11.1 Roll, Pitch And Yaw

Question 1

What are the three primary axes?

Answer 1

-lateral axis
-longitudinal axis
-vertical axis

Question 2

What moment moves around the vertical axis and what controls it ?

Answer 2

Yaw is controlled by the rudder

Question 3

What moment moves around the longitudinal axis ?

Answer 3

Roll is controlled by the ailerons

Question 4

What moment moves around the lateral axis ?

Answer 4

Pitch is controlled by the elevators

Question 5

What are the primary flight controls of an aircraft ?

Answer 5

-Ailerons
-Elevators
-Rudder

Question 6

What other primary flight control will a large aircraft have that a smaller aircraft won’t?

Answer 6

Roll spoilers

Question 7

What are ailerons and how are they controlled ?

Answer 7

The primary flight control responsible for moments around the longitudinal axis for roll
Controlled by rotational movements of the yoke or side to side movements of the side stick

Question 8

What happens to the outboard aileron as aircraft speed increases on larger aircraft and why?

Answer 8

The outbound aileron on large aircraft is locked out, this is because at high speed large moments are not needed , only minute adjustments over a long distance

Question 9

What are spoilers ?

Answer 9

Roll spoilers or flight spoilers are used to supplement aileron control by reducing lift on the wing with the up going aileron .roll spoilers help to execute an accurate turn and reduce the requirement for a large aileron deflection at high speed.

Question 10

Where are elevators located?

Answer 10

On the trailing edge of the horizontal stabiliser.

Question 11

Why are the elevators located at the end of the empennage?

Answer 11

To exert maximum leverage as it’s the furthest away from the centre of gravity

Question 12

What do elevators do and how are they controlled ?

Answer 12

Elevators control the moment around the lateral axis called pitch they are instinctive to control push the aircraft column, the aircraft goes nose down and vi-ceversa the same for fly by wire side-stick control

Question 13

How do elevators move when an input is made?

Answer 13

They move in synchrony

Question 14

What are stabilators?

Answer 14

A dual purpose control surface that combine the action of elevators and horizontal stabilisers.
Rotate around their horizontal axis to affect the pitch of the aircraft

Question 15

What is different between stabilators and elevators ?

Answer 15

The horizontal stabiliser does not move with the elevators in a normal configurations, whereas a stabilator, the horizontal stabiliser is the elevator, so the horizontal stabilisers move

Question 16

Where are stabilators usually installed ?

Answer 16

In light general aviation aircraft or more commonly In high speed military combat aircraft

Question 17

When a stabilator is on a light general aviation aircraft what is it usually fitted on ?

Answer 17

Anti-balance tabs

Question 18

Why are elevators not used on high speed a supersonic aircraft ?

Answer 18

When a normal shock wave is formed, a problem is formed on the elevator hinge line which can render the control surface ineffective

Question 19

What are variable incidence stabiliser ?

Answer 19

Is a stabiliser that has a limited range of movement and is only used for pitch trimming. Has the advantage of reducing drag due to the reduced need for elevator deflection

Question 20

When an angle of attack is increased on a trimmable horizontal stabiliser what happens to the aircraft ?

Answer 20

A nose down attitude, opposite for a negative angle of attack

Question 21

Why is a trimmable horizontal stabiliser used ?

Answer 21

Accounts for adjustments in passenger and freight distribution, fuel consumption, flap settings and engine settings during flight.

Question 22

How is the angle of incidence controlled on a variable horizontal stabiliser ?

Answer 22

A screw jack mechanism is operated from the flight deck with pitch trim wheels or by electrical servo motors commanded by either a pitch trim switch or autopilot inputs

Question 23

What is a canard configuration?

Answer 23

When the main wings are located at the rear of the aircraft and the horizontal stabilisers are in front of the wings.

Question 24

What are the benefits of canard configuration

Answer 24

-Better pitch control
-better stability
-stall prevention
-high angle of attach manoeuvres
-Control redundancy
-lift and trim

Question 25

What does the rudder do and how is it controlled ?

Answer 25

The rudder contributes to the moments around the vertical axis called yaw. It is controlled by foot pedals in the cockpit.

Question 26

What is a rudder limiter ?

Answer 26

On a fly by wire aircraft, the rudder limiting system restricts the rudder’s amount of deflection with increasing air speed. This is important as increasing air speed can exceed the ultimate load of the vertical stabiliser and cause structural failure

Question 27

During roll, what is a common tendency and how is this fixed ?

Answer 27

Slip is a common tendency of roll, this problem is fixed by using the rudder in flight

Question 28

What is adverse yaw?

Answer 28

Common on light aircraft. The down going aileron has reduced lift causing reduced induced drag on the up going aileron. This causes a yawing effect also known as slip

Question 29

What is used to reduce slip (adverse yaw)?

Answer 29

Fraise ailerons

Question 30

What can happen to an aircraft with a high vertical stabiliser ?

Answer 30

Adverse roll from the side force generated when the rudder is in use acts upon the centre of pressure acting in the opposite way that the rudder is deflected.

Question 31

What is a Dutch roll?

Answer 31

When a swept wing aircraft has instability in yaw and roll, it can oscillate around both axis.corrected by the yaw damping system