Reduction in Swing of a Sonar Body Winched from the Sea by a Helicopter

摘要

When a sonar body is winched from the sea by a helicopter, growth in amplitude of oscillation of the body occurs. This is demonstrated using a two-dimensional mathematical model. To avoid the possibility of collision with the helicopter, an automatic procedure is proposed in which the body is alternately raised and lowered during defined periods of each oscillation. When the prescribed degree of damping is achieved, the body is raised continuously to the trail position. Performance of the method is judged by the amount of additional raise time required. The procedure is applied to the sonar system used on the Royal Australian Navy's Sea King Mk.50 helicopter. (Author)