Aviones supersónicos y la barrera del sonido

During World War II, the world of aviation underwent an impressive technological revolution. Each time the aircraft were able to fly higher and faster. But pilots and engineers ran into the so-called ‘sound barrier’ over and over again. That is, the possibility of exceeding the speed at which sonic waves are transmitted through the air. Approximately 344 m / s at 20 ° C temperature, or what is the same, 1,238.4 km / h.

Despite the technological advances that were being implemented in each new generation of aircraft, it was not possible to overcome the mythical barrier. Each new attempt was crowned with a resounding failure, if not serious accidents.

You ask yourself, why? Among the main obstacles was the fact that in the tests as the aircraft approached Mach 1 (unit of measurement of sound speed) the aerodynamic drag increased exponentially due to what is known as “drag resistance”. compressibility ”that gives rise to what is known as a shock wave. That “shock wave” that when it is crossed causes the well-known “sonic stampede”.

Another problem was the sudden loss of power experienced by jet engines as they approached the sound barrier. Today we know that this anomaly occurred because even though the plane was moving at sub-sonic speeds, the blades of the engine in these conditions if they rotated above the speed of sound which altered its ability to compress air to the combustion chamber.

For all this, it was thought that the proposed goal was unattainable. But against all odds, on October 14, 1947, it was finally achieved. A feat starring United States Air Force pilot Chuck Yeager.

X-1: Supersonic Plane

X-1 Avión supersónico

In 1947, the X-1 was built in the United States. The first experimental aircraft whose sole purpose was to investigate in the field of aeronautics and break the sound barrier.
Who was going to say that this aircraft, the X-1, would set precedents and manage to add more than 50 ‘X aircraft’ to the list, such as the X-15, which in the 1960s reached the limit of space for the first time Exterior. With the X-1 plane it was shown that it was possible to go faster than sound

How did you manage to overcome the sound barrier?

The engines that had been tested until then were jet engines, which, as we have said before, experienced serious problems at high speeds in generating enough thrust to break that barrier due to their way of acting. A jet engine works by ingesting the air from outside, compressing it and increasing its volume through combustion, to finally expel it at higher pressure.

If a conventional jet engine receives a flow of air that, when compressed by the blades, increases its speed above that of sound, it stops working well or directly stops working.

The answer to the problems was the rocket engine. This other type of engine does not require air from outside to generate the thrust it needs, since it has it stored in its tanks. In addition, with a suitable design of the gas expulsion nozzle, these new engines allowed to achieve very high thrusts independently of the external conditions.

Using this type of engine, it was how the X-1 managed to propel itself above the speed of sound, however the X-1 solved another serious problem that so far prevented reaching the speed of sound: aerodynamic resistance, or resistance due to compressibility, which generates what is known as “shock waves.”

Meaning of shock waves

Significado de las ondas de choque

This phenomenon occurs due to the enormous pressure produced by the layers of air in front of the plane, and the resistance they offer to the advance of the aircraft.

Due to the laws of fluid dynamics, the higher the speed, the greater the resistance, that is because when an airplane flies at low speeds the air, which is a fluid, tends to slide around the fuselage increasing its speed. relative, and therefore decreasing its pressure.

In contrast, when flying at supersonic speeds, the layers of air tend to compress at the impact edges of the aircraft, thus generating strong drag, causing exponential aerodynamic drag.

This is why all aircraft designed to reach high speeds – not just the supersonic ones. Commercial jets also reach speeds of 0.85 Mach – they follow the same aerodynamic pattern: swept wings, very sharp noses and slim fuselages.

Supersonic aircraft

Now we know more about supersonic flights, we are going to see below the planes that have reached this milestone and have even surpassed it.

F-15 Eagle

F-15 Eagle

Built by the United States, it is the most mythical airplane in history. Its first flight was in 1972 and it is an aircraft that is expected to continue to be used until at least 2025. Throughout its service, its functions have evolved. At present, there are different configurations for this aircraft such as defense and attack. This plane manages to reach a speed of 3017km / h, almost three times the speed of sound.

Sukhoi Su-27 Flanker

Sukhoi Su-27 Flanker

It emerged as the Russian answer to the American F-15. For many it is the best aircraft of its generation. It was introduced in 1977 and is still being manufactured today. This aircraft manages to reach a speed of 2,500 km / h and has a range of 3,540 kilometers.

This aircraft uses Fly-by-wire technology, which consists of transmitting the orders made by the pilot to a computer system that analyzes and executes them, as long as they are within the safety parameters for the pilot and the aircraft. A similar system is used in Airbus aircraft.

XB-70 Valkyrie

XB-70 Valkyrie

This aircraft is a true rarity. Only two models were made and one of them crashed into an F-104.

It is a plane equipped with six turbojets that can reach up to 3309 km / h, or its equivalent to Match 3.1. Due to such high speed, some parts of the fuselage reached up to 330 ºC in temperature, due to friction with the air.

Concorde

Concorde

The Concorde was the first commercial aircraft to travel at more than twice the speed of sound. It was capable of transporting travelers between New York to London in less than 3.5 hours. It was in service from 1976 to 2003, which took it 27 years of flying. It reached a cruising speed of Mach 2.02 (2,179km / h) with a ceiling of 18,300 meters. It was out of circulation due to a tragic accident that occurred on July 25, where all the occupants and even four people on the ground died.

If you want to know more about airplanes that broke records you can visit this article where we explain the fastest and/or large airplanes.

1 reply
  1. Jason G says:

    F15s official maximum is Mach 2.5, beyond which engine failure or damage was almost guaranteed

    Reply

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