Analysis of radio controlled airplane landing gear using empirical similitude

This thesis uses empirical similitude to compare the drop test result of an RC plane landing gear to a large oleo strut landing gear. This is useful to help create novel designs for applications onto large aircraft, as it is difficult to run experiments on the larger system. A drop test rig was constructed to collect data from an RC plane tire. The system is built similar to a reverse pendulum with the tire at the end of the arm. The accelerometer at the end of the arm records the acceleration, with the important results being the peak accelerations at the impacts. These were exported to Excel files to be read by MATLAB during analysis. The second order ODE system derived from a mass-spring-damper model is coded into MATLAB and compared to empirical data. The code tracks the system as it falls, bounces on the ground, rises back in the air, and repeats, recording position, velocity, and acceleration predicted. The result was then compared to data from the drop test rig. A unitless matrix is derived relating the peak forces predicted by the ODE system to the peak forces of the actual data. The second order system was then scaled up to a large oleo-pneumatic system, creating a matrix of physical parameters. The unitless matrix was applied to this new prediction plot to convert it to “real” data. The resultant plot is compared to empirical data to determine if force plots are comparable. In conclusion, empirical similitude was able to successfully predict peak amplitudes recorded by past literature, though more research is required to confirm accuracy of the results. Successful modeling of an oleo-strut system using an RC tire paves the way for modeling novel landing gear systems in the future.