Concord Supersonic sucessor and the hindersome sonic boom explained if not overcome. YET? The Economist

 "Supersonic air travel"

Quieting the sonic boom could help bring back supersonic flight

"Concorde was grounded 2003.If supersonic flight is ever in  to return, the noise it makes must be toned down. NASA is working on a small single-engined jet, which engineers think will reduce a sonic boom to a soft, faraway thump. Whether such aircraft will be built is a different matter. Technology makes it possible, but the business case is trickier. Small supersonic executive jets might be first into the air,writes the Economist's innovation editor. "


A sonic boom is formed when an aircraft travels faster than the speed of sound, which is around 1,240kph (770mph, or Mach 1) at sea level. Air molecules simply can’t get out of the way fast enough and pile up at certain points on the aircraft. That creates an instantaneous change in pressure, resulting in a wave that contains a huge amount of sound energy. The first wave starts at the nose and others are created along its length. At the rear of the aircraft, a “recompression shock” is formed when the rapid pressure change switches back to normal pressure. As they radiate away, the waves tend to coalesce to form two main shock waves. This is why a supersonic jet passing overhead is often heard as a distinctive double boom.

Innovations Tweaking the design of a supersonic jet could modify the shape of these shock waves so that they produce a less sudden and intense sound (see article). NASA is working on a small experimental 

single-engined jet, which engineers believe will be able to reduce a sonic boom to something that resembles a soft thump in the distance. Among the aircraft’s features are a long triangular-shaped nose and an engine inlet blended into the upper wing (pictured). These are designed to smooth out the shock waves. The aircraft will also fly a little slower than Concorde, which cruised at Mach 2. If all goes well, the American aerospace agency hopes to begin trial flights around 2019 to see if the “low boom” this test aircraft is supposed to create is acceptable to the public. If it is, then its noise “signature” might become a certification standard for future supersonic passenger aircraft.


Whether such aircraft will be built is a different matter. Modern aerospace technology certainly makes it possible, but the business case is trickier. This is why some think small supersonic executive jets might be first into the air. A number of groups are planning them, including Aerion, a company based in Nevada, which is developing a Mach 1.5 executive jet called the AS2. The plan is to have a prototype ready for test flights in 2019. Supersonic airliners with 100 or more seats would be commercially more risky. But if the suits flying in executive supersonic jets prove there is demand for a journey time of six hours to just about anywhere in the world, then someone might build one.



My comment:

Well in the short term Cop21 web conference will have to do-Not quite the Supersonic Aircraft design, stuff of dreams, as was Concord the most beautiful aircraft ever designed and a true tribute to engineering.

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