# 5-18 Aerodynamics

### Lesson List

 Aerodynamics   Birds and airplanes fly even though they are heavier than air.  This is accomplished because of aerodynamics.  Aerodynamics examines the forces of lift, thrust, weight, and drag.  These four forces affect every surface that moves through the air.  A bird is aerodynamically designed.  Its curved, feathered wings create lift.   Its streamlined shape allows it to move through the air with very little resistance.     Engineers who study aerodynamics, try to design airplanes the same way.  They create a shape and design that allows for maximum speed and lift, while minimizing the effects of drag.   Drag occurs when objects are not streamlined.    The curved shape of the wing of a bird or an airplane is called an airfoil.  As an airfoil moves through the air, the air over the rounded surface must travel faster than the air along the flat surface.  This quicker movement of air over the top of an airfoil creates a low-pressure area above the airfoil and a high-pressure area below the airfoil.  This difference in pressure causes the wing to lift.  Gliders and helicopters and all winged aircraft use airfoils to create lift.   Thrust is necessary to lift heavier-than-air machines into the air.   Engines generate a force strong enough to create sufficient lift to overcome the weight of the aircraft.

 Answer the questions below 1. The shape of a bird allows it to fly even though it is heavier than air. 2. Engineers create a shape and design that allows for speed and lift, while minimizing the effects of drag. 3. occurs when objects are not streamlined. 4. The curved shape of the wing of a bird or an airplane is called an . 5. The difference in the air pressure above and below the airfoil causes . 6. Gliders, , and all winged aircraft use airfoils to cause lift. 7. generate a force strong enough to create sufficient lift to overcome the weight of an aircraft. 8. What is necessary to lift heavier-than-air machines into the air? liftdrag thrust 9. Aerodynamics examines the forces of lift, thrust, weight, and airfoils.drag. flight.