How are flaps different than ailerons?
Both flaps are extended or retracted at the same time
How do fowler flaps affect the surface area, camber, and angle of attack?
Fowler flaps increase surface area, camber, and angle of attack
What are the advantages of flaps?
- Increase lift
- Lower stall speed
- Lower takeoff and landing speed
- Shorter landing and takeoff distance
- Easier on landing gear
- Better visibility
- Permits approach with power (less cooling)
What are the disadvantages of flaps?
- Increase induced drag
- Reduce climb performance
- Create momentary sink when retracted
Describe aileron drag
Yawing effect caused by asymmetric drag of aileron drag, causing yaw in direction of the rising wing
Describe the two solutions to aileron drag
Differential aileron: downgoing aileron moves through small angle, reducing drag. Upgoing aileron moves through large angle, increasing drag
Frise aileron: downgoing aileron streamlined into wing, reducing drag. Upgoing aileron nose projects into airflow, increasing drag
What is a trim tab?
Secondary flight control surfaces that are on the edge of larger, primary control surfaces
Describe the two different types of trim tabs
Anti-servo tabs: trim tab for stabilators
Servo tabs: device for moving flight controls on large airplanes
What factors should be considered when climbing?
Visibility, engine temperature, terrain
How should an aircraft be flow to obtain the greatest glide distance?
Aircraft should be flown at maximum load/drag ratio
What factors should be considered when gliding?
Windmilling propeller, effect of wind
Describe the forces acting when an aircraft climbs
Describe the forces acting when an aircraft glides
What is the load factor?
Ratio of load supported to weight of aircraft
What is the load factor in straight and level flight?
What is the load factor when turning?
What is maneuvering speed and how is it relevant to gust loads?
Maneuvering speed is the airspeed limit for an aircraft chosen by the designer. At speeds greater than the maneuvering speed, vertical gusts can cause a sudden increase in the angle of attack which may cause failure of the aircraft
What is a stall?
Decrease in lift caused by angle of attack exceeding the critical angle
Describe washout and how it affects stalling
The wing is designed so that the angle of incidence is greater at the wing roots than the wing tips. This ensures that the root stalls before the tip, providing the aircraft with continued aileron control and resistance to spinning
What are stall strips used for?
Used to improve controllability of an aircraft when it enters stall at a high angle of attack
Describe the relationship between the boundary layer, lift, and drag
The longer the boundary layer adheres to the wing, the greater the lift and the less drag produced
Name ways to increase efficiency by decreasing the interference between the airflow on the underside of the wing and the the airflow on top of the wing
Slots/slats, vortex generators, winglets, drooped wings, wing tip tanks, wing fences
Desribe how vortex generators work
Name a design feature that prevents spanwise flow
How do winglets and drooped wings work?
Winglets reduce drag associated with vortices that develop at wingtips
Drooped wing tips minimize loss of lift from wing tip vortices
How do spoilers affect drag?
Increase drag, slowing an aircraft or making it descend
What flight regime lies between maximum endurance and the stall?