Flight Testing and Evaluation of the Structural Response to Flight Loads of a Small Scale Unmanned Aerial System

F light dynamic loads exper ienced by a 40% scale Yak-54 unmanned aer ial system were simulated, including performance analysis, static testing and analysis, and structural response to static and dynamic air loads. A detailed sensor selection outlines the justification for the choosing of accelerometers and strain gages, and the calibration techniques imposed prior to testing. Static testing was performed on a carbon fiber composite spar to determine the elastic modulus and failure stress and then compared to numer ical technique results. Full integration of the sensors with the platform was completed in preparation for flight testing. An integrated static test was performed to validate the system in which the wings were subjected to a load factor of 2.5g’s and strain was measured at three outboard locations of each wing. The flight test consists of steady level turns and symmetr ical pull-ups. Each maneuver is dictated by a control input. The maximum strain observed during flight was 141 μe at the tip of the r ight wing and the minimum was -188 μe at the mid station of the r ight wing. The accelerometer data collected correlated well to the executed maneuvers, and accelerations as large as 2.6 g’s were observed.