Slashdot Mirror
X43-A on to Mach 10
Cat_Byte writes "On March 28 we read about the X43-A hitting Mach 7 with a successful scramjet test. Prior to that on June 2, 2001 the craft tore itself to pieces during a trial run. Well now they are preparing to hit Mach 10. The upcoming Mach 10 run of the X-43A appears to mark an end of the program. The seven-year, approximately $250 million Hyper-X program was created to provide unique "first time" data on hypersonic air-breathing engine technologies.
"At Mach 7, the front leading edge of the vehicle would see about 2,400 degrees Fahrenheit. At Mach 10, its probably twice that -- twice the heat load essentially," Sitz explained
FYI, Mach 10 is about 2 miles per second."
looking at this, the craft will climb up using the pegasus booster, and the actual scramject flight is horizontal.
Took about 2 mins and wikipedia, don't waste your mod points.
Guys, commercial flight isn't really the goal. Instead, NASA's Hyper-X program, the six-year, $185 million research endeavor of which the X-43A is a part, is aimed at developing vehicles that can deliver payloads into space much more cheaply than traditional rockets.
GMD
watch this
FYI, he was referring to the episode of Star Trek Voyager, where they test out the new engine technology on the shuttle. It goes Warp 10 which apparently causes 2 of the characters to "evolve" into gecko-like creatures. another completely ridiculous plot that took place around the time of the episode where they found Amelia Earhart
Seeing as the speed of sound (at 20 C) is 343 m/s, I must conclude that your conversion is off by quite a bit.
They forgot to teach you that the speed of sound varies with air density and hence altitude, so it's not quite as trivial. Of course the number of seconds and divide by 5 rule is an approximation anyway.
...the craft tore itself to pieces during a trial run.
I was under the impression that the Pegasus boost missle went out of control so they self-destructed it...not that there was a problem with the X-43.
well, they already upped it to a razor with a fricken battery in the razor handle. It's called the Gillette M3Power !
Knock yourself out:
Gillette M3Power -- a MACH3 innovation -- is a groundbreaking, powered wet shaving system for men that delivers a totally new shaving experience resulting in Gillette's best shave ever.
M3Power builds on the heritage of MACH3 and combines Gillette's latest and best razor and blade technologies. M3Power outperforms all other blades and razors in closeness, comfort and safety during and after the shave.
Gillette M3Power features other innovations beyond power: new blades featuring PowerGlide(TM) -- an enhanced blade coating for incredible glide and maximum comfort, a moisturizing Indicator® Lubrastrip(TM) and a technologically-advanced handle.
Features and Benefits:
Gillette M3Power features Micro-Power(TM), a gentle pulsing action powered by a Duracell AAA battery.
The pulsing action stimulates hair upward and away from the skin, making it dramatically easier to shave more thoroughly in one easy power stroke.
The blades are enhanced by a new coating process, called "thin uniform telomer," which provides a perceptible improvement in shaving comfort throughout the life of the blade.
The blade cartridge features an Indicator® Lubrastrip(TM) infused with Vitamin E and Aloe for added moisture.
A new handle features strategically-placed gripping surfaces that enable men to shave confidently and safely at any angle. The power button is centrally located on the handle for maximum control, and the Duracell AAA battery is easy to insert and replace.
The razor is shower-safe, allowing a man to shave wherever he prefers.
Casual Games/Downloads
The energy radiated by a blackbody is proportional to the fourth power of temperature. But since there's a probably whole lot of convection going on, cooling is probably more a matter of moving the heat from the front of the thing to the back, and the naive idea of how things work is probably not too useful.
On a serious note, there are at least technically multiple leading edges on most craft (including this one).
There's the leading edge of the wings, the horizontal stabilizers, the vertical stabilizer, etc. A combat aicraft might have more leading edges for external hardpoints - really, the front-facing part of any protrusion from the fuselage. Whether the nose/front of the fuselage itself is 'technically' a leading edge or not.
Xentax
You shouldn't verb words.
I think it should be made clear that the first run was unsuccessful due to a rocket booster failure. NASA self-destructed the booster for safety's sake.
The X-43 did not rip itself to pieces on the first run.
-AC
That's the speed you need if you decide to turn off the engines and still want to leave earth's gravity. Achieving LEO is easier - you only need to go 17k mph and you can use a second rocket powered stage to help you get there. What a scramjet helps you do is use atmospheric oxygen rather than carrying your own. That saves a lot of mass.
but Mach 10 won't be 2 miles per second because they are not flying at sea level.
... )..... (sorry, i know it's bad expressed) being about 287.15 for air
Mach number is the square root of the product of gamma, R, and T. Being:
gamma a propertie of the gas (1.33~1.44 aprox for air),
R the constant of the gas (universal R over Molecular Mass for every kilo
And T is the absolute temperature of the gas;
According to the International Atmosphere model, the temperature of air drops 6.5K every kilometer until you reach 11Km, beyond it remains constant until 22km, where it again rises.
So, if depending of the height (and particular condition of the day and the state of atmosphere) the Mach speed varies
As i haven't seen at what height they are flying, you can calculate yourself the Mach speed if you find the numbers.
So is very probable that they are flying at really great heights where the mach value greatly differs from sea level Mach, what is taught to children, as other poster suggested
Values of temperature of atmosphere can be found looking for ISA model (International Standard Atmosphere)
By the way, i am using SI; so, if you find a table with Farenhait (or whatever it is spelled) you can convert a farenheit degree to kelvin via:
(TF-32)/1.8+273 = kelvin
PD: Sorry for my bad english
Check out wikipedia on the subject:o city
http://en.wikipedia.org/wiki/Escape_vel
Assuming it is somewhat accurate, escape velocity at 5,592 miles is closer to 15,882 mph. That is to say, if you can accelerate from the ground, you only need to reach a top speed of 15,882 mph in order to obtain an orbit at a distance of 5592 miles. So 7,500 mph is more like 1/2 of the way there...
Nerd rage is the funniest rage.
It's incorrect to use temperature to describe something as "twice as hot," since temperature is an intrinsic value - not a "quantity" to be counted like length, mass, etc, but rather a relative scale, defined by the Zeroth law of Thermodynamics to describe the direction of heat transfer.
It would be somewhat more correct to possibly describe something as having twice as much internal energy (heat), because units of heat (joules or BTU's) are quantifiable units. Keep in mind that this still wouldn't lead to twice the temperature on an absolute scale, since the specific heat of virtually anything is variable with temperature - hence, you can't correctly surmise that just because there's twice as much heat then there must be twice as much temperature.
When you're not looking, this sig is in Latin.
"Parsec" is a measure of distance, not time. So if this is a quote, it's a stupid one. If you made it up, consider yourself corrected.
I feel better now, thank you.
At that speed a brick is a "lifting body". Reminds me of the F-15 a.k.a. the "Aluminum Lawn Dart" (or world's most expensive lawn dart) because if you turn off the engine thats what your flight path looks like.
Density affect on the speed of sound in different mediums different materials
D6 63 0D 70 89 81 BB 8E 7B 7C 5F 5D 54 EA AB 73
So is mine:There are not supporting facts in the Wired blurb because it's public record. The thing in Wired is a little easier to read.
There are no trails. There are no trees out here.
No, but it will install Gentoo on your home PC.
Prior to that on June 2, 2001 the craft tore itself to pieces during a trial run
Actually, it's the rocket launcher that veered out of control.
A plane takes the rocket+X43 into a given altitude, the rocket launches bringing itself and the X43 to about Mach 3 and then the scram jet can take action, bringing the X43 up to Mach 7 after separation from the rocket.
It's the rocket that failed on the first attempt. Not the X43-A.
And how does that 2 miles per second size up compared to the speed required in order to escape the Earths Gravity and reach orbit?
The Earth is about 8,000 miles diameter, so LEO (about 100 miles above the surface) is 8,200 miles diameter, or 8100*3.1416=25447 miles around. Something in LEO orbits approximately every 90 minutes, it goes 25447/(90*60)=4.7 miles per second. So this 2 miles per second is a little less than half the speed needed to be in orbit.
So while getting into outer space (as SpaceShipOne recently did) is a big achievement, getting enough speed to be in orbit is much more so, requiring even more acceleration.
Tag lost or not installed.
It is a true statement that a Parsec is a measure of distance. But that doesn't rule it out as a unit of time. Special Relativity tells us that time and distance units are interchangeable, because the speed of light is a constant value in all reference frames.
So, while I'm sure the original Star Wars quote wasn't meant to delve into the intricacies of modern physics, it certainly isn't technically wrong. Of course, since a Parsec is about 39 years, I certainly wouldn't want to be piloting for that amount of time...
Oops ... that should have read "... since 12 Parsecs is about 39 years..." You must actually READ your post when you preview it :-)
The whole big deal with the parsec thing is that Han essentially skimmed the event horizons of black holes to get to kessel faster, shaving off time, but in the end, it actually shaved off distance due to spatial anomolies. (sp.)
Read the Han Solo star wars books for it to make sense.
That's the F-16 Lawn Dart. The F-15 has two engines, and has made much less of a reputation as a ground penetrator, perhaps because of the redundancy. The F-16 has only one, which typically fails, rather than being turned off.
Language students: Don't try to learn English here. This ain't it.
something in earth's orbit hasn't escaped earth's gravity at all. Escape velocity is 11.2Km / sec or over 25,000MPH to leave the earth and never return on an unpowered trajectory. The common weather satellites I read about only have to achieve 17,000+ MPH, so 6Km/sec or almost 4 miles/sec seems a good answer
I've always been amused by this as the claim may in fact be valid and boastable...
Now I'm not claiming Lucas knew what he was doing but....
Suppose that the Kessel Run is getting from point A to point B, but the difficulty is not the distance per se but some 'stuff' between the two points. Maybe a vast dangerous asteroid field, or globs of a mysterious sticky substance, or lions, and tigers, and bears, oh my!
Regardless, most people are forced to fly around the 'stuff' and so the the Kessel Run is a long distance, but the truely skilled can go through with a shorter distance implying higher skill and so more impressive....
Just a random thought...
The 12 parsec thing was a mess up that Lucas made, but that the books cleared up. They put Kessel next to a cluster of black holes, so doing the run in less distance actually speaks volumes about the capablities of the ship.
OK, that was a little too flip. More details.
Consider a coordinate system fixed to the aircraft, with a Mach 10 flow passing around it.
A scramjet (supersonic combustion ramjet) uses a series of oblique shock waves to compress (and slow down) air in order to get it to combust. In a ramjet, the throat of the engine sets up a shockwave perpendicular (normal) to the free stream velocity. Any time you have a so-called "normal" shock wave, the downstream flow is always subsonic. With an oblique shockwave (oblique relative to the free stream velocity), you can have that shock wave compress and slow down the flow, but it will remain supersonic.
The problem with ramjets is that as they get closer to around Mach 5 or 6, their drag starts increasing in a non-linear fashion (meaning that going a little faster gets you a lot more drag), because the normal shock wave won't permit the downstream air to go a little bit faster (since it MUST be subsonic).
So, you have to figure out a way to allow the flow in the combustion chamber to remain supersonic. To do this, you arrange for the airframe and the engine intake to set up a series of oblique shock waves that compresses the flow, but allows it to remain supersonic. You then attempt to start a fire in that supersonic airflow (imagine trying to light your zippo while holding it out a car window and multiply that difficulty by about a million).
That's a scramjet. The drag comes from all those shockwaves (hence wave drag) and is related to the frontal area of the aircraft (which usually looks rather like a doorstop in profile, the entire frontal area is basically the ramp to the inlet of the engine). Wave drag is proportional to the square of frontal area. (never mind the skin friction drag, which will get worse and worse as you go faster and faster and eventually make your airframe go melty melty).
To make matters worse, consider what would happen if you're hurtling along at Mach 10, and you make a sudden correction in pitch. In all likelihood, you're going to upset the carefully orchestrated shock waves that are making the air play nice in your engine. If you're lucky, the aircraft just slows down (HARD) and resumes stable operation. If you're unlucky, one of the shockwaves will become a normal shock wave at the narrowest part of your engine, and it will be exactly like you hit a mountain. At Mach 10.
Does that clear things up? Honest, I don't mean to be patronizing. I'm far from an expert on this subject, but I do know more than your average Joe.
Why yes, I AM a rocket scientist!
The Kessel run is in fact around extremely dangerous things. It is near the "Maw", a black hole complex, full of hundreds of black holes. In one perticuler book, he sets it. He is racing his friend, who performs a hyperjump, and damages his ship. Han jumps in closer than ever rescues his friend. He thus sets the record for the kessel run, going the shortest distance and closest to the Maw.
Help Fight SPAM today!
Mach 1 = exactly the speed of sound in the medium of travel. Always.
This is useful because the way the medium flows changes significantly at the speed of sound - you have subsonic flow (what airliners fly in), transonic flow (what no one flies in because its ugly), and supersonic flow (what jet fighters fly in). There's also hypersonic flow, but its not as well defined a transition, and has a lot in common with supersonic flow.
Anyway. Mach numbers are useful because they're a similarity number; so much of flight is dependent on the aerodynamic properties of the flow, and equal Mach numbers implies equal aerodynamic flow properties, even if the actual atmosphere is different.
A jet pilot at 10km will produce a sonic boom at > Mach 1. A jet pilot at sea level will produce a sonic boom at > Mach 1. Any object at any altitude will produce a sonic boom if its moving faster than Mach 1. That's why the Mach number is useful.
---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
No, temperature is in degrees Celsius or in Kelvin. There's no such thing as a 'degree Kelvin'.
Real Daleks don't climb stairs - they level the building.