Flight Controls Flashcards
Name primary flight controls
Ailerons
Elevator
Rudder
Name secondary flight control systems
Wing flaps
Spoilers
Trim systems
How to Ailerons influence the airfoil
Ailerons change the pressure of airflow around the airfoil, which allow the pilot to control roll about the longitudinal axis
What is adverse yaw
when a plane rolls to the left or right (video says roll but it means rotate). When an aileron is pitched down, the plane will yaw in that direction. Thus you need to use rudder pressure to account for the adverse yaw
What systems are used to counteract adverse yaw
- Coupling the Ailerons and rudder
- Differential ailerons; aileron that deflects downward doesn’t deflect as much as the opposite one that deflects up, thus decreasing drag on the aileron that deflects down
- Frise Type Ailerons - Ailerons that move on an offset pivot which causes them to be pushed into the airstream when pushed upwards which causes drag. The ailerons also have slots which allow for smoother airflow over the lower aileron, making it more effective at high ends of attack.
- Flaperons - combined aspects of ailerons and flaps
T-Tail aircrafts must:
Make large control movement when flying slowly to control the nose because the horizontal stabilizer is removed from exhaust blast and prop wash thus doesn’t remove constant airflow
What is a stabilator?
Works like an elevator but the entire horizontal stabilizer moves up and down along a pivot point. Canard design airplanes have stabilizers on the nose of the aircraft
What are ruddervators
combination of rudder and elevators (v shaped tail of plane). They can be controlled separately.
Most common high lift devices on an aircraft?
Flaps. Attached to the trailing edge of wing and increase both lift and drag for any angle of attack.
Describe the 4 types of flaps
Plain - Simple; increases camber thus increases lift but increases drag. High drag for little lift
Split - deploy from lower surface of wing and increase lift more than plain flap; causes high drag for little lift
Slotted - Most popular flap; allows high energy air to flow from bottom to top of wing; Causes greater lift force than either plain or split flap.
Fowler - Work must like slotted flaps. They change the wing’s camber and increase the wing’s surface area. They slide back and down rather than just down
Describe the 4 most common leading edge wing devices
Fixed slot - delay airflow separation until higher angle of attack. Does not increase wing’s camber but increases lift.
Movable slot - Same as fixed slot but open when angle of attack is increased or by the pilot.
Leading edge flap - Increase camber of the wing and are commonly used with trailing edge flaps to reduce the nose down pitching tendency.
Leading edge cuff - Increase wing’s camber and increase lift. Front edge of wing is pushed down and forward allowing for more air to connect with the upper surface of the wing at higher angles of attack, thus reducing the aircrafts stall speed.
How do spoilers help an aircraft?
They reduce lift and increase drag over the wing’s surface. They’re used in gliders to control descent and in large aircraft to control adverse yaw by increasing drag on the lower wing.
Deploying spoilers on both sides of an aircraft do what?
Slow down the plane and reduce ground roll by transferring weight to the wheels and thus increase breaking efficiency.
What do trim systems do?
Used to relieve the pilot of the need to maintain constant pressure on the flight controls and usually consist of controls in the airplane and small hinge devices attached to the trailing edge of one or more of the primary flight control surfaces.
How are trim systems controlled?
Small vertically mounted control wheel controls the trim tab on the elevator causing the plane’s nose to pitch up or down. The pilot usually establishes a desired power setting, pitch attitude, and configuration and then trims the controls to relieve the pressure required on the controls.
