Since the first airplanes took to the air, continuous improvement of aviation technology has continued. An integral part of each
aircraft is devices that serve to move it on the ground (or water) in order to accelerate before takeoff or to brake after landing.
It is an enchanting sight to watch how the seemingly cumbersome mechanical system of the aircraft (landing gear), consisting of many elements, after separation from the runway easily folds, acquiring a compact outline, and hides under the shields in its fuselage or wings.
The classic "ground" landing gear of an airplane consists of two main elements - struts and wheels, also called pneumatics. In those cases when it is required to create an opportunity for operation on snow cover or water, some aircraft models provide for the installation of replaceable elements in contact with the landing surface, it can be skis or floats.
Until the mid-thirties of the 20th century, the fixed-wing aircraft landing gear dominated the global aircraft industry. It was undoubtedly more reliable, but it created great aerodynamic drag, which required various engineering tricks, such as additional fairings and a thinning of the profile of the main struts. Over time, such a scheme was largely abandoned, although some types of aircraft of the so-called "small" aviation use it to this day. An example is the "celestial centenarian" An-2, the design of which has not been amended since 1949.
The development of fighter aircraft required an increase in speed. The racks, previously equipped only with shock absorbers, became more complicated, and the mechanism of picking up wheels in the plane or the fuselage posed difficult technical tasks for the engineers, but the result was worth it. The IL-16 aircraft chassis was a revolutionary solution, they were first cleaned on a mass-produced fighter, which gave our volunteer pilots the opportunity to win victories in the skies of warring Spain.
In its diversity, few structural elements can compare with the aircraft chassis. The scheme that has received the greatest distribution in modern aircraft manufacturing is a three-legged one. It involves two main racks and one auxiliary (most often - the bow, taking on up to 9% of the weight of the aircraft). However, even half a century ago, an additional support was most often installed on the tail.
In addition to the main three pillars, some
aircraft designs also had insurance. She took the burden in the event of an unsuccessful landing (for example, IL-62). With an increase in take-off weight, the two main supports were few. The number of pneumatics in the An-124 Ruslan reached 24. According to the multi-rack layout, the Boeing-747 aircraft landing gear was also designed.
Landing is the most crucial moment in the entire flight, every pilot knows this. Therefore, both the reliability of the design and the materials for the manufacture of chassis struts are very high. The durable precision alloys from which they are made provide the ability to withstand loads with multiple margins. And in order for the number of take-offs to always coincide with the number of landings, reserve, emergency rack release systems are also being created. Just in case.