CH. 3 A Aerodynamic Principles (VOCAB) Flashcards
LIFT
The upward force created by the effect of airflow over and under the wing
WEIGHT
Downward pull of gravity
THRUST
Force which propels airplane forward
DRAG
Backward, or retarding, force which limits the speed of the airplane
VECTORS
Arrows that show the force acting on an airplane
NEWTON’S 3 LAWS OF MOTION
- Newton’s first law states that a body in rest tends to remain at rest, and a body in motion tends to remain moving at the same speed and in the same direction
- Newton’s second law states that when a body is acted upon by a constant force, its resulting acceleration is inversely proportional to the mass of the body and is directly proportional to the applied force. force= mass x acceleration (F=ma)
- Newton’s third law states that for every action there is an equal and opposite reaction
BERNOULLI’S PRINCIPLE
Bernoulli’s principle states that as the velocity of a fluid (air) increases, its internal pressure decreases
AIRFOIL
Any surface, such as a wing, which provides aerodynamic force when it interacts with moving stream of air
LEADING EDGE
The front of the wing
TRAILING EDGE
The back of the wing
UPWASH
The deflection of the oncoming airstream upward and over the wing
DOWNWASH
The downward deflection of the airstream as it passes over the wing and past the trailing edge
ANGLE OF ATTACK
The angle formed by the wing chord line and relative wind
WHAT ARE THE FOUR FORCES ACTING ON AN AIRPLANE IN FLIGHT?
Lift, weight, thrust & drag
WHAT IS UNACCELERATED FLIGHT?
Straight-and-level flight when lift=weight & thrust=drag
VENTURI
[picture]
RELATIVE WIND
The airflow which is parallel to and opposite the flight path of an airplane
COEFFICIENT OF LIFT
(CL) A way to measure lift as it relates to angle of attack. Every airplane has an angle of attack maximum lift occurs
What causes a stall?
Caused by the separation of airflow from the wing’s upper surface. A stall always occurs at the same angle, regardless of airspeed, flight attitude, or weight
CRITICAL ANGLE OF ATTACK
Angle at which the plane will stall
BOUNDARY LAYER / TYPES
Thin layer of air above the wing’s surface showing the a reduction in speed to air’s viscosity or stickiness
Laminar Boundary Layer - smooth air
Turbulent Boundary Layer - turbulent air
ASPECT RATIO
Aspect Ratio=Span/Average Chord
PLANFORM
Overhead view of an aircraft
2 TYPES OF DRAG
- Parasite Drag
beings at forward movement
(form drag)-shape effect
(interference drag)-protruding objects causing interference
(skin friction drag)-speed=more friction slow=less friction - Induced Drag
begins at lift
reduce angle of attack, reduce lift, reduce induced drag
byproduct of lift bc of the rearward component of lift
Va
Maneuvering speed - is the speed is at which full and abrupt controlled movements can be imputed and the airplane will stall before it will reach its maximum structural limits
LD MAX
Maximum Lift / Minimum Drag (point where induced drag and parasite drag meet on the drag curve) = resulting in best glide
WHAT PRODUCES INDUCED DRAG?
Induced drag is the rearward component of lift caused by the downwash & wing tip vortices
WHAT IS CONFIGURATION?
The position of the landing gear and flaps
VASI / PAPI
Visual approach slope indicator
Precision approach path indicator
DISPLACED THRESHOLD
NOBODY IS ALLOWED to land in the displaced threshhold Must land on the runway (past the cheverons - begins at the white line- touchdown zone)
YOU CAN taxi and begin roll in displaced threshold
STANDARD TRAFFIC PATTERN
Left pattern
NONSTANDARD TRAFFIC PATTERN
Right pattern
GROUND EFFECT
Associated with the reduction of induced drag.
Disruption of three-dimensional airflow pattern around plane causing a reduction in wingtip in wingtip vortices and a decrease in upwash and downwash.
RELATIONSHIP BTWN GROUND EFFECT AND INDUCED DRAG
In ground effect, induced drag is decreased and excess speed in the flare may cause floating when the plane is within one wingspan above the ground
STABILITY
The characteristic of a plane in flight that causes it to return to a condition of equilibrium, or steady flight, after it is disturbed
POSITIVE STATIC STABILITY
The initial tendency to return to the position from which it was displaced
POSITIVE DYNAMIC STABILITY
The period of time through a series of successivley smaller oscillations the aircraft displays
THREE AXES OF FLIGHT
Longitudinal (roll / ailerons)
Lateral (pitch / elevator)
Vertical (yaw / rudder)
CENTER OF GRAVITY (CG)
The theoretical point where the entire weight of the airplane is considered to be concentrated
CENTER OF PRESSURE
The point along the chord line where lift is considered to be concentrated aka Center of Lift
CG RANGE
The distance btwn the forward and aft limits for the position of the CG
UNACCELERATED FLIGHT
The four forces are in equilibrium
The airplane’s wing’s shape is designed to take advantage of which principle(s)?
Newton’s law and Bernoulli’s principle
Identify three methods you can use to control lift during flight
Lift is controlled by airspeed, changing angle of attack or flaps
Will the wing’s angle of attack increase or decrease when trailing edge flaps are lowered?
Increase
Is it more desirable for the wing root or wingtips to stall first and why?
Wing root - If wingtips stall before the root, the disrupted airflow near the wingtip can reduce aileron effectiveness to such an extent that it may be impossible to control the airplane about tits longitudinal axis
Explain why induced drag increases as airspeed decreases
Induced drag is caused by the downwash created by wingtip vortices formed when the wing is generating lift. As the air pressure differential between the upper and lower surfaces of the wing becomes greater with an increase in angle of attack. stronger vortices form and induced drag is increased. Since the wing is usually at a a low angle of attack at high speeds, and a high angle of attack at low speeds, a relationship between induced drag and speed can be determined. induced drag is inversely proportional to the square of the speed
The reduction in the induced drag due to ground effect is most noticeable when the airplane is within what distance from the earth’s surface?
One wingspan
