Lesson 9 Principles of Flight Flashcards
The _______ around an airfoil is the primary source of lift.
pressure differential
Bernoulli’s Principle
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
Newton’s Third Law of Motion
“For every action, there is an equal and opposite reaction”
secondary source of lift
A ________ of lift is an upward force generated by air striking the underside of an airfoil and being deflected downward.
secondary source
The ________ for an aircraft in flight flows in a direction parallel with and opposite to the direction of flight.
Relative Wind
Name the Three Principle Airfoils that produce lift:
- Wing
- Horizontal tail surface
- Propeller
Name the parts of an Airfoil:
- Leading edge
- Chord Line
- Trailing Edge
________ is the imaginary straight line drawn from the leading edge to the trailing edge of a cross section of an airfoil.
Chord Line
The _______ is the acute angle formed between the chord line of an airfoil and the direction of the air striking the airfoil. (relative wind)
Angle of Attack
The ______ is the curvature of the airfoil from the leading edge to the trailing edge.
Camber
Wing Planform
shape or form of a wing as viewed from above
Name the Four Forces affecting Flight.
- 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)
Name the Three key properties of the atmosphere that affect air density and a/c performace:
- Temperature
- Altitude
- Water Vapor (Humidity)
Lapse Rate
decrease in temperature with height
Does pressure increase or decrease with height?
Decrease
Name the Three different types of propellers:
- 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)
Name the Three Axes of Rotation of an Aircraft:
- Longitudinal (roll)
- Lateral (pitch)
- Vertical (yaw)
Name the primary control surfaces, what axis and what they control:
- Ailerons: Longitudinal, Controls Roll
- Elevator: Lateral, Controls Pitch
- Rudder: Vertical, Controls Yaw
_______ are small, adjustable, hinged surfaces on the trailing edge of the primary control surfaces.
Trim Tabs
The purpose of _____ is to lessen the manual pressure the pilot must apply to the control surfaces.
trim tabs
_____ are located inboard on the wing’s training edge and are used to increase lift.
Flaps
What happens when you extend flaps?
- Lift Increases
- Drag Increases
- Lowers stall speed
- Allows for steeper approach to runway without increased speed
The extension of flaps causes an increase in ______ .
Drag
Lift is provided by _____ on helicopters.
rotor blades
The collective controls the _____ of the rotor blade (angle of attack).
PITCH
The function of the ______ is to regulate the Revolutions Per Minute (RPMs).
Throttle
The ______ controls the tilt of the rotor blade which controls the direction of flight.
cyclic
Autorotation
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)
A ______ occurs when the airfoil reaches a “critical angle of attack”, which is approximately ___ to ___ degrees on most airfoils.
Stall; 15; 20
Name the Three Primary causes of stalls:
- Insufficient airspeed
- Excessively Violent Flight Maneuvers
- Severe wind shear
Name the Three Primary Types of Icing:
- Structural Icing
- Pitot-static system Icing
- Carburetor Icing
______ changes the shape of the airfoil, reducing lift and adding weight.
Structural Icing
When ________ occurs, the airspeed indicator becomes unreliable.
pitot tube icing
When ________occurs, all three instruments are affected, e.g., airspeed, vertical speed indicator, and altimeter.
static vent icing
____________ 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.
Carburetor Icing
Aircraft system failures may occur due to: (5)
- electrical failures
- mechanical failures
- hydraulic failure
- engine failure
- engine fire
