11.9 Flashcards
What’s manoeuvre load control
Using control surfaces to move the centre of lift inboard during manoeuvres so that the bending moment is reduced so there’s a reduction in load on the wing
**
As the root is thicker so it can take the loads compared to the outer wing
Why are cable operated systems often used
Strong
Lightweight
And food at transferring loads over a large distance
Why are cable operated systems often used
Strong
Lightweight
And food at transferring loads over a large distance
What size control cables are usually used in aviation
7x19 flexible
7x7 flexible
What’s the purpose of the guards on the pulleys
Close fitted guards that prevent jamming or cables slipping off when they slacken due to temp changes
How accurate is a tensiometer
98%
What do tension regulators do
Allows cable under all conditions like expansion and contraction of cable and aircraft to be taken in and out equally to maintain uniform tension
What’s a disadvantage of a push pull control rod
What’s there overall advantage
Heavy weight and harder to route without complicating the control system
They can accept both push and pull loads without a parallel system
What are bell cranks used for
Used in conjunction of control rods and are frequently used to change direction
What are bell cranks used for
Used in conjunction of control rods and are frequently used to change direction
When are torque tubes used
When a twisting motions needed in a control system
Eg. Ailerons flaps slats
What are screwjacks used for
Moving surfaces that experience extreme aerodynamic loads like horiz stab and leading and trailing edge flap
What two critical functions do PCU’s do
They position the flight control surface in a response to mechanical or electrical commands
Represent a principle structural element capable of withstanding flight loads and providing protection against flutter
What two sections is the servo control unit divided into
Power section
Distribution section
What two sections is the servo control unit divided into
Power section - converts the hydraulic pressure to mechanical force
Distribution section
What are the two main operating MODES of the servo control unit
Control or active mode
Damping mode
What’s the damping mode of the servo control unit used for
A gust damper for control surfaces when the ac is on the ground
What are manual ans power assisted flying controls known as
Reversible flying controls
Can the pilot still move the controls on the event of a hydraulic failure in a power assisted control system
Yes
What do screw jacks do
Convert rotary motion to linear travel
What’s the reason for not utilising pneumatics to its full potential for flying control systems
Bc aids compressible
What mode is the electronic pcu in operation at below cruise speed
Normal mode
When there’s a single hydraulic or electric failure on the pcu what modes selected
Bypass
When there’s a single hydraulic or electric failure on the pcu what modes selected
Bypass
When the pcu had a failure or not power at or above cruise speed what mode is the electric pcu in
blocking/damped mode
Major advantage of fly by wire
Weight saving
What are the gyroscopes used for in ac and how many are there
3
And to sense movement on the roll, pitch and yaw axis and sends signals to the computers to move the appropriate actuators
What’s used to perform test on fly by wire systems
BITE
What’s used to perform test on fly by wire systems
BITE
What are the two fly by wire laws
Normal
Alternate
What’s a benifit of fly by wireless
Weight saved
What type of aircraft control systems don’t require artificial feel
Mechanical flight controls
What’s the basic artificial feel system
Spring box
What’s the basic artificial feel system
Spring box
Why do the spring artificial feel provide greater resistance say higher speed
To prevent over stressing ac structure
Why do the spring artificial feel provide greater resistance say higher speed
To prevent over stressing ac structure
What does yaw damper prevent
Dutch roll
What speeds can mach tuck occur at
0.75-1.2
What’s the mcrit number
The m crit number is the point on the ac where the first molecule of air reaches the speed of sound over the aircraft
What’s Mach tuck caused by
The centre of pressure moving aft on the wing
What’s used t prevent mach tuck
Mach trim
At what speeds would ac required additional amount of structural reinforcements for the loads generated by moving large control surfaces
650km/h
At what speeds would ac required additional amount of structural reinforcements for the loads generated by moving large control surfaces
650km/h
What do gust locks do
Lock the controls when the ac is parked
When a control surface is checked for static balance on a balance stand what does the downward travel of the trailing edge indicate
Upward travel of the trailing edge indicate
Under balance
Over balance
Are better flight operations Gaines from static overbalance or under balance
Nose heavy static overbalance
Whats used to determine that the control surface is balanced before carrying out balancing procedures
Bubble protractors
What’s the main advantage of the calculation method of balancing
Can be performed without removing the control surface from the ac
What’s rigging
Established the correct position of the main components in transmission system and adjusting the rods and cables accordingly
What’s rigging
Established the correct position of the main components in transmission system and adjusting the rods and cables accordingly
How’s a control Column checked to see if it has been rigged correctly
By checking the rig pin hole is alligned with adjoining structure
How’s a control Column checked to see if it has been rigged correctly
By checking the rig pin hole is alligned with adjoining structure
How’s a control Column checked to see if it has been rigged correctly
By checking the rig pin hole is alligned with adjoining structure
What’s the pitch attitude
How’s it calculate
Angle between longitudinal axis and artificial horizon
A of a sensor
What’s a of a
Angle between oncoming air and a reference line in wing or fuselage
What a of a gives max lift
14
What happens to a of a during climb if slats retract
Increases so can lead to stall
What happens to a of a during climb if slats retract
Increases so can lead to stall
What happens to a of a during climb if slats retract
Increases so can lead to stall
