Roll, pitch, and heave stabilization device for air-cushion-borne vehicles

In an air cushion vehicle having a main air cushion enclosed by an upper platform, fixed sidewalls and inflatable planing seals at the ends, a system for stabilizing the vehicle comprising:

• a source of pressurized air;
• means within said vehicle for distributing the air from said source to maintain said main air cushion and to inflate said planing seals, said inflated planing seals exerting a force between the water surface and the upper platform proportional in strength to the air pressure within the seal;
• control means responsive to the position of a trailing edge of each of said planing seals to control the relative air pressure between the inside of said planing seals and said main air cushion in such a manner that the vertical and rotational movements of the vehicle relative to the water surface as a whole over the area underneath said vehicle are dampened and minimized;
• a skeg extending from the stern approximately along the centerline of said vehicle, with two of the said inflatable planing seals mounted at the stern of said vehicle, one of the said seals mounted between the starboard fixed sidewall and said skeg, the other of said seals mounted between the port fixed sidewall and said skeg, the air pressure inside each of said inflatable planing seals being controlled separately by said control means so as to dampen and minimize the roll movements of the air cushion vehicle relative to the water surface as a whole underneath the stern of said vehicle.

In an air cushion vehicle having a main air cushion enclosed by an upper platform, fixed sidewalls and inflatable planing seals at the ends, a system for stabilizing the vehicle comprising:

• a source of pressurized air;
• means within said vehicle for distributing the air from said source to maintain said main air cushion and to inflate said planing seals, said inflated planing seals exerting a force between the water surface and the upper platform proportional in strength to the air pressure within the seal;
• control means responsive to the position of a trailing edge of each of said planing seals to control the relative air pressure between the inside of said planing seals and said main air cushion in such a manner that the vertical and rotational movements of the vehicle relative to the water surface as a whole over the area underneath said vehicle are dampened and minimized, said control means further comprising:
• a bypass duct for each inflatable planing seal that permits air to flow to the main air cushion from the inside of said seal;
• a control valve in each bypass duct;
• and
• a position sensing and connecting means between each of said planing seals and its corresponding control valve which controls the position of said valve according to the position of a trailing edge of said planing seal, said control causing the relative air pressure inside said seal to be a function of the distance between the upper platform of the vehicle and the surface of the water beneath said planing seal, said function being adjusted to dampen and minimize the roll, pitch, and heave movements of the air cushion vehicle relative to the water surface as a whole over the area underneath said vehicle.

An automatic pitch, roll, and heave stability control system for air cushion vehicles comprising:

• an upper platform with a port side, a starboard side, a bow end, and a stern end;
• a pair of rigid sidewalls mounted underneath the upper platform on the port and starboard sides;
• a bow planing seal with one edge flexibly attached to the bow end of the upper platform, a second edge in substantially continuous contact with the surface of the water, a third edge sealing against the port sidewall, and a fourth edge sealing against the starboard sidewall;
• a bow flexible pneumatic chamber positioned between and pressing apart the bow planing seals and the upper platform;
• a skeg attached underneath and extending from the stern of said upper platform approximately parallel to and approximately half way between said port sidewall and said starboard sidewall;
• a stern starboard planning seal with one edge flexibly attached to the stern of the upper platform, a second edge in substantially continuous contact with the surface of the water, a third edge sealing against the starboard sidewall, and a fourth edge sealing against said skeg;
• a stern starboard flexible pneumatic chamber positioned between and pressing apart the stern starboard planing seal and the upper platform;
• a stern port planing seal with one edge flexibly attached to the stern of the upper platform, a second edge in substantially continuous contact with the surface of the water, a third edge sealing against the port sidewall, and a fourth edge sealing against said skeg;
• a stern port flexible pneumatic chamber positioned between and pressing apart the stern port planing seal and the upper platform;
• at least one source of pressurized air to pressurized said pneumatic chambers and to create a main air cushion which is contained by said upper platform, said sidewalls, said planing seals, and said skeg;
• air ducts which allow air to flow between each pneumatic chamber and the main air cushion and the sources of pressurized air;
• a valve in each air duct connecting a pneumatic chamber with the main air cushion which can be adjusted to control the flow of air through the duct;
• a position sensing and control means between each of said valves and the corresponding planing seal, each of said means controlling the valve so that the air pressure inside the pneumatic chamber attached to said corresponding planing seal is a function of the distance between the upper platform and the edge of said planing seal which is in substantially continuous contact with the surface of the water, said function adjusted to dampen and minimize the roll, pitch, and heave movements of the air cushion vehicle relative to the water surface as a whole over the area underneath said vehicle.

A system for stabilizing an air cushion vehicle having a main platform, rigid sidewalls attached thereto on the port and starboard sides, and a source of pressurized air comprising:

• a plurality of planing seals attached to the platform on the bow and stern ends of the vehicle, with at least one said seal attached to each end, one edge of each seal being attached to the platform and another edge of each seal permitted to move so that it is in substantially continuous contact with the surface of the water, the size, shape and position of the seals being adjusted so that a main air cushion is developed from air provided by the pressurized air source and confined by the main platform, sidewalls and planing seals;
• a plurality of variable volume pneumatic chambers, at least one said chamber connected between a movable portion of each planing seal and the main platform so as to exert a force between the platform and the seal;
• a plurality of air supply ducts to provide pressurized air from said pressurized air source to each of said pneumatic chambers and to the main air cushion;
• a plurality of air exhaust ducts, with at least one connected to each pneumatic chamber to allow air flow out of said pneumatic chamber;
• a plurality of valves with at least one valve in each of said air exhaust ducts installed so as to regulate the flow of air through said air duct;
• a plurality of position sensing and control means, one of said means connected to each of said valves, said means controlling the position of said valve so as to cause the air pressure in the corresponding pneumatic chamber connected to the exhaust duct containing said valve to vary as a function of the distance between the main platform and a movable portion of the corresponding planing seal attached to said corresponding pneumatic chamber, said function being adjusted so as to dampen an minimize the vertical movements of that portion of the main platform immediately above said corresponding planing seal relative to the water surface underneath said corresponding planing seal.

A system for stabilizing an air cushion vehicle having a main platform, rigid sidewalls attached thereto on the port and starboard sides, and a source of pressurized air comprising:

• a plurality of planing seals attached to the platform on the bow and stern ends of the vehicle, with at least one said seal attached to each end, one edge of each seal being attached to the platform and another edge of each seal permitted to move so that it is in substantially continuous contact with the surface of the water, the size, shape and position of the seals being adjusted so that a main air cushion is developed from air provided by the pressurized air source and confined by the main platform, sidewalls and planing seals;
• a plurality of variable volume pneumatic chambers, at least one said chamber connected between a movable portion of each planing seal and the main platform so as to exert a force between the platform and the seal;
• a plurality of air supply ducts to provide pressurized air from said pressurized air source to each of said pneumatic chambers and to the main air cushion;
• a plurality of air exhaust ducts, with at least one connected to each pneumatic chamber to allow air flow out of said pneumatic chamber;
• a plurality of valves with at least one valve in each of said air exhaust ducts installed so as to regulate the flow of air through said air duct;
• a plurality of position sensing and control means, one of said means connected to each of said valves, said means controlling the position of said valve so as to cause the air pressure in the corresponding pneumatic chamber connected to the exhaust duct containing said valve to vary as a function of the roll and pitch of the air cushion vehicle and the distance between said main platform and a movable portion of said corresponding planing seal, said roll, pitch and distance measured by remote sensors and used to compute said function, said function applied to said valves by servo mechanisms, and said function being adjusted so as to dampen and minimize the roll, pitch and heave movements of said air cushion vehicle with respect to the water surface as a whole over the area underneath said vehicle.

A system for stabilizing an air cushion-vehicle having a main platform, rigid sidewalls attached thereto on the port and starboard sides, flexible finger seals at the bow, and a source of pressurized air comprising:

• at least one planing seal attached to the platform on the stern of the vehicle, one edge of each seal being attached to the platform and another edge of each seal permitted to move so that it is in substantially continuous contact with the surface of the water, the size, shape and position of the seals being adjusted so that a main air cushion is developed from air provided by the pressurized air source and confined by the main platform, the flexible finger seals, sidewalls and planing seals;
• a plurality of variable volume pneumatic chambers, at least one said chamber connected between a movable portion of each planing seal and the main platform so as to exert a force between the platform and the seal;
• a plurality of air supply ducts to provide pressurized air from said pressurized air source to each of said pneumatic chambers and to the main air cushion;
• a plurality of air exhaust ducts, with at least one connected to each pneumatic chamber to allow air flow out of said pneumatic chamber;
• a plurality of valves with at least one valve in each of said air exhaust ducts installed so as to regulate the flow of air through said air duct;
• a plurality of position sensing and control means, one of said means connected to each of said valves, said means controlling the position of said valve so as to cause the air pressure in the corresponding pneumatic chamber connected to the exhaust duct containing said valve to vary as a function of the distace between the main platform and a movable portion of the corresponding planing seal attached to said corresponding pneumatic chamber, said function being adjusted so as to dampen and minimize the vertical movements of that portion of the main platform immediately above said corresponding planing seal relative to the water surface underneath said corresponding planing seal.