Activity 2.1 – Forces
Purpose
Daniel Bernoulli, an eighteenth-century Swiss scientist, discovered that as the velocity of a fluid increases, its pressure decreases. How and why does this work, and what does it have to do with aircraft in flight?
What Bernoulli was able to show is what is sometimes called Bernoulli's Law of Pressure Differential for fluids. Since air is a fluid, this pressure difference is important and in this activity you will discover why.
Equipment
· Computer with Internet access
· Engineering notebooks
· Pencil
Procedure
In this activity, you will follow along in a presentation of Bernoulli’s Principle, and learn through Internet research and class discussion, about the four forces acting on an airplane during flight.
Answer the following questions during the introduction of this activity:
1. Why are aircraft categorized into heavier-than-air and lighter-than-air vehicles?
2. List several types of lighter-than-air and heavier-than-air vehicles.
3. What is a force?
Go to NASA Virtual Skies at the following URL: http://virtualskies.arc.nasa.gov/main/maeronautics.html and Click on Tutorial. Then click on the different sections to read and find the answer to the following questions.
4. How does a hot air balloon float?
5. What is buoyancy, and how does it relate to balloons?
6. List and describe (in your own words) the four forces acting on an airplane during flight.
Force 1:
Force 2:
Force 3:
Force 4:
On the diagram below, label the four forces acting on an airplane during flight.
Go to NASA Glenn Research website URL: http://www.grc.nasa.gov/WWW/K-12/airplane/geom.html to find the following definitions. Then label the parts of the wings in the drawings below.
Leading Edge
Trailing Edge
Chord
Angle of Attack
Mean Camber Line
Camber
Thickness
Follow along and answer the following questions as your instructor demonstrates Bernoulli’s Principle using NASA FoilSim website: http://www.grc.nasa.gov/WWW/K-12/FoilSim/index.html.
1. With all the airfoil settings at the default, is there a difference between the speed of the air above the wing and the speed of the air below the wing?
Upper Air Speed______Lower Air Speed______
2. In this configuration, is there a difference in the air pressure above the wing and below the wing?
Upper Air Pressure ______Lower Air Pressure______
3. In this configuration, is there lift?______If so, how much? ______
4. After changing the camber (wing curvature) to 0.5, is there a difference between the speed of the air above the wing and the speed of the air below the wing?
Upper Air Speed______Lower Air Speed______
5. In this configuration, is there a difference in the air pressure above the wing and below the wing?
Upper Air Pressure ______Lower Air Pressure______
6. In this configuration, is there lift?______If so, how much? ______
7. After resetting and then changing the angle of attack to 10 degrees, is there a difference between the speed of the air above the wing and the speed of the air below the wing?
Upper Air Speed______Lower Air Speed______
8. In this configuration, is there a difference in the air pressure above the wing and below the wing?
Upper Air Pressure ______Lower Air Pressure______
9. In this configuration, is there lift?______If so, how much? ______
10. Next, return to the Internet at Virtual Skies website URL: http://virtualskies.arc.nasa.gov/main/maeronautics.html and Click on Tutorial. Go to “Tools of Aeronautics,” and read the information on the wind tunnel. Before testing the shapes in the virtual wind tunnel, write your prediction of what will happen to the lift and drag on each shape.
Conclusion
1. In order for an airplane to fly, what must happen to the four forces?
2. What are three factors that can change the speed and pressure of air flow around a wing, and thus increase the amount of lift?
3. In your own words, what makes a wing or airfoil work?
4. Will any shape work for an airfoil? Why or why not.
Project Lead The Way®
Copyright 2006
GTT – Flight and Space Unit – Lesson 2 – Activity 2.1 – Forces – Page 1