WRIGHT FLYER ON-LINE
Up, Up and Away
Secondary Lesson Plans

TABLE OF CONTENTS

Pioneers of Scientific Method
Up, Up, and Away-Analyzing Coefficient of Lift Data
Wind tunnel test data
Up, Up, and Away-Analyzing Coefficient of Lift Data, Teacher Page
Bibliography (Resources)

Objectives

• Students will understand the historical significance of use of the scientific method in developing the first airplane.
• Students will learn to appreciate the process involved in developing a new technology
• Students will analyze a graph plotting angle of attach versus coefficient of lift (C_L).
• Students will create a graph plotting angle of attach vs. C_L for the data collected in the Wright Flyer wind tunnel data collected at Ames Research Center.
• Students will compare and contrast atypical lift curve graph with the graph they have created and will hypothesize reasons for any variations.
• Students will compare and contrast graphs from the full scale wind tunnel testing with graphs from other tests conducted and models created by the AIAA.

STANDARDS LINK

These activities support the following National Science Standards:

• Teaching Standard A-Teachers of science plan an inquiry-based science program for their students.
• Teaching Standard B-Teachers of science guide and facilitate learning.
• Teaching Standard E-Teachers of science develop communities of science learners that reflect the intellectual rigor of scientific inquiry and the attitudes and social values conducive to science learning.
• Content Standard K-12-As a result of activities in grades K-12, all students should develop understanding and abilities aligned with the following concepts and processes:
  
  • systems, order, and organization
  • evidence, models, and explanation
  • constancy, change and measurement
  • evolution and equilibrium
    
• Content Standard A-As a result of activities in grades 9-12, all students should develop abilities necessary to do scientific inquiry and understandings about scientific inquiry.
• Content Standard B-As a result of their activities in grades 9-12, all students should develop an understanding of motions and forces.
• Content Standard E-As a result of activities in grades 9-12, all students should develop abilities of technological design and understandings about science and technology.
• Content Standard G-As a result of activities in grades 9-12, all students should develop understanding of science as a human endeavor, nature of scientific knowledge, and historical perspectives.
• Program Standard B-The program of study for all students should be developmentally appropriate, interesting, and relevant to student's lives; emphasize student understanding through inquiry; and be connected with other school subjects.
• Program Standard C-The science program should be coordinated with the mathematics program to enhance student use and understanding of mathematics in the study of science and to improve student understanding of mathematics.

This activity supports the following National Mathematics Standards:

• Standard 1-Mathematics as Problem Solving
  In grades 9-12, the mathematics curriculum should include the refinement and extension of methods of mathematical problem solving so that all students can apply integrated mathematical problem-solving strategies to solve problems from within and outside mathematics; recognize and formulate problems from situations with and outside mathematics; and apply the process of mathematical modeling to real-world problem situations.
• Standard 2-Mathematics as Communication
  In grades 9-12, the mathematics curriculum should include the continued development of language and symbolism to communicate mathematical ideas so that all students can reflect upon and clarify their thinking about mathematical ideas and relationships.
• Standard 3-Mathematics as Reasoning
  In grades 9-12, the mathematics curriculum should include numerous and varied experiences that reinforce and extend logical reasoning skills so that all students can construct simple valid arguments.
• Standard 4-Mathematical Connections
  In grades 9-12, the mathematics curriculum should include investigation of the connections and interplay among various mathematical topics and their applications so that all students can use and value the connections between mathematics and other disciplines.
• Standard 5-Algebra
  In grades 9-12, the mathematics curriculum should include the continued study of algebraic concepts and methods so that all student can use tables and graphs as tools to interpret expressions, equations, and inequalities.
• Standard 6-Functions
  In grades 9-12, the mathematics curriculum should include the continued study of functions so that all students can represent and analyze relationship using tables, verbal rules, equations, and graphs.
• Standard 10-Statistics
  In grades 9-12, the mathematics curriculum should include the continued study of data analysis and statistics so that all students can construct and draw inferences from charts, tables, and graphs that summarize data from real-world situations.

WRIGHT FLYER ON-LINE Pioneers of Scientific Method Student Page

The Wright Brother were more than just bicycle mechanics that happened onto an airplane design that actually flew. They used the scientific research method in a way that we now take for granted but that was not common among their contemporaries. They were among the first to systematically discover the principles and formulas that would assure flight.

Probably their best scientific research was wind tunnel research. The Wright Brothers had reason to suspect that airfoil data just accepted as true was in fact flawed. They designed a wind tunnel to verify the data. The Wrights conducted meticulous research with very detailed, accurate records. All their work was carefully documented.

The Wright Brothers were not loners in their research. They contacted the Smithsonian Institution for any and all available information. They studied the work of other researchers and consulted with others in pursuit of the dream of flying. They knew how to collaborate, argue, and keep quiet at the appropriate times. It is said that the Wright Brothers were excellent at playing devil's advocate. Orville would take one position and Wilbur would argue the opposite point of view. Throughout the argument, they would find that they had switched position and ended up arguing the opposite viewpoint.

The Wright Brothers were truly pioneers in use of the scientific method, and their methodical work resulted in the development of a technology that has truly changed our way of life in the 20th century.

Activities: Research the work of Orville and Wilbur Wright and present examples of their use of the scientific method. (Possible topics include: propeller design, kite testing, glider testing, wing warping, aileron design, engine design, etc.) Research methods of transportation in 1999. Report on the evolution of modern transportation during the past 100 years. Conduct research to learn about the AIAA project to build, test, and fly a 1903 Wright Flyer replica to commemorate the 100th Anniversary of the first flight at Kitty Hawk. Prepare a presentation to share what you have learned with other students.

WRIGHT FLYER ON-LINE
Pioneers in Scientific Method
Teacher Page

The Wright Brothers provide an incredible example of the use of the scientific method. The process they used is easy to understand and provides a great model for students on how the scientific method is applied in the real world. This activity provides the students with opportunities to delve into the work of Orville and Wilbur. The first activity focuses just on the work of the Wright Brothers. The second suggested activity is much broader in its scope and allows students to investigate changes in transportation methods that were the direct and indirect result of the work of the Wright Brothers. The AIAA Project in and of itself is also very interesting. Students will find it very informative to learn of the tenacity of the engineers spearheading this project in the face of many challenges and setbacks. Hopefully pursuing these activities will provide students with the experience in using a variety of resources, including electronic media, for obtaining information.

The student presentations are also an important part of this activity. It is designed to help students learn to express their findings in a coherent, understandable, and interesting manner. If possible, it is suggested that students prepare multimedia presentations. This will help them learn how to use multimedia presentation tools and techniques.

WRIGHT FLYER ON-LINE
Up, Up, and Away-Analyzing Coefficient of Lift Data
Student Page

MATERIALS NEEDED

• Graph Paper
• Calculator
• Graphing calculator (optional)
• Graph link and computer (optional)

Lift is the name given to the force that enables an airplane to rise off of the ground. The lift must be greater than the weight of the airplane for the airplane to be able to takeoff. Lift is a force and can be quantified using the following formula:

force = pressure x area Theoretically, the amount of lift obtained from a wing should be proportional to the pressure and the wing area. In reality, the lift force is not exactly equal to the product of pressure and area. The portion of the force being transformed into lift is measured by the coefficient of lift(CL). CL is determined by dividing the measured lift by the dynamic pressure and the wing area. The value for CL varies with the angle of attack. Angle of attack is measured between the airstream and an imaginary line between the leading and trailing edges of the wing. The graph shown (graph 1) represents a typical curve of angle of attack versus coefficient of lift. This is called the lift curve.

QUESTIONS

1. Why do you think C_L varies with the angle of attack.
2. For a pilot, what is the advantage of plotting lift of coefficient versus angle of attack.
3. The maximum value on the y-axis is called the C_L max. What information does this value provide?
4. At approximately 14° the graph turns downward. How would you explain this?
5. As the graph turns downward, the negative slope can be gentle or abrupt. How would expect the plane to react in each situation.
6. The y-intercept on this graph is .2 . Explain why the y-intercept is not 0.
7. When would you expect the y-intercept to be 0?
8. What is determined by the slope of the lift curve?
9. Between 0° and 14° , the lift curve is a straight line. What conclusion can be drawn from this?
10. For the graph given the C_L max is 1.4. Compare this wing with one that has a C_L max of 1.0.
    In preparation for the anniversary of the first flight of the Wright Brothers, the American Institute of Aeronautics and Astronautics (AIAA) has built a replica of the 1903 Wright Flyer. This replica will be tested in the wind tunnels at Ames Research Center. (Data available March/April 1999?) Two of the data sets collected are angle of attack (alpha on the data table) and coefficient of lift (C_L). Plot this data using angle of attack as the independent variable (x-axis) and C_L as the dependent variable (y-axis). You may create the plot manually, use a computer, or a graphing calculator.
11. Compare and contrast your graph with the one pictured above. Explain the similarities and differences.
    Shown on the graph below are graphs generated from computer modeling and scale model testing. As part of the Wright Flyer Project, two member of the Wright Flyer Project, have calculated some of the major aerodynamic characteristic of the airplane. Using two different computer programs, James Howford and Stephen Dwyer have calculated load distributions, lift and pitching moment for the Flyer replica. Probably the best scientific work by the Wright Brothers is their wind tunnel testing. They used a small wind tunnel to validate some airfoil data obtained from other researchers, but systematic wind tunnel tests of their complete aircraft has never been found. To fill this gap in the data, two series of wind tunnel tests have been conducted through the AIAA Wright Flyer Project. The first used a 1/6 scale model built of wood and fabric, with steel truss wires, very similar to the original airplane. The main goals of the test was to obtain data about the effectiveness of wing warping. The second set of wind tunnels test used a 1/8 stainless steel model.
    
    
12. Why is the lift curve graph for the wood and fabric model different from the lift curve graph for the steel model?
13. Compare the graph you created from recent wind tunnel test data with the graph from the testing of the wood and fabric model. Explain the similarities and differences.
14. Compare the graph you created from recent wind tunnel test data with the graph from the testing of the steel model. Explain the similarities and differences.
15. Compare the graph you created from recent wind tunnel test data with the graph from the computer model. Explain the similarities and differences.
16. Which model seems to provide the closest model for the actual Wright Flyer replica data? Support your conclusion.
    
    
    Wind Tunnel Test Data
    
    As stated earlier, for takeoff to occur the lift force that must overcome the weight of the aircraft. Lift expected can be calculated from the coefficient of lift data obtained in the wind tunnel testing. The formula for this calculation is shown below.
    
    Lift = Coefficient of lift x Area of the wing x Dynamic air pressure
    
    This can be expressed using in the following manner using variables:
    
    F_L = C_L x S x q
    
    The wing area on the Wright Flyer is 500 ft². The dynamic pressure in the tunnel will be 2.05 lb./ft². (Note: You will notice that English units are used. Since the aeronautics industry began in the United States, the world accepts and uses the units commonly used in the United States.)
    
    Using the wind tunnel test data runs 43 and 44 and the formula above, complete the following table.
    
    

    Alpha	Coefficient of Lift	Lift

    
    
    

17. If the replica of the Wright Flyer weighs 750 lbs., what is the minimum angle of attack required to overcome the weight and allow the Flyer to leave the ground?

WRIGHT FLYER ON-LINE
Up, Up, and Away-Analyzing Coefficient of Lift Data
Teacher Page

Vision

Graphing is a skill that many students find tedious and boring. The availability of graphing calculators has eliminated some of the tedium, but students still don't seem to grasp the value of graphing. This activity provides students the opportunity to graph actual data from a test being conducted in a real world setting. They are creating the same graphs that will be created and analyzed by the AIAA engineers spearheading the Wright Flyer Project. Hopefully participating in this project will lead students to an understanding of the value of visual representations of data and the analyses that can be conducted using this visual representations.

DISCLAIMER

As part of this activity, the students are provided with a typical lift curve for aircraft. The point where the curve turns and the slope becomes negative is where stall occurs. As this activity was discussed with the engineer in charge of the Wright Flyer Wind Tunnel Testing, he was concerned that during the testing the angle of attack may not reach the point where stall will occur. This was not seen as a problem because it provides the students with the opportunity to speculate on reasons for the differences.

Since we do not know exactly how the model will respond in the test (hence the reason for the testing), it is impossible to predict in advance what the graphs generated from the data will reveal. When the data is obtained and the graphs are generated, more information will be provided to help you as teachers guide your students through this analysis.

Answers to Activity Questions

1. Why do you think C_L varies with the angle of attack.
   
   Coefficient of lift is how efficiently the wing is transforming dynamic pressure into lift. With a greater angle of attack, the efficiency increases to a certain angle.
   
   
2. For a pilot, what is the advantage of plotting lift of coefficient versus angle of attack.
   
   Coefficient of lift increases as the angle of attack increases. Therefore lift increases. The advantage of the lift curve is that it tells the C_L and therefore lift available for a certain angle of attack.
   
   
3. The maximum value on the y-axis is called the C_L max. What information does this value provide?
   
   As the angle of attack increases, lift will not increase indefinitely. There comes a point where the angle is too steep and the C_L plummets. This is called the stalling point. The aircraft will then drop because the weight is greater than lift. The pilot must make sure the angle of attack stays below this value.
   
   
4. At approximately 14° the graph turns downward. How would you explain this?
   
   As the angle increases, the airflow will separate from the top of the wing producing a wake of turbulent air over this surface. There is still some pressure on the lower wing surface, but this decreased amount of lift is not enough to overcome gravity.
   
   
   
   
5. As the graph turns downward, the negative slope can be abrupt or gentle. How would expect the plane to react in each situation?
   
   A very abrupt dropoff indicates a sudden stall and a gentle change in slope indicates a more gradual stall.
   
   
6. The y-intercept on this graph is .2 . Explain why the y-intercept is not 0.
   
   The graph provided with this activity is for a cambered wing. (If the distance from the chordline to one surface is greater than the distance to the other surface, the wing is cambered.) On this particular graph, the angle of attack must go to negative 2 for zero lift.
   
   
7. When would you expect the y-intercept to be 0?
   
   If the wing or airfoil is symmetrical, a zero angle of attack will produce a coefficient of lift of zero.
   
   
8. What is determined by the slope of the lift curve?
   
   The slope of the curve determines how rapidly C_L increases with the angle of attack.
   
   
9. Between 0°f and 14° , the lift curve is a straight line. What conclusion can be drawn from this?
   
   The straight line indicates that C_L is directly proportional to the angle of attack.
   
   
10. For the graph given the C_L max is 1.4. Compare this wing with one that has a C_L max of 1.0.
    
    This wing would produce more lift before stall than the wing with a lower C_L max.
    
    
11. Compare and contrast your graph with the one pictured above. Explain the similarities and differences.
    
    More information on this will be provided when the wind tunnel test data is available.
    
    
12. Why is the lift curve graph for the wood and fabric model different from the lift curve graph for the steel model?
    
    The wood and fabric model was more fragile than the steel model. Some of the results may be biased due to distortions of the wing surface.
    
    
13. Compare the graph you created from recent wind tunnel test data with the graph from the testing of the wood and fabric model. Explain the similarities and differences.
    
    One of the main purposed of the tests using the wood and fabric model was to obtain data for the effectiveness of wing warping. The structure was relatively fragile and suffered damage and warping during the test.
    
    
14. Compare the graph you created from recent wind tunnel test data with the graph from the testing of the steel model. Explain the similarities and differences.
    
    This model allowed engineers to test using more realistic conditions without damaging the model. Because the steel model has larger struts for strength at the higher test speeds, the minimum drag coefficient is large than that for the fabric model
    
    
15. Compare the graph you created from recent wind tunnel test data with the graph from the computer model. Explain the similarities and differences.
    
    The lift-curve measured with the steel model is very closely matched by the calculation based on the theoretical computer model. This suggests that the Wright Brothers had an incredible understanding of aerodynamics.
    
    
16. Which model seems to provide the closest model for the actual Wright Flyer replica data? Support your conclusion?
    
    Information on this question cannot be provided until after the tests are completed.
    
    
17. If the replica of the Wright Flyer weighs 750 lbs., what is the minimum angle of attack required to overcome the weight and allow the Flyer to leave the ground?
    
    Use the chart created to determine where the lift first exceeds 750 lbs.

BIBLIOGRAPHY

Wright, Orville and edited with an introduction and commentary by Kelly, Fred C. How We Invented the Airplane: An Illustrated History. Dover Pulications, Inc. New York. 1988.

Smith, H. C. "Skip". The Illustrated Guide to Aerodynamics (2nd Edition). Tab Books, A Division of McGraw-Hill, Inc. New York. 1992.

Hecht, Eugene. Physics: Algebra/Trig (2nd Edition). Brooks/Cole Publishing Company. Pacific Grove. 1998.

Jex, Henry R. and Culick, Fred E. C. Flight Control Dynamics of the 1903 Wright Flyer. AIAA Paper no. 85-1804-CP. AIAA 12th Atmospheric Flight Mechanics Conference. Snowmass, Colorado. August 19-21, 1985.

A special thanks to Mr. Craig Hainge at NASA Ames Research Center

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