## CFI Brief: Aerodynamics Questions

To control yaw! I know you have been anxiously awaiting the answer to last week’s teaser question, and there it is: answer A. The purpose of the rudder is to control yaw about the vertical axis of the aircraft. As promised here are a few more questions to test your knowledge of the information presented over the last few weeks.

1. When do the four forces that act on an airplane in equilibrium?
A—During un-accelerated flight.
B—When the aircraft is accelerating.
C—When the aircraft is at rest on the ground.

2. What is the relationship of lift, drag, thrust, and weight when the airplane is in straight-and-level flight?
A—Lift equals weight and thrust equals drag.
B—Lift, drag, and weight equal thrust.
C—Lift and weight equal thrust and drag.

This next question is a little bit tougher and deals with Bernoulli’s Principle—this may be a term you are not yet familiar with but I encourage you to do some research and studying to gain insight into Mr. Bernoulli. You can find this information on page 2-1 of The Student Pilot’s Flight Manual by William Kershner.

3. Which statement relates to Bernoulli’s principle?
A—For every action there is an equal and opposite reaction.
B—An additional upward force is generated as the lower surface of the wing deflects air downward.
C—Air traveling faster over the curved upper surface of an airfoil causes lower pressure on the top surface.

Good Luck! Answers will be posted on Monday.