samedi 2 mars 2019

The future "Concorde" will have to be silent







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March 2, 2019

Boom - Supersonic Passenger Airplane

Several projects are underway to recreate a supersonic aircraft, 50 years after the Concorde's first flight. But he will have to be quieter.

Fifty years after the first test flight of the Concorde, March 2, 1969, the supersonic is still dreaming: several projects are underway in the United States but in the hour of increasing environmental requirements, the future aircraft at very high speed will have to be quieter.

A flight 50 years ago

The supersonic aircraft Concorde took flight 50 years ago in Toulouse, south-west France, under the command of test pilot André Turcat in front of a crowd of journalists and curious, admiring the "big white bird" ".

Born in November 1962 from a bilateral agreement between London and Paris, the supersonic project experienced, from the start, strong turbulence. The two partner companies, British Aircraft Corporation (now BAE Sytems) and Sud-Aviation (predecessor of Airbus) diverged on the characteristics of the aircraft: long-haul capable of crossing the Atlantic for the first, medium-haul for the second, like the famous Caravelle.

The name of the project was disputed, between "Concord" and "Concorde", although the word refers to the identical agreement in both languages. In 1967, Britain's Tony Benn, Secretary of State for Technology, decided that the final "e" would be added to "Concord" to mean "Excellence", "England", "Europe" and "Entente cordiale".

It will take nearly seven years and 5500 hours of test flight for Concorde to be allowed to start its commercial life, under the colors of Air France and British Airways

In the 1970s, the Concorde took off with a noise level of 119.4 decibels - now unacceptable in view of international standards - and the supersonic "bang" caused by the crossing of the sound barrier by the aircraft flying at a speed of cruising speed Mach 2.04 (2.500 km / h), twice the speed of sound, forbade him to fly over inhabited areas.

The first Concorde

"The economic interests of supersonic business jet projects can only be confirmed if the regulation allows the overflight of land and the lock is the supersonic bang," says Gerald Carrier, head of the applied aerodynamics department of the Onera, the French center for aerospace research.

"It is on this lock that have focused research for 10 years on the side of NASA. It must be recognized that they played a role in the advances that now allow us to reasonably believe that a supersonic low-boom aircraft is at hand, "he adds.

In July, NASA and Onera signed a research partnership on the supersonic bang. The "beautiful white bird", which has been a commercial fiasco, has been sheltered since 2003.

"Since the 1960s, the noise of subsonic aircraft has been divided by four," said Bruno Hamon, head of the Office of Environmental Performance of Aircraft at the General Directorate of Civil Aviation (DGCA).

Today, he explains, a standoff between Europeans and Americans in the commission created by ICAO, the United Nations agency specializing in air transport, to define acoustic standards for a supersonic future .

Possible "regression"

"Europeans want supersonic standards to be subsonic and Americans (...) want the standard to allow their aircraft projects to go on the market," says Hamon.

The US position in favor of "a less ambitious standard than that of subsonics" would be perceived "as a regression", with "reactions to be feared by the public", he continues, denouncing the idea of ​​putting on the market an airplane that would make more noise "while the subsonic aviation conceded huge efforts" in this direction.

On the subject of the "bang", whose "intensity is that of the two explosions of a final fireworks", according to Mr. Hamon, Europe collaborates in the project Rumble (Regulation and Norm for Low Sonic Boom Levels ) to assist ICAO in defining an acceptable standard for the supersonic bang.

NASA X59 QueSST plane

Several supersonic aircraft projects, all the size of a business jet, are being studied by start-ups in the United States, including Aerion, the most advanced, with a capacity of 8 to 12 passengers, the Spike S-512, of the same capacity, and the Boom project, the most ambitious, to carry 45 to 50 passengers.

The US manufacturer Boeing also unveiled in June its concept of "hypersonic" airliner, he hopes to fly Mach 5 - five times the speed of sound - for a possible commissioning in 20 or 30 years.

And two months ago, NASA signed an agreement with Lockheed Martin on the development of a supersonic "Avion-X", which will have the mission to cross the wall of sound without producing the "bang" and thus flying over the territories inhabited. "The risk is not zero to see America develop a supersonic," said Thursday Eric Trappier, CEO of Dassault Aviation.

"Technically, we have the skills to make a supersonic airplane (...) The problem is the standards," he continued, adding furthermore not to be "sure that the business plan is very credible" .

Related articles:

NASA’s Quiet Supersonic Technology Project Passe Major Milestone
https://orbiterchspacenews.blogspot.com/2018/11/nasas-quiet-supersonic-technology.html

NASA’s Experimental Supersonic Aircraft Now Known as X-59 QueSST
https://orbiterchspacenews.blogspot.com/2018/06/nasas-experimental-supersonic-aircraft.html

New Supersonic Technology Designed to Reduce Sonic Booms
https://orbiterchspacenews.blogspot.com/2017/08/new-supersonic-technology-designed-to.html

Images, Text, Credits: AFP/Boom/AP/NASA/Orbiter.ch Aerospace/Roland Berga.

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