Class One - Aerodynamics Flashcards
Empennage
vertical and horizontal stabilizers in the back
Wings
creates lift
Fuselage
Pilot, crew and baggage
Power plant
engine in front (or on wings)
Landing gear
normally fixed wheels
Roll Motion
On longitudinal axis, stabilized by wings, controlled by Aileron, pilot control is twisting yoke left or right
Pitch Motion
On lateral axis, stabilized by horizontal stabilizer, controlled by elevator, pilot control is pushing or pulling yoke forward or back
Yaw Motion
On vertical axis, stabilized by vertical stabilizer, controlled by elevator, pilot control is rudder peddals
Aileron
Moves plane on its longitudinal axis. Controls the wings by twisting the yoke left and right for a roll motion
Elevator
Moves plane on its lateral axis. Controls the horizontal stabilizer by moving the yoke forward and back for a pitch motion
Rudders
Moves plane on its vertical axis. Control the vertical stabilizer with the rudder pedals for a yaw motion
Lift
Upper chamber has more curvature and makes air have more distance to travel, causing velocity of the air to move faster, lower pressure. Lower chamber causes air to move slower, higher pressure. Air flows from high pressure to low pressure, creating lift
Chord Line
Imaginary line connecting the leading edge to the training edge of the wing
Angle of attack
Angle between the chord line and the relative wind (airflow hitting the wing)
Airfoil design
shape of wing that creates lift
Newton’s first law of motion
every object will remain uniform unless acted upon by external force (airplane will move when force is applied to)
Newton’s second law of motion
Force equals the mass times the acceleration. The acceleration rate of an object is directly proportional to the applied force and inversely proportional to its inverse mass (more force applied = more acceleration)
Newton’s third law of motion
For every action there is an equal and opposite reaction (thrust, p factors - left turning tendencies)
Bernoulli’s Principle
What happens to air passing over the curved top of a wing. As velocity of a moving fluid increases, pressure within the fluid decreases.
Four fundamentals of maneuvering a plane
Straight and level flight, turns, climbs and descents
Thrust
Power that pulls the plane forward with the airfoil shape of the propeller, while the aircraft engine provides that power.
Drag
the force that resists the movement of an airplane through the air
Parasite Drag
Drag that is not associated with the production of lift. It increases as the square of the airspeed. Comprised if forces that slow aircraft movement (wing struts, anything that sticks up)
Induced Drag
Drag caused by the same factors that produce lift; its amount varies inversely with airspeed. As airspeed decreases, the angle of attack must increase.
Form Drag
Anything sticking out into the air stream, obstructing airflow (Wheels, antennas, rivets)
Interference Drag
Comes from the intersection of air streams that cause eddy currents, turbulence, or restricts smooth airflow (intersection of the wing and the fuselage)
Skin Friction Drag
Aerodynamic resistance due to the contact of moving air with the surface of the aircraft
Lift to Drag Ratio
the amount of lift generated by an airfoil compared to its drag, showing airfoil efficiency. (aircrafts with higher L/D ratios are more efficient than those with lower)
Drag curve
As speed increases, parasitic drag increases; and as speed decreases, induced drag increases.
Weight
the downward force on the airplane, caused by gravity which opposes lift. It is the combined load of the aircraft itself, crew, fuel, cargo and baggage.
Wingtip Vortices
air that sneaks from underneath the wing where the pressure is high, to the top where the pressure is low, causing a spiral of air trailing off the wingtips that moves outward, upward and inward, trailing behind the wing.
Wake Turbulence
the hazardous aspects of wingtip vortices. The intensity of the vortex is a function of the aircraft size, speed and configuration (flap setting). Strongest vortices are produced by heavy aircraft flying slowly with wing flaps and landing gear retracted (Heavy, slow, clean)
Ground Effect
area above the ground where the aircraft experiences an improvement in performance (wingspan length of the surface)
What are greatly reduced because of ground and water interference?
Wingtip vortices, up-wash and downwash
Ground effect is simply a reduction of induced drag because…
as the aircraft comes within a wingspan length of the surface, there is a change in the 3 dimensional airflow of the aircraft because the vertical component of airflow is restricted by the surface
Stalls
rapid decrease in lift caused by separation of airflow from the wing surface by exceeding the critical angle of attack
True or false: A stall can occur at any pitch attitude or airspeed
True
True or false: In a stall, the wing completely stops producing lift
False. In a stall, the wing does not totally stop producing lift. Rather it cannot generate adequate lift to sustain level flight
True or false: A given aircraft always stalls at the same Angle of Attack (AOA) regardless of airspeed, weight, load factor or density altitude.
True. The stalling speed of an aircraft is not a fixed vale for all flight situations.
The critical AOA varies from what degree when a stall occurs?
16-20 degrees depending on the aircraft’s design. Up to 22 degrees
The critical AOA can be exceeded in what three flight situations?
Low speed, high speed and turning
Low Speed Stalls
Practice stalls (approach to landing stall or power off stall). The lower the airspeed becomes, the more the Angle of attack must be increased. AOA must be increased to retain the lift required for maintaining altitude.
High Speed Stalls
Aircraft is in dive (accelerated stall). AOA changes abruptly from low to very high.
Turning Stall
Centrifugal force is added to planes’ weight and the wing must produce additional lift to counterbalance the load.
FAA test question: In regards to privileges and limitations, private pilots may…
not pay less than the pro rata share of operating expenses of a flight
FAA Test question: During a spin to the left, which wing(s) is/are stalled?
Both wings are stalled
Maneuverability
The quality of an aircraft that permits it to be maneuvered easily and to withstand the stresses that are imposed on it.
Controllability
The capability of an aircraft to respond to the pilots controls especially in regards to flightpath and aircraft attitude.
Left turning tendencies are caused by:
- Torque reaction from the engine and propeller
- Corkscrewing effect of the slipstream
- Asymmetric loading of the propeller (P-factor)
Torque reaction
Causes an additional turning moment around the vertical axis, forcing the left side of an aircraft down and placing more weight on the left main landing gear. This yawing moment on the takeoff roll is corrected by the right rudder.
Corkscrew effect (slipstream effect)
The wind blown back by the propeller spirals around the airplane and strikes the left side of the vertical stabilizer, causing the tail to swing right and the nose to yaw left.
Asymmetric loading (P-Factor)
When a plane is flying at a high Angle of attack, the downward moving blade has a higher resultant velocity. This creates more lift than the upward moving blade, moving the center of thrust to the right of the prop disc area, and causing a yawing moment toward the left around the vertical axis.
Rate of turn
amount of time to complete a turn. Same airspeed and angle of bank, rate is a constant. Airspeed increases and rate is constant, the rate or turn will increase.
Radius of turn
amount of horizontal distance required to complete a turn. Increase in airspeed results in an increase in the radius of the turn. Increase in the angle of the bank results in a decrease in the radius of the turn.
