Hypersonic Jets Prepare to Soar

aviation ^ | 28 September 2007 | Chris Kjelgaard

[Freeport]

Sustained hypersonic flight above speeds of Mach 5 by vehicles using air-breathing, jet-fuel-powered engines could become achievable within the next dozen years.

Successful recent ground tests of jet-fueled, ramjet/scramjet demonstrator engines by Pratt & Whitney Rocketdyne and Aerojet represent important progress toward flight-testing of three separate hypersonic-vehicle programs.

In September, Pratt & Whitney Rocketdyne (PWR) completed 10 months' testing of a sub-scale combustor for a hydrocarbon-powered, dual-mode ramjet engine designed to operate over a wide range of Mach-number speeds -- that is, multiples of the speed of sound.

Using JP-7 jet fuel, PWR ran the combustor successfully at a variety of Mach numbers from Mach 2.5 to Mach 6.0, demonstrating "desired operability and performance" at each speed, the company said.

Under a DARPA/U.S. Air Force program, Boeing is making the X-51A hypersonic demonstrator aircraft, with the aim of making the first test flight in 2009. Pratt & Whitney Rocketdyne is making the X-1 JP-7 jet-fuel scramjet engine for the X-51A, which is also known as the WaveRider, because effectively it will surf the shock wave of compressed air that the aircraft creates in front of it as it flies at speeds well in excess of Mach 5. Credit: Pratt & Whitney

In April 2007, Pratt & Whitney's X-1 JP-7-fueled demonstrator scramjet engine completed a simulated Mach 5 flight of the X-51A WaveRider -- officially known as the Scramjet Engine Demonstrator - WaveRider, or SED-WR -- at the NASA Langley Research Center in Hampton, Va. The demonstrator engine, which has fitted with full authority digital engine controls and a closed-loop thermal management system that uses the fuel itself as a coolant, was designated the SJX61-1. Credit: Pratt & Whitney Rocketdyne

[Sonny M]

bump

[OCC]

Orion should have been flying 6 years ago..

Instead we have to wait 6 years for this Orion to fly.

[jaydubya2]

" What’s the New York to Paris time of that flight?"

Why would you want to go to Paris?

[Kevmo]

I heard a rumor that the Aurora used some “external burning” on its wing. Basically, you shoot some fuel just behind the shock wave and use the shock wave as part of the containment of the explosion, which is taking place ON THE WING. That would make for an exciting civilian ride, eh?

[Eagles Talon IV]

Mach is, depending on altitude, about 650mph at 36000 ft so mach 5 is about 3250mph. It’s about 3600 miles. from NY to Paris so it looks like it would take about 1 hour 10 minutes.

[Kevmo]

I guess you can even catch the rumors on the web these days. It’s a lot easier than it used to be.

http://www.sushi-x.com/gallery/nonseq/aurora/aurora.html

Aurora, America’s hypersonic spyplane.

Aurora is a general name for a family of hypersonic vehicles. The unusual version depicted here has two modes of propulsion, a ram jet for traveling at subsonic, and supersonicspeeds, and an external burning engine for hypersonic travel. In the latter case, fuel is sprayed within the shockwave created by the vehicle, and the enormous temperatures generated by hypersonic speeds ignites the fuel. The explosion propels the craft forward, similar to squeezing a wet pumpkin seed between your fingers.

[DoughtyOne]

Exciting... yeah! Count me in.

For commercial use, not if this is the true configuration. The Aurora was reported to have used pulse engines. That may also rule it out as a commercially viable transition.

[DoughtyOne]

Thanks Kevmo. I’ll check your link out later.

[Kevmo]

Darn, I wish those hypersonic eggheads at Area 51 would be more considerate and build technology that might filter down to me some day!

[N. Theknow]

What time does your flight arrive?

5 minutes before takeoff.

[evets]

China just landed men on mars.

[Calvin Locke]

I’m pretty sure SR-71 used JP-7, too.

[Shryke]

JP-7 was actually developed for the SR-71 (its A-12 predecessor). It was used in the cooling, then hydraulics, THEN for fuel. HUGE amounts of modern avionics came from that aircraft’s development.

[longtermmemmory]

I think the magic number is $400 to go from NY to London in less than one hour.

If they hit that price in todays dollars it will be society altering.

[raygun]

ping

[Zetman]

I guess you can even catch the rumors on the web these days. It’s a lot easier than it used to be.

Wikipedia has an article about Aurora too. So much for the theory that "loose lips sink ships"....

I don't want to look up the HTML right now to "linkasize" this (feeling lazy), so you'll have to just use old-fashioned cut and paste to put the following URL into your browser....

http://en.wikipedia.org/wiki/Aurora_aircraft

[avacado]

"... and NYC to London is 3460 miles."

Is that a great circle distance or a straignt line on a map?

[Kevmo]

Pretty good article in Wiki, thanks.

I love that linked interview with Paul Czysz.

http://www.americanantigravity.com/articles/574/1/Aurora—Beyond/Page1.html

[AFreeBird]

Constructing an air frame that can withstand that kind of stress is not exactly easy. Ever read up on what happens to the SR-71 during its flights?

Yep, the fuel takes tighten up and stop leaking, and the titanium flight surfaces heats and warps a bit. Essentially, after it has cooled down, you have a new aircraft after every flight. Well, new or different flight characteristics than the previous flight.

Makes sense they're using the 71's fuel, and using it in the engine cooling system just like the BlackBird.

That Kelly Johnson sure was ahead of his time.

[AFreeBird]

Opps. takes = tanks