Patent GB-975558-A (GB)
IPC: B60V1/00
Abstract: 975,558. Air cushion vehicles. HOVERCRAFT DEVELOPMENT Ltd. April 14, 1961 [April 20, 1960], No. 13784/60. Heading B7K. A vehicle is at least partly supported above a surface by a pressurized gas cushion formed beneath it and contained for at least part of its periphery by a gas curtain issuing from a supply port (or ports) in the bottom of the vehicle and adjacent the periphery thereof, at least part of the gas of the curtain being recovered through a recovery port (or ports) parallel to and inboard of the supply port, and has at least one supply duct supplying gas to the supply port and at least one recovery duct recovering gas from the recovery port, the two ducts being positioned along side one another and each tapering in cross-section from a minimum to a maximum, and means adjacent the maximum cross-section of the recovery duct for energizing gas from that duct and feeding the gas to a supply duct at its position of maximum crosssection. Fig. 1 is a horizontal section through the supply and recovery ducting of a vehicle, and Fig. 2 is part vertical section through its periphery. Ducts 1 and 2 are divided by vertical partitions 15 and 16 into supply ducts 3, 4, feeding an annular supply port 11, and recovery ducts 5, 6 connected to an annular recovery port 13. By suitably disposing the partitions 15, 16, the cross-sections of sections 3-6 are tapered suitably to accommodate the variation in mass flow at different points along the length of the sections. The curtain fluid is air, and air recovered into sections 5, 6 is fed through compressors 7, 8 into supply sections 4, 3, respectively. Flaps 18 upstream of the compressors can be opened to supply ambient air for setting up the curtain and cushion, and to replace air that is not recovered from the curtain by port 13. The curtain gas may be engine exhaust gases. In Fig. 3, ducts 23, 24 are divided by partitions 32 into supply ducts 25, 26, and recovery ducts 27, 28, the sections again being suitably tapered as dictated by mass flow requirements. Air from both recovery ducts is fed through compressor 21 and duct 22 to both supply ducts 25, 26. A flap 33 can be opened to supply ambient air to the compressor for setting up the curtain and cushion and making good air losses. This arrangement is suitable when the air issues from the supply port with a rearward velocity component to provide propulsion, the airflow in the ducts along the side of the vehicle being in the direction of motion. Also, from the symmetrical nature of the airflow in Fig. 3, no turning moment is created. A plurality of concentric curtains can be used, each having its own supply and recovery ducting. Fig. 8 is an underneath view of a larger vehicle, having supply and recovery ports 51, 52 respectively, communicating with multiple supply sections 53 and sections 54 formed in a duct 50 by partitions 55. Adjacent supply and recovery sections are connected through compressors 57 driven by engines 59. The auxiliary air supply flaps such as 18, Fig. 1, and 33, Fig. 3, may open to any source of air above atmospheric but below normal cushion pressure. With multiple concentric curtains, auxiliary air supply for the inner curtain system may be at a higher pressure than that for the outer curtain system.