Recently, a foreign company announced that it will modify a short take-off and landing kit for a long-range UAV, which can enable the UAV to take off and land from a shorter land-based runway and aircraft carrier deck.
In maritime warfare, seizing air supremacy is the key to victory. At present, carrier-based unmanned aerial vehicles can already undertake various complex and changeable maritime combat and reconnaissance tasks with the support of the "air-space-sea" information network system. It can be said that in the aircraft carrier aircraft system, the UAV has become a rising "new star".
However, for more than half a century, the development of ship-based unmanned aerial vehicles has been slow, and countries around the world have invested huge amounts of money and achieved little results. Taking the X-47B carrier-based unmanned aerial vehicle developed by the United States as an example, a total of more than 1 billion US dollars was invested in five years before and after, and it was finally forced to shelve due to technical performance. So, what kind of development process has the UAV gone through on board? What technical problems need to be overcome in the development of ship-based unmanned aerial vehicles? This article is for you to interpret them one by one.
"Nesting" at sea, drones in a row of passes
One day in 1959, on the U.S. Navy's Keeling-class destroyer, the crew hurriedly removed the items on the deck to clear the take-off position for the drone. At noon, the command room controller issued a command, and the QH-50 drone accelerated from the deck and rushed to the predetermined sea. On this day, humans achieved their first shipborne drone flight.
Four years later, the U.S. Kilodane Company upgraded the QH-50 UAV and developed the QH-50C UAV, which officially entered the US Navy. However, at that time, the electronic system computing power was limited, and the QH-50C UAV took off and landed entirely on the radio remote control of the ship's personnel, and often ran out of control and fell into the sea, which brought a lot of problems to the later improvement work of scientific researchers.
How to adapt drones to sea flight? Aviation designers from various countries have worked hard to improve the "brain" of unmanned aerial vehicles - Israel has learned from the experience of the use of "fierce dogs" small unmanned aerial vehicles and improved the reliability of flight control systems by equipping short-range remote control unmanned aircraft systems; Northrop Grumman of the United States has taken a different approach, through the introduction of civilian helicopter technology, in the "Scout" series of ship-borne unmanned aerial vehicles equipped with automatic control systems, improve the stability of maritime flight.
For some time, military enterprises in various countries have actively solved the flight problems of ship-borne unmanned aerial vehicles. However, due to the difficulty of research and development of ship-based unmanned aerial vehicles, many uncertainties, difficulty in improving work and many other problems, to this day, carrier-based UAV flight is still in the evolution stage of accidents.
So, where is the difficulty of "nesting" at sea by drones? After more than half a century of exploration and practice, researchers from various countries have summarized the 3 difficulties that need to be overcome when drones are on board:
The first is the power off - to solve the problem of short take-off and landing. At present, most long-flight UAV ground take-off and slide distance is more than 1,000 meters, and the distance of the UAV from the aircraft carrier is less than one-third of the land base.
To solve this problem, some countries have begun to seek innovative breakthroughs - Israel is experienced in the field of miniaturized aero engines, and its latest "Pioneer" unmanned reconnaissance aircraft is equipped with high-horsepower two-cylinder two-stroke engines, reducing the take-off and landing distance of UAVs to 70 meters; Austrian Siebel has worked the aerodynamic layout design of the S-100 UAV, increasing the lift of the aircraft by combining the rear landing gear with the tail fin, reducing the weight of the fuselage, and letting the UAV "go with the wind" like flying a kite.
The second is the endurance pass - to reduce corrosion in the marine environment. Ship-based unmanned aerial vehicles flying at sea must effectively cope with the erosion of high temperature and humidity at sea and mold salt spray, so there are high requirements for the environmental adaptability and corrosion resistance of materials.
To fight corrosion, materials come first. At present, the X-47B carrier-based UAV and the Ka-37 UAV, which are in the leading position in technology, both use aluminum alloy components and carbon fiber/epoxy composite materials, which can not only improve corrosion resistance, but also effectively reduce the radar reflection area.
The third is to collect and close - increase the number of unmanned aerial vehicles. If you want to park more carrier-based drones in a limited space, you must not only develop folding wing technology, but also work modular formation.
A foreign designer applied the idea of "modular assembly" to the V-247 "vigilance" carrier-based UAV. The UAV additional module can be stored separately from the airframe, which cleverly solves the problem of low space occupancy.
Landing on the ship at sea, one by one to see the skill
In future maritime operations, how fast will the drones be dispatched?
A foreign scientific research institution gave the answer: 30 aircraft were dispatched in 40 seconds. Aircraft carriers are like strong bows, and the efficiency of the ship-based UAV's dispatch and recovery determines whether they can find an opportunity in future naval battles.
At first, the land drone completed a one-click return by recording the GPS coordinates of the take-off point, and the route planning only needed to return to the original route according to the initial flight trajectory. However, ships at sea spend most of their time sailing, and the way of returning directly to land drones is undoubtedly "carving a boat and seeking a sword".
In order to help the carrier-based UAV successfully find the "way home", researchers usually set up two sets of control systems inside the UAV, and the UAV operator can intervene in the automatic control program through remote control to guide the UAV to adjust the predetermined route in time to achieve a rapid return.
However, even if the aircraft carrier is close at hand, the drone landing is still difficult. A series of problems such as complex maritime weather, narrow landing decks, and ships moving at any time have always plagued researchers.
At first, carrier-based drones were hit by crash net recovery. The barrier system needs to erect a more complex pole and mesh surface, and after the ship-based UAV hits the net, it will cause structural damage, low recovery efficiency and high failure rate. According to statistics, the failure rate of shipborne unmanned aerial vehicle recovery accounts for more than 80% of the failure rate during the entire mission period. The X-47B UAV has failed two attempts to land on the US Navy's "George Bush" aircraft carrier due to malfunction problems.
In recent years, with the development of intelligent technology, ship-based unmanned aerial vehicles have formed an operation mode of human-machine collaboration, and the ability to retract and release has been significantly improved. The landing of the ship-based UAV in the human-machine cooperation mode presents three characteristics:
The first is intelligent planning. Shipboard UAV landing is limited by the tail air flow field, deck motion interference, landing gear strength, and the use conditions of the block cable, which requires comprehensive consideration of various factors. Through a number of advanced technologies such as conformal descent rate control, approach power compensation, and direct force control, researchers generate the optimal landing trajectory of the carrier-based UAV. In addition, with the use of deck motion compensators, the landing stability of shipboard UAVs has been significantly improved.
The second is precise control. The flight quality of ship-based unmanned aerial vehicles is very demanding, and any small deviation may cause irreparable losses. When disrupted air currents strike, the operator's reaction speed cannot keep up with the rapid changes in wind. In order to solve this problem, the researchers decomposition of the module, the automatic control system is connected with the deflection effect of different rudder surfaces, and each rudder surface is accurately controlled to generate lift against the air flow, improving the landing stability of the shipboard UAV.
The third is automatic guidance. Carrier-based UAVs need to have autonomous take-off and landing capabilities. At this time, the landing guidance system comes in handy, providing the UAV with accurate information on the relative position of the touch point, attitude parameters, etc., to achieve "immortal guidance". At present, a French company has developed an automatic deck take-off and landing system, and has successfully completed the landing test many times under day and night and bad weather conditions.
The future protagonist, the prospect of improving combat strength can be expected
In the new century, more and more military experts have begun to pay attention to a question: With the accelerated evolution of the form of war and the increasingly complex situation of maritime struggle, how can ship-based unmanned aerial vehicles better expand their functions and tasks?
Taking the QH-50 UAV as an example, its design was originally aimed at attacking submarines, but the UAV bomb compartment was small, and it could only carry 2 torpedoes, which was difficult to complete the attack task, and was once reduced to a training target aircraft.
This problem refers to the modernization of weapon systems by shipborne unmanned aerial vehicles. A strong bow needs to be matched with a strong arrow. In order to improve the attack capability of ship-based UAVs, the expansion and efficiency of weapon systems are crucial, and modification measures such as increasing plug-in points and adding bullet compartments have become the first choice for upgrading ship-based UAVs. At present, some attack ship-based UAVs can carry 8 to 9 missiles, and the attack capability should not be underestimated.
At the same time, the study of miniaturization of precision-guided weapons is also very critical. Many countries have put forward strict requirements for UAV airborne weapons: when designing airborne weapons, the weight should not exceed 50 kg, which can be used by active and researched UAV equipment and meet the requirements of other small UAVs.
In addition, foreign researchers are also working hard to improve precision strike capabilities, and have launched a number of customized precision guided weapons for UAV to help ship-based UAVs improve strike efficiency.
On the road of generating the combat power of ship-based unmanned aerial vehicles, it is indispensable to the innovative design of tactics. In view of the small size, large number and low cost of unmanned aerial vehicles, some national scientific research institutions have proposed the concept of UAV swarm warfare, through a short period of time and rapid launch of many unmanned aerial vehicles, so that they share information with each other, coordinate to perform offensive or defensive tasks, and suppress opponents with numerical superiority.
In recent years, carrier-based unmanned aerial vehicles are actively changing from a coordinated manned-aircraft combat mode to an independent operation mode of unmanned aerial vehicles. In this innovative exploration team, not only the United States, Russia and other traditional military powers, but also Turkey, Israel and other emerging countries, they are committed to opening up the communication links between various aircraft platforms, to help ship-based UAVs adapt to fast-paced, strong confrontation of maritime operations.
Looking around, the future of the sea battlefield will have a place for carrier-based UAVs, although the "road to ship" is difficult, but the UAV has a series of advantages such as personnel protection, low cost and complex environmental adaptability, attracting countries to continue to invest a lot of talent and funds, carrier-based UAVs become a "new star" in naval warfare or will be just around the corner. (Qi Chengrong, Jiang Zihan, Ma Sheng)
Source: People's Liberation Army Daily