Flexible skirt components for air cushion vehicles

Abstract

An inflatable skirting assembly acting as a barrier to the supporting cushion of a gaseous cushion supported vehicle, the skirting assembly being constructed from a single sheet of flexible material suspended from the vehicle to form an unrestrained loop in a vertical cross-section.

I claim as my invention: .[.1. In a vehicle of the type adapted for hovering over a surface on at least one cushion of pressurized gaseous fluid, said vehicle comprising a rigid base structure having a flexible skirting assembly attached to at least a portion of the periphery thereof and extending downwardly from said rigid structure, the improvement wherein the skirting assembly comprises essentially a single continuous substantially one piece sheet of flexible substantially fluid-impermeable material depending downwardly from a first line on the undersurface of said rigid structure, then upwardly to a substantially coplanar second line on the undersurface of said rigid structure spaced apart from said first line, the space encompassed by said sheet being inflatable and said sheet being free from restraining and bracing members to form a free hanging, unrestrained and unbraced loop considered in a substantially vertical cross-section, and said sheet, when inflated, being capable of deflection so as to pass over obstacles..]. .[.2. The invention according to claim 1 wherein said sheet is suspended by its opposing terminal edges at said first and second lines of dependency from said rigid base structure..]. .[.3. The invention according to claim 1 wherein the space encompassed by said sheet of flexible substantially air-impermeable material is maintained at a uniform pressure throughout..]. .[.4. The invention according to claim 3 wherein said sheet of flexible substantially air-impermeable material is provided with ports in its lower portion, through which pressurized air is discharged so as to generate and maintain said gaseous cushion..]. .[.5. The invention according to claim 4 wherein said ports comprise holes formed in the sheet..]. .[.6. The invention according to claim 4 wherein said sheet is of woven fabric having weft and warp threads, and wherein the weft threads have been removed from the region of the sheet in which the ports are provided, and the remaining warp threads are gathered together to form bunched tension members which act as webs between adjacent ports..]. .[.7. The invention according to claim 4 wherein said sheet of flexible substantially air-impermeable material has attached thereto flexible nozzle extensions, said extensions being coincident with said ports, and comprising at least two flexible walls depending from said sheet, one of said walls being inboard of said ports and the other wall being outboard thereof..]. .[.8. The invention according to claim 7 wherein said flexible nozzle extensions are restrained to incline inwardly toward the cushion by means of a flexible diaphram interconnecting the lower portion of said inboard 
     
        flexible wall and said sheet..]. .[.9.  The invention according to claim 7 wherein members are attached and supported within said inflatable sheet to form an aerodynamic lead into the ports..]. .[.10. The invention according to claim 7 wherein retracting means are provided for raising and lowering said skiriting assembly with respect to said rigid structure of the vehicle..]. .[.11. The invention according to claim 10 wherein said retracting means includes means to at least partially collapse said skirting assembly during retraction..]. .[.12. The invention according to claim 11 wherein said retracting means comprises a winching mechanism adapted to retract at least one edge of said sheet..]. .[.13. The invention according to claim 12 wherein said retracting means retracts said skirting assembly to be stored in the rigid structure of the vehicle when not required..]. .[.14. The invention according to claim 13 wherein the upper portion of said skirting assembly is provided with inlet means in said sheet for permitting an ingress of air to the interior of the skirting assembly when the pressure of air exterior to said skirting assembly exceeds that within said skirting assembly, said means comprising a flexible flat member within said skirting assembly and situated so as to cover an orifice formed in the surface thereof and hinged along one edge to permit opening and closing of the orifice..]. .[.15. The invention according to claim 13 wherein said retracting means includes a common cable having an end portion bifurcated so as to engage opposing terminal edges of said sheet within said rigid structure, the walls of said sheet extending outwardly in opposite directions from said point of engagement to said first and second lines of dependency..]. .[.16. The invention according to claim 15 wherein said retracting means further comprises resiliently mounted members located between said points of engagement and said lines of dependency for urging together the walls of said sheet during retraction of said skirting assembly..]. .Iadd. 17. In a vehicle of the type adapted for hovering over a surface on at least one cushion of pressurised gaseous fluid, said vehicle comprising a rigid base structure and a flexible skirting assembly attached to at least a portion of the periphery of the base structure, the improvement wherein the flexible skirting assembly comprises essentially a substantially one piece sheet of flexible substantially fluid impermeable material forming a single continuous length extending downwardly between a first line on the undersurface of said rigid base structure and then upwardly to a substantially coplanar second line on the undersurface of said rigid base structure spaced inwardly from said first line of attachment to form a loop in vertical cross section that is free from internal rigid restraining and bracing members, the space being encompassed by said sheet being inflatable outwardly away from said rigid base structure, ports disposed in the lower portion of the loop formed by said flexible material, and flexible nozzle extensions cooperating with said ports, said flexible nozzle extensions comprising flexible walls depending from the loop formed by the flexible material, wherein the loop formed by the flexible material is of woven fabric having weft and warp threads, and wherein the weft threads have been removed from the region of the flexible material in which the ports are provided, and the remaining warp threads are gathered together to form bunched tension members which act as webs between adjacent ports. .Iaddend..Iadd. 18. In a vehicle as claimed in claim 17 the improvement wherein said flexible nozzle extensions are restrained to incline inwardly toward the cushion by means of a flexible diaphragm interconnecting the flexible nozzle extensions and the loop. .Iaddend.