Experiment Exploring the Relation between Angle of Attack and Lift Force of Model Wings.

Hypothesis

The lift force generated by a model wing reaches its maximum when the angle of attack is 45 degrees above the horizontal plane.

Experiment Setup →

Data Collection

Precedure

Set up the wind tunnel and measure the weight of the model wing and its standing structure. Turn on the fan and record the displayed weight until the measurement becomes stable. Adjust the hinge to change the angle of attack, then put it back into airflow and record data. For this experiment, 14 different angles of attack are tested, ranging from -10° to 90°. Each angle is tested multiple times to reduce error.

Data

The actual weight of the model wing and its standing structure is 304.9 g.

AOA (°)	Measured Weight (g)	Lift (N)

Graphical Representation

Analysis

The graph shows that lift increases with angle of attack up to about 30°, where it peaks. Further increases of angle of attack after 30° will cause lift to decrease.

The model wing generate approximately no lift when it is completely horizontal or vertical.

The graph as well shows that with negative angle of attack, meaning the leading edge of the model wing points down, the lift force is also negative.

Conclusion

The lift force generated by a model wing reaches its maximum when the angle of attack is about 30 degrees above the horizontal plane.

Reflection

There are a few possible flaws of this experiment.

• Firstly, angle of attack is not the only factor that determines the lift force; different conbination of angle of attack and other factors such as airfoil shape and wind speed may lead to different result.
• Secondly, the drag force was not considered in the designing of the experiment setup; it may or may not cause significant error in measurement.
• Lastly, the testing equipments and wind tunnel structure are rudimentary; it could affect airflow and change control variables.

Future experiment with more sophisticated equipments testing different combination of angle of attack, airfoil shape, and wind speed can be done to give a more certain conclusion.