Supersonic Concept Plane Would Shush Sonic Booms

A new design concept for a futuristic faster-than-sound aircraft could break through legal barriers to supersonic flights over land by shushing the sonic booms created by such vehicles.

The concept aircraft, envisioned by aerospace company Lockheed Martin, would revolutionize supersonic cruising by relying upon a so-called "inverted-V" engine-under wing configuration, where the engines sit atop the wings rather than beneath, NASA officials said in a statement.
Full article: FOXNews.com - Supersonic Concept Plane Would Shush Sonic Booms

X-51A Races To Hypersonic Record

The Boeing X-51 is an unmanned scramjet demonstration aircraft for hypersonic (Mach 6, approx. 4,000 mph or 6,400 km/h at altitude) flight testing. The X-51 WaveRider program is run as a cooperative effort of the United States Air Force, DARPA, NASA, Boeing and Pratt & Whitney Rocketdyne. The program is managed by the Propulsion Directorate within the United States Air Force Research Laboratory (AFRL).[2] The X-51 had its first captive flight attached to a B-52 in December 2009. The test vehicle successfully completed its first free-flight on Wednesday.