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The Allsopp Helikite is a type of kite-balloon or kytoon designed by Sandy Allsopp in the United Kingdom in 1993. [1] This Helikite comprises a combination of a helium balloon and a kite to form a single, aerodynamically sound, tethered aircraft, that utilises both wind and helium for its lift.
The Helikite, created by Allsopp Helikites Ltd., comprises a semi-rigid helium-filled balloon, having a rigid carbon-fiber spine, with the balloon shaped aerodynamically. The balloon is generally oblate-spheroid in shape in which solid spars provide attachment points for payload equipment.
In most winds, the aerodynamic lift is greater than the aerostatic lift from the helium.
The Helikite design is intended for all-weather, high-altitude operations. The balloons' shape allows it to be flown in any weather or for altitudes up to 7000 feet. In wind, both the main aerodynamic lift and the aerostatic lift are at the front, while the spar weight and keel are at the stern.
This gives Helikites various advantages over traditional aerostats. [2] Traditional aerostats need to utilize relatively low-lift helium gas to combat high winds, which means they need to have a lot of gas to cope and so are very large, unwieldy, and expensive. Because Helikites utilize wind lift, they only need to be a fraction of the size of traditional aerostats in order to operate in high winds. Helikites fly at many times higher altitudes than traditional aerostats of the same size. Being smaller, with fewer construction seams, means Helikites have minimal problems with gas leakage compared to traditional aerostats, so Helikites use far less helium.
Helikites do not need ballonets and so are simpler in construction than traditional aerostats, as Helikites do not need constant electrical power to keep them airborne. Helikites are also extremely stable and so are good aerial platforms for cameras or scientific instruments. Tiny Helikites will fly in all weathers, so these sizes are popular as they are very reliable but still easy to handle and do not require large expensive winches. Helikites can be small enough to fit fully inflated in a car but they can also be made large if heavy payloads are required to be flown to higher altitudes. Helikites are one of the most popular aerostat designs and are widely used by the scientific community, military, photographers, geographers, police, and first responders. Helikites are used by telecom companies to lift 4G and 5G base stations for areas without cellphone coverage.
Helikites range in size from 1 meter (gas volume 0.13m3) with a pure helium lift of 30g, up to 14 meters, (gas volume 250m3) able to lift 117 kg. Small Helikites can fly up to 1,000 feet altitude; medium-sized Helikites, up to 3,000 feet altitude; and large Helikites, up to 7,000 feet altitude.[ citation needed ]
A Helikite is a new type of tethered aerostat with its own official classification, distinct from any type of balloon.
The US Customs classifies a Helikite as "other non-powered aircraft", while the British Civil Aviation Authority's Air Navigation Order has created its own classification of "Helikites" as distinct from "kites" and "balloons".
Customs authorities classify the Helikite as a type of kite because of the considerable positive aerodynamic uplift in wind.
Helikites are used for aerial photography, lifting antennas, radio-relay, advertising, agricultural bird-control, position marking, and meteorology. The military also use Helikites as jungle marker balloons, for lifting radio-relays, and raising surveillance equipment.
45m3 Desert Star Helikites flown from Rapid-Response Helikite Launch Trailers are used by British Telecom to lift 4G base stations to supply cellphone coverage for emergencies, temporary events and blackspot areas.
After various sea-trials by Norwegian and British oil-spill response organizations, they determined that Helikites were the only compact aerostat capable of reliably operating at sea for their purposes. For this reason, small rapid-response surveillance Helikites are part of the emergency oil-spill response system of Scandinavia and the UK for operations in the Arctic Ocean.
Due to their stability, Helikites are capable of successfully operating non-gyrostabilised cameras.
The British Army military Helikite surveillance system has 34 m³ volume and lifts a lightweight gyro camera with EO/IR capabilities. The US surveillance Helikites are 75m³ and carries a larger gyro camera system and targeting equipment. These aerostats outperform a conventional aerostat of twice the size. These Helikites can lift surveillance equipment above the range of small arms fire, effectively making Helikites unassailable to most common threats.
The smallest Helikite ever made was of just 0.028m³ (1 cubic ft). It flew well despite its tiny size. The largest Helikite made so far is 250m³ (8,750) cubic ft which has a net helium lift of 117 kg. This has been used by the Max Planck Institute for flights up to 7,000ft for cloud droplet research, flying from ocean research ships steaming across the Atlantic. [3]
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or the dynamic lift of an airfoil, or, in a few cases, direct downward thrust from its engines. Common examples of aircraft include airplanes, helicopters, airships, gliders, paramotors, and hot air balloons.
A kite is a tethered heavier-than-air or lighter-than-air craft with wing surfaces that react against the air to create lift and drag forces. A kite consists of wings, tethers and anchors. Kites often have a bridle and tail to guide the face of the kite so the wind can lift it. Some kite designs do not need a bridle; box kites can have a single attachment point. A kite may have fixed or moving anchors that can balance the kite. The name is derived from the kite, the hovering bird of prey.
Unpowered aircraft can remain airborne for a significant period of time without onboard propulsion. They can be classified as gliders, lighter-than-air balloons and tethered kites. 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.
A blimp, or non-rigid airship, is an airship (dirigible) without an internal structural framework or a keel. Unlike semi-rigid and rigid airships, blimps rely on the pressure of the lifting gas inside the envelope and the strength of the envelope itself to maintain their shape.
An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air.
Kite aerial photography (KAP) is a type of photography. A camera is lifted using a kite and is triggered either remotely or automatically to take aerial photographs. The camera rigs can range from the extremely simple, consisting of a trigger mechanism with a disposable camera, to complex apparatus using radio control and digital cameras. On some occasions it can be a good alternative to other forms of aerial photography.
An aerostat is a lighter-than-air aircraft that gains its lift through the use of a buoyant gas. Aerostats include unpowered balloons and powered airships. A balloon may be free-flying or tethered. The average density of the craft is lower than the density of atmospheric air, because its main component is one or more gasbags, a lightweight skin containing a lifting gas to provide buoyancy, to which other components such as a gondola containing equipment or people are attached. Especially with airships, the gasbags are often protected by an outer envelope.
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.
A gas balloon is a balloon that rises and floats in the air because it is filled with a gas lighter than air. When not in flight, it is tethered to prevent it from flying away and is sealed at the bottom to prevent the escape of gas. A gas balloon may also be called a Charlière for its inventor, the Frenchman Jacques Charles. Today, familiar gas balloons include large blimps and small latex party balloons. For nearly 200 years, well into the 20th century, manned balloon flight utilized gas balloons before hot-air balloons became dominant. Without power, heat or fuel, untethered flights of gas balloons depended on the skill of the pilot. Gas balloons have greater lift for a given volume, so they do not need to be so large, and they can stay up for much longer than hot air balloons.
A hybrid airship is a powered aircraft that obtains some of its lift as a lighter-than-air (LTA) airship and some from aerodynamic lift as a heavier-than-air aerodyne.
An airborne wind turbine is a design concept for a wind turbine with a rotor supported in the air without a tower, thus benefiting from the higher velocity and persistence of wind at high altitudes, while avoiding the expense of tower construction, or the need for slip rings or yaw mechanism. An electrical generator may be on the ground or airborne. Challenges include safely suspending and maintaining turbines hundreds of meters off the ground in high winds and storms, transferring the harvested and/or generated power back to earth, and interference with aviation.
Balloons and kites were the first inventions used in aerial warfare and their primary role was observation. Balloons provided an unreliable and stable means of elevating an observer high over the battlefield to obtain a birds-eye view of troop positions and movements. An early instrument of aerial intelligence collection, they were also useful for creating accurate battlefield maps, an important ingredient for battlefield success. Incendiary balloons also have a long history. The incendiary balloons carry hot air or something that can catch fire to destroy enemy territory. They could also hold small bombs for combat. The history of military ballooning dates back to the late 18th century, when the Montgolfier brothers, Joseph-Michel and Jacques-Étienne, first demonstrated the potential of hot-air balloons for military use. The first recorded military use of balloons was during the French Revolutionary Wars, when the French military used balloons to gather intelligence on the movements of the enemy. Balloons were also used during the American Civil War, where they were used for reconnaissance and communication. Balloons had a decline after several incidents in the interwar period.
An observation balloon is a type of balloon that is employed as an aerial platform for gathering intelligence and spotting artillery. The use of observation balloons began during the French Revolutionary Wars, reaching their zenith during World War I, and they continue in limited use today. Synonyms include espionage balloon, reconnaissance balloon, spy balloon, and surveillance balloon.
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.
A tethered, moored or captiveballoon is a balloon that is restrained by one or more tethers attached to the ground and so it cannot float freely. The base of the tether is wound around the drum of a winch, which may be fixed or mounted on a vehicle, and is used to raise and lower the balloon.
The Tethered Aerostat Radar System (TARS) is an American low-level airborne ground surveillance system that uses aerostats as radar platforms. Similar systems include the EL/M-2083 and JLENS.
A lifting gas or lighter-than-air gas is a gas that has a density lower than normal atmospheric gases and rises above them as a result. It is required for aerostats to create buoyancy, particularly in lighter-than-air aircraft, which include free balloons, moored balloons, and airships. Only certain lighter than air gases are suitable as lifting gases. Dry air has a density of about 1.29 g/L at standard conditions for temperature and pressure (STP) and an average molecular mass of 28.97 g/mol, and so lighter-than-air gases have a density lower than this.
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 AeroLift CycloCrane was a unique US hybrid airship which adopted helicopter derived airfoil control for low speed flight manoeuvring by spinning on its axis. It was intended to be a heavy load lifter, initially aimed at the Canadian logging industry. A proof of concept vehicle flew at times during the 1980s, but no large production aircraft were built.
Unpowered flight is the ability to stay airborne for a period of time without using any power source. There are several types of unpowered flight. Some have been exploited by nature, others by humankind, and some by both.