mohammad ali amini - School of Mechanical Engineering, Universitjz of Tehran, Tehran, Iran
moosa ayati - SchooI of Mechanical Engineering, University of Tehran, Tehran, Iran
mohammad mahjoob - SchooI of Mechanical Engineering, University of Tehran, Tehran, Iran

Air—data measurements are one of the essential observations in aircrafis system identification. Implementation of airspeed measuring systems in flapping wing UAVs is almost a new field. Because of intensive high amplitude oscillations on the body of omithopters, there are still a lot of questions about the validation of such implementation. In this work, measurements of a low cost Pitot tube i11 a condition similar to flapping flight has been studied. Movements of an average-sized omithopter (1.2 meters wingspan and 600 grams weight) are simulated with a 2-DOF mechanism and the effect of such movements on airspeed measurements are investigated in a wind tunnel. The tests were conducted at different airspeeds (6-12 n1/s), angle of attacks (0-30 degrees) and Pitot tubes (three Pitot tubes with different tube diameters). The results reveal that below an upper bound for mean aoal, airspeed measurement errors are smaller than 2 percent of airspeed values. On the other hand, above that upper bound, an averaging process over one flapping range can significantly reduce measurement errors. However after specific mean aoas. direct or averaged air- speed measurements have large errors.

air-data measurement, air-speed, angle of attack, omithopter instrumentation, flapping flight