It takes six months to manufacture the retractable equipment responsible for bringing the high-flying machine into contact with the ground. Emergency support, smooth movement on the ground, landing and takeoff of the airplane fall on the characteristics of its landing gear. How is this mechanism designed, if it manages to withstand the pressure of several hundred tons at full throttle? At the same time, most often remaining gracefully and functionally hidden during the iron bird’s dive.
Given a filled fuel tank with a displacement of more than 600 liters, a Boeing aircraft can weigh between 170 and 210 tons. A severe impact of the machine on landing seems inevitable with such a significant weight. Planes designed to transport goods and valuable cargo in general can exceed 300 tons. If one imagines that much iron coming down from the sky, let alone what is inside it, one can only marvel at the fact that the aircraft remains intact.
Even a significant percentage of emergency landings are made without noticeable damage, given that the airplane lands on an uneven surface, often with a large number of foreign objects or difficult terrain. An outstanding American pilot was once able to land a passenger airliner directly on the Hudson River. Thanks to his skill at the controls, he thus prevented what would have been the first catastrophe in American history since the Twin Towers tragedy.
The titanium disks built into the wheels of modern aircraft are very strong and incorruptible against all surfaces. They consist of two equal halves, tightly bolted together. For reliability, they are also treated with an adhesive compound. The adhesive ensures that the wheels are completely sealed; the disc cage squeezes the tire layers closely together, and does not even seem to allow air to break through the outer casing.
It’s no coincidence that during a tire inspection, they try to inflate them with water: if water gets inside at a certain height, it freezes and provokes malfunctions. And abnormalities in the wheels are as serious a problem as in the wings and tailplane. In this respect, an airplane is more vulnerable than a bird; after all, nature is difficult to furnish even with the help of technological progress.
One can only admire the impenetrability of the tires used on airplane landing gear. A car tire can be spoiled almost on the spot, sometimes it can be punctured by a stationery button lying on the road. Rubber wears out quickly on regular trips, and rarely can withstand heavy impacts with the ground or asphalt.
In fact, the landing gear is the part of the machine that can compete in the complexity of its organization with its other parts. The development of an airplane’s landing gear takes more than half a year. To achieve effective shock absorption, it is necessary to balance the density and lightness of the protruding rails with the wheels. By the way, cushioning – a word that is so often used in the context of the airline industry and engineering – means “softening”.
The creators of landing gear are essentially merging the air plane with the ground plane; embodying the possibility of realizing trajectories of motion that flow seamlessly from ground to sky. This was once as unthinkable as colonizing Mars. It was believed that if something dropped from a great height, it would surely crash: this was the pragmatic approach.
Shock-absorbing landing gear struts maintain safety during the careful and consistent movement of the airplane at all intervals when it makes contact with the solid. Their shape, bends, and degree of angles are so arranged that all the weight bearing down on the wheels on impact is primarily distributed to them. They may be said to take the onslaught of the collision of the apparatus with the ground upon themselves. Cargo planes and colossal business jets are also equipped with dampers to increase stabilization. Cars, on the other hand, don’t have such strong and elaborate shock struts, so drivers rely on the quality and brand of tires.
The wheels for landing gear are not divided into different types in terms of quality, simply because they are always made without a hitch.
There can be no other option for flying vehicles. In price ratio with automobile ones, they go far ahead. They include many layers of rubber, laid one after another with reinforced layers of steel cord. Before gravel begins to rise from under the wheels, in the form of dark haze and individual large granules, they simply glide across the surface for a few seconds. This unobtrusive return to the hard surface allows for a quick adaptation to the surface in order to successfully start spinning.
Even at speeds in excess of 400 kilometers per hour, the planes adapt thanks to the struts and multi-layer solid wheels to the landing strip, and produce a comfortable and smooth landing. This happens day in and day out and quite naturally as part of the routine. Any pilot realizes that a soft landing is much more difficult than a takeoff and requires a comprehensive approach to the situation. Rubber alloys get very hot under such circumstances. What keeps them from melting is, again, their multilayers and speed control, which prevents them from burning up instantly.
The wear resistance of aircraft tires is determined by longitudinal depressions and distortion of the ornamentation running along the wheels. Signs that a tire is running out of potential depend on various subtle nuances that only professionals are familiar with. Indicators on the treads, the elasticity of the material and individual signs that are not immediately apparent…. It is interesting that, as a rule, a dozen wheel covers (by the number of wheels) are enough for 7-10 flights of cargo airliners. Just imagine what would happen if car tires could only last 10 trips in a row!
If we are talking about passenger flights, such airplanes are ready to withstand regular landings up to 500 times before complete wear and tear. The tires are inflated with nitrogen and the pressure is up to 14 atmospheres at a time. Dozens of layers of rubber that make up the wheels are filled to the brim at once. Sometimes the media flashes news that a plane’s tire burst during speeding. At the same time, passengers clearly heard a sudden pop. This does not say anything good, except for the fact that the accident occurred on the runway, and therefore no one was injured.
Actually, tires are probably the most wearable part at the disposal of an iron bird.
And the larger the size of the airliner, the more tires are needed and the more grandiose they are. Before tires are replaced, airlines put them through a thorough overhaul. Repair does not cost as much as replacement, especially in such holdings there are always qualified craftsmen. Only after a series of rehabilitations are the tires disposed of and replaced with fresh ones.