Li Ming, an engineer from an aviation repair plant in Dalian, talks about the efficacy and design principles of ejection seats-the final safety of
pilots
Sun Chang, Song Ru, Meng Jinling
Not long ago, the US F/A-18E "Super Hornet" was flying for training When an accident happened, the fighter plane crashed and hit the ground and caused an explosion. Smoke billowed from the scene. Fortunately, the pilot used the ejection seat to escape safely.
fighter jet ejection seat ejection moment. The profile photo
serves as the pilot’s last safety reliance. The ejection seat is an aviation life-saving equipment that can use rocket power to bounce the pilot off the aircraft and make it land safely in an emergency.
During World War II, the world was born with the first ejection seat. After that, the ejection seat quickly pushed away. Today, with the advancement of science and technology, the ejection seat has undergone iterative development, which can meet the escape needs of fighters in unfavorable attitudes and high-speed flight conditions, and support a "safety barrier" for the lives of pilots at the last critical juncture. The
rocket ejects in seconds, the pilot’s self-rescue "artifact"
In the fierce air confrontation, the battle situation is changing rapidly, and the flight status of the fighter plane is full of many uncertain factors. Once the fighter plane is under loss control, the pilot must flee the plane as quickly as possible. In the First World War, the aircraft designer equipped the pilot with a parachute. When the pilot needed to abandon the plane to escape, the pilot had to open the cockpit cover, climb out of the cockpit, jump off the fuselage and open the parachute. The probability of escape was relatively low.
With the upgrading of military aircraft, high-speed, multi-attitude flight conditions have brought more severe challenges to pilots’ escape. Traditional escape methods are no longer possible due to time constraints. Until World War II, the catapult life-saving method came into being. The
designer spent a lot of energy on shortening the escape time. The ejection and escape action of modern fighters is almost instantaneous. Statistics show that it only takes 2.48 seconds from the time the pilot activates the ejection seat to the fully opened parachute.
So, in such a short ejection moment, how can the ejection seat ensure that the pilot can help himself successfully? Z1z
slow-motion playback, we found that ejection is actually a very complicated process.
When the ejection is needed to escape, the pilot only needs to pull the ejection handle, the ignition mechanism and the rocket launcher can be activated sequentially in 0.4 seconds, which is equivalent to the time of blinking an eye.
At the moment when the ejection handle is pulled, the restraint device on the seat will tightly "tie" the pilot's body to the seat, making preparations for the ejection start, and avoiding collision with equipment in the cockpit during ejection.
At the same time, the combat opportunity adopts the method of throwing away the hatch cover as a whole or blasting and smashing it, breaking the obstacle of the cockpit cover to the ejection, opening the escape route for the pilot to prevent the pilot from colliding with the hatch cover.
After this series of ejection preparation actions are completed, the seat will enter the ejection phase through the ballistic and rocket power. Z1z
ballistic ejection, as a primary power, will quickly bounce the seat away from the aircraft, while rocket ejection will bring the seat to a safer height, ensuring that the pilot maintains a safe distance from the aircraft and ensuring that the parachute can be opened smoothly.
realizes this series of actions relying on the "brain" of the ejection seat-the program control system. The system issues instructions to correct the flight trajectory in real time to ensure that the chair bounces to a safe height for parachuting, then release the stable decelerating parachute, choose the best time for the separation of the chair, and open the parachute safely. Is this the end of
ejection escape? of course not. The
ejection seat not only allows the pilot to get out of the cabin in seconds, but also protects the pilot from landing safely and resists various dangers while waiting for rescue.
During the landing phase, the pilot’s life-saving bag will automatically open, the lifeboat will automatically inflate, and the built-in beacon will send out a distress signal. After landing safely, pilots can use dozens of wild life-saving products such as life-saving manuals, flares, rations, sea water desalinators, etc. in the life-saving kits for self-rescue.
is not only that, according to the characteristics of the mission, some ejection seats are also equipped with life-saving products in different geographical environments such as deserts, cold regions, and tropical jungles. These life-saving products help pilots cope with various harsh environments and stage a real "PUBG Mobile".
The most complicated design process, the safest escape system
Flying is the career of the brave. Since the Wright brothers invented the first airplane, flying dreams and unknown risks have gone hand in hand. When the plane is lostAfter control, how can the pilot return to the ground safely? It has always been an important subject for designers to study.
As early as the middle of the 18th century, humans tried to jump from the sky with a big umbrella. In 1797, French physicist Garnerin jumped from a height of 1,000 meters and landed safely with a large umbrella woven of soft fabric. The design of the aerial escape device during this period was relatively simple, and it was mostly used in commercial performances, but this was the prototype of a parachute. During World War I, smart designers used parachutes to save a large number of pilots' lives.
However, by the time of World War II, German designers discovered this problem: As fighters flew faster and faster, only a parachute could no longer guarantee the safety of the pilot.
They concluded that it is extremely difficult for the pilot to open the hatch from the cockpit when the speed of the fighter plane is greater than 600 km/h. Even if the hatch can be opened, the moment the pilot jumps out of the narrow cockpit with a heavy parachute on his back, encountering a high-speed airflow is tantamount to an "head-on collision." The
designer realized that it was urgent to develop a device that would allow pilots to escape as quickly as possible while flying at high speeds. The front and back of the invention of the
ejection seat is a period of continuous struggle between humans and death. In fact, the design concept of the ejection seat originated from an accidental experience-
during World War II, due to an improper operation, explosives exploded in the German bunker. Several soldiers were exploded seven or eight meters high. This accident brought the designer. Design inspiration: Can you develop an explosive device that will "blast" the pilot out of the cabin when encountering danger.
They tried to use highly elastic rubber bands as power, but they failed. It was not until 1940 that a compressed air-powered ejection seat was installed on the jet prototype He-280. This was the first time that humans survived a fall at an altitude of 2,370 meters and achieved the "first show" of ejection seats. However, this seat has the disadvantages of low ejection force, large weight of the compressed air cylinder, and easy gas leakage. It has not been mass-produced. The first-generation ejection seat of
came out after World War II. It uses the principle of ballistic ejection and uses the power of gunpowder to shoot people and seats out of the cockpit as "cannonballs". However, the first-generation ejection seat had limited ejection power and could not meet the requirements of low-altitude ejection, and was soon eliminated.
In order to solve the problem of low-altitude ejection, a foreign research department proposed a "two-stage ejection mechanism" method, that is, when the ejection mechanism bounces the seat to a certain height, the rocket pack is activated, pushing the pilot to a higher parachute height. As a result, the second generation of ejection seats came out. This generation of ejection seats introduced the "zero-zero" ejection concept, which can eject at zero height and zero speed, and its safety is significantly improved.
However, "zero-zero" ejection is not enough. After the ejection seat exits the cabin, it is equivalent to a small, irregular aircraft. Once the aircraft has an unfavorable flight attitude, the ejection direction is difficult to predict, and it may even shoot to the ground, which reduces the pilot’s survival rate. In the development of the third-generation ejection seat,
's clever designer adopted the design of seat stabilization system and direction sensing system to meet the needs of escape in a variety of flight attitudes, and the safety was significantly improved. The famous Russian K36 ejection seat The chair is the representative of this generation of ejection seats. At present, the ejection seat is widely used in Su-30 and Su-27 fighters.
With the rapid development of science and technology, rocket thruster technology has become more mature. As the main power of the ejection seat, the 15 times the acceleration of gravity generated by the rocket thruster can carry parts weighing up to hundreds of kilograms to achieve ejection. This is also one of the most complex devices in the design of a fighter.
integrates "black technology". The "private customization"
ejection process of military aircraft seems to be only a short moment, but behind every thrilling escape of the pilot, there is the wisdom of the designer. The
ejection seat itself is a complex project involving multiple systems such as ejection control, stable deceleration, and remote ignition. For a successful ejection, multiple programs and related components such as program control, human chair stabilization, and human chair separation must be closely coordinated and work together. Z1z
ejection escape is a thrilling journey. At the moment of ejection, the pilot has to withstand about 15 times the acceleration of gravity, which is equivalent to 15 forces of his own weight acting on the body. The huge impact force will make the pilot instantly dizzy or even unconscious. In addition, the ejection process has to withstand repeated tests such as low temperature, high speed, and strong air currents.Test.
is subject to various "harsh" conditions, and the development of ejection seats is very difficult. It is not only necessary to ensure normal operation under various extreme flight conditions, but also to take into account the various physiological parameters of the pilot and the multiple requirements of the installed weight. During the decades of research and development, the ejection seat has gradually integrated dozens of disciplines such as aerodynamics and fluid mechanics, with extremely high technological content. It is even more difficult to make an ejection seat with superior performance. At present, only a few countries in the world have independent research and development capabilities. Z1z
has multiple systems, strong coordination and high degree of electromechanical integration are the main features of modern ejection seats. Among dozens of technical indicators, ejection performance is one of the most critical indicators. However, the difficulty of simulating the ejection state under high-speed flight in the air through ground tests can be imagined. After years of research,
designer finally developed a simulation test method-rocket skid slide test.
This test requires a large site, and the length of the slide rail track must reach several kilometers. Through fine welding, the track accuracy is accurate to 0.2 mm, which is equivalent to the accuracy of a hair.
has high-tech test equipment, and the ejection seat can simulate the ejection effect of zero height and full speed on the high-precision track. Finally, after capturing data through a high-speed video camera, and relying on a series of calculations and analysis such as mathematical modeling, it can be judged whether the ejection performance is qualified.
At present, in order to ensure the safety of pilots, ejection seats that integrate high technology and high performance have become "private customization" for military aircraft. Almost all fighters in the world are equipped with ejection seats.
Not only that, with the increase in the probability of air escape of pilots, many national air forces have produced "added value" in their understanding of ejection escape. It is extremely important for the air force's combat effectiveness to survive air crashes for pilots with rich combat experience.
According to statistics, most ace pilots in the world have had the experience of ejection and escape. Every time they survived the catastrophe, they helped them grow into “better pilots”.
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along the way, thank you!
Article source: People's Liberation Army Daily
Editor in this issue: Niu Ruili
Chief Editor : Champions League Hao Yuan Peng
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