1. Rockwell X-30
The National Aerospace Plane Program (NASP) aims to develop a supersonic air-breathing monopolar vehicle for orbit. Because the aircraft was developed under the leadership of Rockwell, this aerospace aircraft is also known as the Rockwell X-30 (Rockwell X-30).
The plane is expected to measure 95.7 meters long and weigh 136 tonnes. At the start of the project, scientists believed that if a supersonic combustion ramjet engine was used, the aircraft could reach a maximum speed of Mach. 8 per hour due to atmospheric friction. This will consume a lot of energy. Later research showed that if the energy was compensated, speeds of Mach 20 were possible.
The shape of the X-30 is designed based on aerodynamics. The shovel-shaped front fuselage can compress the air in the engine, and the rear fuselage forms an integrated exhaust port. The wings are designed with very peSmall fins for balance. This design is good for high-speed flight, but not for takeoff and deceleration.
When the X-30 flies, the temperature of most fuselage surfaces is expected to reach 980 degrees Celsius, and the maximum temperature of the front and engine parts of the aircraft may exceed 1,650 degrees Celsius. This requires the use of lightweight and high temperature resistant materials for the fuselage. At that time, titanium and aluminum compounds, advanced carbon composites, titanium metal body composites (TMC), and silicon carbide fibers were all used in the fuselage design. fuselage. McDonnell Douglas used titanium composite materials to make a fuselage section 1.2 meters high, 2.4 meters wide and 2.4 meters long. The researchers also built a carbon fiber cryogenic hydrogen chamber. In 1992, these modelshad passed mechanical load and high temperature tests of 820 degrees Celsius.
2. NASA X-43
As part of NASA's Hyper-X project, the X-43 supersonic unmanned test vehicle is actually the smaller A version of the -30. The X-43 is 3.7 meters long and weighs 1,300 kilograms. It can still fly at high speeds without propulsion. However, the X-43 is only a one-off test aircraft.
The first design of the X-43, the flight. The X-43A's supersonic combustion scramjet engine mainly uses hydrogen as a raw material. The engine only starts working when the speed reaches Mach 4.5 or higher, so it needs a rocket to provide thrust.
Scientists added a booster rocket to the X-43A. When altitude and lifeesse reached the predetermined value, the booster rocket automatically separated from the X-43A. Then the X-43A used its own engine. flight. During high-speed flight, compression shock waves generate a large amount of heat. To prevent heat from melting the plane, scientists set up a water circulation system behind the engine fairing and leading edge air circulation underhood. During flight, the water circulation system starts working when the speed reaches Mach 3.
3. US Air Force Boeing. In 2004, the project was transferred to the Department of Defense's Advanced Research Projects Agency and then to the Department of the Air Force's Rapid Response Capabilities Office.
The X-37B uses Rocketdyne AR2-3 engines, measures 8.9meters long, 4.5 meters wide, weighs around 5 tonnes and has two vertical tails. It looks like a space shuttle, but is a quarter the length of an airplane. It can operate in low Earth orbit at an altitude of 177,000 to 800,000 meters, with a speed of 177 kilometers per hour.
In terms of design, the X-37B uses high temperature resistant silica porcelain to replace the previous carbon fiber wings. Additionally, the thermal protection system, avionics technology and automatic guidance system are all demonstrated. the plane. . The X-37B uses a fuel cell system powered by solar electronic panels and lithium-ion batteries.
4. Boeing In 2004, Boeing and Pratt & Whitney began collaborating to buildire the Surfer supersonic test aircraft. In September 2005, the aircraft was built and designated X-51A.
The Boeing X-51A is a supersonic unmanned test aircraft that uses hydrogen as fuel and uses the SJY61 supersonic combustion ramjet engine with a speed of Mach 6 (6,400 kilometers per hour) . In fact, the first design of the X-51A engine was intended for use on the X-43C airframe. However, the X-43C project was suspended in March 2004.
Ground testing of the X-51A began in late 2006 and successfully completed the ground engine wind tunnel test on June 27, 2006.< /p>
In April 2007, the ground flight simulation test was successfully completed. On May 26, 2010, the first powered flight test of the X-51A was successful. The B-52 carrier rocket carried the X-51A to an altitude of 15,200 meters. When the speed reached Mach 4.5, the X-51A separated from the rocket. . In this test, the X-51A flew at Mach 5 and lasted more than 200 seconds.