What is the name of the round geometric window on an airplane? The windows on the plane are round to prevent it from falling apart

Airplane windows are called portholes. On modern airliners they always have a rounded shape - if not round, then certainly oval. Many people wonder why this particular form was chosen? After all, square and rectangular windows are successfully used in the windows of houses and cars. What is the difference, is this choice random?

It turns out that rounded windows are used in aircraft construction for a reason; practice itself dictated that people need to choose this particular form.

Pre-50s airplane windows

At the dawn of aircraft construction, rectangular windows were actually used, more reminiscent of the windows of modern cars. They did not cause any problems until the 50s, before the beginning of the jet age in aircraft manufacturing. The first experiments in this direction were made in Britain, where they created an airliner called the Comet - already a jet, but with old rectangular windows. It was an exceptional aircraft for its era.

Interesting fact: The Comet airliner had a pressurized cabin and other characteristics unique for that time. But by 1954, two aircraft of this series simply fell apart in flight, which necessitated a revision of their characteristics and design features.

Why were the Comet planes damaged?

A window in the shape of a rectangle or square has four weak points, which are located just in the corners. If you subject a house with ordinary rectangular windows to any significant physical stress, for example, you will notice that cracks will start from the corner parts of the windows, and only then will begin to spread to the entire structure. During takeoff, during the flight, the aircraft also experiences very significant loads. During flight, the pressure inside the aircraft body is as much as 3 times higher than the pressure outside; when landing, the pressure on both sides of the aircraft body is equalized. The airframe is also affected by temperature changes, which cause slight changes in the dimensions of the airframe.

As a result, if there are square or rectangular portholes, so-called metal fatigue accumulates in the corner parts, they become brittle and vulnerable. This subsequently leads to metal ruptures in these very places.

This is exactly what happened with the Komet aircraft. Initially, designers and experts were at a loss and could not find the cause of the problems. Later, when multiple pressure drops on the cabin were simulated under laboratory conditions, it was discovered that the housing began to burst as a result, and the ruptures came right from the corners of the window.

Under the influence of external factors, small ruptures and cracks on the fuselage quickly increase, the body of the aircraft is literally torn into pieces, which is what happened with two sides of the Comet series. A weak point leading to accidents has been discovered.

Development of round windows for aircraft

Next, experiments were carried out on the first sides with rounded windows of the modern type. Multiple repetitions and various tests have clearly shown that such a problem does not arise with them. Rounded structures have taken root in the aircraft industry; they are still used today, as they do not create additional risks, eliminate dangerous situations, and fully justify their use. Modern aircraft fly even faster than Comets, they experience more significant overloads, but the body successfully withstands them - largely thanks to the rounded windows.

Round windows evenly distribute the load on them and do not have the ability to concentrate it at certain points. In addition, when choosing rounded shapes, it is easier to ensure cabin sealing, which is absolutely necessary when taking into account modern speeds and flight altitudes of air transport.

Today, aircraft manufacturing uses glass with a special curve, with a carefully calibrated composition, which protects the safety of passengers and crew. Not only do they not transfer a concentrated load to the body, but they also protect against the risk of cracks and other damage on their surface.

Thus, the rounded shape of airplane windows was not chosen by chance. It eliminates the risk of accidents and does not concentrate the load on the body. Practice has shown that the load is concentrated at the corners of rectangular or square portholes, these places are subject to increased wear, and subsequently to deformation and ruptures. During the flight, this can lead to an accident, depressurization of the cabin, or rupture of the metal body.

Round windows have proven themselves well in practice; they do not create additional risks, which is why they are actively used in the aircraft industry. The practice of their use has been for more than 60 years. There is no need for designers to change this solution; it was chosen correctly.

The reason is ridiculously simple: square windows. This was one of those annoying little things that are easy to miss when designing; but as soon as something happens, they become obvious even to a child.

The square window consists of four 90-degree notches, which means it has four weak points. If there was pressure on your house, the crack would certainly go through the corner of some window.

Have you noticed that the windows on all planes are round? This is not done for beauty - the round shape does not allow the plane to be torn into pieces. The pressure is distributed along the entire curve instead of cracking at the corners (as it turned out) and tearing the plane to shreds.

Believe me, it wasn't easy to find out. Experts had no idea why the plane's structure was falling apart until they tested the structure by repeatedly simulating cabin pressure. Of course, the fuselage eventually burst, and the rupture began precisely from these notorious corners. Since then, all aircraft have only round windows.

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Why are airplane windows round? Why are the tips of the wings curved upward? And why do passengers enter from the left side of the board?

Everything related to aviation is thought out to the smallest detail. Perhaps this is why the plane is the safest form of transport. And yet why is it designed this way?

website answers the 8 most popular “whys” about airplanes.

1. Why are airplane windows round?

In the early 1950s, de Havilland produced an aircraft called the Comet. An airplane that was considered a true miracle of aviation. However, a year later it fell to pieces in the air. A few months later, the same thing happened to two more aircraft.

Engineers ran diagnostics on every cog in the plane and found the problem. The cause of the disaster turned out to be the plane's windows - they were square. The fact is that the corners of the windows bear a large load, which increases even more during the flight. Engineers solved the problem by rounding the corners of the windows. Thanks to this, flying has now become much safer.

2. Why are the tips of the wings curved upward?

During flight, the pressure from below the plane is higher than the pressure from above. Therefore, the air strives for equilibrium and tries to move from an elevated area to a lower one. The easiest way to do this is on the wings of an airplane. It was only when the air reached the tips of the wings that it broke off and created strong turbulence.

The nose of a military fighter is sharp. The sharper the shape, the more streamlining and the faster the plane. But due to the long nose, the runway is difficult to see, so ordinary passenger planes have a rounded nose.

But British engineers solved this problem and in 1969 made one of the fastest passenger aircraft, the nose of which can change its inclination. During takeoff and landing, the nose is lowered, and during flight it is brought to a vertical position.

This strange design is made for one reason only: this way, pilots can better see the runway during takeoff and landing.

4. Why are planes white?

Most planes are white, and for good reason. There are several reasons:

Heat reflection. If an airplane is painted white, it accumulates less heat. This is better for passengers and more economical for the airline.
White paint is cheaper. Painting an airplane white is several times cheaper than painting it in any other color.
Bird strike prevention. Birds see reflections from white surfaces better and do not collide with aircraft.
It's easier to see cracks and dents on white. White parts are easier to recognize in a crash and damage to the hull is easier to spot.

5. Why is the entrance on the left?

Not all, but many aircraft models have the main passenger entrance on the left. There are 3 versions of why this is the case.

Version 1. Luggage is loaded on the right side (the luggage hatches are on the right), so it is also unsafe to let passengers in on the right.
Version 2. There is an assumption that this migrated to airplanes from ships: passengers entered along a ladder onto the left side of the ship.
Version 3. Previously, the commander always sat on the left. The location of the passenger door, also on the left, gave him a better view and allowed him to more accurately adjust the plane to the passenger area.

6. Why are some planes so strangely shaped?

You've probably heard about the plane, which is also called invisible. It has such an unusual shape for one simple reason: it flies as one solid object. This makes it faster, can carry more luggage and uses less fuel.

The design of airplanes is inspired by birds. Birds of prey adopt this posture to increase their flight range and be less noticeable.

However, the production of an aircraft of this shape is very expensive, so it is not used in civil aviation.

7. Why do planes seem spacious?

Round windows to provide access to light, built into the sides of airplanes and ships, are a common sight. It is difficult to imagine that they did not always have such outlines. So why are the portholes round? There are a number of explanations for this.

Portholes on ships

The windows built into the sides of ship hulls were not always round in shape. In historical photographs you can see ships with square and rectangular windows that look like regular vents.

The rounder shape that is more familiar to us is due to higher strength parameters. Roundness makes it possible to evenly distribute the load created by differences in pressure and temperature. This “negates” the risk of cracks and, as a result, rupture of the ship’s hull. For the same reason, all load-bearing parts of ship hulls, as well as doors and hatches, are rounded.

The second reason for the widespread use of round windows is ease of manufacture.

Previously, window frames were made from cast brass blanks, followed by processing on lathes. The round pieces were much easier to make. In addition, during installation it was easier to seal them, protecting them from leaks.

Modern round portholes on ships are completely waterproof. As additional protection in case of severe bad weather or rough waters, the portholes are equipped with storm covers made of metal or removable shields.

Windows on airplanes

Even before the middle of the last century, square windows were installed on passenger planes. Airplanes such as the Caravel even had triangular windows.

The turning point was the tragedy that occurred in 1953. In those years, the jet aircraft industry was actively developing. One of the first to enter the world market was a supersonic airliner called Comet. In terms of technical characteristics in those days it had no equal. But contemporaries remembered the supersonic airliner for the reason that it crashed at the moment of takeoff. 56 passengers died. Over the next year, two more similar disasters occurred. "De Havilland Comed" was removed from flights, discontinued and the causes of the accidents began to be investigated.

As it turned out later, the key cause of the tragedies was the depressurization of the aircraft body due to microcracks that appeared in the corners of the windows. To understand, as the plane climbed to altitude, there was a rapid drop in external pressure, while the pressure inside the plane remained more stable. The pressure difference provoked the expansion of the housing. As a result, tension was created in the body material, and it began to gradually change its shape. The square window acted as a kind of obstacle to the distribution of stress, forcing it to change its direction and thereby causing an increase in pressure. Peak stress points formed at the corners of the square windows, causing cracks to form in these areas.

After this, the windows on the plane are made exclusively round or oval. They distribute pressure along the entire curve, minimizing the risk of deformation.

In fact, the windows of modern passenger aircraft, such as the wide-body twin-engine Boeing Dreamliner, are more likely not round in shape, but rectangular with beveled and rounded corners. This engineering solution allows you to “bypass” places where fatigue stresses are concentrated.

It is noteworthy that according to the instructions, the window curtains must remain open during takeoff or landing of the aircraft. This precaution allows you to solve two problems at once: it allows passengers to more easily and quickly adapt to the natural light outside, and crew members at any time, with a quick glance, visually assess the condition of the aircraft and, if necessary, take appropriate measures in a timely manner.

In addition, the polymer curtains must be retracted so that in the event of an emergency at the time of mechanical damage, they do not injure nearby passengers.

Today, the need to use curtains on windows has practically disappeared, since round windows on airplanes are made automatically darkening. The degree of darkening of the windows is determined by the crew. If it is necessary to dim by 99%, you can program in just a couple of minutes both all windows at the same time and selectively individual windows in the cabin.

Jet aircraft manufacturing was just beginning in the 1950s. The first airliner was the Comet, the brainchild of de Havilland (British aircraft manufacturing company; approx. mixednews). It was an ultra-modern jet passenger aircraft with technical characteristics unique for that time and a pressurized cabin. Unfortunately, in 1954, two Comets broke up mid-flight, killing a total of 56 people.

The square window consists of four 90-degree notches, which means it has four weak points. If there was pressure on your house, the crack would certainly go through the corner of some window.