A Direct Model Pitch Measurement with a Laser Interferometer Using Retroreflectors

摘要

A laser interferometer was developed to measure pitch angles of test models in a wind tunnel environment. Small retroreflectors imbedded flush with the surface of the test item provided the necessary reflected light for optical processing of pitch information. The first tunnel measurements indicated pitch measurements could be made providing the retroreflectors remained illuminated with the expanded laser beams. Because of the axial motion of the model relative to the optics systems, provisions for scanning the laser beams to follow retroreflector motion was incorporated. Using an actual test model, data were taken demonstrating this tracking capability. Calibration data were also taken comparing the interferometer data with the tunnel standard inclinometer. (Author)