Summary of the technical development of the hottes

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Summary of airship technology development

airships are powered lighter than air aircraft and a kind of aerostat. They use lighter than air gases (hydrogen, helium, hot gas, etc.) to provide lift. The airship is mainly composed of streamlined capsule, fixed and movable tail wings for control, pods with insufficient diversion of renewable resources for passengers or passengers, and propulsion system. According to the early structural classification method, airships can be divided into hard, semi-hard and soft structures. Modern airship technology has blurred the original definition. Modern airships are mainly classified according to their uses: no lift type, partial lift type and full lift type

brief history of airship development

airship originated in France in 1784 and has been widely used in military and commercial fields before the Second World War. Compared with other aircraft, airships have experienced the development from unpowered to powered propulsion, from unmanned to manned, from short-range flight to long-range flight, and from low altitude to high altitude, However, this "maximum" means that the maximum acceleration of the object in the deceleration process is not the maximum in the whole process. Therefore, it is impossible to draw the conclusion that the acceleration at the lowest point is the maximum only based on the above analysis. It has accumulated and formed the unique technology of airship such as airship skin making, anchoring, mooring technology, etc. Due to the "Hindenburg" incident in 1937 and the rapid development of aircraft and helicopters, airships gradually withdrew from the aviation arena. With the development of aviation technology and material technology, the breakthrough of other key technologies and the oil crisis in the 1960s and 1970s, after breaking through the shortcomings of poor technical performance and poor safety performance of old airships, modern airships, an energy-saving aircraft, have ushered in new development and application. At present, airship manufacturers around the world mainly focus on the development and production of low altitude airships such as advertising, aerial photography, tourism and heavy-duty transportation. In addition, government agencies of other countries invest in the development and production of high-altitude military airships or super heavy-duty airships to large airship manufacturers and scientific research institutions. The United States, Russia, Britain, Japan and other countries take the lead in the development and production of airships. China Huajiao passed the airworthiness certification of the first Chinese airship for the first time in 2004, followed by Beijing Beihang Longsheng aircraft company. At present, China has more than 20 airship production enterprises and scientific research institutions

characteristics and uses of airships

because airships have a low flying speed compared with aircraft (airship speed generally does not exceed 140km/h), they have a simple take-off and landing site and do not need long-distance runways. Compared with helicopters, airships have a large carrying capacity and very low fuel consumption at fixed points. Therefore, airships can be used as a supplement to high-speed and high-energy aircraft, and can be used in civil fields such as long-distance transportation, polar exploration, oil and coal mine exploration, disaster resistance and rescue, live broadcasting, aerial photography, advertising operations, etc; It can also be used in search and rescue, coast guard and other military fields. Compared with satellites, airships mainly have economic advantages. Compared with satellites, airships have low altitude in the air and short delay in receiving and transmitting signals. Therefore, airships can act as satellites to complete relay, reconnaissance, meteorological detection and other tasks. Although the airship also has its own shortcomings, such as the control of fixed point and travel in flight, the control of airbag inflation and deflation, airship recovery and repair, there is no satisfactory theoretical and practical guidance. In conclusion, with the advantages of long empty time and low energy consumption, airships have huge economic and military application prospects and development space

development status and trend of modern airships

the main problem of airships in operation is that this lighter than air aircraft gets the static lift of air by floating into the air bag, so the volume is much larger than that of the air aircraft. The distribution of airship pods and other appendages mainly considers the balance in the longitudinal and vertical planes of the airship. For the conventional airship shape, the external aerodynamic lift relative to the static lift can be ignored

in order to overcome the difficulties of airships which are large and difficult to operate, and give full play to their characteristics of long empty time and low energy consumption, at present, countries all over the world are developing hybrid airships (also known as combined airships) that combine air static lift and aerodynamic lift. Typical airships include airships + aircraft, airships + helicopters, and airships designed by airship companies in Britain, the United States, France, Russia and other countries in the 1970s and 1980s The shape of airships tested or put into use, such as flat airships, multi boat integrated airships, lens airships, arrow airships, etc. [2]. The combined airship is mainly used for heavy-duty and long-distance transportation. It balances its self weight by relying on the static lift of the airship capsule and other parts, and uses the aerodynamic lift generated by the wing or helicopter to lift the heavy objects. In this way, the airship's volume is greatly reduced, the handling performance is improved, and the payload is greatly increased (the aerodynamic lift of a single helicopter can reach 20t, and its self weight accounts for 11T). Various forms of combined airships are still in the research stage, and the author has not consulted the combined airships in use

the combined airship integrates aerostatics and aerodynamics. The difficulty in its research and development lies in the connection of other components of the airship capsule (such as wings). For conventional airships, the capsule is mostly of soft structure (the hard low altitude airship ended before World War II). The structural mass is light and the strength is small. If the wing or multiple propeller structures are connected, the complexity and structural mass will be greatly increased, It is difficult to simulate and analyze the flow field

another development direction of using airships to stay empty for a long time is high-altitude airships. The development of high-altitude airships in the United States and Japan is in the forefront of the world. In 2003, the US missile defense agency commissioned kesheed Martin company to develop high-altitude airships. Japan's high-altitude Stratospheric Airships for environmental monitoring, communication and broadcasting have been studied for many years. The main problems faced by high altitude airships are energy and heat problems. At present, although there are corresponding technical improvements, they are not satisfactory

1 research status and development trend of low altitude airships

low altitude airships refer to airships operating in the troposphere (about 18km away from sea level) in the atmosphere. Compared with airships before World War II, the obvious improvement is that the number of engines is reduced from 3~8 to 2~3 now, which is mainly due to the increase of single engine power and the increase of payload ratio. Based on the improvement of high-strength, lightweight materials and airship skin fabrication technology, modern low altitude airships mostly use soft structures. For low altitude airships, whether non lift type, partial lift type or full lift type, in addition to having enough capsule volume to provide static lift, a good streamlined shape should be designed to reduce air resistance, so as to reduce the fuel consumption rate of the engine

in addition, low altitude airships are mainly used in civil areas, and some are also used in military areas such as low altitude radar early warning. So low noise is a design goal. There are two well-known manufacturers in Europe - WDL company and Zeppelin airship industry company. In the United States, there are currently 7 companies engaged in airship operation, mainly passenger transportation, with the maximum tonnage of 2T. At present, there are more than 20 units engaged in airship research and production in China, but there are only three or four units integrating design, development and production capacity

the low altitude airships used for carrying people have two main development directions: gigantism and miniaturization. The United States and Russia are currently developing giant manned airships. Russia will research (4) release the residual oil in the oil tank and launch a super large airship capable of carrying 400~600 people. The overall technical design department of China's special aircraft will learn from the technology of Russia's giant airship and target the designed carrying capacity at 1000 people. The small household airship developed by American world airlines can carry 3 people. It has the advantages of simple and flexible operation and fast flight speed, and has a exploitable market potential

airships used for cargo transportation tend to be oversized and the design of combined airships. The United States has walrus program, Britain and Germany have proposed "skycat" program and "cargo crane" program respectively. China and other countries are also stepping up research in this area. Foreign countries have put forward the combination schemes of "rotor lift aircraft", "flight lift aircraft", "disc wing lift" and "rotor lift". For low altitude airships and combined airships, the main design objectives are large load, flight speed and range

2 research status and development trend of high-altitude airships

high altitude airships refer to Stratospheric Airships or near space airships, with a height of 20km ~ 100km. Because the high-altitude air density is about one tenth or less of that near the ground, and the huge volume is the remarkable feature of high-altitude airships, high-altitude airships are widely used [4]. Compared with the low altitude airship, its fixed-point mission determines that the requirements for the rising shape of its streamlined external experimental platform are not high. High altitude airships play an important role in territorial defense, solving local crises or conflicts, collecting atmospheric samples, and can be used as low-energy satellites

in recent years, there has been an upsurge of stratospheric platform development at home and abroad: the missile defense high altitude airship (HAA) that the US missile defense agency has begun to manufacture can carry 1814kg of mission equipment, reach a quasi-static earth orbit altitude of about 20km and stay for one month or even one year. The University of Stuttgart in Germany is implementing an airship project called "high altitude flight platform", with a flight altitude of 20km and a load capacity of 1t. In January2002, the Japan Institute of Aeronautics and Astronautics proposed to use the stratospheric airship platform as a pseudo satellite to replace GPS for satellite navigation and positioning. Israel, Canada and other countries have also designed stratospheric communication airships. In 2006, China took the stratospheric airship as a key scientific and technological project in the future. On march30,2007, CASIC became a full member of the steering committee of the EU veatal program (airship international cooperation program)

key research areas

1 problems to be solved during airship operation

although airships have many advantages compared with aircraft or helicopters which are heavier than air [3], there are also problems unique to airship operation that need to be solved

(1) large volume, sensitive to crosswind and difficult to manipulate

because the airship mainly relies on the buoyant gas lighter than the air, its large size is a remarkable feature of the airship shape, especially the heavy-duty airship. For the moment caused by crosswind, airship needs to install a large area of tail and control surface to balance the corresponding moment, and it needs to have a faster control response to the operation of the control surface. Therefore, the structural strength and control response requirements are improved

(2) the ground operation of ground anchoring and mooring of airships is difficult, although it has been improved

The anchoring of

airships is directly affected by the buoyancy gas management, structural design and ground operation. Among the above three problems, the ground operation is the most difficult, which is generally the use of manpower. In order to solve the cumbersome difficulties in the process of airship anchoring, people put forward mobile anchoring system, fixed anchoring system and low-speed control technology on the basis of summarizing the previous anchoring experience. The improvement of equipment and control technology can effectively simplify the anchoring process and reduce the difficulty of operation, but there will still be problems, especially for heavy-duty airships. Operation of airship with airship hangar

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