|
Wingsail
A wingsail, twin-skin sail or double skin sail is a variable-Camber (aerodynamics), camber aerodynamic structure that is fitted to a marine vessel in place of conventional sails. Wingsails are analogous to Wing, airplane wings, except that they are designed to provide lift on either side to accommodate being on either Tack (sailing), tack. Whereas wings adjust camber with Flap (aeronautics), flaps, wingsails adjust camber with a flexible or jointed structure (for hard wingsails). Wingsails are typically mounted on an unstayed spar—often made of Carbon-fiber-reinforced polymer, carbon fiber for lightness and strength. The geometry of wingsails provides more lift, and a better lift-to-drag ratio, than traditional sails. Wingsails are more complex and expensive than conventional sails. Introduction Wingsails are of two basic constructions that create an airfoil, "soft" and "hard", both mounted on an unstayed rotating mast. Whereas hard wingsails are rigid structures that are s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sail
A sail is a tensile structure, which is made from fabric or other membrane materials, that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails may be made from a combination of woven materials—including canvas or polyester cloth, laminated membranes or bonded filaments, usually in a three- or four-sided shape. A sail provides propulsive force via a combination of lift and drag, depending on its angle of attack, its angle with respect to the apparent wind. Apparent wind is the air velocity experienced on the moving craft and is the combined effect of the true wind velocity with the velocity of the sailing craft. Angle of attack is often constrained by the sailing craft's orientation to the wind or point of sail. On points of sail where it is possible to align the leading edge of the sail with the apparent wind, the sail may act as an airfoil, generating propulsive force as air pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wing
A wing is a type of fin that produces both Lift (force), lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform (aeronautics), planform. Wing efficiency is expressed as lift-to-drag ratio, which compares the benefit of lift with the air resistance of a given wing shape, as it flies. Aerodynamics is the study of wing performance in air. Equivalent Foil (fluid mechanics), foils that move through water are found on Hydrofoil, hydrofoil power vessels and Sailing hydrofoil, foiling sailboats that lift out of the water at speed and on submarines that use diving planes to point the boat upwards or downwards, while running submerged. Hydrodynamics is the study of foil performance in water. Etymology and usage The word "wing" from the Old Norse ''vængr'' for many centuries referred mainly to the foremost limb (anatomy), limbs of birds (in addition to the architectural aisle). But in recent centuries the word's meaning ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Downwind
In geography and seamanship, windward () and leeward () are directions relative to the wind. Windward is ''upwind'' from the point of reference, i.e., towards the direction from which the wind is coming; leeward is ''downwind'' from the point of reference, i.e., along the direction towards which the wind is going. The side of a ship that is towards the leeward is its "lee side". If the vessel is heeling under the pressure of crosswind, the lee side will be the "lower side". During the Age of Sail, the term ''weather'' was used as a synonym for ''windward'' in some contexts, as in the ''weather gage''. Since it captures rainfall, the windward side of a mountain tends to be wetter than the leeward side it blocks. The drier leeward area is said to be in a rain shadow. Origin The term "windward" has roots in both Low German and Old English. The word "lee", which means a place without wind, comes from the Old Norse "hle" for "cover" and has been used in marine navigation in Germ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broad Reach
A point of sail is a sailing craft's direction of travel under sail in relation to the true wind direction over the surface. The principal points of sail roughly correspond to 45° segments of a circle, starting with 0° directly into the wind. For many sailing craft 45° on either side of the wind is a ''no-go'' zone, where a sail is unable to mobilize power from the wind. Sailing on a course as close to the wind as possible—approximately 45°—is termed ''beating'', a point of sail when the sails are ''close-hauled''. At 90° off the wind, a craft is on a ''beam reach''. The point of sail between beating and a beam reach is called a ''close reach''. At 135° off the wind, a craft is on a ''broad reach''. At 180° off the wind (sailing in the same direction as the wind), a craft is ''running downwind''. A given point of sail (beating, close reach, beam reach, broad reach, and running downwind) is defined in reference to the true wind—the wind felt by a stationary observe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point Of Sail
A point of sail is a sailing craft's direction of travel under sail in relation to the true wind direction over the surface. The principal points of sail roughly correspond to 45° segments of a circle, starting with 0° directly into the wind. For many sailing craft 45° on either side of the wind is a ''no-go'' zone, where a sail is unable to mobilize power from the wind. Sailing on a course as close to the wind as possible—approximately 45°—is termed ''beating'', a point of sail when the sails are ''close-hauled''. At 90° off the wind, a craft is on a ''beam reach''. The point of sail between beating and a beam reach is called a ''close reach''. At 135° off the wind, a craft is on a ''broad reach''. At 180° off the wind (sailing in the same direction as the wind), a craft is ''running downwind''. A given point of sail (beating, close reach, beam reach, broad reach, and running downwind) is defined in reference to the true wind—the wind felt by a stationary observ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lift (force)
When a fluid flows around an object, the fluid exerts a force on the object. Lift is the Euclidean_vector#Decomposition_or_resolution, component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag (physics), drag force, which is the component of the force parallel to the flow direction. Lift conventionally acts in an upward direction in order to counter the force of gravity, but it is defined to act perpendicular to the flow and therefore can act in any direction. If the surrounding fluid is air, the force is called an aerodynamic force. In water or any other liquid, it is called a Fluid dynamics, hydrodynamic force. Dynamic lift is distinguished from other kinds of lift in fluids. Aerostatics, Aerostatic lift or buoyancy, in which an internal fluid is lighter than the surrounding fluid, does not require movement and is used by balloons, blimps, dirigibles, boats, and submarines. Planing (boat), Planing lift, in which only the lower po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle Of Attack
In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a Airfoil#Airfoil terminology, reference line on a body (often the chord (aircraft), chord line of an airfoil) and the vector (geometry), vector representing the relative motion between the body and the fluid through which it is moving. Angle of attack is the angle between the body's reference line and the oncoming flow. This article focuses on the most common application, the angle of attack of a wing or airfoil moving through air. In aerodynamics, angle of attack specifies the angle between the chord line of the wing of a fixed-wing aircraft and the vector representing the relative motion between the aircraft and the atmosphere. Since a wing can have twist, a chord line of the whole wing may not be definable, so an alternate reference line is simply defined. Often, the chord line of the Wing root, root of the wing is chosen as the reference line. Another choice is to use a horizontal line on the fuse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Wind
Apparent wind is the wind experienced by a moving object. Definition of apparent wind The ''apparent wind'' is the wind experienced by an observer in motion and is the relative velocity of the wind in relation to the observer. The ''velocity of the apparent wind'' is the vector sum of the ''velocity of the headwind'' (which is the velocity a moving object would experience in still air) plus the ''velocity of the true wind''. The headwind is the additive inverse of the object's velocity; therefore, the ''velocity of the apparent wind'' can also be defined as a vector sum of the ''velocity of the true wind'' minus the ''velocity of the object''. Apparent wind in sailing In sailing, ''apparent wind'' is the speed and direction of wind indicated by a wind instrument ( anemometer) on a ''moving'' craft (on water, land or ice) in undisturbed air. It is composed of the ''combined'' speeds and directions of the craft and wind observed by a ''stationary'' wind instrument—the ''true ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Close-hauled
A point of sail is a sailing craft's direction of travel under sail in relation to the true wind direction over the surface. The principal points of sail roughly correspond to 45° segments of a circle, starting with 0° directly into the wind. For many sailing craft 45° on either side of the wind is a ''no-go'' zone, where a sail is unable to mobilize power from the wind. Sailing on a course as close to the wind as possible—approximately 45°—is termed ''beating'', a point of sail when the sails are ''close-hauled''. At 90° off the wind, a craft is on a ''beam reach''. The point of sail between beating and a beam reach is called a ''close reach''. At 135° off the wind, a craft is on a ''broad reach''. At 180° off the wind (sailing in the same direction as the wind), a craft is ''running downwind''. A given point of sail (beating, close reach, beam reach, broad reach, and running downwind) is defined in reference to the true wind—the wind felt by a stationary observe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point Of Sail
A point of sail is a sailing craft's direction of travel under sail in relation to the true wind direction over the surface. The principal points of sail roughly correspond to 45° segments of a circle, starting with 0° directly into the wind. For many sailing craft 45° on either side of the wind is a ''no-go'' zone, where a sail is unable to mobilize power from the wind. Sailing on a course as close to the wind as possible—approximately 45°—is termed ''beating'', a point of sail when the sails are ''close-hauled''. At 90° off the wind, a craft is on a ''beam reach''. The point of sail between beating and a beam reach is called a ''close reach''. At 135° off the wind, a craft is on a ''broad reach''. At 180° off the wind (sailing in the same direction as the wind), a craft is ''running downwind''. A given point of sail (beating, close reach, beam reach, broad reach, and running downwind) is defined in reference to the true wind—the wind felt by a stationary observ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reefing
Reefing reduces the area of a sail, usually by folding or rolling one edge of the canvas in on itself and attaching the unused portion to a Spar (sailing), spar or a , as the primary measure to preserve a sailing vessel's stability in strong winds. Restoring full sail area is termed ''shaking out'' a . Whereas Fore-and-aft rig, fore-and-aft rigged vessels store the unused portion of the sail on a boom (sailing), boom (below the sail), square rig, square-rigged vessels stow the unused portion on a spar above the sail. Reefing may occur by rolling the sail around its Sail components, luff or Foot (sailing), foot, either on a rotating stay or within a spar. Fore-and-aft rigs Sails may have built-in alternative attachment points that allow their area to be reduced. In a mainsail, reefing cringles may be installed in the sail; a cruising boat will typically have two to three pairs. These are pulled down to the boom to form a new tack and clew, reducing the sail's area. The first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
