Aviation Week Apr 2, 2012
link to www.aviationweek.com
NASA is claiming a breakthrough in the design of supersonic aircraft, with wind-tunnel tests proving it is possible to design configurations that combine low sonic boom with low cruise drag, characteristics once thought to be mutually exclusive.
The tests involved scale models of small supersonic airliners designed by Boeing and Lockheed Martin and aimed at entry into service about 2025. Although the measured shock wave signatures are at the high end of what would be publicly acceptable, they proved the design tools could produce a supersonic business jet capable of unrestricted overland flight, says Peter Coen, NASA's Supersonic Fixed-Wing project manager.
NASA's target for the under-track boom from a 2025-timeframe small airliner is a perceived noise level of 85 decibels (PNLdB). Boeing's design achieved 81 PNLdB, and Lockheed's 79 PNLdB. "That's 25dB less than Concorde and 20dB less than the best we achieved under HSR [NASA's High Speed Research supersonic-transport program, canceled in 1999]," he says.
But the European Concorde airliner only flew supersonic over the oceans. These "business" planes are designed to fly the rich rulers over land (us). Since they fly faster than sound, you cannot hear them coming. However, anything that flies faster than sound must leave a shock wave of super-fast (faster than sound) moving air behind in its wake, that we perceive as a "boom." NASA says it can fix or mitigate this, but physics says otherwise.
Time to occupy the airports.