Theoretical Analysis and Model Test for Tail-Flick of Hovercraft

摘要

Hovercraft is a kind of high-speed vehicle that glides close to thesurface of the water. Due to the existence of the air cushion, tail-flickcould happen to hovercraft. Tail-flick is a kind of special instabilityphenomenon with certain security risks, and is characterized by suddenincrease in the rate of turning and the drift angle, speed decreasing, andwildly fluctuating for the angle of trim and heel, even leads toshipwreck in severe case. In this paper, a model was selected as theobject of study according to some type of air cushion vehicle. Thereason of tail-flick was analyzed by researching on the variationcharacteristic of motion parameter with the theoretical model of fourdegree-of-freedom manipulative motion. The mechanism of tail-flickhas been verified and further analyzed through free running model tests.The results show that tail-flick would take place at most initial sailingspeed in hovercraft, which is closely related to some factors such assailing speed, drift angle, and angular accelerated velocity. In addition,the higher angular velocity corresponds to the smaller drift angle whentail-flick is occurring. Furthermore, the tail-flick safety zone wasdetermined by calculation analysis.