NASA to Attempt Mach 10 Flight Next Week

Dirak writes "NASA intends to break its own aircraft-speed record for the second time this year by flying X43a scramjet ten times faster than sound. On November 15 the X-43A supersonic-combustion ramjet - or scramjet - will again take to the skies aiming for Mach 10."

Comments

Re:To Bad for the sonic Boom.

[Cheeko]

I think there is little to no interest in this as far as combat aircraft. NASA's main interest is in using scramjets to produce aircraft like vehicles that can "fly" into space affordably. As I understand it aside from their ability to operate at high speeds more efficiently than rockets, they also allow for much higher altitude functionality than a standard jet engine. This would allow a space plane to get high in the atmosphere, then use a small rocket boost to get into orbit.

I believe the idea behind a functional vehicle would be something like a standard jet engine getting a craft up to mach 1 or 2, then a ramjet taking over and getting a craft up to mach 5 or so, and then a scramjet taking a ship up to mach 10-15, at which point a rocket boost pushes it through the last bit of thin atmosphere into orbit. I may be wrong, as my knowledge on this was material read 4-5 years ago, but that seems to be what I remember.

Supposedly a nother great thing about scramjets is their simplicity, very few moving parts, which allows for high reliability. Or as high reliability as can be expected for something working under the strain of Mach 10.

Re:What is the Speed of Sound?

[bleckywelcky]

It's a record for an air-breathing engine. The SS get's lofted into orbit by self-contained solid rocket boosters that carry fuel and oxidizer together and burn it without air and then drops out of orbit. An air-breathing engine carries fuel with it and adds that to the surrounding air and pushes it all through it's combustion chamber.

Re:What is the Speed of Sound?

[kuwan]

The space shuttle isn't designed to fly like an airplane, it (like other rockets) are designed to get you into space. If you'll read a little more of the article:

The accomplishment will be included in the 2006 Guinness World Records book, set for release this time next year, as follows:

"On 27 March 2004, NASA's unmanned Hyper-X (X-43A) airplane reached Mach 6.83, almost seven times the speed of sound. The X-43A was boosted to an altitude of 29,000 m (95,000 ft) by a Pegasus rocket launched from beneath a B52-B aircraft. The revolutionary 'scramjet' aircraft then burned its engine for around 11 seconds during flight over the Pacific Ocean."

...

The X-43A flight easily set a world speed record for an air-breathing engine aircraft. The previous known record was held by a ramjet-powered missile, which achieved slightly more than Mach 5. A ramjet operates by subsonic combustion of fuel in a stream of air compressed by the forward speed of the aircraft itself, as opposed to a normal jet engine, in which the compressor section (the fan blades) compresses the air. A scramjet (supersonic-combustion ramjet) is a ramjet engine in which the airflow through the whole engine remains supersonic.

The highest speed attained by a rocket-powered airplane, NASA's X-15 aircraft, was Mach 6.7. The fastest air-breathing, manned vehicle, the SR-71, achieved slightly more than Mach 3. The X-43A more than doubled the top speed of the jet-powered SR-71.

An airplane that goes Mach 10 will be an amazing achievement for an air-breathing engine (a.k.a. non-rocket) aircraft.
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Re:What is the Speed of Sound?

[AyeRoxor!]

Just like 1 Atmosphere is air pressure at sea level, Mach 1 is the speed of sound at sea level.

Interestingly enough, according to Google Math, Mach 10 is ~127 miles a minute. Assuming it takes them at least 5 or 10 minutes to achieve Mach 10 (I have no frigging idea), they are going to cover some serious distance. Sheesh.

At Mach 10, you will circle the Earth in under 200 minutes.

Damn I love Google math.

Re:What is the Speed of Sound?

[Jetson]

I guess when an article says 10 times the speed of sound it means the speed of sound at sea level right?

Mach "speed" is expressed as a ratio and is usually relative to the local environment. You can increase your Mach ratio either by climbing at a constant absolute speed or by accelerating at a constant altitude (although climbing at an increasing absolute speed works best :-P).

The problem with using altitude to improve your Mach ratio is that it decreases your indicated airspeed (the air felt by the wings). There comes a certain point with some high-performance aircraft where the indicated airspeed is just above stall and the Mach ratio is just below the aircraft's design limit. This is called the "coffin corner" because once you reach that speed/altitude it's virtually impossible to descend or slow down without losing control of (or destroying) the aircraft.

Rutan's Space Ship One solved this problem by intentionally stalling the aircraft in a stable high-drag attitude and staying in that configuration until safely back into the flight envelope.