NASA reports that its X-43A hypersonic research aircraft flew successfully on Saturday, breaking speed records and marking a new milestone in aircraft propulsion design. The X-43A Hyper-X (nice gallery here) was attached to a modifed Pegasus rocket that was flown to launching altitude by a B-52B mother ship. Once separated from the B-52, the Pegasus rocket boosted the X-43 to 95,000 feet, allowing the scramjet to operate for about 10 seconds, the first time an aircraft with that type of propulsion has flown freely. The aircraft reached a speed of over 5,000 miles an hour, just over Mach 7, a record speed for an aircraft with an air-breathing engine. The X-43 flew for several minutes before landing in the Pacific Ocean as planned; there were no plans to recover the aircraft.
A scramjet, or supersonic combustion ramjet, is a type of engine that uses the supersonic speed of the air being forced through the engine for its compression rather than a conventional jet engine’s compressor blade cycle. Although mechanically a lot simpler than conventional jet engine, the aerodynamics of the scramjet are quite complex; this series of pages does a good job explaining some of the science behind the flight. This first successful flight (a previous flight in 2001 ended in failure when the Pegasus booster malfunctioned) is a very significant advance in aircraft propulsion design; as CNN points out, “Some observers compared Saturday’s accomplishment to the Wright brothers’ first powered flight.” I’m very happy to see something that I studied only as theory in college come to fruition…
