Chapter 5: Aerodynamics of Flight Flashcards
What are the forces that act upon all aircraft in flight ?
Thrust, Drag, Lift, Weight
In straight, level, unaccelerated flight, what forces oppose each other ?
Thrust = Drag, Lift = Weight
If a flight path is not horizontal, how must the 4 force vectors be described ?
Lift, weight, thrust and drag vectors must be broken down into horizontal components.
What is Angle-of-Attack (AOA)
The acute angle between the chord line of the airfoil and the direction of the relative wind.
Describe the relationship between AOA and Airspeed
Inversely Proportional. A large AOA at low airspeeds produces and equal amount of lift at high-airspeeds with low AOA.
Describe Lift as it relates to an aircrafts velocity.
Lift is proportional to the square of the aircrafts velocity. i.e and airplane traveling at 200 knots has 4 times the lift as and airplane traveling at 100 knots.
What is air density affected by ?
Pressure, Temperature, and Humidity.
What forces are affected by air density.
Lift and Drag
Describe air density in terms of temperature and humidity.
Warm air is less dense than cool air and moist air is less dense than dry air.
What is lift-to-drag (L/D) ratio ?
L/D indicates an airfoils efficiency. Amount of lift generated by and airfoil relative to its drag.
Describe AOA relative to lift and airspeed.
A large AOA at Low airspeed generates the same amount of lift at high airspeeds with low AOA.
Name the types of parasitic drag.
Form drag, Interference drag, skin friction drag.
What is form drag ?
The portion of Parasitic drag generated by the aircraft due to its shap and airflow around it.
List three examples of form drag.
engine cowling, antennas, landing gear.
What is interference drag ?
Created by the intersection of airstreams that creates currents, turbulence or restricts smooth airflow. Then most interference drag is observed when two surfaces meet at perpendicular angles.
