Polaris solar PV net news: after the Ching Ming Festival, the world’s largest solar-powered airplane “shinin 2nd” (Solar Impulse), from Chongqing to Nanjing. In recent days, people in this frame from the U.A.E. capital of Abu Dhabi’s interest in flying big planes are not reduced, it represents the high-tech, what is the application in the next debate. This reporter recently interviewed experts in Shanghai, an in-depth analysis of the frame of large aircraft operating by the light.
Effective in reducing CO2 emissions
The world economy, particularly in the Asia-Pacific economic growth rapid growth in air traffic, the aviation industry’s impact on the environment is increasingly become a focus of the aviation community, and become one of the most important driving force of technology development. Reduced or no fossil fuel to make flight is a dream for humans for a long time, scientists and adventurers trying to turn a dream into reality for years. Medium-term research on solar-powered aircraft began early in the 20th century, until the 70 ‘s of last century, as the cost of solar control, solar-powered aircraft’s design and construction was completed, but only for microcomputers.
“Sun power 2nd,” is not first frame will solar conversion for power provides flight power of aircraft, this zhī qián, regardless of he of “brother” “Sun power 1th,” or more earlier by United States national aviation cum space Department (NASA) and United States unmanned machine manufacturers Aero Vironment company cooperation development of “Sun God,”, aircraft are once will in sky clouds between constantly challenge solar flight of height and length.
“In fact internationally there have been many such attempts to research institutions or companies, have also experienced a lot of problems. “Shinin 2nd” is definitely a green aircraft than any other, it “shinin 1th” improvements have been made on the basis of, and should be described in the integrated aspects of aircraft performance. “The school of Aeronautics and Astronautics, Shanghai Jiaotong University Associate Professor Song Wenbin said.
It is understood that carbon dioxide emissions from aviation currently has 2% per cent of total global anthropogenic carbon dioxide emissions, and at a 3% rate increase every year. Some flights has been used exclusively by the petrochemical aviation fuels and derived from waste cooking oil into bio-jet fuel made of blended fuels, from Shanghai to Hong Kong which will reduce carbon dioxide emissions to 25 tonnes. Weight reduction design
The design of an aircraft requires combination of factors, “Sun power 2nd” aerodynamics, materials and structures, electronics, ergonomics and other advanced technologies are integrated. “Solar power is relatively small, it is a challenge for the aircraft. “Song Wenbin explained, it must first overcome” weight “problem. “Sun power 2nd,” of body using carbon fiber material, hosted capacity high weight light, which some carbon fiber plate each square meters of weight only has 25 grams; to reduction heavy, cockpit not equipped with booster and air conditioning system, but through cabin body using light insulation insulation, and the for pilots equipped with special flight clothing to against flight in the encountered of “ice fire double days”; also, store power of solar panel also selection thin paragraph. In this way, the aircraft weight control at 2300 kg, which is equivalent to the weight of a car, only 1% the weight of Boeing 747 aircraft. “In addition, the aircraft also reduced the weight of carrying fuel to use solar energy. “Song Wenbin said.
Large aircraft and light, and will be very much affected by airflow and aerodynamic efficiency and stability is also a big problem. Wingspan affect the induced drag of air resistance, with a wingspan smaller the longer the induced drag. “For the design of civilian aircraft, wingspan were bound by factors such as runway width, often is a” hard constraint “. Biggest A380 wide-body aircraft models of the 80-meter wingspan is limited, but for a small solar-powered aircraft aircraft, 72 m is already very long. In addition to considering the weight of actual use must refer to reality, if too broad there is no airport to land, so you need to balance consideration rather than indefinite extension wing. “Song Wenbin thinks” shinin 2nd “great wingspan 72 m is the best feature of this solar-powered aircraft aerodynamic design, one of the even more size to get more solar wing can not be designed to be wide enough, but supplemented by layout of solar panels on the fuselage.
In addition, speed is also “shinin 2nd” the key to safe flight. Its takeoff speed of 35-kilometer km/h cruising speed: 90-kilometer km/h, maximum speed of only 140-kilometer/hour. Song Wenbin explained that for this type of solar-powered aircraft, speed will cause excessive air load increased weight caused by computing 90-kilometer/h is probably the best speed. Because of this, the “Sun power, 2nd” recently arrived in Ahmedabad more than 1500 km from Muscat took 14 hours and 14 hours of ordinary commercial aircraft can fly from Shanghai to half a world away in New York City.
In addition to the comprehensive win, Song Wenbin, the “Sun power 2nd” also frontier exploration in cockpit design. Throughout the flight, most challenging segment is going to be a few days later set out across the Pacific Ocean from Nanjing arrived in United States in Hawaii this section. This long period of time of flight is expected to take about 5 days, during which pilots will be 3.8 cubic meters continued to work in the cramped cabin and short breaks. “When the environmental and space is limited, how to get comfortable for pilots to keep flying for a long time is a subject worth exploring. “Song Wenbin said.
Carrying more than unlikely
So, whether solar can become the aircraft’s main energy source? It is this “Sun power 2nd” focused much of the focus. It together on the wings, fuselage and tail sticking 17248 135 μm thick silicon thin-film solar cell conversion efficiency of 23%. These batteries can produce maximum power 70-kilowatt, power output up to four single power 13.5 kW electric motor drives four 4 m diameter two-bladed propeller to power the aircraft. When the sunlight is sufficient surplus power to the onboard lithium polymer rechargeable battery.
Shanghai Jiao Tong University School of mechanical and power engineering, solar power generation and refrigeration Engineering Research Center Director Professor Wang Ruzhu, said solar power low, and sustain one’s flight is still possible, if you want to carry more people on the use of civil aircraft is not likely. “However, in the use of small spacecraft such as satellites, the use of solar energy is very popular. ”
Pure dreams of solar-powered aircraft already have, but its implementation requires both individual technical progress also requires a comprehensive integration capability enhancement. Song Wenbin, the “Sun power 2nd” pure solar flight around the world is a good validation of the aircraft for long endurance flight is feasible. “The ultimate aims to be applied in practice in the future. But for now, in practical application is still some distance in the future. “He said,” such as a solar-powered aircraft can show how many people and goods, nor how much real value in commercial airports accept landing is debatable. However, in small loads such as unmanned aircraft implementation as well as of great significance. Meanwhile, can further promote the green concept of aviation to promote the research and development of new technologies. ”
“Shinin 2nd” world tour to fly day and night is another adventure in the history of human flight, also made people see the possibilities of solar power as a clean energy source. Solar-powered plane or very far from ordinary people, but development of solar energy technology in China not far behind. Professor Wang Ruzhu said, especially solar energy for use in civil construction field, provide residents with living energy, China has great prospects.
Original title: “shinin” on behalf of airplanes in the future?