1. Theory of Flight All are demonstrated by the flight of the bird!
Objectives
Four forces of flight
Parts of an airfoil
Bernoulli and Newton
Three axis of control
All are demonstrated by the flight of the bird!
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Intro to Flight

2. Four Forces of Flight
Upward force, opposes gravity, supports weight of aircraft
Variable with throttle — pulls an aircraft forward
Artificial
Natural
Artificial
Retards forward movement
Natural
Gravity - constant in level unaccelerated flight,
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Intro to Flight

3. Important Terms
Airfoil – component (such as a wing) designed to produce lift, thrust or directional stability
Wind - air in motion
Relative wind - flow of air opposite flight path of an airplane
Angle of attack – angle formed by the chord line and relative wind
Relative wind
Chord line
Flight Path
Angle of attack -- α
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Intro to Flight

4. Bernoulli’s Theorem (1750)
High speed low pressure
Ping pong ball supported by Bernoulli
Air flowing over paper…
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Intro to Flight

5. Factors affecting Bernoulli’s Induced lift
- Camber
- airspeed,
- angle of attack
Impact, planar Downwash effect (Isaac Newton’s Third Law of Motion 1700)
- Angle of attack
“For every action there is an equal and opposite reaction”
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Intro to Flight

6. Mathematics of Flight Lift = CL x R x (½Velocity)2 x A
Coefficient – a factor that contributes to producing a result
Area of the wing (average chord x wing span)
Coefficient of lift (airfoil design and angle of attack)
Lift = CL x R x (½Velocity)2 x A
Speed (doubling speed provides 4 times lift)
Altitude (density of air)
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Intro to Flight

7. Stall—airflow separation from the wing Caused by high angles of attack
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8. Thrust--Basic Concepts
Internal combustion engines derive power from changing chemical energy into mechanical energy.
A small amount of fuel is burned to produce a large volume of hot gas.
The gas pressure provides mechanical or reactive movement.
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9. Four Stroke Engine
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10. What about Drag?
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11. What about Thrust & Drag
Power Available
(fixed pitch)
400 lbs.
Max Speed 100%
TAS 75% Power
Best Climb Vy
Stall Speed
Airspeed 42 73
134
143
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12. Control Surfaces Right Aileron Rudder Elevator Left Aileron 4/26/2017
Intro to Flight

13. Three Axis of Control A real or imaginary line on which an object rotates
Longitudinal Axis
Lateral Axis
Center of Gravity
Vertical Axis
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14. Balancing the Airplane on the Center of Pressure
Center of Lift (CP) is behind the CG CP CG
Arm
Need for negative lift on the horizontal stabilizer
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15. Defining the Essentials
Arm
Arm
Weight
Weight
Fulcrum
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Intro to Flight 15 15

16. Aircraft Stability CP – Center of Pressure (Lift)
- Lift moves CG aft
CG – Center of Gravity
Determine
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Intro to Flight

17. Important Terms — A new Language
aerodynamics - the forces of air in motion
aeronautics - science of flight in the atmosphere
aerospace - combination of aeronautics and space
AGL - Above Ground Level MSL – Mean Sea Level
air - mixture of gases 79% N, 19% O and 2% other
aircraft - machine capable of flying through the air.
airplane - kept aloft by aerodynamic forces on wings and is thrust
airfoil - component, such as a wing designed to produce lift, thrust or directional stability
aviation - art, science & technology of flight in the atmosphere
aviator -person operates aircraft during flight
camber -curved part of an airfoil (leading to the trailing edge)
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Intro to Flight

18. Important Terms chord - line drawn from leading to its trailing edge
drag - force retards forward movement of an aircraft in flight
downwash- downward movement of air behind the wing
leading edge -the front part of an airfoil
lift - upward force, opposes gravity, supports weight of aircraft
relative wind - flow of air opposite flight path of an airplane
static - standing still, or without motion
supersonic - faster than the speed of sound.
Subsonic is below the speed of sound
thrust - the force which moves an aircraft forward in flight
trailing edge - the back part of an airfoil
wind - air in motion
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Intro to Flight