Performance of the Air-Cushion–Surface-Contacting Hybrid Vehicle for Overland Operation

Abstract

The air-cushion concept has been considered for application to off-road transport ever since the early days of its development. Recently, the rapid increase in resource exploration and exploitation in remote areas has stimulated new interest in applying air-cushion technology to overland transportation. It appears to offer solutions to a wide variety of cross-country transportation problems.

Although existing vehicles fully supported by an air cushion can function overland, experience to date indicates that considerable improvements in controllability and manoeuvrability are required for continuous overland operation. One practical solution is to provide some degree of surface contact.

The feasibility of an air-cushion–surface-contacting hydrid vehicle has been demonstrated by the Benin Terra-plane BC7, Vickers-Armstrongs Hovertruck, etc. However, the operating performance, capabilities and limitations of this type of vehicle have not been investigated in a systematic way.

This paper attempts to provide a theoretical basis for evaluating and optimizing the performance and design of the hybrid vehicle. The basic power requirements of this type of vehicle are first analysed and compared with those of the fully-air-cushion-supported vehicle. The approaches to minimizing the power consumption and to improving the economics of operation are then investigated. It is found that among other design parameters, the load distribution between the air-cushion and the ground-contacting gear of the hybrid vehicle has a considerable effect on its power requirements. For a given vehicle in a particular type of terrain, there is an optimum load distribution which minimizes the power consumption. Finally, an analytical approach to evaluating and predicting the controllability and mobility of this kind of vehicle is discussed. It is found that using the wheel as a yaw-control device for the hybrid vehicle is quite effective. It is also shown that wheeled propulsion has limitations in cross-country operation. In order to provide the hybrid vehicle with adequate off-road mobility, an auxiliary air propulsive system appears to be necessary.