CGI Flight Theory & Principles 2

Question 1

If an airplane's airspeed is doubled while angle of attack remains constant, how does lift change?

Accepted Answer

Lift increases by a factor of four

Answer

Lift varies with the square of velocity, so doubling airspeed quadruples lift.

Question 2

In straight-and-level flight, how does induced drag change as airspeed increases?

Accepted Answer

It decreases because a lower angle of attack is required

Answer

Induced drag varies inversely with the square of airspeed because less angle of attack is needed at higher speeds.

Question 3

At the airspeed for maximum lift-to-drag ratio (L/Dmax), which condition exists?

Accepted Answer

Induced drag equals parasite drag

Answer

Total drag is lowest where the induced and parasite drag curves intersect, which is the L/Dmax point.

Question 4

An airplane enters ground effect during landing. What is the primary aerodynamic result?

Accepted Answer

Induced drag decreases, causing a tendency to float

Answer

Ground effect restricts wingtip vortices and downwash within about one wingspan of the surface, reducing induced drag.

Question 5

Wingtip vortices are strongest when the generating aircraft is:

Accepted Answer

Heavy, clean, and slow

Answer

Vortex strength is greatest at high angles of attack, which occur when an aircraft is heavy, clean, and slow.

CGI - Certified Ground Instructor Practice Test