Flight Control (redone) Flashcards
Mechanical flight control system
Sport & small general aviation aircraft
Modern aircraft are controlled via
Electrical interface:
- Electric Motors
- Digital Computers
- Fiber Optic Cables (Fly-by-Wire systems)
Name the two types of flight control systems
Primary: Ailerons, Elevator, Rudder
Secondary: Wing Flaps, spoilers, trim systems
What does the Primary control system control?
Airflow around the airfoil thus moving the aircraft around its 3 axis of rotation
Ailerons control what axis
Longitudinal axis (roll)
What is adverse yaw
When the plane rolls to the left or right
To roll right, which aileron will do what?
Right aileron moves up, left aileron moves down
What does adverse yaw cause during a left roll?
Left aileron moves up, right aileron moves down producing drag causing the plane to yaw right.
What is adverse yaw and how do you counteract it?
When the plane yaws towards the outside of a bank (towards the lowered aileron). Use rudder pressure.
When is the effect of adverse yaw magnified?
At slower speeds because of the decreased effectiveness of the vertical stabilizer & rudder.
What 4 systems are used to counteract adverse yaw?
- Coupled ailerons and rudder
- Differential ailerons (aileron that deflects downward doesn’t deflect as much as the aileron that deflects up) to balance drag
- Frise Type Ailerons - they move on an offset pivot and have slots
- Flaperons - combine aspects of ailerons & flaps
What does the elevator control?
Pitch about the lateral axis
This is a characteristic of a T-tail plane
Remove horizontal stabilizer from exhaust blast and prop wash. Pilot must make larger movements at slow speeds to control pitch of nose.
What is a stabilator?
Entire horizontal stabilator moves up and down.
Describe a Canard design airplane?
Horizontal stabilizer is on the front of the plane before the main wings. Results in less drag for lift
What axis does a rudder control?
Vertical axis (yaw)
Left pedal will cause rudder to deflect in which direction?
Left
What are ruddervators?
Combination rudder and elevator. They work much like flaperons
Name secondary flight controls
- Wing flaps
- Leading Edge Devices
- Spoilers
- Trim Systems
Flaps are the most common what
High lift devices
Flaps increase what
lift and drag
Name 4 types of flaps
Plain, split, slotted, fowler flap
Describe plain flap
Most simple design. Increases camber of wing to increase lift and drag.
Describe split flap
Deploy from lower surface of wing and increase lift more than plain flap. Both the plain and split flap design cause high drag for little lift
Describe slotted flap
Most popular flap. Allows high energy air to flow from bottom of wing to top of the wing. Causes much greater lift force than plain or split flap.
Describe Fowler flap
Change camber and increase wings surface area by sliding back and down rather than just down.
4 most common types of leading edge devices
Fixed slot, movable slot leading edge flap, leading edge cuff
Describe fixed slot
Leading edge device. Delay airflow separation until a higher angle of attack. Does not increase wings camber but still increases lift.
Describe movable slot
Leading edge device. They open when angle of attack is increased or by the pilot. Work the same way as fixed slot
Describe leading edge flap
Leading edge device. Work to increase the camber of the wing and are used with trailing edge flaps to reduce the nose down pitching tendency
Describe leading edge cuffs
Leading edge device. Works to increase wing’s camber and lift. Front edge of wing is pushed down and forward allowing for more air to connect to the upper surface of the wing at higher AOA thus reducing the stall speed.
Describe spoilers
Help by reducing lift and increasing drag over the wings surface. Used in gliders to control decent & in large aircraft to control adverse yaw. When used together they slow down plane and reduce ground roll by transferring weight to wheels thus increasing breaking efficiency
What are trim systems used for?
Used to relieve the pilot of need to maintain constant pressure on the primary flight control surfaces
What type of trim systems exist
Elevator, rudder, aileron trim systems
What is configured before adjusting trim
- Establish desired power setting
- Establish desired pitch attitude
- Establish desired configuration
What is a balance tab?
Trim system that automatically moves opposite of control input to automatically relieve some pressure required to be held by the pilot
What is an antiservo tab?
Work like balance tab by opposing force of pilot and making stabilizer less sensitive.
Ground adjustable tab
Adjusted from ground to prevent skidding L or R during cruising flight
What can autopilot work with?
- Inertial navigation systems
- Global positioning systems
- Flight computers
