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NASA Prototype Plane Scheduled To Attempt Mach 5+
Logic Bomb writes: "Mach 5 -- 5 times the speed of sound, or 5000 mph -- is a speed that so far has eluded jet-powered aircraft (the existing record for a production craft is about mach 2.1). NASA, however, has high hopes for its latest attempt, the X-43A. Using a booster rocket, the prototype will be accelerated to mach 5, at which point its engine will be scooping enough oxygen to power the craft at those speeds on its own. Hopefully, it will fly at speeds up to almost mach 7 for 10-15 seconds before shutting off and plunging into the Pacific. An article from the Los Angeles Times has more details." Not to be confused with the X-33 and X-34 projects.
For quite a while there have been persistent rumours of a US military aircraft that flies at Mach 5 using liquid methane as a fuel. That would nix the "first aircraft to travel at this speed" claim.
Are there actual records of the US craft's existence, or does it remained a rumour?
The SR-71's top speed record was Mach 3.24, which is still the record for air breathing propulsion powered aircraft. (Of course there've been plenty of rumors of top secret planes even faster.)
The F-15 can fly Mach 2.5 at high altitude, & many current fighter aircraft can fly Mach 2.1.
The X-15 (which was rocket powered) reached speeds of over Mach 7, which was the fastest human piloted aircraft ever. The space shuttle reaches Mach 25 (~17,000 mph) in order to reach orbit.
Logic Bomb seems to be under the impression that The speed of sound is 1000mph. It's more like 730-750mph last time I checked.... Mach 7 is 5000 mph, not Mach 5.
The mph speeds are correct as stated, but all of the mach speeds are off. The SR-71 does go 2100mph, but thats nearly Mach 3, not Mach 2.1. And the new craft in question which will go 5000mph is Mach 7, not 5.
Just nitpicking here folks, but someone should clarify this....
-Julius X
-Julius X
remove "-whatkindofspamdoyoutakemefor-" from email to send
Ya what a WASTE of time to fly real fast! Its a shame we throw away money on stuff like that! I mean, who wants to go gallavanting around really fast! And in the AIR too! WHAT MADNESS! If God intended us to fly he'd have given us wings! If God intended us to go faster than 20mph he'd have given us turboprop thighs!
I, for one am OFFENDED that we are wasting money on fruitless projects like flying fast. It would be better spend on expanding the west wing of my 8 bendroom mansion, or paying some immigrant to scrape barnacles off my yacht.
New York to Los Angeles in a half hour. Wow.
In completely unrelated news:
Every window from New Jersey to Nevada was broken today, which officials are at a loss to explain. It appears to have been a sharp earthquake which rattled houses and businesses across the country. Seismologists have reported that every one of their seismographs recorded a large spike, possibly a new type of fault slippage previously unknown.
Officials at UnitedSpace were unavailable for comment.
the AC
Hemos is like...sci-fi fans;he thinks technology is cool, but he hasn't bothered to understand the science it's based on
"Hopefully, it will fly at speeds up to almost mach 7 for 10-15 seconds before shutting off and plunging into the Pacific"
Fortunately the seat cushions can be used as a floatation device.
--Brogdon
This tagline is umop apisdn.
I guess we'll have to wait for the documents to become declassified.
Until then... "Go! Speed Racer! Go-Go! Speed Racer!"
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crazy dynamite monkey
Why do we use Mach as a measurement of speed when it varies with altitude? No one would ever use a measurement of length that varied with what country you were in? Hmmm... I'll make a measurement called "Schnach" which is 1 meter in Australia, but is 3 inches in the US. Brilliant idea, eh?
Actually, if memory serves, Mach 1.0 at mean sea level and mean atmospheric conditions is about 714 MPH at sea level.
However, the speed of sound varies proportionally to the density of the medium, in this case, air. So at higher temperatures, and higher altitudes, the speed of sound increases. At the sort of near-space altitudes at which this thing will probably operate, Mach 5 is close to 5000 MPH.
Learn from the mistakes of others. You won't live long enough to make them all yourself.
Using a booster rocket, the prototype will be accelerated to mach 5, at which point the pilot's face will be torn from his skull. Hopefully, the plane will fly at speeds up to almost mach 7 for 10-15 seconds before getting hit by a Chinese hotdog pilot.
Got Rhinos?
Although the author seems to be confused about the value of Mach 1, some of the responses aren't much more informed. Mach 1 is the speed of sound, which varies greatly depending on the density of the air. At sea level it is usually around 730 mph or so. So it is difficult to say what Mach number the blackbird achieved when it was flying 2,100 mph. You'd have to know the density altitude for the flight. Also, a scramjet engine is not quite the same as a ramjet. The idea is the same, but since air is highly compressible, it behaves differently at different speeds. There are basically four areas of flow: subsonic, transonic, supersonic, and hypersonic. What holds true for supersonic flow is not necessarily true for hypersonic flow. The divisions between these areas of flow depends on the Mach number of the fluid, which is why speeds are rated in Mach numbers and not mph or km/s. So, a different design is required for hypersonic flow compared to supersonic flow. Hope this clears some things up.
Nope, you're wrong too. Speed of sound decreases with increasing altitude (less dense air).
See:
- http://www.grc.nasa.gov/WWW/K-12/airplane/atmos
i .h tml
- http://www.grc.nasa.gov/WWW/K-12/airplane/sound
. ht ml
for the basic information and a cool little demonstrator app. However, even at high altitude, the SOS doesn't change much (-14% is "not much" to me). Now, speed of sound through solid rock, THAT'S fast!One source of confusion is that SOS is about 1100 feet per sec or about 750 miles per hour. People often get the numbers and units swapped.
- Chris
P.S. Wow, I actually used my Aerospace Engineering degree today!
P.P.S. SR-71 has gone to Mach 3 according to public knowledge, but it's widely expected that it went MUCH faster. Hell, most fighter jets can push Mach 2.0, and the SR-71's design point is Speed At All Costs.
One simple rule for its versus it's
This is important aerospace research, and if you read the article, it's pretty easy to see why. The ability to fly at such speeds for intercontinental, oceanic flights is of great societal benefit. Speed of transport will make this work commercially.
The military aspects are a bit more challenging, though. If you're going to build a bomber so fast it can't be shot down, fine--but then you have to either slow down the craft so that the munitions can exit the slipstream, or you have to come up with some design that will allow you to drop iron at high speeds--such as the Valkyrie, which dropped munitions out the tail.
Either is a huge design problem. If you slow the craft down, you have to design a craft that performs at all speed ranges with in-theater fidelity. If you kick the munitions out of the back, you have to compensate for the mass changes with aerodynamics, because you change the center of gravity all the way through the release profile, and you better hold the craft steady during release, lest you hit the bomb on the way out. "Somebody set us up the bomb," indeed!
But this won't replace STS. Yes, a scramjet is nice. Yes, this is similar to rocket-based combined cycle. But we could more cheaply build a reliable, two-stage system to get into orbit. Mass fractions are all you have to look at to wonder why Single Stage To Orbit [SSTO] is some perverted NASA priority. As a NASA sub, I know they don't live in reality, but damn...
But this is, for once, a positive example of your tax dollars at work.
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-- Geof F. Morris
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Oh bother.