AA1202 Drag Flashcards
Define parasite drag
“When the windstream encounters an object in its way, the result is a force opposite the motion of the object called parasite drag.
How is parasite drag effected by airspeed
Dp increases with airspeed
How is parasite drag effected by configuring
Dp, while configured, increases faster as airspeed increases than if clean
Define induced drag
The drag caused by the wingtip vortices created when lift is created. (drag due to lift)
How is induced drage effected by AOA
Di increases as AOA increases
How is induced drage effected by airspeed
Di decreases as A/S increases, becauses AOA is low at high speeds
How is induced drage effected by Weight
Di increases as weight increases, because more lift is required
How is induced drage effected by bank angle
Di increases an bank angle increases in level flight because more lift is required
Define total drag
Total drag is the sum of parasite and induced drag.
how does total drag change vs airspeed
Think a parabola or ‘U’ shaped graph. initially at low airspeeds, Dt is high due to high Di. Then Dt decreases at moderate airspeeds as Di decreases with airspeed and Dp is still low. Finally, Dt increases as Dp increases exponentially as airspeed increases.
Given a graph of total drag vs airspeed, how does weight change the graph?
Greater effect at low speeds and little at high speeds. The right side of the graph is affected little while the left is raised. Overall the graph is shifted up and tiltedright
Given a graph of total drag vs airspeed, how does Bank angle
Greater effect at low speeds and little at high speeds. The right side of the graph is affected little while the left is raised. Overall the graph is shifted up and tilted right
Given a graph of total drag vs airspeed, how does configuration
Greater effect at high speeds and less at low speeds. The right side of the graph is raised while the left is only raised slightly. Overall the graph is shifted up and tilted lealeft.
Where does L/D max occur
When total drag is at a minimum in the middle of the graph of Dt vs Airspeed
