Low-wing and high-wing aircraft: why such a difference?

What can be said in general about the design? Aircraft, if you look at it from the outside? Fuselage, tail and wings. We'll focus on the latter in more detail today. Take a closer look: some airliners have wings on top, others have wings on the bottom, and still others have wings that go through the center of the body. Why complicate things so much: couldn't they have built them using the same design?


At the dawn of aviation, the possibility of attaching a wing in different ways was not immediately considered. At that time, they experimented with monoplanes and biplanes: they could not decide which was better.



Finally, attention was paid to the method of installing the wing. After a series of studies, it turned out that this seriously affects the aerodynamic qualities of the car and not only.

High-wing aircraft

As the name suggests, these are aircraft with the wings positioned at the top. Note that this type of configuration is mostly typical for transport aircraft. And this is natural: it is easier and faster to load an aircraft if its wings are at the top and do not interfere with the free passage of equipment.


And the low-lying "belly" allows to do without a bulky ramp, expensive high landing gear. There is also a banal reason: if the plane is a propeller, then with a low position of the planes the propellers would touch the ground.


What about aerodynamics? It is better than that of low-wing aircraft by 4-5%. The fact is that the wing forms a kind of single common plane, which the upper air flows freely around. Also, the high-wing aircraft has better stability: it is reluctant to roll and slide onto the wing. That is why all fighters and sports training aircraft, for which maneuverability is important, are made with the planes located below.


There are other advantages, for example, those associated with landing on unpaved airfields. The engines are high up and dirt and dust get into them less. And if there is an emergency landing? The low-mounted power unit will scrape the ground and fall off. Don't forget about amphibious aircraft, whose engines are located at the top so that water cannot reach them.


However, not everything is so smooth: the design has its negative aspects. To understand them, let's look at its "competitor".

Low-wing aircraft

Almost all large passenger aircraft are made according to this scheme. You can start with the same safety: after all, we are talking about tens, hundreds of lives. If an emergency situation occurs in the air, for example, the landing gear does not release, the aircraft will have to land on its "belly". In this case, low-lying wings stabilize the landing, help the airliner stop faster.


It is also worth mentioning the so-called ground effect. In case of close approach to any surface, the wing's lift force "automatically" increases. This softens the landing, both standard and emergency.


And if the plane lands on the water, its surfaces will maintain buoyancy for a long time. Another point is related to the commercial use of the airliner: the more often and further it flies, the more profitable it is for its owner. Therefore, maintenance time should be minimal. On low-wing aircraft, the engines are located under the wings, so it is convenient to carry out maintenance work, the efficiency increases. This placement of turbines also reduces noise in the cabin.


What can be said about the mid-wing? Such a scheme is currently widespread only on military vehicles, since it makes the structure more rigid and durable.

Summary

The above, however, does not mean that all transport aircraft are high-wing and passenger aircraft are low-wing. For one reason or another, designers have made and continue to make exceptions. The main thing is the purpose of the aircraft, for which it is built.