Lesson 5 Flashcards
What are the basic requirements of controls?
Not too light
Not too heavy
Control forces should vary with IAS
No lag - controls should be responsive
Harmonised - similar for pitch/roll
What is the
axis of rotation
control
primary effect
secondary effect
of
aileron
axis of rotation:
Longitudinal
control:
Lateral
primary effect:
Roll
secondary effect:
Yaw
What is the
axis of rotation
control
primary effect
secondary effect
of
elevator
axis of rotation:
Lateral
control:
Longitudinal
primary effect:
Pitch
secondary effect:
(speed)
What is the
axis of rotation
control
primary effect
secondary effect
of
rudder
axis of rotation:
Normal
control:
Directional
primary effect:
Yaw
secondary effect:
Roll
Suggest some combined controls (3)
Ruddervator
Elevon
Taileron
What type of controls have a mechanical connection between the control column and control surfaces.
Conventional -
full feedback to pilot
What type of controls have a mechanical link and are augmented?
Partially powered controls -
Pilot still gets feedback
What type of controls does not have any mechanical connection to the control surface?
Fully powered controls -
No pilot feedback
What can be used in an aircraft with fully powered controls to reduce the chances of the pilot demanding too much control deflection and overstressing the aircraft? (3)
Springs
Bobweight
Fly-by-wire
Name types of aerodynamic balance
(1x hinge)
(2x balance)
(4x tab)
Inset hinge
Horn balance
Internal balance
Balance tab
Anti-balance tab
Servo tab
Spring tab
Which aerodynamic balance will move the position of the hinge (usually aft) and what does it do to the forces?
Inset hinge
Which aerodynamic balance sticks out ahead of the control surface, forward of the hinge?
Horn balance
Which balance has an internal chamber which can be split into two by a flexible seal?
How does this work?
Internal balance
Two halves of the camber are exposed to the static pressure on the upper/lower surfaces.
As the control surface is deflected then the static pressures will change, creating a pressure gradient and helps the pilot, making the aircraft controls lighter.
Which balance is similar to a trim tab but moves with the same control but in the opposite direction?
Balance tab (not the same as a trim tab)
The balance tab moves in the opposite way to the control surface
Which balance is works the opposite to the ‘balance tab’? It moves in the same direction as the control surface.
Anti-balance tab
Which balance system can be use in the case of hydraulic failure?
Servo tab
What balance system acts like a servo tab at higher speeds and a regular control surface at lower speeds.
Spring tab
Name a balance that is NOT aerodynamic.
Mass balance
Control flutter would be dampened (or prevented) by which type of balance
Mass balance
Fly-by-wire normal law:
What does forward/aft on the sidestick command?
g-force
Fly-by-wire normal law:
What does left/right on the sidestick command?
Roll rate
What are the two forms of protection?
Soft - can be overridden
Hard - can’t be overridden
In alternate law, what does side stick command?
Same as ‘Normal law’
In direct law, what does side stick command?
Now a direct relationship with the control surfaces.
What protections do you have in ‘normal law’
Hard and Soft
What protections do you have in ‘alternate law’?
Soft only
What protections do you have in ‘Direct law’?
None
When talking about FBW law, what do failures cause?
A degradation to a lower law.
When you manoeuvre an aircraft, what will resist this?
Aerodynamic damping
What would effect the strength of aerodynamic damping?
Wingspan - longer is stronger damping
Density - weaker in low density
When we draw a RAF line, the angle is used for AoA. What does the length represent
TAS
Describe a fries aileron
To fix adverse aileron yaw
when the aileron is going up, the leading edge points down into the airflow creating drag on the downwind wing
What are the 4 ways you can prevent adverse aileron roll
Differential ailerons
Frise ailerons
Roll spoilers
Coupled controls
What are the two configurations that can be used for trimming?
Elevator and trim tab
Trimmable horizontal stabiliser
Why may you want to trim the aircraft with the nose up?
Climb
Slower
forward CG
Trim tab moves in same/opposite direction to elevator?
Opposite
Which direction does the trim tab move in when you rotate the trim wheel for nose down?
Nose down = trim tab up
Which direction does the trim tab move in when you rotate the trim wheel for nose up?
Nose up = trim tab down
When you trim the aircraft, the physical control column does what?
Stays in the trimmed position.
What drag is introduced with the use of the trim tab?
trim drag
Name 3 disadvantages of using elevator trim tabs.
Creates trim drag
Reduces elevator effectiveness
Can run out of elevator authority (so limit CG range)
When using trim tabs there is a risk of running out of elevator authority. How do we guard against this?
Use CG limits
Where is a THS hinged
centrally
At what stage can you not feel when the aircraft is in/out of trim?
Before takeoff
What’s the name of the angle between the Relative Air Flow (RAF) and the longitudinal axis? (clear when operating the rudder)
Beta angle
Is weight or lift greater in a climb?
Lift is less than weight in a climb
If lift is greater than weight then how can an aircraft still climb?
Thrust
How man ‘g’ is the load factor in a climb?
Load factor in a climb is less than 1g
Equation:
Lift, weight, gamma
Lift = weight COS$gamma;
