A heave control system for amphibious hovercraft has been designed and tested. The central element in the system being an axial flow, lift-fan whose blade angles are continuously varied by means of feedback signals from a pressure transducer located in the front end of the hovercraft cushion and from an accelerometer measuring the heave acceleration. Results from experiments, conducted on the Cranfield Whirling-Arm facility, have shown that the system provides a rapid and effective means of controlling the heave acceleration, and, in addition, produces a valuable reduction in craft drag whilst traversing waves. An extensive parameter identification programme, using a non-linear optimisation algorithm, was constructed and applied to the control sub-system, such that a full mathematical model of the controlled craft was obtained. This was then used to design an optimum control with particular reference to passenger ride comfort. Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.