the pilot to make adjustments during flight to make an unbalance correction

Question 22

What are flaps and salts designed for?

Answer 22

Adjusting the wing shape and size to increase lift at takeoff and drag at landing

Question 23

What is aircraft power used for?

Answer 23

The power from the engines is used to overcome drag but has a secondary effect of increasing lift by increasing air flow over the wing.

Question 24

A typical helicopter has 3 flight control inputs. Name them .

Answer 24

Cyclic
Collective
Anti-torque pedals

Cyclic and collective inputs may be linked together by a mixing unit.

Question 25

What do the three control inputs do?

Answer 25

Cyclic: causes aircraft to move in that direction.
Collective: causes aircraft to climb or descend.
Anti-torque pedals: keeps nose pointing in correct direction.

Question 26

Aerodynamically speaking, what does a flight or performance envelope of an aircraft represent?

Answer 26

The capabilities of design in terms of altitude and speed.

Question 27

What is Rate of Climb (ROC)?

Answer 27

The expression of increase in vertical position, in feet per min or metres per second.

Question 28

What is Vy?

Answer 28

Speed for the best ROC

Question 29

What is Vx?

Answer 29

The speed for best angle of climb (AOC)

Question 30

Aircraft performance has a direct effect on the?

Answer 30

Airspace and visibility needed to perform certain manoeuvres and instrument Approach manoeuvres.

Question 31

5 categories of typical aircraft have been established, based on 1.3 times the stall speed in the landing configuration at max certified landing speed. What is this called?

Answer 31

Vat. And it forms the basis for relating aircraft manoeuvrability to specific instrument approach procedures.

Question 32

Relate aircraft category to nominal Vat…

Answer 32

Category: Nominal Vat:
A. Less than 91kts IAS
B. 91kts to 120kts IAS
C. 121kts to 240kts IAS
D. 141kts to 165kts IAS
E. 166kts to 210kts IAS

Question 33

Aerodynamic stall is ….. stall, not …..stall

Answer 33

Wing stall, not engine stall

Question 34

All fixed wing aircraft have a minimum speed at which they can maintain level flight. This is called the?

Answer 34

Stall speed

Question 35

As the aircraft climbs in altitude, will the stall speed increase or decrease?

Answer 35

Increased. Plotted on a graph of speed vs altitude, it will form a diagonal line.

Question 36

The maximum altitude whereby no additional increase in speed will result in an increase in altitude is known as the?

Answer 36

Service Ceiling

Question 37

The area where altitude for a given speed can no longer be increased in level flight is known as?

Answer 37

Zero rate of climb

Question 38

Laminar flow may also be referred to as?

Answer 38

Streamlined flow

Question 39

The point at which flow separation occurs is called the…

Answer 39

Boundary layer