11.9 flight controls Flashcards
define a primary flight control
flight controls that provide movement around the 3 axis
what are the primary flight controls
ailerons, elevators, rudder
for steady flight what state must an aircraft be in
state of balance
what do the ailerons control and along what axis
roll around the longitudinal axis
where are the ailerons located
outboard trailing edge, sometimes inboard
what movement do elevators control and around what axis
pitch, around the lateral axis
what movement do rudders control and around what axis
yaw, around the vertical axis
what is static balancing
object remains stationary when supported by the centre of gravity
what 2 ways can surface be out of static balance
underbalance, overbalance
does static balancing add weight behind or in front the hinge line
behind
what is dynamic balancing
all rotating forces are balanced
what do you need to do if you carry out repair on flight control surfaces
re-balance them
what are the 3 most common rebalancing methods
calculation method, scale method, balance beam method
what is the main advantage of calculation balancing
you dont have to remove the control surface from the aircraft
what is used in the balance beam method
specially fabricated tool
what materials are usually used to balance control surfaces
lead or steel
what do some larger aircraft use to balance control surfaces
depleted uranium
what does aircraft rigging do
adjusts the travel of flight controls
how do you adjust flight control travel
adjusting cables and electronic controls
whats the use of a rig pin
used to check correct positions
what position do rigging pins set flight controls in
neutral
whats the function of the stick shaker
warning of stall
what is pitch attitude
angle between the longitudinal axis and the horizon
what is AOA
angle of attack
define angle of attack
angle between oncoming air or relative wind and aircraft wing
if the angle of attack get too high what happens to the airflow over the wing
separates from the wing
what angle of attack gives maximum lift
14 degrees
what are the 5 common types of trim system
trim tabs, servo tabs, balance tabs, spring tabs, anti balance/servo
whats the only flight trim tab that goes the same direction as the flight control
anti balance/servo
whats yaw trim controlled by
rotary knob
whats ALA
active load alleviation
what load control techniques are used to reduce loads in manoeuvring
manoeuvre load control, gust load alleviation
employing EMC and GLA can result in what
weight saving and the same weight for larger wwingspan
whats the strategy behind manoeuvre load control
use the wings control surfaces to move the centre of lift inboard
whats the strategy behind gust load alleviation
fly by wire aircraft deflect surfaces to battle gust loads
what is the function of trailing edge flaps
increase camber of the wing and increase lift and slow speed control
what are the 5 kinds of trailing edge flaps
plain, split, slotted, fowler, fowler slotted
whats the most simple form of trailing edge flap
plain flap
whats the most common trailing edge flap in use today
slotted flaps
what type of flap do most large aircraft also have
leading edge flaps
when are ground spoilers used
on ground
when are flight/roll spoilers used
in flight
when are speed brakes used
in flight
what are control cable sizes and typically made from
7x7 and 7x19 made from flexible steel
what are used to guide control cables along their length
fairleads
what could incorrect tension on control cables cause
loss of control on flight surfaces
whats used to measure flight cable tension
tensiometer
why do some aircraft use tension regulators
because of change in temperature and condition
when is the only time cables have strength
under tension
when is the time push/pull rods have strength
always
whats a disadvantage of push pull rods
cant go around corners and are heavier
whats used on push pull rods to check the thread engagement
witness holes
what do bell cranks do
change direction of movement
whats installed when a angular or twisting motion is needed
torque tubes
when are screwjacks used
on flight surfaces that undergo alot of aerodynamic loads
what are PCUs
power control units
what is the servo control unit divided into
power section, distribution section
what are the 2 main operating modes of the servo control unit
control/active mode, damping mode
in power assisted control, what assists the pilot in moving flight control surfaces
hydraulics
in the servo control unit what is always proportional to the follow up movement
input movement
in a fully powered control explain the movement the pilot makes and the flight control feedback
the pilot feels no feedback from the flight control as they are not connected
when are pneumatic systems used for flight control movement
usually back up systems
during operation below cruise speed what mode is the PCU in
normal mode
what are the 3 modes of the PCU
normal, blocking/damped, bypass
what PCU
power control unit
what is FBW
fly by wire
how is fly by wire stability achieved
three gyroscopes
what is BITE
built in test equipment
what are the 2 laws associated with fly by wire
normal law, alternate law
when does mach tuck happen
when an aircraft transitions through the transonic region
aircraft using mechanical flight controls will lock then on the ground, how
using gust locks
