Ejection seat, the skyguard of the skyguard

Some people say that the last line of defense to save pilots' lives is the fighter jet's ejection life-saving system.

Since World War II, the speed of aircraft has exceeded 500 km/h. At such a high speed, pilots can no longer climb out of the cabin to parachute in the strong wind. It is not uncommon for pilots to be blown onto the wings and die. In the practice of military aviation lifesaving, people have observed that the faster they get away from the aircraft, the safer the pilots will be.

The ejection life-saving method was first proposed by the German army during World War II. Since then, it has developed into various forms such as open ejection seats, detachable ejection seats and ejection cockpits. In essence, they all rely on a power device to eject the pilot from the aircraft and then land using a parachute.

The most widely used of these is the ejection seat. The MK series ejection seats produced by the British ejection seat manufacturer Martin-Baker alone have saved the lives of 7,675 flight crew members.

The Heinkel He 219 was the first aircraft in the world to be equipped with an ejection seat.

Image source: wikipedia

The ejection seat is usually used as a pilot's seat. When the aircraft is in a critical moment and cannot be saved, the pilot will activate the ejection life-saving system. The ejection seat control handle is usually between the pilot's knees. It is a brightly colored pull ring. Just pull it upwards and the ejection life-saving system will automatically start working, which greatly shortens the escape time and increases the possibility of a successful escape for the pilot.

The yellow pull ring is the ejection seat control handle. Image source: wikipedia

After pulling the handle, the cover-throwing rocket automatically ignites, flipping the canopy cover open and throwing it backwards, which is the first step of ejection. If the fighter jet uses a cover-penetrating ejection, it will be faster, with almost no waiting, and the detonating cord on the canopy will accurately shatter the glass and open the ejection channel.

The canopy is covered with curved detonating cords.

Image source: Guangyu Liu, Microstructure and mechanical properties of tin-based alloys for miniature detonating cords

Schematic diagram of the ejection method, which first lifts the glass hatch and then ejects the seat. Image source: wikipedia

When the life-saving passage is opened, the power device of the ejection seat is automatically activated. First, the ejector on the back of the seat pushes the pilot and the seat upward and separates them from the cabin. At the same time, the seat's built-in emergency oxygen supply system starts to supply oxygen to the pilot, and the seat belt is automatically locked, firmly fixing the pilot on the backrest of the seat to prevent the violent maneuver from causing harm to the pilot.

Then, the rocket engine at the bottom of the seat started up, and the person and the seat suddenly accelerated, and quickly rose to a safe altitude on the "rocket". At this time, the overload was as high as more than ten Gs, and the person would be temporarily unconscious under such an overload. If the pilot was still conscious, he would see the crashed plane continue to fly forward under him.

The new ejection seat is able to collect data such as the aircraft's attitude and speed, automatically control the ejection trajectory, and prevent the pilot from ejecting "headfirst" toward the ground when the aircraft's attitude is bad. Therefore, it can work at extremely low altitudes and can even perform a "zero-zero ejection" when the aircraft is at zero speed and zero altitude.

At the 2003 Mt. Home Air Show, the F-16 pilot successfully ejected 0.8 seconds before the plane crashed and suffered only minor injuries.

Image credit: SSgt Bennie J. Davis III

It is worth mentioning that if the fighter is a two-seater, as long as the handle of one ejection seat is pulled, both pilots will be ejected from the cabin. This is for two reasons. First, once ejected, the appearance of the aircraft will be destroyed and it will not be able to fly normally. There is no need for the other pilot to stay in the aircraft. Second, it can help the comrade escape when he is incapacitated and unable to save himself. The two pilots will be ejected one after another, with an interval of about 1 second to prevent the ejection seats or other parts from colliding in the air.

When ejecting, the front and rear seats do not eject at the same time.

Image credit: US Navy

After successfully leaving the aircraft, a small parachute will automatically deploy on the back of the ejection seat. This parachute is called a stabilizing damping parachute, which is used to stabilize the flight attitude of the seat. Under the adjustment of the stabilizing damping parachute and the fine-tuning engine, the pilot and the seat gradually stop rotating due to inertia, and the speed is also slowed down to a level suitable for opening the parachute.

After ejection, the stabilizing parachute on the back of the seat opens

Image credit: US Navy

When it comes to the stage of preparing to open the parachute, the heavy seat body has basically completed its mission. The parachute opener shoots out the parachute stored in the seat, which connects the pilot and the life pack. At the same time, the remaining seat belts automatically open, and the person and the seat are separated - this sounds a bit like the process of a rocket taking off. The two-stage propulsion device composed of a catapult and a rocket engine provides power for the "rocket". The various components are separated after completing their mission, and the "payload" actually transported by the "rocket" is the ejected pilot himself. The launch vehicle sends payloads such as satellites and spacecraft into space to perform missions, and the ejection seat, a special "rocket", is launched to protect the precious "payload" in times of crisis. Within two or three seconds after the parachute is opened, the large parachute of dozens of square meters can be fully unfolded and slowly land with the pilot.

The parachute equipped with the ejection seat carried the test personnel down

Image credit: DoD / MIlitary Affairs

A successful landing does not mean that you are completely out of danger. It is entirely possible that a pilot who is ejecting and parachuting will land in an uninhabited wilderness, forest, or even on the sea. He or she will have to face all kinds of harsh natural environments alone before rescue arrives. At this time, the life-saving bag fixed under the parachute can come in handy. As part of the ejection life-saving system, the life-saving bag is usually stored under the seat. At the critical moment of ejection life-saving, it can provide signal generators, positioning equipment and other devices to help the pilot call for help; life rafts, medicines, daily necessities, etc. can maintain the pilot's vital signs while waiting for rescue.

If it is during wartime, the situation will be even more complicated. A lone pilot is usually a high-value target that the enemy is very interested in. Therefore, pilots who have successfully parachuted need to take the initiative to hide and use the weapons in the life-saving kit to defend themselves and wait for search and rescue by their own troops.

Survival kits and self-defense weapons equipped by the 169th Fighter Wing of the U.S. National Guard

Image credit: SC Air National Guard

Unlike passenger planes that put safety first, fighter jets are meant to fight and confront each other. Fighter pilots fly steel blades at speeds several times faster than the speed of sound, and are destined to face more dangers. The ejection life-saving system provides the last layer of protection for military pilots in critical moments. Every successful ejection means that a soldier can return safely from the battlefield. Perhaps in the future, unmanned equipment will be able to replace flesh and blood to win wars, but before that, people will still need to carry the burden of guarding the airspace.

Produced by: Science Popularization China

Author: Aloysius

Producer: China Science Expo

The article only represents the author's views and does not represent the position of China Science Expo

This article was first published in China Science Expo (kepubolan)

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