Principles of Flight

Question 1

What is the name for the initial tendency of an aircraft to develop forces that further remove the aircraft from its original position when disturbed from a condition of steady flight?

Answer 1

Negative static stability

Question 2

During the entry to a right turn, the nose of the aircraft swings to the left before it follows into the right turn. What kind of turn entry is this and how is it corrected?

Answer 2

This is a slipping turn, which is corrected by more right rudder pressure as the turn is initiated.

Question 3

What is the name for the initial tendency of an aircraft to develop forces that return the aircraft from its original position when disturbed from a condition of steady flight?

Answer 3

Positive static stability

Question 4

What kind of oscillations are the result of negative dynamic stability and positive static stability in an aircraft?

Answer 4

divergent oscillations

Question 5

What kind of oscillations are the result of positive dynamic stability and positive static stability in an aircraft?

Answer 5

convergent oscillations

Question 6

What is it called when the aircraft experiences airspeed increases and decreases as it works to maintain a constant angle of attack for a given trim?

Answer 6

Phugoid Oscillations

Question 7

What happens to the vertical component of lift and the sink rate as the angle of bank is increased?

Answer 7

The vertical component of lift decreases and sink rate increases.

Question 8

What is the purpose of wing dihedral angle?

Answer 8

To increase lateral stability.

Question 9

During flight with zero angle of attack what can be said about the pressure along the upper surface of the wing?

Answer 9

It is less than atmospheric pressure.

Question 10

Which is the critical engine on most light multi engine planes with clockwise rotating propellers?

Answer 10

The left engine, because the resultant thrust (due to p-factor) of the running right engine acts with a much greater arm and creates stronger yaw to the left.

Question 11

If the center of gravity of an aircraft is moved from the aft limit to beyond the forward limit, how will it affect the cruising and stalling speed? Why?

Answer 11

The cruising speed will decrease in the stalling speed will increase. The tail has to generate more downward force to balance the heavier nose and the wings must fly at a higher angle of attack to produce more lift to counteract that force.

Question 12

Why do you roll level before recovering from a nose low unusual attitude?

Answer 12

To minimize the increased load factor to just what is needed to raise the nose. Also, to avoid tightening a spiral dive.

Question 13

Why don’t you roll level before recovering from a nose high unusual attitude?

Answer 13

The additional horizontal component of lift helps reduce negative forces on the airframe in the pushover.

Question 14

How is stall speed related to load factor?

Answer 14

Stall speed increases in proportion to the load factor.

Question 15

What kind of oscillations are the result of neutral dynamic stability and positive static stability in an aircraft?

Answer 15

continuous oscillations

Question 16

What kind of a turn produces more centrifugal force than banking force?

Answer 16

A skidding turn.

Question 17

Which wing drops when a cross controlled stall or skidding turn becomes a spin? Why?

Answer 17

The inside wing drops because it is more stalled due to being at a higher angle of attack, blanketed by the fuselage and subject to spanwise flow that further reduces lift.

Question 18

Which wing drops when a slipping turn progresses to a stall? Why?

Answer 18

In a slipping turn, the outside wing is at a higher angle of attack somewhat blanketed by the fuselage, so it stalls first.

Question 19

Explain a slipping turn.

Answer 19

In a slipping turn, not enough rudder is used to counter the adverse yaw created by the lowered elevator and as a result the rate of turn is less than required for the angle of bank. The ball is on the inside of the turn because the centriputal force is greater than the centrifugal force.

Question 20

What is a coordinated turn?

Answer 20

A coordinated turn is one in which the rate of turn is matched to the bank angle, which causes the nose of the aircraft to be directly into the relative wind throughout the turn.

Question 21

How does the inclinometer in a turn coordinator work?

Answer 21

In a coordinated turn, the centripital force (horizontal component of lift) and the centrifugal force are equal which holds the ball balanced in the middle opposite the lift vector. In a slipping turn, the centripital force is greater than the centrifugal force, which pulls the ball to the inside of the turn. In a skidding turn, the centrifugal force is greater than the centripital force, which pulls the ball to the outside of the turn.

Question 22

What are the forces of flight?

Answer 22

Lift, weight, thrust and drag.

Question 23

What is lift?

Answer 23

Lift is the force that acts upward, perpendicular to the relative wind as a result of airflow passing over the wing.

Question 24

What is drag?

Answer 24

Drag is the force that opposes thust. It is generated by the resistance of the aircraft and its parts moving through the air.

Question 25

What is unaccelerated flight?

Answer 25

When lift equals weight and thrust equals drag, the aircraft is in steady flight.

Question 26

What are factors that increase the stall speed?

Answer 26

Increased load factor

Banking

Increased weight

Forward CG loading

Icing

Question 27

What are factors that decrease stall speed?

Answer 27

Flaps

Aft CG

Question 28

Decreasing the weight does what to the stalling speed?

Answer 28

The 1G stalling speed is decreased.

Question 29

Where is the center of lift located?

Answer 29

On training aircraft, aft of the center of gravity, at the theoretical point where all the lifting force is assumed to be concentrated.

Question 30

Angle of Attack is the angle between the wing’s ___________ and the __________.

Answer 30

Chord Line, Relative Wind

Question 31

In straight-and-level, unaccelerated flight, the sum of opposing forces acting on the aircraft is always ___.

Answer 31

Zero

Question 32

If you load an aircraft tail-heavy, the center of gravity (CG) will be aft and the nose will more easily pitch ___ than if it were in a forward loading configuration.

Answer 32

Upward

Question 33

What is ground effect and how does it affect the aircraft?

Answer 33

Ground effect is the range from the ground to 1/2 wingspan height in which induced drag is greatly reduced. It occurs because the wingtip vortices and downwash have something to push directly against.

Question 34

What happens to induced drag and parasite drag as your true airspeed increases?

Answer 34

As you accelerate and your true airspeed increases, the amount of parasite drag will rise exponentially due to increased aircraft interference with the air. However, induced drag decreases because you need a lower angle-of-attack in order to maintain a desired altitude at a higher true airspeed.

Question 35

What are the components of parasite drag?

Answer 35

Skin Friction Drag - caused by everything that is not perfectly smooth about the airplane’s surface

Form Drag - caused by the vertical cross section of the airpane

Interference Drag - caused by mixing airflows at right angles

Question 36

What are the components of total drag?

Answer 36

Parasite drag - increases as the square of the true airspeed

Induced drag - increases with angle of attack and therefore decreases as true airspeed increases

Question 37

As an aircraft’s weight increases, its maneuvering speed (Va) ______.

Answer 37

Increases.

Because a heavy aircraft flies at a higher angle of attack, it will reach the critical angle of attack sooner when a full control input is placed on the aircraft. Because of that, Va increases as the aircraft’s weight increases.

Question 38

As CG moves further aft, what happens to stability?

Answer 38

Less stable

Question 39

What is the load factor of an aircraft in a constant altitude, 60 degree bank turn?

Answer 39

2.0 G