Posted on 10/22/2001 11:42:40 AM PDT by LA-Lawyer
Rocket scientists to attempt first full-scale test of futuristic jet engine
The Associated Press
CANBERRA, Australia (AP) Scientists this week hope to achieve the first successful full-scale test of a scramjet, a futuristic propulsion system that could lead the way to a new generation of smaller, cheaper rockets. An international consortium known as Hyshot will conduct the first atmospheric test of the jet engine Thursday at a military rocket range in the desert of central Australia.
Conventional rockets must carry both fuel such as liquid hydrogen and liquid oxygen to burn it. Scramjets, or supersonic combustion ramjets, need only carry fuel, potentially halving a rocket's weight.
"Another term for this sort of engine is air-breathing," said Susan Anderson, a Queensland University engineer with the project. She explained that the jet sucks air from the atmosphere and compresses it in the combustion chamber, which is then injected with fuel.
With no moving parts, the jet is mechanically simple. The challenge lies in getting it up to speeds at which combustion can occur. The Hyshot scram jet is designed to combust at Mach 7.6, nearly eight times the speed of sound, which is 750 miles per hour at sea level.
If all goes as planned, the Hyshot scramjet will be fired as the payload on a rocket to an altitude of about 25 miles. The rocket's nose cone will then be thrown off and the 5.3-foot scramjet will begin falling, gaining speed as it goes.
Anderson said it will reach Mach 7.6 at about 23 miles above the earth, at which point the chamber will be injected with fuel and "we'll hope we get combustion."
Scientists believe the engine one day could be used to build aircraft capable of flying from London to Sydney in a few hours, a flight that takes at least 18 hours by passenger jet.
It's more immediate use would be as second-stage boosters in commercial satellite launch vehicles. As no liquid oxygen needs to be carried, the weight of the rocket can be substantially reduced, making room for extra payload and smaller rockets.
Australia's University of Queensland is leading the project. The 35-foot Terrier-Orion rocket that will carry the scramjet has been provided by a U.S. member of the consortium, Astrotech.
The Australian Defense Department is providing the launch facility and about 30 members of its Aircraft Research Development Unit to help carry out the experiment.
NASA attempted to test its own scramjet, the X-43A, on June 2, but the jet was destroyed when the rocket used to launch it malfunctioned.
During another test in the United States in August, a four-inch scramjet prototype was fired from a 130-foot cannon at a speed of Mach 7.1. The scramjet engine aboard the titanium projectile then ignited, propelling it 260 feet in a fraction of a second, before crashing into steel plates set up to stop it.
This was a Reagan initiative and I've always wondered what happened to it. I guess it's just much harder, or was funded much worse, than I anticipated.
From what I understand, creating an airplane to use this technology would require an engine nacelle that can be modified in flight. The vehicle would take off like a traditional jet, gain altitude like one of today's high-bypass jets, then fly like a scram jet before slowing down. Unfortunately, the configuration of the nacelle isn't the same for all three types of jets. Computers would have to force the nacelle walls to flex to accomodate the changes.
I can't wait until the day it actually flies.
Shalom.
This was a Reagan initiative and I've always wondered what happened to it. I guess it's just much harder, or was funded much worse, than I anticipated.
From what I understand, creating an airplane to use this technology would require an engine nacelle that can be modified in flight. The vehicle would take off like a traditional jet, gain altitude like one of today's high-bypass jets, then fly like a scram jet before slowing down. Unfortunately, the configuration of the nacelle isn't the same for all three types of jets. Computers would have to force the nacelle walls to flex to accomodate the changes.
I can't wait until the day it actually flies.
Shalom.
...Initially this was a US project as part of the Regan / Bush NASP development system. The so-maligned "orient-express". Clinton killed it when he took office in the early 1990's. It was only a matter of time that the project would be developed. To bad it had to happen off shore.
The good news is that the money that was taken away from NASP went into AIDS research, and for Diversity Studies in college. (sarcastic remark)
waittaminute!
The atomic weight of hydrogen is 1.0074
The atomic weight of hydrogen is 15.9994
If the rocket is 100% efficient, producing H2O, you're mixing (by mass) 2 units H with 16 units O. So eliminate the O, and your fuel mass is reduced to 2/18, or about 11% of original. Now figure you're probably halving the number of pumps, tanks and plumbing, and it seems like you'd be going a lot lower than 1/2 original weight. Unless for some reason the scramjet engine is more massive than a rocket's, but even there it seems you could use a "cold" airflow sceme similar to a jet engine's to keep the linings "cool", requiring less ceramic lining...
Have we got any real rocket scientists (engineers) here who can comment on this? Somehow I just can't trust the press when it comes to understanding anything technical...
The SR71 uses a Ram jet system at mach 3.5 by bypassing the air around the stopped turbines and compressor fans (not needed at such a high speed as it would be have inefficient shock patterns around the fan blades and the air pressure would be so high inside the combustion chamber before ignition that air dissociation or plasma would reduce efficiency as it would absorb energy for dissociation from the engine).
The Super sonic ram jet or Scramjet does not slow down the air to subsonic speeds because the air intake is so high (hypersonic) that decreasing the relative air velocity to subsonic speed would increase pressures too much and cause dissociation. So the air is kept supersonic inside. However it creates some problems with respect to making proper fuel air mixtures and to reaccelerate the air out to hypersonic speeds.
THe matter anti-matter engine is years away and is only to be used for gigantic space projects. Manufacturing matter and antimatter to be mixted and stored requires very complicated systems that are not within reach yet that I know. The thing that comes closest is the electrical rocket that shoots plasma out by means of magnets pulsing out ionic plasma. Those plasma are however material only, and not antimaterial.
Basically just a open end tube, the air get compress in the front by the high speed.
Little know fact is that the SR 71 used this, at speed, up to 95% of the air entering the engine inlet bypasses the jet engine itself and is mix with fuel in the afterburners to act as a ram jet
Oh is that the AIDS research gays hoped Clinton would achieve except for the Clintonesque Catch 22 that prevents people from getting the drugs because of the FDA? Hmmm. tooo bad.
Why not scale this up?
I saw a special on Nova a fews years ago about a scientist who in the late 60's was building multi-stage cannons based on WWII Nazi technology. He originally hoped to use the technology to launch satellites, but when his funding was cut by NASA, he went into the illegal arms trade and was eventually killed by Israeli commandos.
Why can't this technology be used to build cannons large enough to launch scramjet-equipped satellites? Seems like that could save a ton of money.
There's sort of a multiplier effect at work here. Not needing to carry oxidizer means that you don't have to expend energy accelerating it. That in turn means that you don't have to carry as much fuel to accelerate the useful payload. Since you don't need fuel to accelerate oxidizer, you don't have to accelerate that fuel either, so you can get by with even less fuel. Etc.
The same process applies to the tanks you no longer need to carry oxidizer and the pumps you no longer need to pump it. After the numbers stop rattling around, you've easily got a factor of 2 savings in the amount of fuel you need to do the same job as the original rocket was doing.
Just as an aside, the space shuttle main engines run fuel rich, so there's always unburned hydrogen in the exhaust. The performance is a little better that way.
This system should work fine as a booster stage for launch to orbit.
It's only one stage, though. Something is needed to get it up to lightoff speed, and once it is out of the atmosphere, something else will have to work as a rocket because this will be out of gas.
No the higher up the faster you can fall There was an Air Force test of parachutes for high alt. In a high alt. jump from a balloon the jumper went supersonic in freefall
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