The middle fuselage of the B-2 needs to be deep enough to accommodate the cockpit and bomb bay, but the length should be as short as possible to avoid excessive resistance at high subsonic speeds. The chord length of the outer wing of the central fuselage is determined by the engine compartment, stealth air inlet and tail nozzle. When B-2 flies at high subsonic speed, the thick supercritical airfoil accelerates the airflow velocity on the upper surface of the wing to supersonic speed. Except for the area behind the nozzle, the trailing edge of the B-2 flying wing has nine large control surfaces. The rearmost "beaver tail" is a whole movable control surface, which is used to offset the bumps caused by vertical gusts when flying at low altitude. On the outermost side are a pair of separated airfoils called "speed brake-Rudder". The remaining six aileron surfaces are used for pitch and roll control, and the outermost pair is also used as aileron at low speed. B-2 has no vertical tail, which is different from traditional aircraft. The aircraft is yaw neutral, that is, when B-2 turns left or right, it will not produce centering aerodynamic force. B-2 is controlled by Northrop's patented speed brake rudder at the trailing edge of the outer wing. Speed brake-The rudder can crack up and down, and it can crack at the same time as speed brake. When it cracks asymmetrically, it can be used as a rudder. Because of the boundary layer on the surface of the flying wing, the speed brake-rudder must crack at least 5 degrees to work. Therefore, in normal flight, the speed brake-rudders on both sides are in the open position of 5 degrees, so they can work immediately when they need to be controlled, which is why the speed brake-rudders in the B-2 flight photos we saw are all open. The open speed brake rudder will affect the stealth effect of the aircraft, so when the B-2 arrives in the war zone, the speed brake rudder will be completely closed.
Most of the surface of B-2A is covered with a special elastic material, which keeps the surface uniform in conductivity and reduces the radar wave reflection at joints or joints. In design, the invisible parts (such as the air inlet) will be coated with radar absorbing material (RAM), and its composition is still highly confidential. RAM is a multi-layer spray coating, which contains components that can convert radar wave energy into heat energy. After the whole machine is coated with a coating with a proper thickness, radar waves reflected from both sides of the coating will interfere with each other and cancel each other after the radar waves with a specific wavelength are irradiated on the coating. A similar concept is the coating of optical lenses, which can eliminate unnecessary light. Four ge f11100 afterburner turbofan engines are installed in the engine compartment on both sides of the central fuselage of the B-2A, each with a rated static thrust of 86 18kg. F 1 18 is developed on the basis of F 10 1-X, and it is a fighter model of B- 1 bomber F10/engine. Compared with F 10 1, f1-x has a smaller low-pressure external bypass cylinder, which reduces the bypass ratio from 2: 1 to 0.87: 1. The engine with low bypass ratio only needs a smaller intake and exhaust system, so it was selected by B-2. The air inlet of the engine is far away from the leading edge of the wing to avoid being irradiated by radar waves below. Because the B-2 adopts a thick flying wing structure, the engine can be buried deep in the flying wing, and the flat air inlet and curved air inlet on the upper surface of the flying wing can ensure that the airborne radar cannot directly illuminate the front of the engine from above, let alone from below. In this way, the B-2 can adopt a simpler air inlet, and there is no problem just by modifying the lip with sharp teeth.
The boundary layer airflow separated by the boundary layer separation plate of B-2 inlet is mixed into the tail nozzle to reduce the exhaust temperature and infrared radiation. The airflow passing through the partition also expands and is guided to various internal airflow pipes, which are collectively called secondary airflow systems. This includes ventilation of accessory transmission and engine compartment installed on engine block, ram cooling airflow of heat exchanger of environmental control system and airflow of bypass circuit. When working at low speed on the ground, the air flow of the engine is increased through four diamond-shaped engine auxiliary intake valves, which are located at the top of the intake hood and in front of each engine intake. The operation when the auxiliary intake valve is opened reduces the mass flow ratio of the main intake and the corresponding sharp lip rotation loss. B-2A has two crew members sitting side by side in the ACEII ejection seat, with the pilot on the left and the mission commander on the right. There are four large windshields at the front and sides of the cockpit. Passengers enter and leave the cockpit through the belly door. In an emergency, the ejection seat pops out through the fragile door at the top of the cockpit. The mission commander is responsible for navigation and weapon delivery, but both crew members can complete the whole mission alone. There are four color CRT displays in front of each passenger, with a data input panel on the right and a set of throttles on the left. There is also a third passenger seat behind the cockpit, but it is rarely used. The seat also has an ejection seat with a fragile door at the top. The navigation system of B-2A was originally composed of two systems, each of which can navigate independently, but the accuracy will be higher when working together. One is inertial measurement unit, and the other is Northrop NAS-26 astronomical inertial unit. NAS-26 was originally developed for ghost long-range cruise missiles. It is a photoelectric telescope system with a stable base, which can lock the pre-selected stars on cloudy days. The observation window of the system is located on the left side of the windshield.
B-2A airborne radar is a /APQ- 18 1 phased array radar, which is manufactured by Hughes. This kind of phased array has two radar antenna arrays, and its characteristic is that it can scan different angles and different directions only by changing and combining the positions of signal arrays without additional rotating or swinging antennas. Its working frequency is 12- 18GHZ, with small sidelobe and strong anti-electronic interference ability. There are 2 1 working modes * *, among which the most prominent are synthetic aperture radar working mode and anti-synthetic aperture radar mode. The former is mainly used to scan the land landforms, and can clearly obtain the land scanning image with the distance of 16 1 km, which can be used by aircraft to bomb ground targets; The latter is mainly used to identify and capture maritime targets, and the longest effective distance can reach 128km. In addition, the B-2A bomber can use terrain matching and terrain avoidance technology to make it fly close to the ground and penetrate into enemy airspace at low altitude to carry out bombing missions. The two rotating bomb racks of the B-2 bomber can carry 16 AGM- 129 cruise missiles, 80 MK82 or 16 MK84 ordinary bombs or 36 CBU-87 cluster bombs. When using the new TSSM long-range attack ammunition, the carrying capacity is 16. When using nuclear weapons, you can carry 16 B63 nuclear bomb. In addition, AGM- 129 cruise missiles can also carry nuclear warheads. In February 2002, B-2 enhanced its ability to use JASSM, an air-to-surface missile outside the joint defense zone. The fuel tank occupies most of the space inside the outer wing part. Two large bomb compartments are arranged side by side under the fuselage between the engine compartments. Each bomb bay can be equipped with an advanced rotary pylon developed by Boeing, eight 908kg ammunition, and two bomb rack components can be installed to mount conventional ammunition. The B-2A with improved avionics and equipment performance can carry AGM- 154 combined long-range weapon and GBU-28 5000-pound laser-guided bomb. In addition, it can also carry AGM- 158 joint air-to-ground missiles. 40,000 pounds (18,000 kg): carrying MK 82,500 pounds of low-resistance general bombs (80 in total) and 27,000 pounds (12,000 kg): 750 pounds of cluster bombs (36 in total) carried by stacked bomb racks; 16 rotary launcher assembly (RLA): It can carry 2,000 pounds of weapons (such as Mk 84 2,000 pounds of low-resistance general bombs, GBU-3 1 joint direct attack ammunition or B-666).