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Unpowered Aircraft
Unpowered aircraft can remain airborne for a significant period of time without onboard propulsion. They can be classified as fixed-wing gliders, lighter-than-air balloons and tethered kites. This requires a trajectory that is not merely a vertical descent such as a parachute. In the case of kites, lift is obtained by tethering to a fixed or moving object, perhaps another kite, to obtain a flow of wind over the lifting surfaces. In the case of balloons, lift is obtained through inherent buoyancy and the balloon may or may not be tethered. Free balloon flight has little directional control. Gliding aircraft include sailplanes, hang gliders, and paragliders that have full directional control in free flight. History The first manned aircraft were kites, balloons and gliders. Man-lifting kites were used in ancient China and Japan, often as a punishment for prisoners. Unmanned hot-air balloons and toy "bamboo-copters" are also recorded in Chinese history. The first manned free fligh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hanggliding03042006
Hang gliding is an air sport or recreational activity in which a pilot flies a light, non-motorised foot-launched heavier-than-air aircraft called a hang glider. Most modern hang gliders are made of an aluminium alloy or composite frame covered with synthetic sailcloth to form a wing. Typically the pilot is in a harness suspended from the airframe, and controls the aircraft by shifting body weight in opposition to a control frame. Early hang gliders had a low lift-to-drag ratio, so pilots were restricted to gliding down small hills. By the 1980s this ratio significantly improved, and since then pilots have been able to soar for hours, gain thousands of feet of altitude in thermal updrafts, perform aerobatics, and glide cross-country for hundreds of kilometers. The Federation Aeronautique Internationale and national airspace governing organisations control some regulatory aspects of hang gliding. Obtaining the safety benefits of being instructed is highly recommended and indeed a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potential Energy
In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. Common types of potential energy include the gravitational potential energy of an object, the elastic potential energy of an extended spring, and the electric potential energy of an electric charge in an electric field. The unit for energy in the International System of Units (SI) is the joule, which has the symbol J. The term ''potential energy'' was introduced by the 19th-century Scottish engineer and physicist William Rankine, although it has links to Greek philosopher Aristotle's concept of potentiality. Potential energy is associated with forces that act on a body in a way that the total work done by these forces on the body depends only on the initial and final positions of the body in space. These forces, that are called ''conservative forces'', can be represented at every point in space by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gliding Competitions
Some of the pilots in the sport of gliding take part in gliding competitions. These are usually racing competitions, but there are also aerobatic contests and on-line league tables. History of competitions In the early days, the main goal was to stay airborne for as long as possible. However, flights could last for days and some pilots killed themselves by falling asleep. This type of duration contest was abandoned by 1939. From the earliest days of gliding there was also 'free distance' flying. Pilots launched themselves from a hill top, attempting to glide as far as possible. Once pilots learned to exploit ridge lift and thermals, flights could be extended further. Eventually they mastered flying from thermal to thermal, resulting in ever longer retrieves. As the pilots and gliders became better, the winner of a competition day might fly so far that they could not get back to the competition site for the next day. Turn-points were therefore used. Those pilots who m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gliding
Gliding is a recreational activity and competitive air sport in which pilots fly unpowered aircraft known as gliders or sailplanes using naturally occurring currents of rising air in the atmosphere to remain airborne. The word ''soaring'' is also used for the sport. Gliding as a sport began in the 1920s. Initially the objective was to increase the duration of flights but soon pilots attempted cross-country flights away from the place of launch. Improvements in aerodynamics and in the understanding of weather phenomena have allowed greater distances at higher average speeds. Long distances are now flown using any of the main sources of rising air: ridge lift, thermals and lee waves. When conditions are favourable, experienced pilots can now fly hundreds of kilometres before returning to their home airfields; occasionally flights of more than are achieved. Some competitive pilots fly in races around pre-defined courses. These gliding competitions test pilots' abilities to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kite Types
Kites are tethered flying objects which fly by using aerodynamic lift, requiring wind (or towing) for generation of airflow over the lifting surfaces. Various types of kites exist, depending on features such as material, shape, use, or operating skills required. Kites may fly in air, water, or other fluids such as gas and other liquid gaining lift through deflection of the supporting medium. Variations in design of tethering systems and lifting surfaces are regularly introduced, with lifting surfaces varying in stiffness from limp sheet material to fully solid material. Manufacture Kites may be built by the flier or by a dedicated kite manufacturer, which may be a member of the Kite Trade Association International (KTAI), which also includes kite retailers. Materials Kites have been made from the following materials: *Plastic – for example, a Styrofoam-only kite *Organic materials – such as plant leaves and grass *Paper *Textiles such as rip-stop nylon, nylon, or Dac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Altitude Wind Power
Airborne wind energy (AWE) is the direct use or generation of wind energy by the use of aerodynamic or aerostatic lift devices. AWE technology is able to harvest high altitude winds, in contrast to wind turbines, which use a rotor mounted on a tower. The term high-altitude wind power (HAWP) has been used to refer to AWE systems. However, semantically HAWP might also include wind energy conversion systems that are somehow positioned at a large height from the ground or sea surface. Various mechanisms are proposed for capturing the kinetic energy of winds such as kites, kytoons, aerostats, gliders, gliders with turbines for regenerative soaring, sailplanes with turbines, or other airfoils, including multiple-point building- or terrain-enabled holdings. Once the mechanical energy is derived from the wind's kinetic energy, then many options are available for using that mechanical energy: direct traction, conversion to electricity aloft or at ground station, conversion to laser or mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kite Control Systems
Kite types, kite mooring, and kite applications result in a wide variety of kite control systems. Contemporary manufacturers, kite athletes, kite pilots, scientists, and engineers are expanding the possibilities. Single-line kite control systems High-altitude attempt single-line control systems On-board angle-of-attack mechanisms were used in the 2000 altitude record-making flight; the operators' designed adjuster limited kite line tension to not more than 100 pounds by altering the angle of attack of the kite's wing body. The kite's line had a control: a line payout meter that did not function in the record-setting flight. However, some special tether line lower end used bungee and pulley arrangements to lower the impact of gusts on the long tether. Control of a kite includes how other aircraft see the kite system; the team placed a radio beacon (using two-meter frequency detectable for 50 miles) on the kite; for sight visibility, strobe lights were hung from the kite's nos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kytoon
A kytoon or kite balloon is a tethered aircraft which obtains some of its lift dynamically as a heavier-than-air kite and the rest aerostatically as a lighter-than-air balloon. The word is a portmanteau of kite and balloon. The primary advantage of a kytoon is that it remains in a reasonably stable position above the tether point, irrespective of the strength of wind, whereas ordinary balloons and kites are less stable. The kytoon has been used for many purposes both civil and military. History In 1919, a handbook was published giving extensive details to support the kite balloon crafts being used in the military. Described is the first kite balloon made in 1893 by Captains Parseval and Sigsfeld at the Berlin works of the Prussian Balloon Battalion; theirs was the "predecessor of the ''Drachen'' balloon." "This was the first real kite balloon flying like a kite with a fairly constant angle and direction relative to the wind and remained practically unchanged until the beginning o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kite Line
In kiting, a line is the string made of cotton, nylon, silk or wire, which connects the kite to the person operating it or an anchor. Kites have a set of wings, a set of anchors, and a set of lines coupling the wings with the anchors. Kite lines perform various roles: bridle, control, tug, or special duty. Successful kiting in particular kite applications depends in large part on the kite line's specifications and handling. The integrity of kite lines is affected by wear, reeling, contact with chemicals, loss of strength from knottings, ultraviolet rays of the sun, repeated cycles of use, and damaging actions during use. There are historically classic specifications of kite lines. Kite lines for small toy kites differ greatly from kite lines used for kite tugs that pull commercial cargo ships across the ocean. Sport kites using kite line sets of two or three or four lines at a time have a need for very low stretch in the lines. Single-line recreation kite lines may do well with str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program, aeronautics research, and outer space, space research. NASA was National Aeronautics and Space Act, established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science. NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968-1972 Apollo program, Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion (spacecraft), Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew Program, Commercial Crew ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kite Balloon
A kite balloon is a tethered balloon which is shaped to help make it stable in low and moderate winds and to increase its lift. It typically comprises a streamlined envelope with stabilising features and a harness or yoke connecting it to the main tether and a second harness connected to an observer's basket. Kite balloons are able to fly in higher winds than ordinary round balloons which tended to bob and spin in windy conditions.Ege, 1973, pp.128–129 They were extensively used for military observation during World War I and similar designs were used for anti-aircraft barriers, as barrage balloons in both world wars. Design and development Developed in Germany from 1893 by ''Parseval'' and ''Sigsfeld'', the main component of a kite balloon is its tubular-shaped envelope, similar to that of a non-rigid airship, giving it its British and French nicknames of "sausage". This was inclined at a nose up angle to about 30–40° from the horizontal, which resulted in it producing som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balloon (aircraft)
In aeronautics, a balloon is an unpowered aerostat, which remains aloft or floats due to its buoyancy. A balloon may be free, moving with the wind, or tethered to a fixed point. It is distinct from an airship, which is a powered aerostat that can propel itself through the air in a controlled manner. Many balloons have a basket, gondola, or capsule suspended beneath the main envelope for carrying people or equipment (including cameras and telescopes, and flight-control mechanisms). Principles A balloon is conceptually the simplest of all flying machines. The balloon is a fabric envelope filled with a gas that is lighter than the surrounding atmosphere. As the entire balloon is less dense than its surroundings, it rises, taking along with it a basket, attached underneath, which carries passengers or payload. Although a balloon has no propulsion system, a degree of directional control is possible through making the balloon rise or sink in altitude to find favorable wind di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
