Make a Comment • Email Link • Send Letter to Editor IPFS News Link • Transportation: Air Travel Boeing believes mach 5 hypersonic passenger planes might have better economics than mach 2 ... 08-13-2018 • https://www.nextbigfuture.com by Brian Wang A mach 5 hypersonic plane would also use standard Jet-A fuel. Liquid methane or some combination of those fuels are also options for the commercial aircraft. A mach six aircraft requires a supersonic combustion ramjet (or "scramjet") engine, a technology that still isn't mature after decades of research and demonstration. A mach five might be able to just modify the lockheed spyplane engine technology. The Lockheed SR-71A spyplane flew at speeds up to Mach 3.2 using two Pratt & Whitney J58 engines. The J58 featured a unique configuration called a turboramjet. The engine functioned like a turbojet up to about M2, then diverted air from the compressor into ducts that emptied in the afterburner. Boeing's hypersonic airliner also would use a turboramjet configuration, with some variations compared to the J58. Instead of ducting only a portion of the airflow around combustor over M2, Boeing's concept might bypass all of the airflow around the engine core at higher speeds. Watch Streaming Broadcast Live: LRN.fm DLive Live Chat Telegram Share this page with your friends on your favorite social network: