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Scramjet Test Successful 300

Posted by michael from the zero-to-six-thousand-in-one-second dept.
An Anonymous Coward writes: "The Sacramento Bee is running this story about the first powered device to achieve "hypersonic" speeds in the Earth's atmosphere. In a series of DARPA-sponsored tests, at Arnold Air Force Base in Tennessee, a scramjet engine, encased in a titanium projectile, was fired from a 130-foot cannon, at an initial velocity of Mach 7.1. The scramjet's engines then ignited, and the object moved another 260 feet, in just 30 milliseconds, before it came to rest in a series of steel plates designed to halt the flight. Peak acceleration: about 10,000 G's. Elapsed time, including cigarettes & pillowtalk: less than a second. PS: According to this nifty page at NASA, Mach 7.1 is about 5406 MPH, whereas 260 ft, per 0.03 seconds, is about 5909 MPH."
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Scramjet Test Successful More

Scramjet Test Successful

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  • Rent a Concorde and fill it with a lot of explosives. It's that easy ...
  • So, anyone want to set up a pool betting when the first "then we strapped a SCRAMJET on the back of Bob's old VW Bus" story appears?

  • I can see my first flight on one these babies now (Score:5, Funny)

    by case_igl ( 103589 ) on Wednesday August 29, 2001 @03:56AM (#2229031) Homepage
    Ladies and gentlemen, welcome aboard LotsaCashSpentDevelopingThis Airways.

    Flight Attendant #1:
    "Once we reach our cruising altitude we will begin our complimentary beverage service. Coke products are free while beer, wine, and liquor may be purchased for..."

    (interrupted by Flight Attendant #2):

    "LotsaCashSpentDevelopingThis Airways welcomes you to Paris DeGaulle Airport. The local time is 12:14pm."

    • What's the point? Do you really think flying 10x faster will get you there much faster?

      Time to get to airport: 2 hours

      Time waiting at airport: 1 hour

      Flight time: 30 minutes (probably longer or shorter, depending on destination, weather, etc.)

      Time waiting for bags: 1 hour

      Time getting transportation: 30 minutes

      Time getting to where you want to go: 2 hours
      (Yes, all numbers are approximate. YMMV)

      I don't think flying faster would help...

      • What's the point? Do you really think flying 10x faster will get you there much faster?

        I guess you've never flown from Australia to the UK (or vice versa). I'd tolerate quite a bit to reduce the ~22hrs spent in the air....

        ...although, judging from the acceleration rates, being squashed flat at take off like a cartoon character probably is a bit more than I'd put up with, not to mention the sudden braking at the destination ... :)

        "The prototype, ... was destroyed when it punched through a series of steel plates designed to halt the flight. "

        Ouch!

        Simon

        • Looks like it's time for someone to invent the physics-defying-star-trek-inertial-damper things then.

          That reminds me.. Must send off for that patent. :)
          • Well, that part of Star Trek isn't that physics defying. It's quite simple really, all you have to do is push a sufficiently heavy object in front of you, the gravity of which will counteract any forces felt from acceleration.

            Sure for shipboard use you'd want a sufficiently heavy object of small compass, such as a black hole...

            Granted, getting such a system to work, is a tall order, but that's an engineering problem, not a physics one. ;-)

            No, what irks me about the inertial dampers is the human factors thing; with the crew being thrown out of their chairs with every phaser blast, having to take precious time out to scramble back into them, why on earth don't they have seat belts? ;-)

      • I think that the market for these engines is not your average Chicago to New York flights, but your New York to Paris/Sydney/Hong Kong/Tokyo/[insert your favorite overseas city here] type of flights, i.e., those flights that are already over about 6 hours (closer to 10+ hours) with conventional aircraft. They have to be on those longer flights because they have to fly so high up before going supersonic to avoid having the shockwaves shatter every pane of glass from New York to Los Angeles. Besides, you can't just take off at mach 1 (much less mach 7.1); that would be kind of dangerous if you weren't in a space-shuttle quality harness...
        • As I see it is in less expensive surface-to-orbit vehicles. Use a standard RAMJET to acheive mach whatever-the-hell-you-need-to-start-the-SCRAMJET. SCRAMJET kicks in, and slingshots you out of the atmosphere, where conventional rockets can then manoeuver you. Hopefully, this could be made into a completely re-useable space shuttle.

          Ideas quoted in this post are not mine, they come from a book called Silver Tower by an author I can't remember now. They used a magnetic launching track to get the shuttle up to the speed where the RAMJET would work, then the RAMJET until they could turn on the SCRAMJET.
          • There's been lots of discussion on /. about using scramjets as cheap earth to orbit vehicles. The big advantages they offer is that they don't need to carry their own oxidizers (for the in-atmosphere part of the flight, anyway) and if they're hooked up to a pair of wings you can fly it like a plane. The downside of course is that you can't use it from a standing start and another engine on board used solely to get it to scramjet speeds is just dead weight thereafter.
      • Flight time: 30 minutes (probably longer or shorter, depending on destination, weather, etc.)

        And I always thought it was a stereotype that Americans didn't realise there were countries outside the States.

        Oh, sorry, you've heard of Mexico and Canada too - I saw it on South park ;-P

      • I would quibble with your 'time waiting for bags' - in my experience it rarely takes more than 15 minutes, though when flying to the US I often have to queue for a long time at immigration before collecting my bags (after which it takes 5 minutes to collect the bags).

        You forgot to include taxiing time which is often 30 minutes or more of the gate-to-gate time.

        Still, I'd be happy to cut my 10 hour trans-atlantic flights down to 1 hour.

    • Re:I can see my first flight on one these babies n (Score:1, Funny)

      by Anonymous Coward
      and...

      "Please wait while our molecular reconstructor negates the effect of the 10,000G acceleration. We will begin by fixing our first-class passengers..."
    • Of course, if they are going to use these for commercial flights, I suggest we all invest heavily in steel plate manufacturing companies.
    • Of course at 10kG, by the time they arrive in Paris, all passengers will have changed into some kind of schnitzel.
  • According to this nifty page at NASA, Mach 7.1 is about 5406 MPH, whereas 260 ft, per 0.03
    seconds, is about 5909 MPH.



    Well, given that the projectile in question was accelerating at ~10K G for that 260 ft, from a starting velocity of Mach 7.1, one would expect the mean velocity over the 260 ft to be somewhat higher, eh?

    • I believe that the 10K Gs was referring to the acceleration from rest until it hit the target....in the barrel: 130 feet to reach 5400mph (28080000 feet per hour -- 468000 feet per minute -- 7800 feet per second in a fraction of a second....10k Gs seems pretty reasonable there
    • I think 10K G's is the peak (instantaneous) acceleration.
    • Starting at 2300 m/s and ending at 2600 m/s over 80 m gives you an acceleration of (2600**2-2300**2)/(2*80) ~ 9200 m/s**2, which is ~ 1000 g. OTOH, from 0 m/s to 2300 m/s over 40 m is 66000 m/s**2 (~6700 g), but nothing actually says the acceleration was uniform so 10000g peak inside the barrel is not that far fetched.
    • $ units '260ft/5406mph' seconds
      * 0.032791847
      / 30.495385

      Given that only 1 significant digit was given, .03 seconds is appropriate for mach 7.1. (remember your rounding rules). I presume that nasa's measurements were more accureate than 1/100th of a second, but they just didn't bother to print all those extra digits in the news release. Most news releases are edited by english majors, not physicists or mathematicians. They probably thought that .03 seconds was as accurate as mach 7.1 (fewer significant digits, but the same number of printed digits).
  • Very impressive indeed.

    But if possible, could the posts include a conversion into metric.

    Its just it takes me a little while to do the conversion on my slide rule.

    I am sure the rest of the civilised world(ie SI unit using countries) can understand.

    Thankyou.
    • As a guide to our international readers, here is a quick reference. Here in the US, meters are what the gasman reads. Gram is a kind of cracker. Kilos are what is hidden in tire wells at the border crossing in Tiajuana. Megatons are what we drop on people who speak in funny languages.
  • But doesn't the speed of sound change with the air-pressure? If I remember highschool physics correctly, sound has a higher velocity in a denser medium.

    --Ryv
    • Yes. The speed of sound increases with the density of the medium through which it propogates. For instance, the speed of sound through the crossection of average slashdot posters is aproximatly 8450 M/s.
  • The prototype, which resembles a gothic spire and measures just 4 inches in diameter, was destroyed when it punched through a series of steel plates designed to halt the flight. If this scramjet engine technology is so small, could this possibly be retrofitted, (I have no idea of the fuel needed to power this or it's economy, but im speaking theoretically) to give proper thrust needed for larger vehicles, such as, a jump-jet style civilian vehicle? The flying automobiles out of television sci-fi? Is this possible or am I just not getting the whole idea..
    • If this scramjet engine technology is so small, could this possibly be retrofitted


      Nope, sorry. Basically a scramjet needs to be travelling at extremely high speeds before it can even function, that is why they launched it from a cannon. (Getting it up to operational speeds fast).

      A scramjet airplane would need another type of engine to first get it up to multi-mach speeds
    • It runs primarily on compressed liquid hydrogen and requires an air flow well in excess of the speed of sound to ignite. Hence firing it out of a cannon. Any use you make of this is going to require a rocket engine or really good jet engine to even get it started, but once it gets going the prediction is that it can reach Mach 10 or more which is better than most or all conventional rockets in Earth atmosphere IIRC. For weapons it looks great, perhaps also for launch vehicles. However anything involving people is a little iffy if you can't control the acceleration enough that someone can be semi-comfortable. But who knows, check back in 10 years and see what they've thought up.

    • intended use (Score:4, Interesting)

      by rneches ( 160120 ) on Wednesday August 29, 2001 @06:43AM (#2229270) Homepage
      The idea behind these sorts of technologies (scramjets and ramjets) is to fly very efficently, especially in the higher atmosphear. The technology to beat, in this case, is non-air breathing propultion (a.k.a. rockets). Because scramjets are air breathing, it is not neccesary to bring along an oxidizer, allowing for considerable weight savings.

      Because of this, scramjets are critical for efficent, practical single-stage-to-orbit vehicles. The idea is that you operate in scramjet mode until the atmosphear thins out too much to sustain combustion, and then you start adding your own oxidizer. This will effectively turn the engine into a rocket motor. With scramjets, you could build a shuttle that would actually be fairly inexpensive to operate. Also, since the most expensive part of any mission is boosting into low earth orbit, any savings in the first stages of flight would dramatically bring down to costs for any mission, but especially heavy ones (like a manned mission to Mars).

      The other reason to develop scramjets is for their raw efficenty. The use fuel at a fantastic rate, but at Mach 7, the fuel per unit distance is exceedingly good. Instead of supersonic (in this case hypersonic) flight being a luxury reserved for Concorde flyers, it would become the cheap, practical way of getting around. Of course, it would only make sense for the really long flights (like Chicago to Sidny), but the implications could be trans-global flights that cost less than regional flights.

      Scramjets are very, very cool, and not just because they go fast.

      • In order for the scramjet to work though you have to be moving fast enough to collect enough oxygen from the air. So you'd need yet another system to start you off, be it rockets, jets or a being shot out of a big bloody gun ;-)
      • The big problem with supersonic or better flight for commercial use isn't the fuel economy, it's the fact that many countries (the US being the first that leaps to my mind) don't allow commercial aircraft to fly supersonic over their land at any altitude. Therefor, you either have to land the scramjet at New York, and then fly subsonic aircraft to the rest of the US (assuming you are coming from Europe), or you have to cruse the scramjet subsonic (this is especially true if you are flying from, say, London to Saint Louis) over land.

        Also, just because of the stresses involved, a supersonic aircraft will need to be much stronger than a subsonic craft like a 7[47]7. More strength == more cost and more weight (== still more cost).

        Also, most scramjets are designed to burn hydrogen, not kerosene (like a commercial jet). Hydrogen requires cryogenic tanks, and has the nasty habit of migrating into the metal, finding any weakness, and setting up shop (a process called hydrogen embrittlement). While hydrogen has a much higher impulse than kerosene per unit weight, it is also more expensive.

        Don't get me wrong - I'm looking at going from the US to the UK for a business trip soon, and I'd love to do it in less than eight hours. But I shan't postpone my trip until these things are flying....

      • Re:intended use (Score:4, Informative)

        by gizmo_mathboy ( 43426 ) on Wednesday August 29, 2001 @08:38AM (#2229419)
        While the thought of having a hypersonic commercial vehicle is enticing, I think the intended use of scramjets are more for the military than anything. Remember this is a DARPA project. There isn't many DARPA projects that made it into the commercial realm. Well, I can think of at least one. ;-)

        Heck, just a hypersonic projectile and/or missile would really change the landscape for Ballistic Missle Defense. Having a velocity several times faster than your target is a major advantage.

        It wasn't mentioned in the article but the projectile used gaseous ethylene at 1000 psi, not hydgrogen, as its fuel. I love my Aviation Week subscription. :-)

        As mentioned in another posting hydrogen embrittlement would be a concern in a larger vehicle, this is a 20% scale model. The biggest barrier is heating. Atmospheric heating is a big deal at Mach 7+.

        A more detailed article can be found here [aviationnow.com] at Aviation Weeks online site.
  • This is great - forget those stupid little rotor blades! 10K G from a small metal tube on his head - lets see Hobbes bounce him NOW!!!
  • I don't think that DARPA is using a stopwatch to calculate this to the nearest millisecond. They use very precise measuring tools that go to an accuracy far greater than a millesecond. The same goes for every number reported in the article. With all of these taken into account, the actual values probably differ than those reported by the illustrious 'sacramento bee'. Therefore, without the actual data, it is pointless to criticize or recalculate, since you are already using erroneous rounded data.
  • Honestly, all I can think of is "what could I tie to that thing?"

    It's like I'm 8, I have a box of GI Joes that need to be punished, 1 scram jet engine, and a role of grey duct tape.
    • The first thing that came to my head was "Can I strap this thing to my R/C car"?

      8570km/h real speed, 1:10th scale car, 85,700km/h scale speed....That's pretty fast for a Alfa Romeo 156.

      Somehow I think I'd lose the C from R/C.

      • Sod that, just use a pulsejet [aardvark.co.nz]...

        ---

        Lameness, lameness, first time I've hit the lameness filter. My first posting was everything above that line. Maybe it *is* lame, but sometimes I haven't got a lot to say...

        Come on, Slashcode authors, SORT IT OUT!

  • 260 ft is 79.25 m, 30 ms is 30 ms, so that's an average speed of 2.641 km/s or 9508 km/h. The initial velocity of 5325 mph is 2.380 km/s or 8570 km/h

    Wow.

    • Thank you... I was just going to say something smart ass about "ok, so they made a cannon that can fire things at Mach 7.1," but you've shown the fact that they were launching a engine bullet out of this case rather than a rock or a cheese log actually made some difference.

      I was thinking... wow, nice cannon. Now I'm wowing in concurance with your wow. O...K... time to go to bed.

  • passenger problem (Score:2, Insightful)

    by jlemmerer ( 242376 )
    if such high velocities are required to ignite the scarmjet, how will they do it in the future. firing it out of a cannon doesn't seem reasonable for me if you want to transport fragile goods such das humans. i heard rumors of bringing the scramjet equpped vehicle to high stratosphere with a carrier aircraft and then drop it to gain speed, but that also seems to be a rough ride.
    • What makes you think they are doing this for passenger flight ?

      Imagine a shell, or a missile, fitted with one of these scramjets. High speed = higher impact energy & greater range.

      Maybe they will use them as part of NMD as a last ditch weapon? You can imagine a developed version having the speed to reach the reentry vehicle, and the energy to do something about it when it did.

      As the fun over the unaffordability of a Concorde replacement has shown, passenger aircraft is the last thing on their minds.

    • There are a few ways of getting around this problem.
      • Drop the scramjet vehicle from a supersonic carrier vehicle.
      • Build a giant rail gun, like in Gundam Wing.
      • Attach JATO or RATO pods to the scramjet, and jetison them once hypersoninc speeds are reached.
      • Use conventional means to reach a high altitude, and acheive hypersonic ingition using a balistic dive.
      • Use an on-board oxidizer to fuel the scramjet like a rocket until atmosphearic ignition is possible.
      • Build the scramjet to work first as a jet. Once at maximum jet speed, lock the jet blades and operate as a ramjet. Once at maximum ramjet speeds, jetison the jet rotors and combustion chamber to expose a scramjet surface.
      There are a couple of other reasonable ways, but those are the ones that come to mind.

  • $$$ (Score:1)

    by Eso ( 205333 )
    Alot of people complain about money spent on military/space research. I remember some outcry when the $125,000,000 (I think) Mars probe was left for dead and abandoned on Mars a while ago, and people bemoaned the waste of tax money. In this instance, $800,000, I don't think it's that big of a waste at all.

    Let's see, Alex Rodriguez makes that much in 5 game days?

    • Re:$$$ (Score:1)

      by ksb ( 517539 )
      I agree, I also bet that NASA spent a shedload more on it's experiment and the damn thing fell apart, I wonder whether the NASA designers used KPH instead of MPH for its maximum speed ;)
  • From the article

    The prototype, which resembles a gothic spire and measures just 4 inches in diameter, was destroyed when it punched through a series of steel plates designed to halt the flight.

    When and if they scale it up, I hope this part of the system is re-designed.
  • Yeah, sure, but what does all this stuff give in real scientific units (meters, meters/second, etc) ?
  • Imagine being able to fly from New York to LA in 30 seconds!!! Wouldn't that rock???

    Sucks you have to be greated by sheets of steel to slow you down to below-puking speeds.

  • Yeah... Now you kow what they call it a SCRAMjet don't ya now.
    'Cause if one of those things came strait for you at 8570km/h, you'd better...SCRAM!

    Ah well, It sounded alot funnier before I typed it.

  • This will make countries even more trigger happy, since they have even less time to react to an incoming missile.
  • According to the article, the scramjet projectile was fired from a cannon at ~5400 MPH. From what I can gather, that much was done without any power from the scramjet system. At that initial velocity, 5400 MPH = 7920 FPS, it would cover the 260 feet in ~30 milliseconds, the total flight time of the projectile, according to the article. I'm not going to do the physics calculations, but I'm going to assume that in .03 seconds, wind resistance isn't going to have much affect on the velocity of the projectile, so what did the scramjet do?
    • Oops, sorry. I can read, though my original post wouldn't show that.. Let me toss some more numbers here, hopefully ones that aren't listed in the original post..

      From 5406 => 5909 MPH is a change of 503 MPH, or ~738 FPS. Doing this in .03 seconds gives an acceleration of 24,591 FPS^2. Dividing by 32 FPS^2 (the force of gravity) gives an average acceleration of 768.5 Gs over the flight of the scramjet. Not that anyone else couldn't figure this out, I just figured I'd do the calculation for you, and maybe make up for my earlier post...
  • What makes this any different from a base bleed boat tail artillary shell? Again DARPA misses the mark. And if the Auroura is not a scramjet, what is it? This test is smoke and mirrors.
    • <i>What makes this any different from a base bleed boat tail artillary shell? Again DARPA misses the mark. And if the Auroura is not a scramjet, what is it? This test is smoke and mirrors.</i>

      Well, this one carries fuel.

      • Re:Auroura (Score:2, Informative)

        by dingbat_hp ( 98241 )

        Well, this one carries fuel.

        To some extent, so does a base-bleed shell.

        Logistically, shells should be square-ended. You get more bang into the the chamber that way.

        Aerodynamically, shells should be pointed at both ends, or in fact, even more pointed at the tail. The trouble with this is that it loses useful volume - although it's commonly done with small arms. The trick with base-bleed is that by burning a slow propellant in the tail of the shell, a high pressure gas plume is generated that makes the shell appear to be long-tailed, aerodynamically. You get the same compact shell layout (although you lose some space for propellant) and you get a long-range shell.

        There are also rocket assist shells, but these are rare - they didn't work too well. They have some uses for heavy calibres with low muzzle velocities, but they lose in accuracy what they gained in range.

  • "Baby on board".

    Hope it was wearing a seatbelt. :)

  • The scramjet's engines then ignited, and the object moved another 260 feet, in just 30 milliseconds, before it came to rest in a series of steel plates designed to halt the flight.


    I can juggle for 30 milliseconds.


    I can ride a unicyle for 30 milliseconds.


    I'm as big a technophile as the next guy, but this smells like an $800k proof-of-concept, engineered to be a PR success?


    Too bad there aren't any accompanying pictures, but with a flight time of less than a second, I guess they'd be hard to get.

    • I can juggle for 30 milliseconds.

      I can ride a unicyle for 30 milliseconds.
      Yes, but can you get a scramjet to ignite for 30 milliseconds? These guys can.
    • At $800 000, someone MUST have taken pictures, and according to the article they did:

      High-speed video and still cameras, as well as X-ray and infrared cameras, recorded the flights.


      Perhaps those pictures are classified information. DARPA is picking up the tab.
    • this smells like an $800k proof-of-concept


      Exactly. It hit the steel plates going 1000 ft/s faster than when it left the cannon. That's a lot of speed to add in a mere 0.03 seconds.


      Too bad there aren't any accompanying pictures, but with a flight time of less than a second, I guess they'd be hard to get.


      Nope. There are plenty of cameras that could take many pictures in such a period of time.

  • can you say tank busting weapon? remember this is a projectile we're talking about, one thats only 4" in diameter. however the 130' cannon might be a liability on the battlefield.

    <ramble>
    on the aviation side, there have been rumors of hypersonic vehicles being tested at Area 51 for ten years now. as far as flying in one, i don't think acceleration to mach9 in less than a few mintues would be enjoyable to your average business passeneger.
    </ramble>
    [nasa.gov]
    this article at NASA gives a better explanation and has some QuickTime movies of the X43A.
  • ballistic missile defence network + scramjet
    cruise missiles = a lot of very pissed-off
    nuclear powers.

  • The cannon is more interesting (Score:3, Insightful)

    by redelm ( 54142 ) on Wednesday August 29, 2001 @06:55AM (#2229285) Homepage
    I can see how this short test worked, and how they can get some scramjet performace data in the 30 ms of free flight. Ain't microelectronics wonderful?

    But frankly, I'm more interested in that super cannon. Mach 7.1 is 7,500 ft/s (2,300 m/s) which is extremely high. It would have a max range (neglecting aerodrag) of 300 miles! Did they use a gas-gun?

    • According to this page [af.mil] at the Arnold AFB site, yes, it used a two stage light gas gun.

      They even have this video clip [af.mil], but it doesn't look like much, I warn ya.

    • They used a very well designed potato gun, designed by the same guy who designed the Mach 1 potato gun reported on this site some years back.

  • stupid question? (Score:3, Insightful)

    by Marcus Brody ( 320463 ) on Wednesday August 29, 2001 @07:23AM (#2229314) Homepage
    From the article:


    Scramjets, or supersonic combustion ramjets, burn hydrocarbon fuel but scoop oxygen out of the atmosphere to combust it....


    ...The Pentagon and National Aeronautics and Space Administration are both studying scramjet technology since it would allow missiles or spacecraft to travel longer distances and carry larger payloads than rockets.


    I'm sure i'm missing something fundamental here, but where the hell are spacecrafts supposed to get the oxygen from?
    I guess they must just mean using scramjet untill leaving the atmosphere, and then use onboard oxygen, but it is a little misleading

    • Re:stupid question? (Score:3, Informative)

      by maggard ( 5579 )
      Missiles and spacecraft are launched from down here at the bottom of the soup. If they can take advantage of the ambient gasses along the way (up, down, sideways) as an oxidizer then there's that much less material they have to lug along. Yes once in space a Scramjet isn't much use but to and from arbitrary "space" the majority of most trajectories are within enough atmosphere that Scramjets would be useful.

      Imagine if your car/bus had to haul along it's own oxidizer in a honking big tank of super-cooled special-purpose gas next to the fuel tank, which is what all liquid-fuel rockets do today. Now imagine someone announced an engine that could possibly dispense with that heavy complex oxidizer tank that's been weighing down your car/bus and instead let the motor just suck in outside air - pretty exciting news eh?

      Right now Scramjets are a tricky exotic tech requiring special materials and designs that push the envelopes for those fields. On the other hand the same was true for jet engines when they were developed yet all large and/or long distance aircraft use them pretty much exclusively today. This may be a technological blind alley or it may never be commercially viable but it's interesting stuff nonetheless, indeed exciting for the aerospace-heads.

  • OK, the point is that this is a scramjet engine, not that it is going fast. The idea folks, is that in future vehicles you can take off to high speed using a mag-sled or a more conventional aircraft and achieve high velocity and high altitude using earths atmosphere and at the last possible moment switch to a rocket engine using Liquid O2 (LOX) that you store aboard.
    Part of the reason launch is so expensive (and dangerous) is that we have to carry LOX from the ground up along with the propellant.
    --mycr0ft
  • Elapsed time, including cigarettes & pillowtalk: less than a second. PS: According to this nifty page at NASA, Mach 7.1 is about 5406 MPH, whereas 260 ft, per 0.03 seconds, is about 5909 MPH."
    <humor>
    Reminds me of the last time I was stopped for speeding. Officer said I was travelling 80 MPH in a 30 MPH zone. I answered, "But officer, that's impossible!" Puzzled, he asked me to explain. "I've only been driving for 5 minutes!"
    </humor>
  • And almost as cool as the LOSAT, which hits around 5000mph [army-technology.com]
  • I can hardly wait for Estes' toy version. Zero to solar escape velocity in three seconds flat!

  • The scramjet's engines then ignited, and the object moved another 260 feet, in just 30 milliseconds, before it came to rest in a series of steel plates designed to halt the flight.

    Sure. Like the way my car "came to rest" in a telephone pole after I tried to drive it home after a fifth of Chivas Regal.

  • America ever hear of the decimal system?
    SI units and whatnot...

    Feet are things attached to legs (last I checked)

    Can anyone convert the velocities to civilised modern measurements? Say meters? and kilometers per hour?

    Next you will have them measuring speed in furlongs per forthnight!
    -wink-

    • # units -v '5406mi/hr' 'km/hr'
      5406mi/hr = 8700.1137 km/hr
      5406mi/hr = (1 / 0.00011494103) km/hr

      # units -v '5406mi/hr' 'furlong/fortnight'
      5406mi/hr = 14531299 furlong/fortnight
      5406mi/hr = (1 / 6.8816973e-08) furlong/fortnight
  • OK, so there are several countries out there that have the ability to destroy the world with a few nuclear bombs... well, that's just bad publicity these days, no government would want to wipe a country like Iraq off the map for good, what about all the innocent people that live there? Even though we have the "biggest guns" here in America, we continue to try and make newer, bigger, better ones, but now instead of blowing up an entire land mass we are making weapons that will be able to hit precise targets and travel at unimaginable speeds.

    So here's the problem: just like every other new military technology, other countries will eventually get it. Hypothetically, let's say Russia makes a cannon that can fire an explosive projectile from Moscow to hit the World Trade Center in NY; they probably wouldn't do that (at least I hope not) but they would sell some of those to a bunch of small rogue countries out there who don't have "political correctness" or care about the welfare of a nation's innocent people. It all seems pretty scary to me. I mean missile defense sort of loses it's significance when the missile is travelling at mach 5.

    What do we do? Well I guess we'd better make sure we have the biggest, best cannons and we have a whole bunch of them so all of those other countries will be too scared to use theirs.
  • Ladies and gentlemen, we'll soon be coming "to rest in a series of steel plates designed to halt the flight". We hope you enjoyed yourself and thank you for flying Scramjet Airlines.
  • Everyone seems so excited about the travel possibilities.

    With an acceleration of 10000 G's, I will weigh 2,200,000 pounds during take-off. Exactly how is my body not going to be crushed to a thin paste before the 10-minute flight to London even gets started? That frog in that blender stood a better chance of survival than me in my trans-continental flight. Just a thought.

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