Download Basic Aeronautics

Basic Aeronautics
Know the principles of basic aeronautics.
1. Describe the effects of angle of attack.
2. Identify the four forces of flight.
Review
Newton’s Three Laws:
1. A body at rest tends to remain at rest, and a body in motion tends to stay in motion,
unless an outside force acts on the body.
2. Force = Mass x Acceleration.
3. For every action there is an equal and opposite reaction.
The Four Forces of Flight
• Increase velocity of air around an airfoil shape = increases
the relative wind as it flows above and below the surface of
the airplane wing.
Angle of Attack
• Formed by the cord of the
airfoil and the direction of the
relative wind or between the
chord line and the flight path.
• Is not constant during a flight.
It changes as the pilot changes
the attitude of the aircraft.
The Four Forces of Flight
• Angle of Attack
The Four Forces of Flight
• Angle of Attack

The angle at which lift stops increasing and
begins to decrease is called the burble point.
The Four Forces of Flight
• Angle of Attack

The point at which the amount of lift generated is no longer sufficient
to support the aircraft in air is called the stalling point.
The Four Forces of Flight
• Lift can be increased in two ways
 Increasing the forward speed of the
airplane.
 Increasing the angle of attack.
• The pilot can increase the forward speed
of the aircraft by applying more power.
The Four Forces of Flight
• Lift Variables
 Atmosphere
 Airfoil Shape
 Wing Area
 Weight
 Thrust and Drag
The Four Forces of Flight
• Air Density and Lift
 Lift varies directly with air
density. At 18,000 feet air
density is about half that at sea
level. At that altitude an
aircraft will need to fly faster
maintain altitude.
•
Lift Variables
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Atmosphere
Airfoil Shape
Wing Area
Weight
Thrust and Drag
The Four Forces of Flight
• Airfoil Shape
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•
It is extremely important to preserve
the characteristic curve that the
designers built into the airfoil.
Dents, mud, and ice are three
common things that can spoil the
built-in shape of the airfoil and
interfere with the performance of
the entire aircraft.
Lift Variables
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
Atmosphere
Airfoil Shape
Wing Area
Weight
Thrust and Drag
The Four Forces of Flight
• Wing Area and Lift
 The greater the surface area of
the wing, the greater the
amount of lift that will be
generated.
 Gliders and sailplanes are very
good examples of how a large
wing surface generates lift.
•
Lift Variables





Atmosphere
Airfoil Shape
Wing Area
Weight
Thrust and Drag
The Four Forces of Flight
• Weight
 There is a point where lift can no longer
overcome weight.
 The airplane must be constructed of the
lightest weight materials that can be used.
 The weight of whatever the airplane carries
also receives very careful consideration.
•
Lift Variables

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
Atmosphere
Airfoil Shape
Wing Area
Weight
Thrust and Drag
The Four Forces of Flight
• Weight
 Where the weight, or useful
load, is placed in the airplane
is another factor that has a
pronounced effect on how well
an airplane will fly.
•
Lift Variables





Atmosphere
Airfoil Shape
Wing Area
Weight
Thrust and Drag
The Four Forces of Flight
• Thrust and Drag
 Thrust is the force that propels the aircraft forward.
 An airplane cannot gain altitude or maintain straight and level flight
unless its engine is producing enough thrust.
 Without the needed thrust, weight has more influence than lift and
pulls the airplane toward the ground.
•
Lift Variables





Atmosphere
Airfoil Shape
Wing Area
Weight
Thrust and Drag
The Four Forces of Flight
• Thrust and Drag
 Drag is present all the time and can be defined as the force that opposes
thrust.
 The friction of air particles rubbing against all parts of the airplane
causes part of the total drag.
 The shape of something may create low-pressure areas and turbulence
that retard the forward movement of the aircraft.
•
Lift Variables





Atmosphere
Airfoil Shape
Wing Area
Weight
Thrust and Drag
Summary
1. Angle of Attack
2. The Four Forces of Flight