1. LIFT

2. The Airfoil Airfoil Characteristics
Top
Leading edge
Trailing edge
Bottom
Airfoil Characteristics
Rounded Leading Edge – to split the air
Sharp Trailing Edge – to reduce turbulence
Flat Bottom
Declining Top

3. Air Flow Air flow is caused by both:
1. the motion of the wing moving forward and
2. natural wind
The air is split in half where it meets the leading edge
The air recombines at the trailing edge
Air on top of the airfoil moves faster than air on the bottom , but why?

4. Venturi Effect As a fluid (air) is compressed it moves faster
The effect of compressing fluids
As a fluid (air) is compressed it moves faster

5. Air is evenly distributed normally

6. Half a Venturi So the air on top of the air foil moves FASTER
The asymetric shape of the air foil causes the air on top to be compressed while the air on the bottom is hardly moved

7. Why is this important?
Bernoulli’s Principle: The pressure air exerts as it moves decreases as the speed of the air increases

8. The faster I make my airfoil go, the more I decrease the air pressure on top of my airfoil

9. Lift How does this help? Pressure on top and bottom are equal
Aircraft on the ground
Pressure on top is less than pressure on bottom
Aircraft moving forward
Lift

10. Which parts does the pilot control???
Calculating Lift
L = (1/2) d v2 s CL
L = Lift, which must equal the airplane's weight in pounds
d = density of the air. This will change due to altitude. These values can be found in a I.C.A.O. Standard Atmosphere Table.
v = velocity of an aircraft expressed in feet per second
s = the wing area of an aircraft in square feet
CL = Coefficient of lift , which is determined by the type of airfoil and angle of attack.
Which parts does the pilot control???
Velocity (speed) and Density (altitude)

11. How can I use this when flying?
Imagine you are flying and you are having trouble keeping the aircraft from losing altitude.
What should you do?

12. Things to know Lift is always perpendicular to the wing (airfoil)
Ground

13. Things to know
Lift must equal aircraft total weight for aircraft to fly level
Weight exceeds Lift will cause aircraft to descend
Lift exceeds weight will cause aircraft to climb

14. Explore
If you were an aircraft designer how would you design an airfoil for:
A passenger airliner
A fighter

15. What is the Venturi effect?
Memory Check
What is the Venturi effect?

16. Where does the Venturi effect occur on the Airfoil?
Memory Check
Where does the Venturi effect occur on the Airfoil?

17. Memory Check
Describe the sequence of events that leads to lift using a thinking map

18. How lift is created Bernoulli Venturi Aircraft moves forward
Air moves around wing
Air on top compresses
Air on top moves faster
Air pressure on top decreases
Pressure differences create lift