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First Ever Scramjet Reaches Mach 10
stjobe writes with the news that a group of US and Australian scientists successfully tested a supersonic scramjet engine in the Australian Outback on Friday. The Sydney Morning Herald reports that a rocket carrying the engine reached mach 10, and climbed to an altitude of 330 miles before the apparatus re-entered the Earth's atmosphere. "Australia's Defense Science and Technology Organization (DSTO) said it was believed to be the first time a scramjet had been ignited within the Earth's atmosphere ... Scramjets are supersonic combustion engines that use oxygen from the atmosphere for fuel, making them lighter and faster than fuel carrying rockets. Scientists hope that one day a scramjet aircraft fired into space could cut traveling time from Sydney to London to as little as two hours."
What about the X-43A? It also ignited successfully and flew under power.
http://en.wikipedia.org/wiki/Boeing_X-43
This is cool, yes, but the emphasis on "first" seems a bit off.
"scramjets are supersonic combustion engines that use oxygen from the atmosphere for fuel"
Scamjets use oxygen from the atmosphere as an oxydizer unlike traditional rocket engines which need to carry their oxydizer. Scramjets still need to carry fuel.
No. I am not a rocket scintist.
Holy cow, no it can't! Not only isn't it going nearly fast enough, but the vast majority of that delta-V came from a conventional rocket. The scramjet experiment only operated for 14 seconds.
This is an experiment. Scramjets are still in the "data-gathering" phase, not the "let's make a realistic engine" phase, nor the "let's make a scramjet-powered craft" phase.
Everybody point at the libertarian and laugh.
This event took place in Australia, and was reported by an Australian paper; therefore, it was correctly reported in the metric altitude of 530 kilometres.
So why was the summary changed by slashdot editors to the imperial unit?
Firstly, not everyone who reads this site is American, and secondly, this is an audience of nerds. I think we can handle kilometres! Even the USA's NASA is all metric now.
The scientists who developed this scramjet used metric, the country it was tested in used metric, the newspaper that reported it used metric, so how about we keep it that way?
This is very interesting to read as I just finished reading Ben Rich's book "Skunk Works" where he talks about the SR71. When president Reagan announced the administration's intention to build a hypersonic airplane, he just shook his head. It's simply not practical, with or without the scramjet engine. The SR71 flew at 85,000 feet at about Mach 3.2, and reaches skin temperatures of 2000-3000 degrees (F I presume) just from moving through the atmosphere. Accelerating to Mach 10 would burn up or otherwise compromise any current building material, except for the carbon-carbon and ceramic materials used on the space shuttle's heat shield, but aren't practical for airplanes. So what good is this scramjet, at least as far as a hypersonic airplane goes? Seems to me all this talk of Sydney to London in 12 hours is a bit fanciful. So the question is, how exactly will this engine be used to accomplish this? The only way to reach hypersonic speeds without burning up is to make the trajectory sub-orbital so that the aircraft is in the thinnest atmosphere possible when it's firing it's engines to go Mach 10. But of course there's not a lot of oxygen at that altitude. And to really achieve sub-orbital trajectory you need a rocket engine, not any kind of air-breathing engine. So my questions are: Is Ben Rich right that hypersonic travel is essentially impossible? Will the scramjet help with a suborbital trajectory? I understand that igniting the scramjet is a breakthrough. Jet turbines at supersonic velocity have always been problematic.
Off-topic, Ben Rich says in his book that the codename Aurora that everyone likes to think refers to some hypersonic aircraft, was actually the codename placed on the B-2 project as Lockheed and Northrop were competing for the contract. It's funny to think that to this day, folks still hang onto this and imagine some mythical hypersonic airplane. Which never existed. Or does it?
330 miles is approximately 5 times the minimum altitude for entry into "space." The Kármán line is at an altitude of 62 miles (100 km) which is the boundary that defines where space begins. 75 miles is where atmospheric drag starts to have an effect. This means the craft traveled well into the Thermosphere. People who travel above 50 miles are called astronauts by NASA.
Yeah nerds, learn KM, not Miles.
No self respecting scientist or nerd would ever use the word MILES in their own documents.
Slashdot is NOT mainstream, get back to being NERDY!!!
Liberty freedom are no1, not dicks in suits.
for consistency, would you prefer if they used the speed of sound in a vacuum?
Blazing Spiders
It was the same fuel as HyShot, plain old hydrogen (plus oxygen gathered from the atmosphere). This scramjet project was named HyCAUSE and the engine was physically a fair bit larger than the successful HyShot flights by the same team a few years back. The team originated from the University of Queensland moved to the Defence Science and Technology Organisation about a year ago. The next flights are a series of ten over five years under the name "HiFire".
getting these to fly without using a rocket to start it. If we can get it to start from say a mach 2 or better sub sonic mach .9, then this will be feasable for more than just bombs. As it is, the only place that this will be of use is in intercontental bombs (small and cheaper).
I prefer the "u" in honour as it seems to be missing these days.
As the theory of relativity breaks down when someone switches the lights off - as C becomes ZERO.
...Einstein didn't think of that.
Oh no
EMail: 0110001101100010010000000110001101110010 0110000101111010011011100110000101110010 0010111001100011011011110110
This is prime example of technology that has almost purely military applications.
However since that does not excite public positively, they are instead fooling the public talking about civilian use.
What might be possible some day is to deliver a bomb from Sydney to London in very short time. Not human passangers.
The inherent heat problems are about 100 times easier to solve, if you imagine
the payload is 50kg of plutonium instead of 5000 kg of humans.
Including airport queues that's only about 5 or 6 hours.
According to wikipedia, (I know), the atmosphere is usually considered to end at 328,000ft. (Karman line)
The Stratosphere goes to 160,000ft. You have to go above 50 miles (264,000ft) to be considered an astronaut, and atmospheric effects are noticeable at 400,000ft during reentry.
Scramjets need an atmosphere anyway, just like ramjets and turbojets. That's the whole idea. The air flows through it, fuel is injected into that air and ignited. Trying to operate a scramjet in a vacuum would make as much sense as trying to operate a turbojet there. Pretty much all 3 are the same jet engine, more or less. A turbojet uses a compressor in the front to push the air into the engine. A ramjet relies on the fact that if you fly fast enough to start with, you get air pushed into the engine anyway. (Plus some clever design of the intake so the flame doesn't go in both directions.) But the air is slowed down to a subsonic speed at the point where the fuel is injected and lit. A scramjet is a ramjet where the air does flow at supersonic speed through the engine, so basically it's choked. You can add the fuel past the choke point and, since waves can't move backwards in a supersonic flow, whatever pressure you generate there by burning fuel can only go towards the back engine. The front of the engine can't "notice" the higher pressure in the back half because a pressure wave would have to travel through that air faster than sound speed, which isn't possible. Another rough description would be that a scramjet is like a turbojet with an afterburner, only without the turbojet. (Sorta like the sound of one hand clapping, I guess;) Instead of having the turbojet push air through a nozzle and add extra fuel to it, the engine _is_ the nozzle and the airplane's existing speed is what pushes air to it. So you just add the fuel and light it. It's an afterburner without a turbojet. But in the end all 3 work by the same basic principle: air comes through the front, fuel is added, hot air comes out the back. No air, no flame, the engine stops. The plans to use a scramjet to get to a highe enough orbit or even leave the planet, involve getting enough speed while still having enough air for the scramjet, or as boosters in addition to the normal rocket engines, or both.
A polar bear is a cartesian bear after a coordinate transform.
Scramjets need an atmosphere anyway, just like ramjets and turbojets. That's the whole idea. The air flows through it, fuel is injected into that air and ignited. Trying to operate a scramjet in a vacuum would make as much sense as trying to operate a turbojet there.
Pretty much all 3 are the same jet engine, more or less. A turbojet uses a compressor in the front to push the air into the engine. A ramjet relies on the fact that if you fly fast enough to start with, you get air pushed into the engine anyway. (Plus some clever design of the intake so the flame doesn't go in both directions.) But the air is slowed down to a subsonic speed at the point where the fuel is injected and lit. A scramjet is a ramjet where the air does flow at supersonic speed through the engine, so basically it's choked. You can add the fuel past the choke point and, since waves can't move backwards in a supersonic flow, whatever pressure you generate there by burning fuel can only go towards the back engine. The front of the engine can't "notice" the higher pressure in the back half because a pressure wave would have to travel through that air faster than sound speed, which isn't possible.
Another rough description would be that a scramjet is like a turbojet with an afterburner, only without the turbojet. (Sorta like the sound of one hand clapping, I guess;) Instead of having the turbojet push air through a nozzle and add extra fuel to it, the engine _is_ the nozzle and the airplane's existing speed is what pushes air to it. So you just add the fuel and light it. It's an afterburner without a turbojet.
Downside: a turbojet can start at zero speed, ramjets and scramjets need enough airspeed to start. Hence all these experiments involve booster rockets.
But in the end all 3 engines work by the same basic principle: air comes through the front, fuel is added, hot air comes out the back. No air, no flame, the engine stops.
The plans to use a scramjet to get to a highe enough orbit or even leave the planet, involve getting enough speed while still having enough air for the scramjet, or as boosters in addition to the normal rocket engines, or both.
A polar bear is a cartesian bear after a coordinate transform.
Message intercepted. Cover blown. Please return to base for debriefing.
Now, that was an explanation! Right now I regret that I'd already posted to this discussion - I can't use my mod points on you. THANKS.
You can't handle the truth.