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New Jet Engine Tested
SpaceAdmiral writes "A revolutionary new jet engine has recently been tested in Australia. It is hoped that the engine, designed by UK defense firm QinetiQ and capable of Mach 7.6, will pave the way for ultra fast, intercontinental air travel. Scramjet (supersonic combustion ramjet) engines have no moving parts and take all of the oxygen they need (to burn hydrogen fuel) from the air, allowing for larger loads than rockets which must carry oxygen for fuel."
First application for Mach 7+ won't be passenger travel, but military (if not already used) where it will not only be fast, but louder than heck - after all Jet Noise is the Sound of Freedom! ;-)
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This was covered earlier!
2 3/2011251
http://science.slashdot.org/article.pl?sid=06/03/
Scramjet's are a revolutionary "new" type of engine, they have just been difficult to get from the concept to pratical stage.
The biggest problem is a way to compress enough oxygen at top speeds to feed the fuel reaction without needing to carry oxygen on board (which would be a rocket).
D.O.U.O.S.V.A.V.V.M.
" Scramjet (supersonic combustion ramjet) engines have no moving parts and take all of the oxygen they need (to burn hydrogen fuel) from the air, allowing for larger loads than rockets which must carry oxygen for fuel."
What??? I'll sue right now. This infringes on the name for my patented propulsion "Spamjet" (tm) system.... a revolutionary aerospace technology by which vehicles set up Hotmail accounts, and then propel themselves across the world by converting the lengthening promises of penis spams into actual thrust.
Scramjet (supersonic combustion ramjet) engines have no moving parts and take all of the oxygen they need (to burn hydrogen fuel) from the air, allowing for larger loads than rockets which must carry oxygen for fuel.
All jet engines take the oxygen they need from the air. Only rocket engines leaving the atmosphere require an onboard source of oxygen. Even the U2, which flew at > 40,000ft got it's oxygen from the surrounding air.
And the Scramjet is a jet engine, not a rocket engine. The difference you were looking for is that scramjet engines do not require a turbine to compress the surrounding air. This allows the engine to move at a much faster speed because turbine engines have an upper speed limit before the stresses pull them apart.
Also, theoretically if the compression was high enough the scramjet could burn jet fuel (kerosene) but there is probably technical difficulties with injection (ie. avoiding hot spots and detonation).
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I am the director, and this is my movie
Scramjet's are a revolutionary "new" type of engine, they have just been difficult to get from the concept to pratical stage.
From what I've seen in all those documentary films showing people testing rocket engines, they were also difficult to get from the concept to the pratical stage.
New ideas bring new challenges.
Can anyone tell me why this engine is revolutionary? NASA has been testing these types of engine for some time.
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For example, the X-43 which hit mach 9.6.
[url]http://www.nasa.gov/missions/research/x43-ma
I'll bet it was a smashing success
If you're going to be hitting the ground at any speed greater than a few feet per second, you might as well make it Mach 7. Not like it's going to make a whole hell of a lot of difference anyway, and the crater will be a lot more impressive.
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Five blades is plenty for me. I want to keep my skin atleast.
More to the point, the distance between San Francisco (in California, USA) and London (in England) is about 5000 miles. That same passenger jet at mach 7 can bring its passengers from London to San Francisco in about 1 hour. The trip would be much cheaper than that offered by a subsonic plane because 1 hour is only enough time for cheap snacks like airline peanuts and Coca-Cola whereas a 14-hour flight would mean an expensive (but low-quality) dinner tray.
On the other hand, a 1-hour flight would facilitate global infidelity. An errant British businessman could fly to San Francisco, have dinner and sex with his squeeze, and then return to London within 4 hours.
It's called a "LASER"
look into it
Furthermore - a scramjet is nearly useless as the first stage of an orbital launcher, because it wants to cruise at a steady speed. An orbital launcher wants to be steadily accelerating. The weight of the rocket fuel saved is less of a penalty than the increase in mass needed for structural reinforcement and insulation. Further yet, rocket fuel is cheap in bulk, it would be nearly twenty times more expensive expensive to fill it with unleaded down at the local mini-mart, scram jet fuel is expensive, even in bulk. (And we haven't even gotten to billions of dollars needed to build the aerodynamic stage.)
Scramjets are a solution looking for a problem, not an answer to any question.
And then you get stuck in traffic, customs, and luggage claim for the 5 hours after your flight. We have the real-world version of Niven's "Long Shot" - a vehicle so fast that the setup/takedown time vastly exceeded it's useful travel time, so as such it was generally useless compared to a vehicle that went a tenth as fast.
Actually, they haven't lost a passenger in a JET aircraft, but they have had several fatal crashes. The most recent was on July 15, 1951 when a Qantas plane crashed in New Guinea killing all 7 passengers and crew. They also had half a dozen other fatal crashes in the 1920s, 30s, and 40s.
Technicallay, Qantas can still say they've never lost a jet aircraft. Though in 1999 one of their 747s over-ran the runway and ended up in a golf course. Nobody died, but the plane was so damaged that it should have been written off. However, Qantas ended up repairing it at a cost of over $100 million -- the most expensive repair in history. Speculation at the time was that Quantas pressured their insurer not to write off the plane as a total loss so that they could continue to claim they've never lost a jet aircraft.
http://www.nas.nasa.gov/About/Education/SpaceSettl ement/Nowicki/SPBI104.HTM
Hardly. An acceleration of 0.25g, which you could barely feel, would get you from 0 to Mach 7 in about 15 minutes.
TODO: Something witty here...
Well, I hate to spoil the party, but we already have the technology for Mach 3+ flight (since, say, 1960: http://en.wikipedia.org/wiki/SR-71_Blackbird and it's not like we've solved the problems with creating cost-efficient passenger versions of that yet.....
r ound" trip appeals it a loooooong way off.
I wouldn't be reserving those tickets for Mach 7 too soon, considering how much harder that's gonna be. Unless the return "go-one-mile-straight-up-and-then-slam-into-the-g
Super fast maglevs will be first - betchya!
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Is anyone working on quiet jet (or other fast) engines? If we want "flyign sportscars", their quiet features are more important than any other except safety. Who wants to get caught up in the "sidestream noise pollution" wars of the mid-21st Century?
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make install -not war
since it doesn't have enough oxygen in the system below mach five for the oxidation of the fuel
This has always bothered me: If the jet must already be traveling at high speed to operate, then how does it get up to high speed in the first place?
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"Can you find a 400 mile high hill, somewhere where there's no air resistance?"
In fact, when I was a young'n, the school was on top of that hill! We had to walk out of the atmosphere in freeze-drying temperatures every day! Kids, these days, get heated pressurized busses! They're spoiled, I say! There's nothing like a walk through the stratosphere to put the world in perspective!
Yeah sure, too bad the first use of scramjets will be in missile weapons.
Why is that too bad? It's a given that the technology will be practical long before it's mature enough to be considered safe for human use. So weapons applications are guaranteed to come online first anyway.
And every dollar the military-industrial complex spends perfecting its scramjet-based weapons systems is a dollar spent on R&D towards a safe, profitable, commercial passenger scramjet.
And it will be far from the first time things have worked out this way. Good things flow out of military research all the time. From medicines to materials to machines, not a day goes by that your life has not been made better in some way courtesy of the military-industrial complex.
Any sufficiently well-organized community is indistinguishable from Government.
Simple, on the way up you have air and therefore great resistance. So it is far better to go up at mach 2-3 and then when in space (no air) turn around and rocket propel yourself back towards the atmosphere, doing most of your acceleration before you hit the atmosphere. This way you have to use much less fuel and a much smaller rocket. Air resistance is a far bigger proportion of the expended energy than that of gravity.
This kind of test has been used at Woomera many times before, originally developed by the British for testing reentry systems for warheads in the 50's, the Black Arrow program. Incidentaly this was so successful that the Americans paid to extend the program so they could use the results.
Basically they stuck the test reentry unit on top of a rocket, flew it to space then used a rocket to propel it towards the ground at up to mach 12, to test the materials and telemetry.
Interestingly the British re-entry warhead design was the opposite of the USA in that it came down pointy end first whereas the US models at that time came down blunt end first. The British design was far better as it came down much faster and therefore was much more difficult to intercept.
Instead of getting people to consume more (faster) travel and burning up the ever decreasing oxygene of the atmosphere in the process, maybe the emphasis should be directed more on things like *reducing* the need for air travel? Just like instead of encouraging road travel, the opposite should be happening. Global warming, remember? Overly dependence on foreign oil etc?
Besides, when there were problems with making the Concorde profitable that flew at a mere mach 2, how in the hell is it going to be possible to create an aircraft that would be stable enough on ground level to take off and land, and still be profitable? The quantum leaps the material science has to make to meet such needs are huge.
No, sir, you do not understand conservation of energy. Consider a prop plane. Over some interval of time, a propeller accelerates a relatively large amount of mass (compared to a jet) a relatively small amount, for a given force: F=ma. The energy in that mass of air is given by E = (1/2)mv^2. Now, in the same amount of time, let's say a jet engine moves half the mass of air with twice the acceleration. This gives us the same force as the prop engine, but the energy lost in the exhaust is 1/2(1/2m)(2v)^2 or (1/4)m4v^2 or mv^2, twice the energy as the air moved by the prop engine - for the same thrust. The air-fuel mixture of the jet engine is irrelevant: it's putting too much work into a fast moving, hot stream of air that we don't need, except at high speeds where props are inefficient because the tips get too close to the speed of sound.
Because a lot of development goes into jets these days, and because they carry so many people, they're pretty efficient in absolute terms, but I guarantee you that if you wanted more efficiency you would get it with a prop plane flying slower than a jet. (I'm not saying that we should do this, mind you.)
Disclaimer: IANAL. This post is, however, legal advice, and creates an attorney-client relationship.
You don't need turbines to get a ramjet to sufficient speed. A ramjet will operate at 400mph - well within the limits of a propeller engine (I believe the Rolls Royce Merlin could manage over 500 in World War II). You simply fold the propellers inwards when the ramjet hits activation speeds.
You're also assuming ramjets are solely for Earth use. Let's say you want to have a flying aircraft operate on Titan. Nice, methane atmosphere. You're extremely limited in the weight you can lug over there, so the less you carry the better. In that case, you'd have an oxygen "fuel" and use your scramjet to pull in the methane. An electrical engine would be an alternative, but you'd have trouble keeping it hot enough to function. A glider would also be good, but you've no thermals of significance.
Back on Earth, a scramjet would be valuable in the event of an emergency. There's an island off the African coast, I believe, which - when (not if) it falls into the ocean, will create a tsunami capable of wiping out the entire eastern seaboard of the Americas for several hundred miles. There simply isn't any combination of aircraft, mass transit or shipping currently in existence capable of getting more than a small percent of people to safety.
The west coast is in as much danger from faultlines, volcanoes and other disaster-causing events, but it probably isn't going to be in danger at the same time.
Thus, a simple mechanism for ferrying massive numbers of people very rapidly from coast to coast would likely eliminate most of the potential for fatalities. True, this does mean that supersonic and hypersonic aircraft will need to fly over populated areas. Oh wah. The RAF do low-level supersonic flights in populated areas all the time. Hasn't killed me ye...ughhhh..
(Seriously, I'd rather have to worry about not getting much sleep during a disaster, if on an evacuation flightpath, than getting permanent sleep if living within a hundred miles of a coastline.)
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Well if you were trying to get to Australia then it might be frustrating, but in fact two weeks on the open ocean is mighty fine. I did four weeks once and regard it as one of the best times of my entire life.