Controls Flashcards
What type of controls are ailerons
Rate controls
What is the formula for the hinge moment (feel)
Hinge moment = f x d
D= distance from centre of pressure of control surface to the hinge
What does a insert hinge do
The hinge connecting the control surface is inset slightly closer to the centre of pressure to reduce the force
What is the max Inset for a hinge
25% from the leading edge > trailing edge
What is a horn balance
Adds area of surface infront of hinge
When elevator is deflected a part deflects in the opposite direction to reduce the force required
What % inset is the horn balance limited to
25% of the chord
What is a balance tab
Deflects in the opposite direction of the control surface to make movements lighter but less effective
You move control surface which is then linked to the tab
What is a anti- balance tab
Works against you
You move control which deflects tab to make controls heavier
Less likely to overstress aircraft
Retaining control feel at low speed
What is a servo tab
You move the tab (not the control surface)
Makes controls lighter
High speeds = makes controls lighter
Slow speed = small force produced by tab = controllability issues
What is a spring tab
Like a servo tab but with a spring
At slow speeds whole control surface moves as not enough force to stretch spring
High speeds = spring stretches to do the same job as servo tab
Solves the problem of low speed control issues
Is a mass balance a aerodynamic balance
NO!!!!!
What are the different types of mass balances
Mass in the horn balance
Mass on boom attached to control surface
Arc shaped mass forward of control surface
How do mass balances work
Moving the cg of the control surface forward meaning it has a lower inertia (wants to move less)
What is the difference between a elevator and a stabilator
Elevator is a camber changing device
Stabilator is a angle of attack changing device
When is the greatest risks during s fin stall
Counteracting asymmetric power on a Engine failure on multi engine aircraft
What direction does the raf need to come from to produce a positive angle on the rudder
Raf from the right = positive
If ailerons are rate control what is rudder and elevator
Displacement
What causes aerodynamic damping
Higher AOA on down going wing = more lift
Lower AOA on up going wing = less lift
If you roll right what was do you yaw
Left
What are frise ailerons
Down going wing = aileron up = leading edge of aileron protrudes below = drag = helps counter adverse aileron yaw
What are differential ailerons
down going wing aileron deflects more than up going going = more drag = helps reduce aileron yaw
How do large aircraft control adverse aileron yaw
Frise ailerons
Spoilers
Control coupling
What would happen if the outboard ailerons were used at high speed on a large jet
Wing twist = adverse aileron yaw
How do spoilers help stop adverse aileron yaw
Down going wing = spoilers up a bit to create more drag
What are the advantages of spoilers as roll control
Don’t suffer from flutter
Leave tailing edge free for flaps
Cause no twisting moment
What is a flaperon
Aileron can drop slightly to give the effect of s flap
What is control coupling
Where a mixer unit interconnects the inputs from the control column and the rudder peddle
What are the advantages of a trimmable horizontal stabiliser
More aerodynamically effective (less drag)
Enables equal pitch up and down control about any trimmed position
Control over a greater cg range
Less sensitive to flutter
What may help a Jamed stabiliser
Reducing speed might help by reducing the size of the out of trim force but will also reduce effectiveness
