a students' magazine / Physics

Two wings “is megl’ che one!” (2)

After Yeager’s glorious feat, thanks to studies which have been made to solve the problems of supersonic speed, many supersonic warplanes have been built. But constructors soon realized that the shockwave, reaching  the ground, created problems to the people of the area. In the previous video you have seen the painted wall tremble  at the sonic boom: often the shockwave caused more serious problems, like damages to tympani or the breaking of glasses, also because at a low altitude a decrease in temperature, and so a decrease in the speed of sound, are registered.
In this video you can listen to and see the effects of a supersonic  flight.  When the plane reaches a speed close to Mach 1, as I said, pressure and temperature drop, and consequently the air around  condenses, producing a vapour cone  and the sonic boom (which however is not a consequence of the condensation).

In 1969 the collaboration between the two companies “British Aerospace” and the French “Aèrospatiale” gave birth to the Concorde, the 2nd supersonic airliner, a transatlantic  which could fly at supersonic speed. The first had been the soviet Tupolev Tu-144, produced in 1968 (although the projects are almost identical!  Someone talks about a spy-story involving Russian and British engineers, but nothing has been proved yet).

The Concorde entered service in 1976, flying the routes Paris-Dakar-Rio de Janeiro, London-Bahrain and later also to NewYork.  It was a great invention, because it allowed 100 passengers to. However, to overtake the speed of sound it had to wait to be over the Atlantic Ocean at the height of 17000 m, in order not to create troubles to people. The cruise speed was Mach 2.

Mach is a measure resulting from the ratio between the speed of the source and the speed of sound : Mach 1 means that you have the same speed of sound, Mach 2 means you are traveling twice the speed of sound,  so 2386,8 km/h. At this speed the plane could reach its destination at a local time which was earlier then when it had left: the slogan that the British Airways used to advertise it was “Landing before taking-off!”

Flying with Concorde you didn’t have first-class comfort, however, and looking out of the porthole you could see the curvature of the Earth and some nice spots of light! 🙂
The total programme cost was of £ 1.3 billion. Ticket costs, consumption of fuel and air pollution were too high, passengers started to decrease, especially after the disaster on 25th July 2000, when because of the blowout of a tyre and the burst of a tank, the airplane crashed into a hotel building, causing the death of 113 people, so in 2003 the Concorde retired from service, after it had flown for the last time with two tears drawn on its nose.
After that moment many researches have been made to create the successor of the Concorde. Now maybe the MIT Institute, in collaboration with the Stanford University, have found the solution in a German engineering study of 1950: Adolf Busemann had shown that a biplane with opposite vertex triangular wings can avoid the sonic boom when it overtakes the speed of sound. But it’s unable to take-off. To solve this problem they have created a prototype that can change the shape of its wings while flying. Moreover, it won’t pollute and it will transport 250 passengers! Let’s hope to be one of them one day! 🙂

Here is an image of the new jet biplane:

Should you be interested, there’s more information at: http://web.mit.edu/newsoffice/2012/supersonic-biplane-0319.html

I hope you’ve found the post interesting!
See you soon guys, Ryder 🙂

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