After the end of World War II, the world's two major camps have begun the research and development of stealth technology, especially after the Soviet Union shot down the U2 stealth reconnaissance aircraft of the United States, it has done a relatively large study of stealth technology in the field of fighter aircraft and put forward a lot of ideas, at that time, some experts of the Soviet Tupolev Aircraft Design Bureau specially wrote an academic article on the manufacture of stealth aircraft, this article was not valued by the Soviet Union, but was deeply studied by relevant people in the United States. And believe that in the future these technologies will be a revolution in a new generation of fighters. So in this context, the U.S. Advanced Research Projects Agency officially approved the design and construction of stealth fighters, the result of this program is the U.S. F-117 Nighthawk stealth attack aircraft that today's weapons old white will share with you.
At that time, the project was handed over to the American Lockheed Company, after all, this company developed the SR-71 reconnaissance aircraft, with good experience, when Lockheed's Skunk Engineering Department used a large number of parts of active aircraft, such as the J85-ge-4A non-afterburner turbojet engine of the T-2 trainer, the YF-16A catapult seat and fly-by-wire control system, the B-52 inertial navigation system and so on.
Through these methods, the Skunk Project came up with a prototype in a very short period of time, which was named Haifran, also known as Yonglan.
The test aircraft was first tested on December 1, 1977, and exhibited excellent low radar detectability, and this experimental prototype is the technical basis for the first stealth fighter in the United States in the future.
In 1978, the United States began to secretly develop and produce a new generation of stealth fighters that could enter the military service, which adopted the most stringent secrecy measures of the US military since the development of the atomic bomb, and the prototype was named YF-117a, which was basically a prototype of the F-117 Nighthawk stealth attack aircraft.
The first prototype flew successfully on June 18, 1981 at the Grove Lake Secret Test Center, with the fuselage painted in tri-color camouflage, numbered 780. After a series of tests and flights, the first production F-117a was tested and tested on February 27, 1982, the year in which the U.S. military began its official service career by receiving F-117a fighters delivered from the Skunk Factory.
In 1983, the following year, the F-117a had basically developed combat capabilities, and in order to maintain the mystery that shrouded the F-117a, the U.S. military had basically been used only at night for the first 5 years of service, hence the F-117a's code name: Nighthawk.
As the world's first stealth fighter, the F-117a attack function can break through the enemy's fire network, suppress the enemy's air defense system, destroy the opponent's tightly defended command post, strategic location, industrial base and other high-value targets with its strong stealth performance, and can also secretly perform reconnaissance missions with stealth performance, which can be said to be far ahead of the world at that time.
The f-117a attack fuselage length of 20.09 meters, wingspan of 13.20 meters, height of 3.78 meters, empty weight of 13.38 tons, the fuselage shape line is basically designed around stealth performance, in the aerodynamic and stealth performance to find unity, the shape of the fuselage is like a bottom triangle and the upper part of the multiple irregular triangular face cone composition.
The wing adopts a high swept-back wing flying wing structure, and the main wing has a very high chordal ratio, so the design is mainly to allow the wing to refract radar waves to the sides to reduce the probability of radar detection, but this large swept wing design will sacrifice a lot of engine efficiency.
The wing edges are designed with slit flaps, which control the movement of the flaps through a quadruple wire-pass flight control system equipped in the aircraft to adjust the flight attitude of the aircraft.
Wing and fuselage fusion the front of the wing is basically the leading edge of the fuselage, the nose has 4 multi-functional environmental data probes, that is, the four all-round airspeed tubes commonly used on the aircraft, used to provide data for the fighter's fly-by-wire control system, the wings are diamond-shaped wing profile shape, these designs are to minimize the scattering of radar waves, and all sides and angles of the fuselage and other strong reflection parts are a large number of radar absorbing materials, these materials are not only a kind, can absorb radar waves of different frequencies.
The early fuselage surface painted desert tricolor camouflage is mainly for test use, and later after service, all painted black, because the absorbing coating is the color displayed, the specific material is not currently disclosed, but there is speculation that it is a particle containing iron oxides, because this ingredient is a famous stealth material, with the characteristics of light weight absorbing effect.
The tail wing is a pair of large V-shaped double tails, tilted backwards to help the fighter maintain balance and assist in maneuvering such as steering, in the front of the fuselage midline, is the pilot's position, the F-117a fighter is a single-seat subsonic jet multi-function stealth attack aircraft, only one pilot is required to operate.
The cockpit uses an articulated cockpit cover that can be opened backwards and upwards and then entered and exited the fighter, the cockpit cover is divided into five pieces, each of which is a whole piece of windshield, covered with multi-layer composite glass, covered with a metal film to reduce radar reflectivity, the cockpit interior is quite spacious, equipped with ergonomic displays and controls, but there is also a disadvantage, that is, the rear field of view is very poor, blind spots are very wide.
The cockpit features the Macdonald Douglas Acesii ejection seat, a rugged, lightweight, and easy-to-maintain seat that is the Air Force's most successful pilot escape system, with a gyroscope control system to stabilize the seat during catapults that has saved more than 500 lives.
In terms of power system design, as mentioned earlier, the large swept angle design of this fighter will lose a lot of engine power, and the fuselage design of the polyhedron will increase the flight resistance and reduce the speed of the aircraft. To this end, the designers installed two engines on the fighter to ensure the thrust required for the aircraft to fly at high subsonic speeds.
The engine uses two ge F404-F1d2 non-after-force turbofan engines of Ge General Electric, which are installed by the buried method, which can greatly reduce the noise of the engine and achieve the stealth ability of sound waves.
The engine's single thrust of 48kn allows the F-117a attack aircraft to achieve a maximum level flight speed of 1111 km / h, which is basically mach 0.9, and after the subsequent replacement of the F412 turbofan engine with greater thrust for the A-12 stealth attack aircraft, the maximum speed of the F-117A is basically close to the speed of sound. These two engines allow the F-117a to have a practical ceiling of 13,716 meters, a range of 1,720 kilometers, and a combat radius of 1,056 kilometers when carrying 2.268 tons of weapons.
Because the fuselage has achieved perfect stealth ability, there is no design plug-in point outside the fuselage, so if you carry a weapon, you cannot carry a secondary fuel tank, of course, you can also choose not to carry a weapon, and choose to carry a secondary fuel tank in the magazine to increase the range for reconnaissance missions.
At the same time, the back of the fuselage is also designed with retractable aerial refueling port, which can increase the range by means of aerial refueling, as a night fighter, it can also be refueled in the air at night, and can be refueled through the night refueling lighting at the top of the cockpit.
The power system has also done a relatively large stealth treatment, first of all, the air inlet is a rectangular air inlet design, in the air intake using 1.9 cm x 3.8 cm, spacing 1.5 cm absorbing composite grating shielded, so that can be a large scattering radar wave can also be in the case of large angle of attack and skid flight, to provide uniform airflow to the engine.
The air inlet is installed with a heating anti-icing device and an auxiliary air inlet, 0.6 meters high and 1.5 meters wide, there is no problem in accommodating the next person, in addition to being able to provide a large amount of air for the engine, part of the cold air can also bypass the engine through the auxiliary air intake and mix with the hot exhaust, so as to achieve the role of cooling the exhaust to reduce the infrared characteristics.
Through this method, the exhaust temperature of the F117A can be reduced to 66 degrees Celsius, and when it comes to exhaust, it has to be said that the exhaust port of the F117a Nighthawk Stealth Attack Aircraft is a platypus-shaped narrow slit spout.
This spout is 1.65 meters long and 0.10 meters wide, which is pasted with the heat-proof tiles used by the space shuttle, and 11 vertical deflectors are designed internally, the first role of the deflectors is to accelerate the exhaust cooling, the second is to be able to channel the flames, and the lower edge is tilted backwards and upwards, which is to reduce the radar reflection of the tail, and can also play a shielding role in the infrared radiation facing downwards, which can play a good double effect of radar and infrared stealth.
The design of the jet port is mainly to avoid excessive infrared features like the exhaust plume, and to minimize the exhaust cross-sectional area to reduce the role of infrared features, and this design also brings a price, that is, there is no room for thrust vector control technology, so the power system of f117a does not have vector propulsion technology.
Through the combination of this series of polyhedral fuselage structures, radar absorbing materials, and platypus exhaust devices, the f117a Nighthawk stealth attack aircraft with a radar reflection cross-section area of only 0.001 square meters has been created.
In terms of weapons, in addition to the 4.7 meters long and 1.57 meters wide weapon compartment, there is no other point to carry, these two weapons compartments can provide a load of 2.3 tons, can carry the AGM-65 "Maverick" air-to-ground missile, GBU-10 bomb, Gbu-27 laser-guided bomb, B61 free-fall nuclear bomb, etc., basically the weapons in the US Air Force Armory can be carried.
With the upper stealth performance and high flight height, in the execution of the mission can basically not rely on the help of the accompanying wingman, only need to cooperate with the electronic system of the upper fuselage to achieve accurate strikes, it is reported that F-117a in the exercise of the infrared target attack accuracy of about 1 meter, although this fighter can carry air-to-air missiles, but its maneuverability visual measurement is not very good, so F-117a may not be very good at air entanglement.
Avionics equipment, a lot of equipment on the aircraft are taken from the existing fighters at that time, the only difference is that the F-117a is not installed with fire control radar and other various radar equipment, mainly to reduce the possibility of detection, its navigation system is mainly composed of global satellite positioning system and high-precision inertial navigation devices, automatic mission planning system can coordinate all attack tasks, plan the attack route, and automatically execute, including the release of weapons.
The fire control system detects and fire-controlled aiming via a dual-field-of-view forward-looking infrared sensor and laser sight under the windshield. The window glass of this sensor is also metallized on the inner surface or covered with a small grid, so that the window and the surface of the body form a flat whole relative to electromagnetic waves, which is used to reduce the cross-sectional area of infrared and radar reflections.
F-117A fighter cost $42.6 million that year, entered service in October 1983, first participated in the war in 1989 Panama War bombing missions, followed by the Persian Gulf War, kosovo war and Afghan war, during the "Desert Storm" operation in 1991, F-117a fighters attacked nearly 1300 times, in the anti-aircraft artillery attacked 1600 valuable targets in Iraq, none of which was damaged, achieved very good results, However, its main task is to carry out bombing and bombing missions, basically acting as a light bomber,
The only combat loss was during the Kosovo War on March 27, 1999, when ground forces shot down an F-117A using old Soviet-made S-125 missiles, which is not much to be said here.
Later, with the more advanced F-22 fighter jet and F-35 fighter jet in service, the F-117a, a fighter using the technology of the late 1970s, also became more and more backward, so it was retired on April 22, 2008, but in recent years, the United States has often appeared F-117a video of the resumption of flight, perhaps it is just hiding behind the scenes.
As for its positioning, as a stealth fighter, the United States positioned it as an attack aircraft, why use the naming convention at the beginning of f? That's because it received its official designation in 1962 before the U.S. Tri-Service Aircraft Designation System.
And the research and development team at that time believed that the design of early stealth aircraft focused on the minimum radar cross-section, rather than aerodynamic performance, so the design of the appearance is very peculiar, so some senior pilots are not very happy to fly, if you choose the attack aircraft a or bomber b to name, there is no fighter f to be attractive, so use f to name, to achieve the purpose of easily attracting top-notch US Air Force pilots to fly.