Controls

Question 1

How is aircraft control defined?

Answer 1

The power of the pilot to maneuver the aircraft into any desired position.

Question 2

Name the three axes, the motion about each axis, and the conventional control that governs the motion.

Answer 2

1. Longitudinal axis - Roll - Ailerons
2. Lateral axis - Pitch - Elevators
3. Normal/Vertical axis - Yaw - Rudder

Question 3

What two things change when a flap-type control is operated, increasing or decreasing lift?

Answer 3

1. The camber of the aerofoil
2. The relative angle of attack

Question 4

What two factors affect the moment a control produces when operated?

Answer 4

1. The size of the force produced
2. The distance the force acts from the center of gravity

Question 5

What four factors affect the force a control produces when operated?

Answer 5

1. The density of the air (altitude)
2. The velocity of the aircraft
3. The shape and size of the control
4. The amount the control is deflected

Question 6

What happens if the pilot pulls the stick back?

Answer 6

The elevator moves up, and the aircraft will pitch nose-up.

Question 7

What are the two different ways of achieving boundary layer control?

Answer 7

1. Passive control
2. Active control

Question 8

What do vortex generators add to the boundary layer to delay separation?

Answer 8

Kinetic energy to re-energize the boundary layer airflow.

Question 9

Name three types of boundary layer control.

Answer 9

1. Vortex generators
2. Wing fences
3. Notched or saw-tooth leading edges, suction, or blown air

Question 10

What is flap asymmetry, and why is it dangerous?

Answer 10

Flap asymmetry occurs when one flap moves slower or does not move in relation to the other side, causing uncommanded roll.

Question 11

What are the two methods used to help the pilot overcome high control forces at higher speeds?

Answer 11

1. Aerodynamic balance
2. Power-operated controls

Question 12

What is aircraft trim used for?

Answer 12

To balance forces on the aircraft so the pilot does not need to hold controls continually.

Question 13

What is a variable incidence tailplane used for?

Answer 13

To trim the aircraft in pitch.

Question 14

What is control surface flutter?

Answer 14

The rapid oscillation of a manual control surface due to an out-of-balance force, which can cause fatigue damage and structural failure.

Question 15

What are the two different methods used to overcome aileron adverse yaw?

Answer 15

1. Differential ailerons - The up-going aileron moves more than the down-going aileron to reduce drag.
2. Frise ailerons - The up-going aileron has a beak that increases pressure drag.

Question 16

What is lift proportional to in terms of velocity?

Answer 16

Lift is proportional to the velocity squared.