Aerodynamics Flashcards
(21 cards)
What are the 4 forces of flight?
lift
weight
thrust
drag
What force causes a plane to turn?
horizontal component of lift
What are the two types of drag?
Induced - caused by the production of lift
Parasitic - caused by the non lift producing parts of an aircraft (fuselage)
angle of attack
angle between chord line and relative wind
Bernoulli’s Principle
air which is moving faster will have lower pressure, and air which is moving slower will have higher pressure.
what angle of attack does a stall occur
critical angle
at higher airspeed, what happens to critical angle
remains the same
static stability
the tendency of an airplane to return to its original flight attitude when it is disturbed.
An airplane that has positive static stability tends to return to its original attitude.
An airplane which has neutral static stability tends to stay in the new attitude.
An airplane with negative static stability tends to move further away from the original attitude.
dynamic stability
the tendency of an airplane, over time, to oscillate.
Positive dynamic stability - oscillations lessen over time
Negative dynamic stability - oscillations increase over time
What is the relationship between stability and maneuverability?
Airplanes which are more stable
tend to be less maneuverable
what effects longitudinal stability?
pitch
location of center of gravity relative to center of lift
lateral stability
roll
dihedral wings increase stability
directional stability
yaw
forward CG increases directional stability
torque effect
the airplane wants to rotate (bank) opposite the propeller rotation, to
the left.
spiraling slipstream
the spin of the prop causes airflow to spiral around fuselage and push on the left side of the vertical tail, causing a left yaw
P-Factor
higher angles of attack the downward (right) blade takes a bigger “bite” of air than the left. Causes left yaw.
Gyroscopic Precession
When a force is applied to a gyro, the effect is applied 90 degrees later in rotation.
When pitching down, causes left yaw.
ground effect
ground surface interferes with the airflow patterns about the aircraft, reducing drag and increasing lift.
Happens within one wingspan from the ground
adverse yaw
the tendency of an airplane to yaw (turn the nose) in the opposite direction of a roll, specifically when banking into a turn
adverse yaw
tendency of an aircraft to yaw in the opposite direction of a turn, due to the wing with more lift (aileron down) having higher drag
How does the 172R design reduce adverse yaw
Frise Ailerons: leading edge of aileron dips down into airflow when raised, increasing drag
Differential Ailerons: ailerons deflect more upward than downward, increasing drag
