Journey of the Dream to Fly

As we studied the various movement of aircraft and their associated aircraft parts, we will study more about other parts of aircrafts

Have you ever wondered about the amount of force with which an aircraft touches down.

The impact force of an aircraft landing can be calculated using the formula F=ma, where:
F: is the force
M: is the mass of the aircraft
A: is the deceleration or change in velocity of the aircraft during landing

It has been observed that it is generally twice the weight of an aircraft. So if our 737-800 has a landing weight of 65 tonnes, the impact on runway at touch down is nearly 130 tonnes.

While the runways are made in such a way that they can take that much impact, what about the aircrafts. The aircraft Undercarriage also designed and manufactured to handle these high landing impacts.

By definition, the landing gear or undercarriage is the part of the aeroplane designed to absorb kinetic energy originated during contact with the runway, be it on landing or take off.

As you can imagine, a landing gear is an essential part of an aeroplane; but even so, it is much more complex than you probably think.

As incredible as it may seem, the first designs relied on human strength for this task, that is, it was the actual pilot who would, by means of his legs, be in charge of starting the take-off run as well as braking when landing.

In 1903, the Wright brothers equipped their aeroplane, the Flyer I, with skis so that the plane would slide on the ground. These were the precursors of landing gear in aeroplanes.

Only shortly afterwards, in 1906, the Santos Dumont brothers equipped their 14-bis with small wheels; however, these lacked any shock absorbers and landings were rather abrupt.

With the Dayton Wright RB-1, in 1920, the first retractable landing gear emerged, and it was activated manually by pilots, by means of a crank. From this moment on, technological progress and development have transformed the first systems into the landing gear we now know.

Types of Landing Gears:

Fixed Landing Gears:
Those which are always visible are fixed landing gear. They are typically used in smaller and lighter aeroplanes with the objective of avoiding being overweight with heavier and more complex systems which would only have a low performance in terms of speed and fuel consumption.

Retractable Landing Gears:
Those which are not visible, or are hidden structurally inside the fuselage of the aeroplane and are activated by the pilot when needed. Commercial aeroplanes or those used in the last part of pilots’ training, have retractable landing gear.

Conventional Landing Gear:
This was the first system used because of wing and engine layout; it was the configuration that was best suited to the center of gravity of the first aircraft. The conventional landing gear is made up of two posts beneath the wings or roughly at the same height of wings, and a wheel at the tail.

Although they have the advantage of being aerodynamically good, in the case of fixed and sturdy retractable landing gear, conventional landing gear has various disadvantages, such as having low visibility on ground, or difficulty landing when there’s turbulence or crosswind.

Tri Cycle Landing Gear:
This type of landing gear consists of two posts which are situated beneath the wings of the aeroplane or fuselage and another post under the nose which also has a directional device.

The tricycle landing gear makes landing much simpler, even if there’s crosswind or tailwind. It also eliminates the danger of flipping over, allowing touch down in a horizontal position.

The number of wheels in a landing gear varies depending on size and carrying capacity of Aircraft. In each strut there can be number of tires and are arranged as single, tendom,double or bogie, as shown below