Part III: Drone Research Report
(six)
Development of drones in countries around the world
United States: Unmanned Combat Armed Rotorcraft
X-51A, submarine shooting drone
Unmanned combat armed rotorcraft
The US Army is committed to providing a more deadly reconnaissance aircraft for future forces during the transition period, either individually or with people or unmanned squads. This unmanned Combat Armed Rotorcraft is called UCAR. Donald Woodbury, project manager for the US Defense Research Institute, said: "We have developed UAVs like trucks, and UCAR is developing into a system vision."
Mr. Woodbury explained: “Whether it is day or night, or under adverse weather conditions, the UCAR system and its modular payload are designed to find the most difficult target – the combatant who is on foot, camouflaged, And other targets hidden in the ground chaos. A single operator of the Army's Future Combat System is either the AH-64D "Apache" or the A2C2 (Army Air Force Command Control, Translator's Note) system "Black Hawk" The individual operators onboard can eventually command one or more drones, passing only a few spoken words. The purpose of the project is to use operational commands that approximate the commands sent to the human system to command them. â€
“The UCAR concept in actual use is very different from the 'shadow', 'predator' and other UAVs actually used,†said Goregue Zuwina, project manager of Northrop Grumman UCAR. Mann explained, "Alternatively one person controls a UAV, you may use one person to control a small team. An operator who is busy with other duties may issue the most advanced instructions for the collaborative team, just to survey a tree row. They have to be busy paying attention to the threat of bullets that overlap with field fires. Automated drones assign tasks and resources between their teams, change the formation in response to aerodynamic conditions, and authorize those who deviate from the order."
Mr. Woodbury acknowledged: "In the field of network-centric warfare, unmanned helicopters may be from a manned attack helicopter, a tactical jet or a future combat system of the FCS Non-Lineage Sight Launch System (FCS NLOS-LS). Summon firepower. Or it can perform communication relay, mine clearance or other tasks. Northrop Grumman has been authorized by Kaman to have a hook for the cargo to be transported. I am not sure to tremble. The reason is that UCAR can only carry a single piece of load; but when you talk about a multi-purpose aircraft, you have the ability to provide logistical support as a core mission."
The versatile UCAR will perform dangerous missions in dark, harsh weather without putting people's lives at risk. Unlike other UAV units, Army Aviation requires highly self-contained aircraft to find obstacles on their own routes at low altitudes and survivability at the closest risk of air defense fire. But the UCAR concept is therefore called the "low-altitude observation helicopter", with sufficient alertness to respond to human commanders' spoken commands, seamless collaboration with airborne members, and the ability to perform tasks again in a dynamic environment. It is a very flexible platform that will be integrated with advanced sensors and weapon systems for discovery, identification, and engagement with enemies. Mr. Woodbury acknowledged that UCAR was identified as an ambitious model from the beginning.
X-51A
The X-51A is the name of the US hypersonic missile development program. The key is to develop a hypersonic ramjet engine that can carry a warhead at a very high speed of 6.5 Mach (6.5 times the speed of sound). Unlike conventional missiles that require large amounts of oxygen, the new missile's engine is capable of mixing its own fuel with oxygen in the air at an extremely fast rate, resulting in extremely high speeds. Moreover, the reusable hypersonic missile is much smaller in size than similar missiles, and only half the size of the latter, but has the ability to attack targets beyond 500 kilometers. The hypersonic missile developed in this way can fly back to the base after dropping the ammunition, so it is more like an airplane. The X-51 diagram and features are as follows:
In January 2004, AFRL selected Boeing and Pratt & Whitney to jointly manufacture the SED-WR verification machine, which was manufactured by Boeing, and Pratt & Whitney produced the engine. In September 2005, the US Air Force officially numbered the program X-51A.
On May 26, 2010, the United States successfully piloted the X-51A flight test aircraft at a military base on the Pacific coast of southern California.
According to the initial flight test plan, the B-52 aircraft placed the entire X-51A test system at an altitude of approximately 15,000 meters. First, the booster continues to burn for 30 seconds, accelerating the entire system to Mach 4.6 to 4.8. During the boosting process, air will enter the scramjet engine of the X-51A Verifier and flow out through the interstage to start the intake and begin to gradually heat the engine and its fuel. After the booster is disengaged, the X-51A verifier will continue to coast for a few seconds with inertia, and then sequentially ignite ethylene and fuel inside the engine to achieve thermal equilibrium and then accelerate with only the combustion of JP-7 fuel. The entire power flight process is approximately 300 seconds and the expected flight speed is Mach 6.5. As all fuel is exhausted, the X-51A verifier will begin to decelerate, followed by a 500-second unpowered flight, gradually falling, and finally falling into the Pacific Ocean.
However, the first test flight did not proceed as planned, and despite the success, there were some unexpected situations.
On May 26, the US Air Force conducted the first flight test of the X-51A demonstrator. When the B-52H carrier equipped with the X-51A climbed to a predetermined height, the X-51A test system consisting of a booster and a verification machine was released at a flight speed of Mach 0.8. After about 4 seconds, the booster fires according to a predetermined procedure, pushing the X-51A verifier to Mach 4.8. Subsequently, the X-51A verifier was separated from the booster and the interstage, and a smooth 180 degree roll maneuver was successfully completed in accordance with a predetermined procedure. During this process, the X-51A verifier changed the air intake from the upper position to the abdomen position, and the flight speed was slightly reduced to Mach 4.73.
Subsequently, the SJY61 super-burning ramjet first ignited ethylene and then transitioned to the ignition and combustion of the JP-7 hydrocarbon fuel. Then, the X-51A verifier began to accelerate gradually, but the telemetry data showed that the acceleration was slightly lower than the design value, and the temperature at the rear of the engine compartment was significantly higher than the design value. The shooting field safety officer found through monitoring data that the X-51A verifier began to decelerate and the telemetry signal was lost, so the test flight was terminated and the aircraft started the self-destruction procedure.
As a result, the SJY61 scramjet engine only worked for 140 seconds and did not reach the expected 300 seconds. The flight speed of the aircraft reached the Mach number of 5 and has not yet accelerated to the Mach number of 6. PWR said that the data initially showed that the SJY61 engine was working according to the design requirements. In the first test flight, the most critical things were realized: igniting ethylene, transitioning to the mixed combustion of ethylene and JP-7 fuel, reaching JP- 7 The condition of fuel combustion, continued to burn only with JP-7 fuel, and continued to work for 140 seconds. The X-51A verifier still has a portion of the fuel remaining in the machine before it is self-destructed.
It can be seen that PWR has fully mastered a series of key technologies and can quickly produce a super-combustion ramjet with a longer burning time. The designed 5-minute flight time is not a limitation of the propulsion system, but is limited to the capacity of the fuel tank. The X-51A retrofit can further increase flight time if the design improves a larger fuel tank.
Although the flight time did not meet the expected goals, the test team was still satisfied with the results. An AFRL spokesperson said that the first flight score is B and the next time will be A. BRL, the manager of AFRL's X-51 program, said that the test flight achieved 95% success and the flight control software was perfect. It is not clear the specific reasons for the slowdown of the acceleration process and the short flight time. The preliminary speculation may be the sealing problem. Or the actuator fails, and it is also believed that it is possible to erroneously estimate the resistance of the X-51A demonstrator during low Mach flight.
In the second flight test of the X-51 "Rider" hypersonic vehicle on June 13, 2011, the second flight of the X-51 was terminated prematurely because the intake of the scramjet engine was not activated. Under the control of the operator, the aircraft splashed off the coast of California.
After the Boeing B-52 aircraft carried the X-51 aircraft perfectly to the launch point, the rocket propeller successfully propelled the X-51 to Mach 5, and the scrambling ramjet engine built by Pratt & Whitney was based on ethylene. Initial fuel, successful ignition. When the JP-7 conventional fuel was subsequently used instead, the intake port failed to start. After the staff restarted and the best conditions were restored, the effort failed.
According to NASA, the reason why the intake port does not start is that the shock wave speed is too fast, and the air pressure of the engine airflow is suddenly reduced. The operation of a scramjet engine relies on extremely accurate shock motion and engine airflow. The absence of wind tunnels allows air to move at hypersonic speeds, so hypersonic testing is extremely difficult.
Air Force project manager Charlie Brink said: "Obviously, we are disappointed, we are looking forward to better results. But we are still satisfied with the data collected on this flight. We will continue to check these data. Learn more about this new technology. Every time you experiment with this exciting new technology, it's a step closer to success."
On August 16, 2012, the US military launched the third launch of the X-51A. According to the plan, the X-51A used for testing was first tested at Edwards Air Force Base in California, and was hung under the B-52 bomber wing after everything was in place; then the B-52 took off from Edwards Air Force Base and flew to The X-51A was released from the altitude of 50,000 feet when it was close to the Pacific Ocean at the Moguo angle missile range; then the X-51A turned on its own power, accelerated to 6 times the speed of sound and climbed to 70,000 feet, and finally fell after 300 seconds of continuous flight. Into the Pacific. And 6 times the speed of sound is equivalent to flying from New York to London in less than an hour. After the launch, the unmanned X-51A rider aircraft was separated from its carrier B-52 Fortress bomber as planned, and the booster rocket was also ignited. However, the failure of a control wing caused the X-51A "Rider" aircraft to fall vertically into the Pacific Ocean after only 16 seconds of flight.
On May 3, 2013, the US Air Force announced that the X-51A "Opporter", which has been developing the unmanned aerial vehicle for nearly 10 years, was flying at 5 times the speed of sound in the fourth and final test. success".
The US Air Force issued a statement on the same day saying that the "passenger" conducted the last test flight over the Pacific Ocean on May 1 and flew about 230 nautical miles in about 6 minutes. This is also the "passenger" in four flights. The longest flight distance in the test.
The video footage released by the US Air Force shows that after taking off from Edwards Air Force Base, a B-52 bomber will carry the "passenger" to the Pacific Ocean for about 15,000 meters to release it. Then, the "Pedestrian" relies on a solid rocket propeller to accelerate to 4.8 times the speed of sound in 26 seconds. After being separated from the propeller, the “passenger†started the scramjet engine and rushed to an altitude of about 18,000 meters. The speed reached 5.1 times the speed of sound and it took about three and a half minutes.
According to the design, the “passenger†is not reusable, so after the engine fuel is exhausted, the “passenger†falls into the Pacific Ocean and self-destructs as planned.
This flight did not reach the design speed of 6 times the speed of sound, but the US military is still satisfied, the US Air Force X-51A project director Charlie Brink said in a statement: "The mission was a complete success. I believe, The lessons learned from the X-51A project will contribute to future hypersonic research and the practical application of the ultimate hypersonic flight.†Boeing, which is involved in manufacturing, issued a statement saying it was “a historic achievementâ€. .
Submarine shooting drone
The US military believes that the naval submarine will play a more important role in the joint expeditionary battle. If the submarine wants to gain an advantage in the war, it must place various sensors outside the submarine. Submarine launch using unmanned aerial vehicles will become the next generation of submarine development. One of the focuses. The drone can be launched from the submarine and can perform real-time reconnaissance, surveillance, early warning, etc., providing submarine support for submarine, taking advantage of information, improving the combat capability of the submarine platform, and effectively integrating the submarine into the sea, land and air. In the network-centric warfare "information big system, enhance the joint strike capability. The use of submarine-launched unmanned aerial vehicles can effectively conceal the position of their own submarines. At the same time, it can expand the search range for sea and air, extend the warning time, and determine the target attack parameters for the surface ships and Trident nuclear-powered ballistic missile submarines. Close air support, relay guidance and attack evaluation are important for the submarine to accurately select, track, aim and target, and are considered to be an important part of the “network-centric warfareâ€, which will significantly improve the Trident submarine platform. The combat capability has brought about new changes in the pattern of “empty and poorâ€. UAVs equipped with attacking weapons such as deep-bomb and anti-submarine torpedoes can directly attack submarines that sail on the surface of the water and in the depth of the submarine, posing a huge threat to the enemy submarine operations.
Since the 1990s, the US military has researched and tested a number of submersible drones, such as those launched by submarine torpedo tubes that perform reconnaissance, surveillance, and target searches. The submarine's ballistic missile launcher is equipped with a low-cost autonomous attack system and a light bomb drone and a reusable 鸬鹚 drone.
US snorkeling drone
Submarine-launched drone launching process
Source: "Weapons and Equipment Research Selected" International Defense Science and Technology Series (2015, No. 5, No. 15) The Management Research Center of China Electronics Science Research Institute compiled / picture from the original report or the Internet.
Part I: US Aircraft Research Report
Part II: Foreign AWACS Research Report
Foreign AWACS Research Report (1): Development History + Early Warning Aircraft Map
Foreign AWACS Research Report (II): US E-3 Series "Wanglou" Early Warning Aircraft
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