CVA 002 aircraft carrier - Catapult
China is looking into catapult technology, and the technology will likely be adopted on the 002, China's third aircraft carrier. "In other words, 002 is entirely different from the Liaoning (001) and 001A, and it will look like US aircraft carrier rather than a Russian one," Li Jie, a naval military expert, said 21 February 2017. China's patent database includes hundreds of patents for aircraft catapults, a topic that is singularly absent at the US Patent and Trademark Office.
The second domestic aircraft carrier will use catapults ["ejection device"], which will greatly enhance the combat effectiveness of aircraft carriers, aircraft carriers equipped with more types of carrier-based combat aircraft to provide possible. However, the media quoted sources as saying that because of the power problem, China in the first ejection carrier will use a more conservative steam ejection, rather than the current US military's most advanced aircraft carrier Ford's use of electromagnetic ejection. The source pointed out that the aircraft carrier nuclear reactor still has some technical problems, so 002 type will use steam ejection.
Under the current state of technology, conventional electric aircraft carriers can provide limited power, which is generally insufficient to support electromagnetic ejection. If it is necessary to use electromagnetic ejection on conventional power aircraft carriers, it is necessary to increase the fuel consumption in order to generate the required power. Under the premise that the fuel capacity of conventional power carriers is limited, it will reduce the fuel carried by carrier-based aircraft, making it difficult to maintain the combat effectiveness of aircraft carriers. At the same time, changing the steam system to the power system will also bring many problems such as control, configuration, and coordination, increasing the complexity of comprehensive management. Therefore, conventionally powered aircraft carriers are generally not suitable for electromagnetic ejection, especially for countries where the carrier technology is not very strong.
The hull module of the bow part of the Fujian ship may come from the original 003 aircraft carrier, and the originally planned steam catapult is relatively short. From the satellite photos of the aircraft carrier base, its length may be just over 100 meters. The length of the electromagnetic catapult has reached about 110 meters. After replacing the longer electromagnetic catapult, the bow part is shorter, and the flame shield of the No. 2 catapult cuts into the angled runway. The flame shield of the No. 1 catapult has run to the side of the front elevator on the starboard side.
Under the leadership of academician Ma Weiming, China successfully broke the electromagnetic ejection technology-related problems, and there is a lot of evidence that China has the J-15 carrier aircraft and large UAV conducted electromagnetic catapult experiment, for these models in the future equipped with ejection aircraft carrier laid a solid foundation.
The Chinese catapult launching system is based on DC, not AC as used by the catapult launching system installed in the Gerald R. Ford carrier. Starting in the late 1880s, Thomas Edison and Nikola Tesla were embroiled in a battle now known as the War of the Currents. Edison developed direct current -- current that runs continually in a single direction, like in a battery or a fuel cell. During the early years of electricity, direct current (shorthanded as DC) was the standard in the USA. But Direct current is not easily converted to higher or lower voltages. Tesla believed that alternating current (or AC) was the solution to this problem. Alternating current reverses direction a certain number of times per second -- 60 in the U.S. -- and can be converted to different voltages relatively easily using a transformer.
As the winner of the People's Liberation Army's top military award in 2017, Rear Admiral Ma Weiming is a familiar name to Chinese. In 2018 his research team developed a medium-voltage, direct-current transmission network to replace the older alternating current system for the country's domestically built Type 002 carrier, which could provide more power for its electromagnetic aircraft launch system (EMALS). The innovative design meant that high-energy consuming launch systems and weapons could now be used on a vessel driven by conventional power.
Defense News reported that China completed construction of two simulated carrier deck runways at its Huludao airbase in Liaoning province in October 2016. One of the test runways at Huludao outfitted with a steam catapult system. China reportedly reverse engineered the system from an Australian carrier, the HMAS Melbourne, which was “sold for scrap to a Chinese company in 1985.”
The "Short Takeoff But Arrested Recovery (STOBAR)" system permits aircraft to takeoff under their own power, with assistance from a curved ramp, and utilizes arrestor wires for landing aircraft. STOBAR does not support the recovery of aircraft landing when airplanes are taking off at the same time.
The system, while functional, is less effective than the catapult system (CATOBAR) utilized on US Nimitz Class carriers. The catapult assisted take-off but arrested recovery (CATOBAR) system provides for faster launching and recovery of aircraft, as well as launching heavier aircraft. This would include large early warning aircraft, anti-submarine aircraft and transport planes, as well as heavier combat aircraft carrying more fuel and weapons than possible with STOBAR launch.
The google.com/patents index includes over 400 patents mentioning "steam catapult", almost all being recent Chinese filings.
Chinese patent CN201089521Y [23 July 2008] disclosed a steam catapult for aircraft carrier-based aircraft, including decks, process control systems, launch systems and lubrication systems. Transmission system including a guide groove open deck aft, moving along the guide groove ejection buffer, the buffer at one end is connected to a catapult annular cable, annular cable surround the front and rear two fixed support wheels, a cylinder disposed in the annular below the cable, the annular piston is fixedly connected at both ends of the cable and the cylinder, the high-pressure cylinder closed at one end has a lubrication system, through a high pressure steam pipe with pneumatic valves connected to the other end of the brake piston disposed vent and buffers.
The one-way steam catapult with linear opening cylinder [Chinese patent CN 102815406 A of 12 December 2012] does not adopt the prior U-type-filling sealing technology, but a linear sealing technology with the combination of a composite steel rope and a counter cylinder to dynamically seal an opening steam main cylinder, which removes the defects of short sealing life and large maintenance of the U-type-filling sealing technology. Also, the steam catapult adopts back tracking motor-driven drag technology to realize the one way steam action of the catapult, thereby resolving the detects of large steam consumption of the U-type-filling sealing catapult and saving the valuable fresh water.
The Slotted type steam-driven catapult for airplane short-distance take-off [Chinese patent CN 103786894 A of 14 May 2014] is a slotted type steam-driven catapult for airplane short-distance take-off. Due to the fact that the main part of an American steam-driven catapult on active service is a slotted steam cylinder, the related sealing technology is high in requirement, and machining, maintenance and repairing difficulties are high. In order to solve the problems, the slotted type steam-driven catapult adopts a creative slotted steam cylinder and sealing technology, machining, maintenance and repairing difficulties are lowered greatly, and independent production can be performed by China. By methods such as expanding the diameter of the steam cylinder, increasing steam pressure and parallelly connecting multiple groups of steam cylinders, catapulting power can be increased, catapulting take-off of heavy carrier airplanes such as Su-30MKK with full oil load can be achieved, the blow radius of the carrier airplanes of China is expanded to above 1500 kilometers, and territory, territorial waters and other national benefits of China can be guarded effectively.
By one account, the Type 002 aircraft carrier will be using steam catapults, not equipped with electromagnetic catapult. Because the development time of the design stage of a 002 type aircraft carrier and electromagnetic catapult project is largely the same, such as aircraft carriers of weapons and equipment, the subsystem of maturity must be far earlier than the beginning of the overall design time, so the 002 aircraft carrier at the beginning of the design there is the inevitable choice of steam catapult, when construction started in 2015, just electromagnetic catapult if successful, 002 aircraft carrier to use electromagnetic catapult, then it meant that the overall design of the ship to start, this is obviously not realistic.
At present, the aircraft carrier of most countries in the world generally use steam catapult. Steam catapult manufacturing is complex, an requires steam boilers, pressure storage tanks, large piston and cylinder, and desalination equipment. The steam catapult usually must maintain a sufficiently high pressure steam, so that in emergency situations aircraft can take off on time only. The steam catapult cylinder, piston and other vapor compression devices, must be maintained with high sealing performance, otherwise it would have insufficient power. The catapult system structure is complex and occupies a huge space. The entire systemis cumbersome, steam leaks are a serious issue, with the loss of a large amount of fresh water. The installation is very large, and requires large numbers of people for complex operations.
A few countries are working on electromagnetic catapult - a flat type linear electric motor, but this is highly technical, difficult to master in a short time, and must have a high electrical capacity. If used continuously the electromagnetic device generates high temperature that could burn out the coil and other electronic devices.
The most advanced American aircraft carrier uses the Electromagnetic Catapult System, or Electromagnetic launcher (EML), to launch carrier-based jets, but China is still testing steam catapults, Li said. "The main difference is that EMLs are more flexible and the system's speed can be controlled, so it can launch aircraft of different sizes."
The difficulty of electromagnetic launch is energy storage, and by 2010 the key energy storage equipment for Electromagnetic catapult was a 50MW/120MJ flywheel prototype. This breakthrough was the key technology. In early 2011, academician professor Ma Weiming of the Naval University of Engineering was awarded the 2010 National Science and technology progress awrd. In his acceptance speech revealed Chinese electromagnetic launch technology research had been successful, and he was hailed as the "father of China electromagnetic catapult".
In 2013, satellite photography of a facility located near the Shanghai Gongjia showed China's electromagnetic aircraft launch another field test. Compared to the Naval University of Engineering in the test field of Wuhan District of Jiangxia Hidden Dragon Island, the Shanghai test site was closer to the actual state of equipment, simulation of aircraft carrier flight deck, electromagnetic catapult strip in the blue deck at the point of departure. From this point of view, the development speed of the electromagnetic launch China indicatedthat the ground tests were underway already from the laboratory to the prototype stage. The ground test facilities in the United States for the Ford electromagnetic launcher came in 2010, which shows that the electromagnetic launch technology in China had been basically synchronized with the United States, just on the ship.
Ma Weiming's team developed the advanced medium voltage DC integrated power system can be unified in the form of electricity for the ship's propulsion load, pulse load, communications, navigation and daily equipment and other power supply, to achieve the comprehensive utilization of the whole ship energy. The integrated power system can not only provide the power platform for the ship load, but also simplify the structure of the ship's power system, improve the efficiency of the ship system, reduce the ship noise level and reduce the ship's life cycle cost.
China has developed its own version of a cutting-edge device previously possessed only by the United States and is poised to use it to boost its aircraft carrier fleet's combat capability. The device, known as an electromagnetic launch system, or electromagnetic catapult, was designed by Chinese engineers to assist planes taking off from aircraft carriers. The system has been tested with J-15 carrier-borne fighter jets, according to Rear Admiral Yin Zhuo, director of the People's Liberation Army Navy's expert consultation committee.
He said on China Central Television in November 2017 that J-15s had made "thousands of takeoffs" using the electromagnetic launch system. Before China developed its catapult, expertise in the technology had long been the domain of the United States, because of the system's complexity and sophistication.
Unlike taking off from a runway on the ground, fixed-wing aircraft on carriers need assistance from a special apparatus to take off because a flight deck is not long enough for a plane to gain sufficient speed to fly. Catapults give them an extra shove. A steel cable attaches the plane to the catapult and drags it rapidly forward for takeoff. With older technology, the pulling force of the cable was powered by steam. Electromagnetic force provides an alternative solution that brings certain advantages.
China's midsize carrier, the CNS Liaoning, uses a ski-jump design for its takeoff ramp - with an upward slope at one end to increase the angle of a plane's wings, thereby generating lift. Large carriers, however, such as those deployed by the US Navy, use catapults.
Electromagnetic launch systems are believed to be the most advanced carrier-based technology for assisting takeoffs. Yin said China was able to develop the device because its engineers have designed a state-of-the-art ship-based power system. The country has outperformed the US in the development of such systems, which are considered by military experts as a game-changing technology in naval hardware, he said.
"Compared with the US, we have better technologies in key parts, such as motor-control devices and power distribution software. We are leaders in the research and development of integrated electric power systems," he said. Yin said that China now possesses proven technologies for both steam catapults and electromagnetic launch systems. He said the Navy's second domestically designed carrier will use a catapult system to assist takeoffs rather than the ski-jump mode.
The Chinese military has yet to announce details regarding the new carrier, but some observers speculate that construction will begin soon in Shanghai.
In November 2017 Chinese sources said that China eagerly hoped to use the electromagnetic aircraft catapult system on the 002 aircraft carrier. The sources said: "(But) the difficulty is that the conventional powered aircraft carriers may not be able to support the electromagnetic aircraft ejection system, and now the problem is solved." The solution came from a team led by Rear Admiral Ma Weiming, a senior engineer in the Chinese navy, who developed a medium voltage direct current (HVDC) transmission network to replace the original AC-based system. The source said that long-delayed 002 aircraft carrier development work or "very fast" start.
According to Wang Ping, a military technologist at the Institute of Electrical Engineering under the Chinese Academy of Sciences, this innovative report says that this innovative design means that high-energy weapons and catapult systems can now be deployed on conventional power boats. This technology can be used not only for aircraft ejection, but also for the launch of missiles and satellites in the future and may even be used to power high-speed trains.
A naval expert familiar with the carrier's plan said China need not mimic the US practice of using nuclear reactors to support electromagnetic-plane catapults and other high-energy weapons on ships because China now has more advanced technology to solve the problem. China now has mature technology, and the People's Liberation Army is narrowing the gap with the United States.
China is likely to use an electromagnetic catapult for fighter jets on its third aircraft carrier, experts said on 18 January 2018. The world's leading electromagnetic catapult technology was developed by a team led by Ma Weiming, an academician of the Chinese Academy of Sciences, a Beijing-based expert, who asked for anonymity, told the Global Times. The technology will likely be used on China's third aircraft carrier - and second domestically made carrier - to revitalize the army through science and technology, he said.
The expert also said that the Central Military Commission has sent signals to adopt scientific achievements to enhance the military's combat capabilities and narrow the gap between China and other powers.
Li Jie, a Beijing-based naval expert, told the Global Times that security is the main concern for those who prefer steam-driven to electromagnetic catapults. Globally, carriers launch aircraft via three basic methods: steam-driven catapult, electromagnetic catapult or ski jump. China's first aircraft carrier, Liaoning, adopted the ski jump approach. Ten of 11 US aircraft carriers use steam catapults.
The USS Gerald R Ford is the only aircraft carrier that uses an electromagnetic catapult, experts said. The new catapult is believed to be more efficient and less damaging to planes. Ma told media his team had conducted successful tests on the technology and are confident about its practical use. As China has overcome the core technological problems of electromagnetic catapults, the technological advantage should be used to enhance combat capability, Li said.
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