control and controllability

what does controllability always appose

the inherent stability restoring moments

if a aircraft is highly stable how much force is needed to deviate it

a lot more

what do control surfaces do

change the airflow over the surface

what provides roll around the longitudinal axis

ailerons

what provide longitudinal control in pitch about the lateral axis

elevators

provides yawing about the normal axis

rudder

what provides a combined function of elevators and ailerons

elevons

what type of wings are elevons fitted on

delta wings

when elevons when they are raised together they act as

elevators

when elevons act independently they act as

ailerons

what is a combined function of the tailplane and ailerons

taileron

when a aileron is deflected upwards and what happens to the wing

it goes down

if a aileron is deflected downwards what happens to the wing

it goes up

what problems do ailerons cause

aileron drag or adverse yaw

to maintain a steady angle of bank angle the aileron must

return back to nutral

what creates more induced drag the up going or down going aileron

the up going

to reduce aileron drag we use differential ailerons, what moves more the up going or down going aileron

the up going moves more than the down

on older low speed aircraft what do we use to counter aileron drag

frise ailerons

in freise ailerons the beak when does the beak project into the airflow

when the ailerons deflected upwards to increase the drag on the down going wing

what are the two types of aileron reversal

high speed and low speed

at low speed at a high angle of attack can cause the aileron to be deflected downwards causing the wing to drop this is because its reducing its

coefficient of lift

high speed aileron deflection(twist) happens when what gets altered

position of the chord line

what can be solutions to aileron reversal

stiff wings

two sets of ailerons

spoilers

how do spoilers help with aileron diversion

spoilers dont cause the same torsional divergence and also add drag to the down going wing

a rudder movment to port gives a lift force to

starboard

the main functions for the rudder are to

keep the aircraft straight during take off and landing

reduce the roll rate and aid in a spin

help the dropped wing in aileron reversal

correct yawing in aysmmetric power conditions

when a elevator is deflected upwards this causes what force and what happens to the nose

a downward force and causes the nose to pitch up

the upward moments of the elevator can cause the AOA and CP to do what

increase the AOA and move the CP forward

to maintain a steady climb or turn the control surfaces are

returned returned back to neutral

if speed is reduced and the elevators are raised what would happen to lift

remain the same

what is aerodynamic balance

to reduce/aid the pilots in control movments

insert hinges help by

striking the surface in front of the hinge to assist control movement

as a rule of thumb insert hinges are limited to 20% of the control surface to prevent

excessive snatching and over balance

what are the two types of horn balance

graduated and standard

standard horn balance are prone to

snatch

graduated horn balance overcome snatching by

progressively increasing the amount of control surface area

internal balance assist the pilot by a

flexible strip

if the CG of a control surface is far from the hinge line this will cause the control surface to oscillate this is referred to

control surface flutter

by carfully adding a predetermined mass to the control surface to bring the CG in line this is called

mass balance

control surfaces that have been repaired of resprayed must

be weighed and check the CG

tabs are used for

control balance to assist the pilot the pilot

servo operation

trimming

balance tabs reduce the hinge moment witch in turn

reduces the effort by the pilot

anti balance tabs connect in a way to move in the same direction as the control surface this to give

more feel so the aircraft isnt over stressed

spring tabs are used to reduce control loads at

high speed

spring tabs move what direction

opposite

servo tabs operate what control surfaces

primary

servo tabs reduce the amount of

effort the pilot has to apply

trim tabs are there to help the pilot from a sustained

input that is needed to maintain level flight

trim wheels provide instinctive movment if the elevator was trimmed to nose down what would happen to the control column

in will also be forward of the neutral line