The document provides information about aerodynamics and the four main forces that act on airplanes - lift, weight, thrust, and drag. It explains how the shape of an airfoil generates lift using both Bernoulli's principle of fluid dynamics and Newton's third law of equal and opposite reactions. However, it notes that neither theory fully explains lift and some aspects of each theory have flaws. It also discusses other factors that influence lift such as angle of attack.

1. Understanding the Airfoil Mr. Presti Northport Middle School Technology

5. Forces Acting on a Plane

6. Tests the Effects To test the effects of pressure and airspeed, take a regular piece of notebook paper and hold it up like the girl at the left. Blow over it and watch what happens. When you blow across an airfoil you are increasing the speed at which the air moves across the top of the airfoil. This decreases the pressure and causes lift.

7. Straight and Level Flight In order for an airplane to fly straight and level, the following relationships must be true: Thrust = Drag Lift = Weight Q1 - What would happen if Drag is greater than Thrust? Q2 - What would happen if Lift is greater than Weight?

9. A Few Words About Fluid Consequently, neither lift nor drag can be created in space (where there is no fluid). This explains why spacecraft don't have wings unless the spaceship spends at least some of its time in air.

19. Air Plane Parts