Aerodynamics Flashcards
What are the four forces that act on an airplane?
Lift, Weight, Drag and Thrust.
What flight condition will result in the sum of the opposing forces to be equal?
In steady-state, straight and level flight, unaccelerated flight. Can be climbing or descending as well.
What is an airfoil?
A device designed to create lift.
What is the angle of incidence?
The angle formed by the longitudinal axis of the airplane and the chord of the wing. It is fixed and cannot be changed.
What is “Relative Wind”?
The direction of airflow with respect to the wing. When a wing moves forward and downward, the wind moves backward and upward. The flight path and relative wind are parallel but in opposite directions.
What is the “angle of attack”?
The angle between the chord line and the direction of relative wind.
What is “Bernouli’s Principle”?
As velocity of fluid increases, pressure decreases. Velocity of airflow above wing is higher than below the wing, therefore it is more pressure under the wing creating lift.
What are several factors that will affect lift and drag?
Wing area, Shape of the Airfoil, Angle of Attack, Velocity of Air and Air Density.
What is “torque effect”?
Based on Newtons 3rd Law, for every action there is an equal and opposite reaction. Propeller is rotating in one direction, causing airplane to roll in the opposite.
How does torque effect affect the airplane on the ground and in the air?
On the ground it makes the plane turn to the left. In the air it makes the plane roll to the left.
What are the four left turning tendencies?
Torque, Gyroscopic Pressecion, Spiral Slipstream and P-Factor.
What is “load factor”?
The ratio of total load supported by the wings to the actual weight and it’s contents. High load factor means stalling at lower airspeeds.
What causes an airplane to stall?
Excessive angle of attack. Airflow separates from the upper surface of airfoil, resulting in loss of lift.
What causes “adverse yaw”?
When making a turn, the wing that is up and higher produces more lift than the other wing, resulting in more drag produced which causes a yawing motion in the opposite direction of the turn.
What is ground effect?
A condition of improved performance when an airplane operates near the ground.
