Observations on performance of three-tube pitot probe

This technical note discusses two questions related to three-tube (pitch or yaw) pitot probes, which are used for measuring the velocity vectors in 2D flows. When a pitch probe is used in flows in which the third component of the velocity is small but not zero, it is important to know the error this causes in the measurement of the velocity vector. Calibration experiments on a pitch probe showed that as long as the yaw angle is less than 14 degre es, the relative error in the velocity measured by the pitch probe is less than 3% and the error in the pitch angle is less than 1 degrees. Typically a pitch or yaw probe can only be used when the angle of attack is less than approximately 50 degrees. The second part of this work addresses the pract ical issues associated with pretilting the probe to measure flows at angles greater than 50 degrees.