The aerodynamic forces on an aircraft are dependent on the angle of the aircraft with respect to the freestream flow. Slight inaccuracies in pitch or yaw angle may have large effects on the airflow measurements, thus impacting the forces measured on the model. The angle of attack correlates extremely well with many parameters being studied during model tests or real flight, such as lift, drag and flight loads. As with other measurements, angle measurement requires both proper instrumentation and proper technique.
There are two different types of angle measurement devices. Those that measure angle during data collection (“wind-on”) and those that are meant to verify the angle measurement device in between test runs (“wind-off”). Both are important for recording accurate angle measurements.
