To test four different angles of attack to determine which one generates the most lift of an airfoil.
- small wind tunnel 2 feet (61 cm) in length, made of either plywood, balsa, or cardboard (check with your science teacher for its construction)
- easel clamp
- 4 balsa airfoils of the same dimensions (each glued to the angled face of an airfoil stand)
- 4 balsa airfoil stands with degree, IS-degree, 30-degree, and 50-degree angles cut into one end on each
- balsa wood testing platform
- digital metric scale
Each airfoil will be tested three times, and each test will run for 15 seconds. The 0-degree angle will serve as a control, and the other angles will act as variables. The highest force reading for each airfoil on the digital metric scale is to be recorded at the end of each test. The only variable in the experiment will be the difference in the angle of attack.
- Using the diagram as a general example, set up a wind tunnel testing assembly. Once the unit is set up, do not reposition the wind tunnel or testing platform. If these components are moved, the flow of air around the airfoil will change, and inaccurate results will be obtained.
- Clamp one of the airfoils and its corresponding airfoil stand upright and place it on the balsa wood testing platform (refer to diagram). Then, place the testing assembly on the scale. The leading edge of the airfoil should be parallel to the edge of the wind tunnel's mouth.
- Calibrate the scale.
- Immediately after the scale has been calibrated, switch on the fan. Simultaneously, begin timing the first l??second test with the stopwatch and record the amount of force indicated on the scale. Then repeat this procedure two more times and record the force readings.
- Repeat steps 2 through 5 three times for each airfoil. Record the highest force reading of the three tests for each separate angle of attack.
- Graph your results.
- From the results shown in your graphs, which angle of attack generated the most lift?
- Why did the angles generate the particular amounts of lift force that they did?