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X-43A Hits Mach 7
quiggy writes "As previously reported, NASA tested the X-43A yesterday. The results are in, and the scramjet hit Mach 7, setting a new speed record. CNN is also reporting the story, with a note that a similar jet could be tested by the end of the year, hopefully reaching Mach 10."
is 3402 meters per second
or 12247 kilometers per hour
or 7610 miles per hour
basically the higher you go, the less air there is, and the slower sound travels. So, the mach number, which is the ratio of your speed to the speed of sound, will be higher at high altitudes if the speed is constant.
Yes, they did it in the 60s. They reached Mach 7 with a manned plane. This one is unmanned. I don't understand why it is such a big deal.
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It also could drastically cut the time of commercial flights -- perhaps shortening the trip between New York and London to less than five hours.
Considering Concorde did that in three hours, thit wouldn't be much achievement. I make it that it could do NY-LON in just over one hour.
What I think they should have said is that it could go from any point on the earth to any other, including the antipodes, in less than five hours.
Mind you, it would take three hours to get through security on departure and an hour on arrival to collect your baggage, if it had arrived with you.
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SCRAM stands for Supersonic Combustion Ram (jet). What makes this different is that the combustion is taking place in air which is moving faster than the speed of sound inside the engine. Conventional Ram jets require that the air inside the engine be moving at less than sonic velocities for combustion to occur.
Conventional Ram jets are limited in top speed by the necessity to slow the incoming air down to sub sonic velocities.
Not only does the SCRAM jet have potential military applications, it can also serve as a 'midrange' stage for a lower cost to orbit booster.
Yeah, Pete Knight went to Mach 6.7 in Oct 67....STILL a record to this day, for a MANNED airplane (X-15 isn't "really" a traditional airplane since it is air launched). Also Pete Knight earned astronaut wings by flying the X15 near 300,000 feet. Several of the X15 pilots received astronaut wings by flying near or over 300,000 feet. Joe Walker, went the highest to 320,000 feet! Sadly, he was killed in the 60's when he was in a formation of planes for an Ad for the general electric engines that all the planes were flying. His "tiny" in comparison jet got too close to the XB-70 bomber (which was suppose to be a Mach 3+ bomber) and it went inverted and smashed into the tail of the bomber, and exploded. Sorry, the early years of test pilots, NASA has always fasinated me, and buddies of mine call me a walking encyclopedia of aircraft knowledge ;)
There's one fundamental difference between an ordinary jet engine and a scram jet engine: The Ramjet has no moving parts.
The all jet engines,operate according to Newton's Third Law of Motion:
For every action, there's an equal opposite reaction
The standard jet engine, invented by Sir Frank Whittle, sucks in air at the front. Then this air is mixed with fuel, and made to combust. The combustion causes the air to exit the engine at a velocity greater than when it came in, thus creating thrust. The escaping air causes the turbine to spin, and this intern activates the compressor, sucking more air in.
The Ramjet has no turbine and compressor unit. Ramjets fly supersonically and have an inlet which injests subsonic air after it goes through a shock wave in front of the inlet. The intake is slowed down aerodynamically, and then mixed with fuel and made to combust. But after about Mach 5, ramjets don't work so well.
The scramjet is almost but not quite entirely like a ramjet. The only difference being in a scramjet the combustion takes place as the air is travelling through the chamber at supersonic velocities.
More about the scram jet. Or another more concise explanation.
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Nothing to see here
It's not. This whole experiment is not at all about speed, and everything about a new engine design.
IIRC, Mach5 is the speed at which the scramjet is released, and ignited... up until then it's just being boosted by a conventional rocket.
During the first test, the scramjet failed.
During this test, it worked, pushing the rocket up another mach or two.
This was not meant to be any kind of speed record.. that's just how fast you need to go to get a scramjet working.
If you want some something that will help understand the scram jet and you have a little aerospace knowledge check out this paper on combustion on a supersonic stream, http://www.anu.edu.au/Physics/aldir/publications/H yslop_hons_thesis_1998.pdf. Its amazeing that this jet can sustain a burn with out a flame holder, at least it looks like it does.
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Indeed. You need to account for friction, though. Wikipedia article on escape velocity.
No, during the first test the rocket booster (the Pegasus) failed, mostly due to being released too low in the thick atmosphere. The entire package was destroyed by mission control before it went totally out of control.
I don't understand why it is such a big deal.
As some have noted, it's because of the engine type - air-breathing - that makes this so significant.
The economics of space travel are dominated by the cost to put something in orbit. Sitting on the launch pad, the payload to weight ratio of the Shuttle system is something like 1:50. Picking up the oxygen just lying around gives you a big increment in payload to weight ratio.
Mach 10 is a record for powered flight; it is not even close to the record of a man-maned craft; IIRC that goes to the Apollo reentry capsules that routinely hit Mach 27 on re-entry. So the heat problem has been solved for quite a while.
The real problem here is that a scramjet engine is very sensitive to its input (the air coming in) as it only spends literally milliseconds in the combustion chamber. So you have to wonder what aerodynamic tricks the X-43A designers are pulling to smooth that flow before it goes into the intake. Notice the side-view of the aircraft; the belly is smooth and curvy in order to produce many small shocks ahead of the intake and slow down the air as much as possible. A terrific aerodynamic feat, I just have to wonder if it will be reproducible (i.e. stable enought and robust to any aerodynamic event) for a manned aircraft. [Yes, I am an aerodynamicist].
It is a speed record for a vehicle driven by an air breathing engine (ie, it gets its oxygen from the atmosphere)
Rockets have gone faster, but they carry their own oxygen.
Let's sum it all up. 1) Escape velocity is IRRELEVANT in the discussion. That applies to unpowered vehicles - not a vehicle under constant power such as this one.
2) As has been already posted. The speed record isn't for ANY vehicle. The record is for a vehicle with an air breathing engine (ramjet, scramjet, etc). It doesn't apply to vehicles such as the X-15, Apollo capsules, the space shuttles, etc as their speeds were/are either rocket powered or unpowered reentry.
3) During the first test the scramjet engine did NOT fail. It was never even fired. The booster engine that was supposed to get the scramjet to mach 5 is what failed. If I remember right the fins or something fell off and it went out of control so the remote detonated the booster and consequently the scramjet testbed attached to it.
4) The toyota corolla attachment won't be out until 2006.
I don't have a physics book handy, but I'm pretty sure mass has nothing to do with the velocity.
From cnn It is the first time a supersonic-combustion ramjet, or scramjet, which uses air for fuel, had traveled so fast, flight engineer Lawrence Huebner told reporters. The University of Queensland Launched the HYSHOT in July 2002. It Hit Mach 7.6. The first people who did this
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Take a look at the photo of the actual X-43.
All the pics were of the Pegasus booster rocket which was dropped from a B-52. You can't even resolve the X-43 in those photos.
That X-43 is smaller than most of the bombs that B-52 has dropped in its lifetime.
In 1994, a paper was written by Miguel Alcubierre which detailed a possible way of obtaining warp drive.
The current problem is that of relitivty, at which there is a certian point where energy stops creating speed, and goes into increasing the mass of the moving object, thus making light speed impossible.
Alcubierre's idea was that the ship doesn't move. Instead, it modifies the space around it much like an esclator. Since the ship doesn't move in relitive terms, it doesn't gain mass or suffer time dialation.
However, at this time, there was a problem with obtaining the required energy, which was quite alot [think total solar output of the sun in its current life, per second].
In 1999, however, Thomas Valone spotted an answer. Zero Point Energy. In a nutshell, one can theoretically harness the binding energy of a particle. This energy, if harnessed, would be enough energy to power an Alcubierre warp drive.
However, both ideas are still in the working stage, and I think we will see Duke Nukem Forever before we see warp drive from either of these two concepts.
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One G is about 22 mph/s, so 1400 mph/10s is a about 6.4 G's.
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Not exactly true. When solving the two-body system, a number of coordinate transformations change the equations of motion into a simple one-body equation that can be solved exactly. The mass in the transformed one-body system is called the reduced mass, which is defined as mu=(A*B)/(A+B), where A and B are the masses of the two bodies in question.
Assuming A>>B (ie, Earth is much greater than the mass of a satellite), this can be rewritten exactly as mu=B/(1+B/A), or w/ a first-order taylor expansion as mu=B-B^2/A. For a standard communications satellite, the second term is approximately 10^-18 times smaller, and can realistically be dropped, and the mass of the satellite is to within measurable uncertainties B.
But you're wrong in general when you say it's independent of the mass of the object it's orbiting. In the system of the moon orbitting Earth, there's about 1% error by replacing the reduced mass by moon's mass. For a more dramatic example look at a binary star system where one star has 3x the mass of another.
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It was taken to mach 5 by the Pegasus, then it accelerated under the scramjet to mach 7
This is not true. The pegasus booster took it all the way to mach 7. The scramjet proved it could make positive thrust, but it did not accelerate, it actually decelerated during those 10 seconds. Maximum speed was at booster burn out. This is according to their press conference yesterday.
Also, see this video: (remove the space in the URL)
http://www-pao.ksc.nasa.gov/kscpao/videos/metafi les/ksc_032504_x-43.ram
In the scramjet reasearch buisiness, 10 seconds is an eternity. Most institutions who are researching this technology are universities and the like who don't have access to B-52s, rocket boosters, and the other equipment needed to actually flight test scramjets. Rather, they are forced to rely on less expensive wind tunnels. To simulate >mach 6 airflow (scramjet operational range), they either use an enourmous piston driven system, or a series of pressure build ups with a simultaneaous release. Regardless of the method, these techniques generally can't provide more than 5 milliseconds of flow time to test the engine. If you compare testing engines in 5 ms bursts to one sustained 10 s flight, the perspective kind of changes your opinion on how long 10 s is.
If you want a good paper on the subject, I suggest this one from the Australian National University.
You're right, scramjet didn't accerlerate to mach 7, the only thing they're testing is that CAN scramjet operate when the air flowing through it is at mach 7. Because in the past, the major problem with scramjet is that when it approaches mach 6, the speed of the airflow literally snuff out the engine. Now they seems to be able to keep the scram jey burning at mach 7 (now they just need that thrust).
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