Principles of Flight 01

Question 1

Load factor is?

Answer 1

Gust load factor, n, is defined as ratio of the lift of an aircraft penetrated in a gust to the aircraft weight. It represents the aircraft normal overload or acceleration encountering a gust and can be expressed as

n = L/W

where L is the aircraft lift under a specific gust load, W is the aircraft weight.

Question 2

Longitudinal static stability

Answer 2

In flight dynamics, longitudinal static stability is the stability of an aircraft in the longitudinal, or pitching, plane under steady flight conditions. This characteristic is important in determining whether a human pilot will be able to control the aircraft in the pitching plane without requiring excessive attention or excessive strength.

If an aircraft is longitudinally stable, a small increase in angle of attack will create a negative (nose-down) pitching moment on the aircraft so that the angle of attack decreases. Similarly, a small decrease in angle of attack will create a positive (nose-up) pitching moment so that the angle of attack increases.

The centre of gravity must lie ahead of the neutral point for positive stability (positive static margin).

If the centre of gravity is behind the neutral point, the aircraft is longitudinally unstable (the static margin is negative), and active inputs to the control surfaces are required to maintain stable flight.

Question 3

Dorsal Fin

Answer 3

The “extension” at the front is called “dorsal fin”. Its main purpose is to improve directional stability in high side-slip situations (asymmetric flight due to engine failure, crosswind landings, etc).

Question 4

Radius of turn

Answer 4

As a general rule of thumb, the diameter of a standard rate turn is approximately 1% of your ground speed. The radius would be half of that. For example, a standard rate turn flown at 100 knots will yield a diameter of approximately 1 nautical mile and a radius of 0.5 nautical miles.

Bank Angle & Radius of Turn:
If the speed is constant…
Increasing the bank angle decreases the radius of turn
Decreasing the bank angle increases the radius of turn

Speed and radius of turn
If the speed is increased without changing the bank angle, the radius of turn increases.
If the speed is decreased without changing the bank angle, the radius of turn decreases.

Question 5

Bank angle and rate of turn

Answer 5

If an aircraft increases speed without changing the bank angle, the rate of turn decreases.

If an aircraft decreases speed without changing the bank angle, the rate of turn increases.

Question 6

Rate of Turn:

Answer 6

The rate depends on a set bank angle at a set speed
The standard rate of turn is 3° per second

Question 7

Speed & Rate of Turn:

Answer 7

If the aircraft increases speed without changing the bank angle, the rate of turn decreases

If the aircraft decreases speed without changing the bank angle, the rate of turn increases

Question 8

Bank Angle & Rate of Turn:

Answer 8

If the aircraft bank angle increases without changing airspeed, the rate of turn increases

If the aircraft bank angle decreases without changing airspeed, the rate of turn decreases

Speed and bank angle, therefore, vary inversely to maintain a standard rate turn

This is important in the instrument environment, such as when holding or on an instrument approach

Question 9

Standard rate of turn

Answer 9

A rule of thumb for determining the standard rate turn is to divide the airspeed by ten and add 5

Example: an aircraft with an airspeed of 90 knots takes a bank angle of 16° to maintain a standard rate turn (90 ÷ by 10 + 5 = 14°)

Question 10

Radius of Turn:

Answer 10

The radius of turn varies with changes in either speed or bank

Question 11

Speed & Radius of Turn:

Answer 11

If the speed increases without changing the bank angle, the radius of turn increases

If the speed decreases without changing the bank angle, the radius of turn decreases

Question 12

Bank Angle & Radius of Turn:

Answer 12

If the speed is constant, increasing the bank angle decreases the radius of turn

If the speed is constant, decreasing the bank angle increases the radius of turn

Therefore, intercepting a course at a higher speed requires more distance, and therefore, requires a longer lead

If the speed is slowed considerably in preparation for holding or an approach, a shorter lead is needed than that required for cruise flight

Question 13

Load factor

Answer 13

A load factor of one, or 1 g, represents conditions in straight and level flight, where the lift is equal to the weight. …

Load factors greater or less than one (or even negative) are the result of maneuvers or wind gusts.

Question 14

Dihedral is…

Answer 14

Dihedral is the upward angle of an aircraft’s wings, which increases lateral stability in a bank by causing the lower wing to fly at a higher angle of attack than the higher wing. What it really means is that you can fly more hands off, even in turbulence.

Question 15

Longitudinal and lateral stability

Answer 15

Longitudinal stability and control is concerned with an airplane’s pitching motion.

Lateral stability and control relates to an airplane’s rolling motion.
Directional stability and control relates to an airplane’s yawing motion.

Question 16

Dont mix Static pressure with Dynamic pressure.

Answer 16

Static pressure is the pressure you have if the fluid isn’t moving or if you are moving with the fluid. Air would press against you equally in all directions. … Dynamic pressure is the pressure of a fluid that results from its motion. It is the difference between the total pressure and static pressure.

The Bernoulli equation states that an increase in velocity leads to a decrease in pressure. Thus the higher the velocity of the flow, the lower the pressure.

Question 17

VMCA (MINIMUM CONTROL SPEED - AIR

Answer 17

VMCA is the minimum speed that, in the event of sudden and complete failure of the most critical engine in takeoff configuration, enables continued directional control and steady flight using full rudder deflection and a maximum of 5° of bank away from the failed engine.

Question 18

Equation of Continuity

Answer 18

The continuity equation is written as:

P x A x V = Constant

where:

P = pressure

V = velocity

A = cross sectional area of flow

Using the Bernoulli equation and the continuity equation, it can be shown how air flowing over an airfoil creates lift. Imagine air flowing over a stationary airfoil, such as an aircraft wing.

Question 19

Stall Speed increases when?

Answer 19

Forward Centre of Gravity

Icing Conditions

High Altitude

Question 20

the rolling moment of an aircraft about its CG is affected by?

Answer 20

angle of sideslip,

aileron deflection,

and

rudder deflection.

Question 21

main contributors to lateral static stability?

Answer 21

wing dihedral,
wing sweep,
fuselage wing relative position/placement,
vertical tail.

Question 22

a positive dihedral is?

Answer 22

stabilising.

Question 23

in side slip with a high wing,

what kind of rolling moment is generated?

Answer 23

stabilising.

Question 24

in sideslip with a low wing,

what kind of rolling moment is generated?

Answer 24

destabilising.

Question 25

Profile Drag or, sometimes called form drag, is?

Answer 25

…the drag caused by the separation of the boundary layer from a surface,

and the wake created by that separation.

It is primarily dependent upon the shape of the object.

… is caused by the air that is flowing over the aircraft or airfoil.

It increases moderately as airspeed increases.