Lesson 9 Principles of Flight

Question 0

The _______ around an airfoil is the primary source of lift.

Answer 0

pressure differential

Question 1

Bernoulli’s Principle

Answer 1

states “the internal pressure of a fluid decreases at points where the speed of the fluid increases”; i.e. as speed increases thru a smaller area, pressure decreases

Question 2

Newton’s Third Law of Motion

Answer 2

“For every action, there is an equal and opposite reaction”

secondary source of lift

Question 3

A ________ of lift is an upward force generated by air striking the underside of an airfoil and being deflected downward.

Answer 3

secondary source

Question 4

The ________ for an aircraft in flight flows in a direction parallel with and opposite to the direction of flight.

Answer 4

Relative Wind

Question 5

Name the Three Principle Airfoils that produce lift:

Answer 5

• Wing
• Horizontal tail surface
• Propeller

Question 6

Name the parts of an Airfoil:

Answer 6

• Leading edge
• Chord Line
• Trailing Edge

Question 7

________ is the imaginary straight line drawn from the leading edge to the trailing edge of a cross section of an airfoil.

Answer 7

Chord Line

Question 8

The _______ is the acute angle formed between the chord line of an airfoil and the direction of the air striking the airfoil. (relative wind)

Answer 8

Angle of Attack

Question 9

The ______ is the curvature of the airfoil from the leading edge to the trailing edge.

Answer 9

Camber

Question 10

Wing Planform

Answer 10

shape or form of a wing as viewed from above

Question 11

Name the Four Forces affecting Flight.

Answer 11

• Lift (upward force)
• Weight (downward force)
• Thrust (manmade force that pulls or pushes a/c thru the air)
• Drag (rearward acting force which resists the forward movement)

Question 12

Name the Three key properties of the atmosphere that affect air density and a/c performace:

Answer 12

• Temperature
• Altitude
• Water Vapor (Humidity)

Question 13

Lapse Rate

Answer 13

decrease in temperature with height

Question 14

Does pressure increase or decrease with height?

Answer 14

Decrease

Question 15

Name the Three different types of propellers:

Answer 15

• Adjustable Pitch (pitch of blades adjusted before flight when a/c is on ground not running)
• Fixed Pitch (cannot be adjusted)
• Controllable Pitch (pitch is automatically varied in flight by a governor)

Question 16

Name the Three Axes of Rotation of an Aircraft:

Answer 16

• Longitudinal (roll)
• Lateral (pitch)
• Vertical (yaw)

Question 17

Name the primary control surfaces, what axis and what they control:

Answer 17

• Ailerons: Longitudinal, Controls Roll
• Elevator: Lateral, Controls Pitch
• Rudder: Vertical, Controls Yaw

Question 18

_______ are small, adjustable, hinged surfaces on the trailing edge of the primary control surfaces.

Answer 18

Trim Tabs

Question 19

The purpose of _____ is to lessen the manual pressure the pilot must apply to the control surfaces.

Answer 19

trim tabs

Question 20

_____ are located inboard on the wing’s training edge and are used to increase lift.

Answer 20

Flaps

Question 21

What happens when you extend flaps?

Answer 21

• Lift Increases
• Drag Increases
• Lowers stall speed
• Allows for steeper approach to runway without increased speed

Question 22

The extension of flaps causes an increase in ______ .

Answer 22

Drag

Question 23

Lift is provided by _____ on helicopters.

Answer 23

rotor blades

Question 24

The collective controls the _____ of the rotor blade (angle of attack).

Answer 24

PITCH

Question 25

The function of the ______ is to regulate the Revolutions Per Minute (RPMs).

Answer 25

Throttle

Question 26

The ______ controls the tilt of the rotor blade which controls the direction of flight.

Answer 26

cyclic

Question 27

Autorotation

Answer 27

the state of flight where the main rotor system is being turned by the action of relative wind rather than engine power
(allows copter to make a controlled landing when the engine is no longer providing power)

Question 28

A ______ occurs when the airfoil reaches a “critical angle of attack”, which is approximately ___ to ___ degrees on most airfoils.

Answer 28

Stall; 15; 20

Question 29

Name the Three Primary causes of stalls:

Answer 29

• Insufficient airspeed
• Excessively Violent Flight Maneuvers
• Severe wind shear

Question 30

Name the Three Primary Types of Icing:

Answer 30

• Structural Icing
• Pitot-static system Icing
• Carburetor Icing

Question 31

______ changes the shape of the airfoil, reducing lift and adding weight.

Answer 31

Structural Icing

Question 32

When ________ occurs, the airspeed indicator becomes unreliable.

Answer 32

pitot tube icing

Question 33

When ________occurs, all three instruments are affected, e.g., airspeed, vertical speed indicator, and altimeter.

Answer 33

static vent icing

Question 34

____________ reduces the fuel/air flow to the engine. Can cause complete engine failure and occurs most often between 20-70 degrees F under conditions of high humidity.

Answer 34

Carburetor Icing

Question 35

Aircraft system failures may occur due to: (5)

Answer 35

• electrical failures
• mechanical failures
• hydraulic failure
• engine failure
• engine fire