11.1 Roll, Pitch And Yaw Flashcards
What are the three primary axes?
-lateral axis
-longitudinal axis
-vertical axis
What moment moves around the vertical axis and what controls it ?
Yaw is controlled by the rudder
What moment moves around the longitudinal axis ?
Roll is controlled by the ailerons
What moment moves around the lateral axis ?
Pitch is controlled by the elevators
What are the primary flight controls of an aircraft ?
-Ailerons
-Elevators
-Rudder
What other primary flight control will a large aircraft have that a smaller aircraft won’t?
Roll spoilers
What are ailerons and how are they controlled ?
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
What happens to the outboard aileron as aircraft speed increases on larger aircraft and why?
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
What are spoilers ?
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.
Where are elevators located?
On the trailing edge of the horizontal stabiliser.
Why are the elevators located at the end of the empennage?
To exert maximum leverage as it’s the furthest away from the centre of gravity
What do elevators do and how are they controlled ?
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
How do elevators move when an input is made?
They move in synchrony
What are stabilators?
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
What is different between stabilators and elevators ?
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
Where are stabilators usually installed ?
In light general aviation aircraft or more commonly In high speed military combat aircraft
When a stabilator is on a light general aviation aircraft what is it usually fitted on ?
Anti-balance tabs
Why are elevators not used on high speed a supersonic aircraft ?
When a normal shock wave is formed, a problem is formed on the elevator hinge line which can render the control surface ineffective
What are variable incidence stabiliser ?
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
When an angle of attack is increased on a trimmable horizontal stabiliser what happens to the aircraft ?
A nose down attitude, opposite for a negative angle of attack
Why is a trimmable horizontal stabiliser used ?
Accounts for adjustments in passenger and freight distribution, fuel consumption, flap settings and engine settings during flight.
How is the angle of incidence controlled on a variable horizontal stabiliser ?
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
What is a canard configuration?
When the main wings are located at the rear of the aircraft and the horizontal stabilisers are in front of the wings.
What are the benefits of canard configuration
-Better pitch control
-better stability
-stall prevention
-high angle of attach manoeuvres
-Control redundancy
-lift and trim
What does the rudder do and how is it controlled ?
The rudder contributes to the moments around the vertical axis called yaw. It is controlled by foot pedals in the cockpit.
What is a rudder limiter ?
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
During roll, what is a common tendency and how is this fixed ?
Slip is a common tendency of roll, this problem is fixed by using the rudder in flight
What is adverse yaw?
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
What is used to reduce slip (adverse yaw)?
Fraise ailerons
What can happen to an aircraft with a high vertical stabiliser ?
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.
What is a Dutch roll?
When a swept wing aircraft has instability in yaw and roll, it can oscillate around both axis.corrected by the yaw damping system