Development of a Full Scale Moth Hydrofoil Control System Test Rig

. The design, construction and evaluation of a test platform to test the International Moth class in real world conditions was undertaken with the aim to investigate the effects of altering the value of the proportional control coefficient on flight modes to provide data for further numerical simulations. Through consultation with industry, technical experts and reviews of literature, a design was produced that allowed foils to be tested over a range of velocities, foil configurations and control systems that would be free to move in pitch and heave, however constrained in roll, yaw, sway and surge. The rig with the degrees of freedom can be seen below in Figure 1. Improvement of an existing electronic ride control system (ERCS) allowed the test moth to be able to fly at a range of depth to chord ratios along with the capability to change the respective flight modes with varying amplitudes. Ultimately, it was concluded that in a real-world environment the differences in drag between the range of values tested resulted in no serious measurable performance gains despite significant motion variations. However, it was apparent that small relationships formed and that it is essential for more research to be conducted in order to validate the data. The rig developed provides an easily accessible method for testing control algorithms in a real-world environment without the need for complex sailing configurations. The rig also allows cheap ways of tuning a system that is ripe for full on-water implementation.