Gleim: Airplanes and Aerodynamics Flashcards
Three Primary flight controls of an airplane are?
Aileron, Elevator (or stabilator) and Rudder.
Secondary Flight controls may consist of ?
Wing flaps, Leading edge devices, Spoilers, and Trim systems.
FLAPS are
Flaps are attached to the trailing edge of the wing and are used during approach and landing to increase wing lift, which allows an increase in the angle of descent without increasing air speed.
Spoilers are:
High drag devices deployed from the wings to reduce lift and increase drag.( found on gliders and high speed aircrafts)
Trim systems
Trim systems are used to relieve the pilot of the need to maintain constant pressure on the flight controls. These include Trim tabs, Antiservo tabs, and Ground adjustable tabs.
Four aerodynamic forces acting on an airplane during flight are ?
Lift: upward acting force
Weight: downward acting force
Thrust: Forward acting force
Drag: rearward acting force
These forces are in equilibrium when the airplane is in unaccelerated flight.
Bernoullis Principle
States that “the internal pressure of a fluid (liquid or gas) decreases at points where the speed of the fluid increases” i.e high speed air flow is associated with low pressure. low speed flow is associated with high pressure. Therefore pressure above wing is lower than pressure below. this generates lift over the upper curved surface of the wing.
What is the angle of attack?
The angle between the wing chord line and the direction of the relative wind.
The critical angle of attack is?
A wing stalls remains constant regardless of weight, airplane loading airspeed etc.
How can an airplane stall?
- An airplane can be stalled in any airspeed in any flight attitude.
- An airplane in a given configuration will stall at the same indicated airspeed regardless of altitude because airspeed indicator is directly related to air density.
- An airplane spins when one wing is less stalled than the other wing. - to enter s spin, an airplane must always be stalled first.
How does Frost form?
Frost forms when the temperature of the collecting surface is at or below the dew point of the adjacent air and the dew point is below freezing.
The water vapour changes it’s physical state through deposition and immediately forms as ice crystals on the wing surface.
How does frost affect airflow?
Frost disrupts the smooth airflow over the airfoil by causing early airflow seperation from the wing. This decreases lift and causes friction and increases drag.
a. Frost may make it difficult or impossible for an airplane to take off
b. frost should be removed before attempting to take off.
What is ground effect?
Ground effect is the interference of ground (or water)surface with the airflow patterns about an airplane.
2. The vertical component of the airflow around the wing is restricted, which alters the wings upwash, downwash and wingtip vortices.
3. An airplane is affected by ground effect when it is within the length of the airplanes wing span above the ground.
4. It may cause an airplane to float on landings or permit it to become airborne with insufficient airspeed to stay in flight above the area of ground effect.
What happens to an airplane when power is reduced?
Airplanes except t-tail normally pitch down when power is reduced(and controls are not adjusted)because the downwash on the elevators from the propeller slipstream is reduced and elevator effectiveness is reduced. This allows the nose to drop.
What happens when the CG in an airplane is located at or rear of the CG limit ?
Develops an inability to recover from stall conditions and becomes less stable at all airspeeds
