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Space Science

Second Test of X-43A Scramjet Tomorrow 325

Posted by michael from the once-the-rockets-go-up-who-cares-where-they-come-down dept.
pinkUZI writes "NASA says its new Hyper-X, a jet capable of flying some 5,000mph - seven times the speed of sound - will be ready to take a test cruise across the Pacific this Saturday. This is actually NASA's second attempt; the first, in 2001, failed when stabilizing fins flew off the plane's booster rocket and controllers ordered the craft destroyed. CNN has the story." NASA's mission web page has more information, photos, etc.
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Second Test of X-43A Scramjet Tomorrow More

Second Test of X-43A Scramjet Tomorrow

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  • still need ... (Score:4, Interesting)

    by pvt_medic ( 715692 ) on Friday March 26, 2004 @10:16AM (#8679664)
    the b-52 to launch the plane. Will they be able to develop on of there that can take off on its own? or will we always be launching them from the underbellies of a big plane.

    • Re:still need ... (Score:5, Informative)

      by Anonymous Coward on Friday March 26, 2004 @10:21AM (#8679715)
      Um, this is primarily a test of an engine, not an aircraft.

      The X1 was also launched from a plane and was the first aircraft to break the sound barrier. Planes such as the SR-71 have far surpassed this speed and takeoff in the conventional fashion.

      I'm not sure what you're referring to when you state "always be launching them from the underbellies of a big plane".
    • Yes, they will be able to do that. For subsonic flight, it would use regular engines. Once it got fast enough, the SCRAMJET would take over. This one gets around all that by using a rocket to accelerate it to the right speed before engine ignition.

    • Re:still need ... (Score:5, Informative)

      by n0mad6 ( 668307 ) on Friday March 26, 2004 @10:27AM (#8679780)
      Obviously if this method of propulsion is used in aircraft that are anything but proof-of-concept, they'll have to take off on their own power. However most of these experimental aircraft are dropped from the belly of an aircraft already at altitude, even manned aircraft like the X-1 and X-15 (both rocket-powered, dropped from a B-29 and B-52 respectively). For the most part, getting the aircraft to the needed altiude on its own would require too much fuel (making the need to design a much bigger aircraft, etc.).

    • Re:still need ... (Score:5, Informative)

      by J. Jacques ( 708438 ) on Friday March 26, 2004 @10:28AM (#8679788) Homepage
      It's a test flight, not a full-fledged production vehicle we're talking about here. The plan is that eventually aircraft will take off under normal jet propulsion, use scramjets to accelerate to escape velocity, and use chemical-powered propusion once they have left the atmosphere.

      • Circumference (Score:5, Interesting)

        by rwiedower ( 572254 ) on Friday March 26, 2004 @10:40AM (#8679915) Homepage

        But if the earth's circumference is around 25,000 miles, and this jet can go 5,000 miles an hour, that would mean it would take only 2.5 hours to get from any location to any other.

        Okay, if it only takes 2.5 hours at top speed to go anywhere on the planet, how much time is spent accelerating and decelerating versus actually flying at Mach 10? And how much fuel are you burning in the process? I remember working at LaRC when they were just starting to test scramjets and I still think the science is good for orbit, but bad for commercial applications.

        • Re:Circumference (Score:2, Insightful)

          by Anonymous Coward
          rwiedower: But if the earth's circumference is around 25,000 miles, and this jet can go 5,000 miles an hour, that would mean it would take only 2.5 hours to get from any location to any other...
          BZZTT Wrong: Earth circumference is 25K miles at GROUND LEVEL. Are you trying to skim the surface? If you just go up 1 mile then you will find the circumference is ~31K etc. etc.
        • Actually, if the circumference is 25 000 miles you can reach any point of the globe in 12 500 miles assuming you use a straight line to get to it.
        • Okay, if it only takes 2.5 hours at top speed to go anywhere on the planet...

          If the security check ins take any longer we'll need speeds like this to get anywhere. Besides, just think how fast all of your luggage can be lost and sent to Burma!

    • Re:still need ... (Score:4, Interesting)

      by Waffle Iron ( 339739 ) on Friday March 26, 2004 @10:43AM (#8679936)
      The B-52 isn't the big deal. Instead, it's multimillion dollar conventional Pegasus rocket booster that gets the test vehicle up to speed. The Pegasus has been in use for a long time to launch small payloads into orbit; it's always dropped from an airplane.

      What I don't quite understand is why they need a rocket capable of reaching orbit just to get the X-43 up to ~mach 5 so it can start it's engines. It seems like overkill to me. I would suppose they only use the Pegasus's first stage; maybe they had some cheap spares laying around.

      • Re:still need ... (Score:5, Insightful)

        by HokieJP ( 741860 ) on Friday March 26, 2004 @11:50AM (#8680690)
        I think they're using it because its cheaper than designing a whole new rocket just for three flights.

        Plus, the plane is the subject of the experiment, so you want to minimize the number of possible failure points in all the other systems. Using a booster thats already proven is a great way to do this. Of course, in flight one it was the booster that failed...

      • Re:still need ... (Score:3, Interesting)

        by MrCocktail ( 468886 )
        An article [rapidcityjournal.com] describing some sc/ramjet technology. For the impatient:

        The scramjet propulsion system uses different kind of technology than traditional rockets. Instead of carrying both fuel and oxygen to ignite, the scramjet uses oxygen in the atmosphere. To get the oxygen to ignite the fuel, it needs to take the oxygen into its combustion chamber at extremely high speeds.

    • Re:still need ... (Score:5, Funny)

      by skinny.net ( 20754 ) on Friday March 26, 2004 @11:25AM (#8680394)
      They don't need the B-52! Because of the power of the X-43a, it is taking off with a B-52 on its back just to show off!

      Please don't mod this informative.

  • scramjet? (Score:5, Funny)

    by SoTuA ( 683507 ) on Friday March 26, 2004 @10:17AM (#8679675)
    I thought it was an HP printer...

    Da-dum-ching!

  • Favorite Quote on Hypersonic Travel (Score:5, Insightful)

    by ansible ( 9585 ) on Friday March 26, 2004 @10:17AM (#8679685) Journal

    Gordon D. Pusch wrote in sci.space.tech: "Hypersonic travel combines all the disadvantages of airplanes with all the disadvantages of rocket flight and all the disadvantages of re-entry --- continuously."

  • Space flight? (Score:4, Interesting)

    by spellraiser ( 764337 ) on Friday March 26, 2004 @10:24AM (#8679743) Journal

    The article starts off with this:

    The space agency's dogged pursuit of extreme speed, officials hope, will ultimately make space flight easier to accomplish.

    OK, so exactly how is this supposed to aid space flight efforts? There is no mention made of that in the article at all.

    I would have thought that the ability to reach incredible speeds in horizontal flight inside the atmosphere is unrelated to both:

    1) Entering orbit (horizontal flight).

    2) Flying in vaccum (different conditions than in atmosphere).

    I'm confused ... any thoughts?

    • Re:Space flight? (Score:5, Interesting)

      by pe1rxq ( 141710 ) on Friday March 26, 2004 @10:30AM (#8679806) Homepage Journal
      It is important as it might enable more efficient ways to bring stuff into orbit.
      At the moment the only viable way to get stuff in orbit is by strapping a shitload of explosives under it.
      Remember, it is horizontal speed that results in the air pushing a winged body upward towards that vaccum so it is not totally unrelated to space flight.

      Jeroen

    • Re:Space flight? (Score:4, Informative)

      by Analogy Man ( 601298 ) on Friday March 26, 2004 @10:33AM (#8679836)
      The trajectory of a conventional rocket accomplishes 2 things...getting up...and getting to orbital speed. This approach really replaces the first nearly vertical portion with a more conventional lifting air breathing propulsion vehicle.

    • Re:Space flight? (Score:5, Informative)

      by Skyfire ( 43587 ) on Friday March 26, 2004 @10:33AM (#8679837) Homepage
      well, if you get your rocket to reach really high speeds at a fairly high altitude inside the atmosphere, you have less altitude for the rocket to fly and less energy that needs to be expended merely to accelerate the rocket. overall this means less rocket fuel needed to reach orbit. also, because you are starting your rocket at a higher altitude you can optimise your rocket motor for a higher altitude which would increase its effiecieny. overall, a Good Thing

      Disclaimer, IANARSBIAITTBO (I am not a rocket scientist, but i am in training to become one)
      • But wouldn't you be using as much, perhaps more, energy overall to get something into orbit that way? Instead of just expending energy getting a rocket and its fuel into orbit, you're putting a plane and its fuel AND a rocket with fuel (even if it is less) into high altitude flight and then firing up the rocket. The energy to move the extra mass of the plane and its fuel has to be taken into account.

        Or have I missed something?

    • Re:Space flight? (Score:2, Informative)

      by Walrus99 ( 543380 )

      As anyone who has taken high school physics should know, to get into orbit does not just require "going up." It requires reaching orbital velocity about 25,000 mph.
      physlink.com [physlink.com]

      A scram jet could be used for part of an orbital flight from about 7 to 10 times the speed of sound. A rocket would probably be used before and after the scram jet, but there would be considerable fuel savings. Of coure once you are outside the atmosphere, a jet is useless and a rocket engine would have to be use.

      Well this is

    • Re:Space flight? (Score:5, Interesting)

      by mikerich ( 120257 ) on Friday March 26, 2004 @10:38AM (#8679899)
      OK, so exactly how is this supposed to aid space flight efforts?
      There is no mention made of that in the article at all.

      Would this be completely unconnected with the Hypersonic Cruise Vehicle [spacedaily.com] (Falcon) concept? DARPA's idea for a global hypersonic bomber that could pre-emptively bomb a country back to stone age before Letterman.

      Still, the Germans beat DARPA to this idea by about 60 years - meet the Sanger Amerika bomber [luft46.com]... an aircraft that would fly right around the planet skipping off the atmosphere like a stone thrown across a pond.

      Best wishes,
      Mike.

      • Re:Space flight? (Score:4, Informative)

        by AKAImBatman ( 238306 ) <akaimbatman@ g m a i l . com> on Friday March 26, 2004 @12:01PM (#8680807) Homepage Journal
        Speaking of Hypersonic bombers blowing shit back to the Stone-age, you might want to look up Project Pluto [wikipedia.org]. These military guys can be some real heartless bastards at times. Still, they make the target go boom, so who can complain?

        • Dear god, the American military of the 1950s really was determined not to get to through to the 1960s.

          Thanks for that scary link, all of a sudden Dubya's NMD plan seems almost rational... ALMOST.

          Best wishes,
          Mike.

          • The bright side of the Pluto Project was that it and NERVA made good proof of concept projects for nuclear propulsion. Given some of the more advanced reactor designs being worked on, it's quite probable that we'll see Nuclear Thermal Rockets for space travel in the near future. As our understanding of these propulsion methods increases, we may even be able to use them to power safe atmospheric flight. :-)

      • Of course, the Japanese realized that sometimes you don't even need airplanes to bomb your enemies [historyhouse.com]. (Okay, so the only documented casualties were from a curious family that found an undetonated bomb on the ground, but it's still kind of interesting)

    • Re:Space flight? (Score:4, Insightful)

      by Gunfighter ( 1944 ) on Friday March 26, 2004 @11:24AM (#8680386)
      I have a friend who works on this project for NASA and I asked the same question. His answer was quite simple: it's not supposed to aid space flight efforts. Keep in mind the first 'A' in NASA: Aeronautics.

      I'm sure we'll eventually be able to deploy scramjet technology to boost space-bound vessels into the upper atmosphere and release them from there to continue under their own power. Given that the scramjet itself currently needs a boost, I think it will be a while before we see such a feat.

  • Let us strap a human to it and sing "The Rocket Man"!

  • Why? (Score:5, Insightful)

    by Wind_Walker ( 83965 ) on Friday March 26, 2004 @10:35AM (#8679865) Homepage Journal
    Forgive me for being so stupid, but what's the point of making a craft that can go Mach 7? The article claims travel benefits, going from New York to London in 2 hours. But honestly, travelling that fast, if anything went wrong you're toast. Turn a little bit to the wrong side, and suddenly you've lost a wing from the shock. No commercial airliner would stand for that.

    The only possible use I can think of is hyper-range weapons. Ground-controlled planes armed with lethal cargo (nuclear or not) could be flown around the globe faster than any ICBM, and guided with better accuracy.

    I'm all for "Science for Science's sake" but I think this is worthless for any practical purposes.

    • Re:Why? (Score:5, Insightful)

      by Hektor_Troy ( 262592 ) on Friday March 26, 2004 @10:48AM (#8679993)
      You know, if anything goes wrong with a regular transatlantic airliner while it's over the North Atlantic, I think it's fairly safe to say you're toast as well.

      Granted, the nice stewardesses tell you that you can use your seat cushion as a floatation device, but two things strike me in that scenario:

      1) What are the chances of surviving initial impact into the ocean when the plane is in a 600 mile an hour vertical dive
      2) Do I really want to float around in the North Atlantic for several days, clinging to a pillow full of beer farts

      And yet, we still do this on a regular basis because guess what - it's actually fairly safe. As will hypersonic travel be, once we get around to getting better materials etc.

      In the 1700's people really believed that if you traveld faster than a horse, you'd die from the shock and that it would be impossible to build a heavier than air flying machine. Guess what - they were wrong, and you will be as well. Some day (if we don't manage to blow up ourselves first).

      • Dive? (Score:5, Insightful)

        by bluGill ( 862 ) on Friday March 26, 2004 @11:02AM (#8680135)

        Mostly I agree, but your first question starts with an incorrect assumption: a 600mph vertical dive. Pilots are trained at ditching an airplane at sea, and planes do float for a short time after this happens. In fact (though I don't know of any specific cases off hand) it has happened before, and many passangers have survived ditching at sea. Vertical dives do not happen in a significant amount of emergency situations, wings are simple devices and don't break all that often, and a wing is all you need to prevent a vertical dive.

        Airplanes have backup batteries, and backup radios. You can be sure that before the plane hits the water emergency people know that it is going down, and about where. They might not be able to get to you in time to save you, but they at least know where to look just in case.

        I'd prefer to float around the North Atlantic than die. Though I think it is safe to assume that if it really is several days before rescure workers find you they will find a dead body. However depending on where the crash happens, rescure workers may find you sooner.

        • Well, to be completely honest, the two points I made were taken from George Carlin's skit about airplane announcements, but imagine if you will, a catastrophic loss of cabin pressure (roof flies off) and it just HAPPENS to take the cockpit with it, just how are the pilots supposed to steer it? Sure, it doesn't happen all that often, but hey - we were talking about unlikely events anyway (like maneauvering (how the devil do you spell that?) a hypersonic aircraft outside of it's safety envelope).

        • Re:Dive? (Score:3, Informative)

          by molarmass192 ( 608071 )
          Even if you survive the crash, you'd die of hypothermia in a few hours. I don't know if you've ever swam in the North Atlantic but I spent a few days at the beach in Nova Scotia in the middle of August and let me assure you that the water was not much over 60F. You die when your body core temp reaches 80F. In 60F water, you've got about 3 hours of survival time immersed. So, in an ideal scenario, unless the rescuers get to you in under 3 hours, you're gonna die anyhow.

        • Re:Dive? (Score:2, Interesting)

          by ValentineMSmith ( 670074 )
          While this [airdisaster.com] wasn't actually a "successful" ditching attempt, IIRC, over half the passengers lived through it. The video link on the site doesn't actually lead to a video of the crash, but I can remember seeing the video on one of those "Real-People-In-Real-Pain" TV shows for which the Fox network is so famous. The Aircraft came to rest roughly 500 metres or so from the beach, and the water was relatively shallow. Several people on the beach waded out and helped the passengers to shore.

    • Re:Why? (Score:5, Insightful)

      by meringuoid ( 568297 ) on Friday March 26, 2004 @10:49AM (#8680001)
      The article claims travel benefits, going from New York to London in 2 hours.

      This is the most tragic thing I've ever read on Slashdot. We USED TO be able to go from New York to London in two hours. It was sixties technology, hacked together by two dying empires looking for some prestige. Now we're looking at a little dart fired off a B-52 and dreaming of flying that fast again someday... What the hell went wrong?

      • Re:Why? (Score:4, Interesting)

        by lfourrier ( 209630 ) on Friday March 26, 2004 @10:58AM (#8680081)
        We USED TO be able to go from New York to London in two hours. What the hell went wrong?

        1) US refusing Concorde at supersonic speed over US territory.
        2) Price of petrol
        3) 2 hours of transatlantic flight, 2 hours to go to the initial airport, 2 hours to go from the final airport...
        4) Looking back at this, it was somewhat an ecological catastrophe

        How will all those factors be taken into account by the sdcramjet developers?

        • Re:Why? (Score:3, Interesting)

          by meringuoid ( 568297 )
          Mmm... Maybe I can forgive the US banning Concorde overland, given the noise it made; I was in Reading last summer, shortly before Concorde was grounded, and heard one _hell_ of a roar filling the whole place. Looked up and there it was, coming up out of Heathrow. There must have been a hundred rock bands there and nothing came close for sheer decibels. Bloody beautiful, though. Just the shape of it stinks of speed.

          The other killer was probably that it couldn't quite carry the fuel to cross the Pacific. T

        • no (Score:3, Informative)

          by mnemonic_ ( 164550 )

          1) US refusing Concorde at supersonic speed over US territory.

          Done for the same reason that most western European countries cited when limiting Concorde flights, i.e. noise. I'd expect less noise to be generated by scramjets because of the lack of fans (reducing aerodynamic and mechanical noise) and more compact combustion of the vapor-fuel mixture.

          2) Price of petrol

          SCRAMJETs will not use kerosene-derived propellant. They will combust hydrogen with oxygen from the atmosphere (maybe you should have done

    • "You're toast", as you've aptly pointed out.

      There's not alot that can be done when your tail section blows out due to improper riveting. You can't do anything but pray and land when the top of the aircraft peels open like a sardine can due to a bad joint that allows a crack to propogate the length of the plane.

      And you know what? People still die falling down a flight of stairs.

      It doesn't matter how fast you go, how close to the ground you are.

      Now you do have good points about wing shock, but, those sp
    • But honestly, travelling that fast, if anything went wrong you're toast. Turn a little bit to the wrong side, and suddenly you've lost a wing from the shock.

      You can bet someone said the same thing when the Wright Brothers put a plane in the air. They're testing this; they're not putting it into production. We still have a lot to learn, and this is a big step in the right direction.

      Good luck to the fine men and women at NASA. We'll be watching.

      • But honestly, travelling that fast, if anything went wrong you're toast.

        Isn't that pretty much true in any tin can moving at supersonic speeds powered by exploding fuel? The Concorde cruises just fine at Mach 2, the SR-71 at Mach 3.3+.

    • Deja Vu ? (Score:3, Insightful)

      by AftanGustur ( 7715 )


      The article claims travel benefits, going from New York to London in 2 hours. But honestly, travelling that fast, if anything went wrong you're toast.

      I imagine this is almost exactly what was claimed when the combustion engine was being developed..

      Just think about it:
      The inventors claim travel benefits, going from New York to Bostin in 3 hours. But honestly, travelling that fast, if anything went wrong you're toast.

    • A Mach 10 aircraft would not be able to fly around the world faster than an ICBM, which travels at ~Mach 25 through orbit and can reach any target in the world 30 minutes after launch from the continental US.

      On the other hand, while a rocket needs to carry its own propellant, the scramjet uses atmospheric air. It is therefore much more efficient, and for a given size and weight constraint, one could build a scramjet powered vehicle that could have some combination of greater speed and range over conventio
    • Like everything else the govt pays for... its an offensive weapon. take a look at the calculations

      ((1 / 2) * (1 000 kg)) * ((7 000 mph)^2) = 4.89619666 x 10^09 Joules

      a 20 kiloton bomb is ~10^13 joules...

      What these means is... if they can put these engines on largers chunks of mass (i.e. increase the mass of the object flying at 7 times the speed of sound). They could have a bomb, with the explosive power of an atomic weapon... without using atomic methods. There is no need to strap a atomic warhead
    • Maybe it's related to these [bbc.co.uk] plans?

      Choice quotes...

      "The US will be able, using aircraft based on its own territory, to strike at individual targets without warning and without the need for foreign bases"

      "The current and future international political environment severely constrains this country's ability to conduct long-range strike missions"

  • Second Post of X-43A Article Today (Score:3, Funny)

    by gravelpup ( 305775 ) <rockdogNO@SPAMgmail.com> on Friday March 26, 2004 @10:35AM (#8679867) Journal
    from the dupes-of-dupes dept. [slashdot.org]

  • Ok, so Jet Propulsion Lab. does space.... (Score:5, Funny)

    by Zaiff Urgulbunger ( 591514 ) on Friday March 26, 2004 @10:36AM (#8679880)
    Slight off-topic, but why do I have to go to Jet Propulsion Laboratory [nasa.gov] to find out about the Mars rovers, and then I have to go to National Aeronautics and Space Administration [nasa.gov] to find out about fancy new jet engines?!

    Is it a cunning plan to out-fox those secret stealing ruskies?
    • I dono, but back in 94 maybe early 95 or so , I was surfing around WPAFB for info on pulsejet engine, which are a hobby of mine. I also saw something interesting done in html and though hmm howd they do that ? Well of course I wiewd the source and found a couple of URL's commented out. Interesting I thought , what behind those... The answer The Advanced Power Directorate, after about 10 minutes of surfing I realized I was in a very classified extranet for the big engine manufacturers , really kinda scared m

    • Re:Ok, so Jet Propulsion Lab. does space.... (Score:4, Interesting)

      by demachina ( 71715 ) on Friday March 26, 2004 @01:55PM (#8682180)

      http://www.jpl.nasa.gov/about_JPL/jpl101.pdf

      The way this reads is there was a race after sputnik to launch the first U.S. satellite. The JPL/Army Orbiter lost out to the Navy's Vangaurd. Vangaurd exploded on the pad and JPL revived Orbiter but they focused on the satellite more than the rocket. They turned their focus to payloads from them on, and NASA came in to being in 1958 and assumed hegemony over rocket R&D elsewhere. As for not changing the name I assume it was:

      A. Sentimental, since the early JPL had a rich history
      B. To cheap to print new stationary and change signs
      C. Geeks busy doing geek stuff and didn't get around to it

      The original founders are a colorful group. Theodore Von Karman was the leader and guding force.

      Jack Parsons, leading chemist, who was part of an "esoteric order" rumored to be fond of drugs and orgies.

      Tsien Hsue-shen is considered to be the father of the Chinese missile and space program. He was held hostage in the U.S. for a number of years during the red scare when he wanted to return home to China. He was released by Eisenhower as part of prisoner exchanges in Korea.

  • Complexity not always a good thing (Score:5, Interesting)

    by Analogy Man ( 601298 ) on Friday March 26, 2004 @10:38AM (#8679896)
    That kind of craft would probably employ multiple propulsion systems including a turbo-jet to reach supersonic speeds, scramjets to take the vessel to the edge of the atmosphere and then chemical rockets to enter the void of space.

    The danger here is that the darn thing will carry all of these systems and have no capacity left over for payload. I recall the Boeing SST back in the late 60's early 70's was based on a swing wing concept. The scale of the mechanical systems to swing the large wing faced them with a difficult choice of a swing wing or passengers...but not both.

    In the physics world one has a sense that they are on to something when the math becomes elegant and simple...I think in the "no moving parts" nature of the scram jet are appealing...a turbofan/scram/rocket combination is not

  • Physics Question (Score:2, Interesting)

    by Pirogoeth ( 662083 ) *
    I've mostly forgotten almost all my physics, so could someone please answer a question for me?

    Why do you need to be going 25,000 mph to get away from the Earth?

    I can jump into the air and get away from the Earth, for a couple seconds anyway, and I'm not going nearly that fast.

    I thought as you got farther away from a body, the gravitational pull decreases using some inverse-square rule.

    As long as you can get airborne and are able to keep moving upwards, why doesn't it become easier to keep going the high

    • Re:Physics Question (Score:4, Informative)

      by GuyFawkes ( 729054 ) on Friday March 26, 2004 @11:02AM (#8680136) Homepage Journal

      In real layman's terms......

      weigh yourself at sea level
      then weigh yourself again at the top of mount everest

      unless you are using *really* accurate scales the two readings will be the same.

      now go back to both locations where you weighed yourself and measure the atmospheric pressure in both places.

      unlike your weight you'll find the pressure is about a third of what it was at sea level.

      pressure in a known and unchanged mixture of gases is another way of counting how many molecules of gas there are in any given cubic meter, or to put it another way, the mass of a given cubic metre.

      so your aerofoil (wing) at the top of everest has about one third of the mass of gas to ride on as it does at sea level.... if your aerofoil is a fixed wing then you can always travel three times as fast (hence needing a scramjet) whereas if your aerofoil is a rotary wing (helicopter) you come up against a hard limit when the out edges of the rotors approach the speed of sound, hence the much lower maximum altitude ever recorded in a helicopter as opposed to a swing wing.

      NB all of the above is really really simplified and therefore full of errors to a physicist / aerodynamics / bernoulli / etc etc etc

      HTH etc

      • Re:Physics Question (Score:3, Informative)

        by mccrew ( 62494 )
        so your aerofoil (wing) at the top of everest has about one third of the mass of gas to ride on as it does at sea level.... if your aerofoil is a fixed wing then you can always travel three times as fast (hence needing a scramjet)

        Assuming the same coffficient of lift, Cl, in order to generate the same amount of lift you would have to have the same "dynamic pressure" (to borrow a Boeing term), then (from Bernoulli equation)

        • 0.5 * densitySL * velocitySL**2 = 0.5 * densityEverest * velocityEverest**2

        If t

    • Indeed, all you would need to do to lift a 5-pound object above the Earth's atmosphere would be to supply an engine which can provide 5.1-pounds of thrust for a VERY long time. Trouble is, when you shut the engine off (or ran out of fuel) you would just fall back to Earth unless you somehow managed to achieve orbital trajectory and velocity. You do the math on how much fuel that would take (a lot - more than you could ever possibly carry). Without escape velocity, the Earth has you - forever! It doesn't

      • Re:Physics Question (Score:4, Interesting)

        by Glock27 ( 446276 ) on Friday March 26, 2004 @11:31AM (#8680462)
        Without escape velocity, the Earth has you - forever! It doesn't matter if you travel as far as the Sun - unless you have escape velocity with respect to the Earth, you're going home. Gaining escape velocity with respect to the Sun is another problem. . .

        Your post was mostly right except for this part. IF (yes that's a big if;) you had sufficient fuel, as you pointed out above, you could fly at 1 MPH to the Moon. And, once you reach the crossover point (where the Moon's gravitational field is stronger than the Earth's), you have escaped in the sense of escape velocity. You won't be going back home.

        Escape velocity is only relevant for ballistic (unpowered) objects.

        Given our current propulsion systems, all of our spacecraft are essentially ballistic except for the new ion powered ones - and those are very low thrust. Practical antimatter propulsion would make things a lot more interesting! :-)

    • The phrase "able to keep moving upwards" is the most important in that sentence. Aircraft are able to fly because they move through air. The higher you go, the less air there is, and the harder it is for a conventional aircraft to remain airborne. At that point you start to need a more traditional wingless rocket booster a la NASA. So far nobody has successfully combined the two technologies but I daresay a lot of people are working on it since it could prove staggeringly useful for cheaply boosting stuff i

  • B-52 Monthership almost as interesting (Score:5, Interesting)

    by Bravo_Two_Zero ( 516479 ) on Friday March 26, 2004 @10:42AM (#8679932)
    Almost as interesting as the X programs is the B-52 mothership that launches them. There was an Air & Space article years ago (no online version at airspacemag.com) about it.

    It's an aging early-model B-52B, evidenced by the non-pointy nose and is 49 years old. There are virtually no spare parts remaining for it, and most of the current inventory (Gs, Hs) don't have any parts commonality.

    Plus, we never sold any of them to other countries, so it's not like there's a stockpile somplace else on the globe. The cost to replace it is prohibitive, given the structural reinforcements needed to carry the craft aloft. Also, the airframe is very young from an hours perspective. In fact, it's the lowest hour B-52 in the inventory.

    The USAF has loaned an H-model to NASA to become the next generation launch platform, but I haven't heard much about it since the 2001 announcement.

    It's a supremely important beast in the research arsenal. And, given our penchant for resurrecting C-64s as web servers and using mame to emulate decades-old cabinet games, it seems like the sort of thing that would interest the average computer geek.

    Like so many things, it's the logistical details of maintaining an archaic aircraft against all odds (and lack of funding) that really become the story rather than the whizz-bang doodad that always gets the front page pictures.

  • What is a scramjet? (Score:5, Informative)

    by Jim Hall ( 2985 ) on Friday March 26, 2004 @10:43AM (#8679934) Homepage

    For those who want to know what a scramjet is, and how it works, check this page [aviation-history.com].

    A ramjet has no moving parts and achieves compression of intake air by the forward speed of the air vehicle. Air entering the intake of a supersonic aircraft is slowed by aerodynamic diffusion created by the inlet and diffuser to velocities comparable to those in a turbojet augmentor. The expansion of hot gases after fuel injection and combustion accelerates the exhaust air to a velocity higher than that at the inlet and creates positive push.

    Scramjet is an acronym for Supersonic Combustion Ramjet. The scramjet differs from the ramjet in that combustion takes place at supersonic air velocities through the engine. It is mechanically simple, but vastly more complex aerodynamically than a jet engine. Hydrogen is normally the fuel used.

    This is all very different from conventional airliner engines, which are a gas turbine/fan nacelle called a "turbofan". (A "turboprop" is a gas turbine driving a propeller instead of a fan, BTW.)

  • A hypothetical assumption. (Score:5, Funny)

    by c.emmertfoster ( 577356 ) on Friday March 26, 2004 @10:45AM (#8679954)
    Let's assume for a moment here that I'm not Buckaroo Banzai and I'm a little bit vague on what the upper limit has been for manned flight (or travel in any medium, salt-plain automobiles or whatever). "Mach seven" really doesn't sound all that impressive. THIS IS 2004! We should be on mach ten-hundred by now.

    For Christ's-sake, in that episode of ST:TNG where Riker had salt-and-peper hair and he didn't play trombone, I clearly heard him say: "WARP THIRTEEN! ENGAGE!" What the hell mach was Tom Cruise going before he entered into coitus with that blonde? What is the top theoretical speed of the current US fighter/and or/stealth aircraft?

    What are the records here, that my tax-dollars are allegedly breaking?

    Don't mod this retarded shit up, this is the uninformed wanting to become informed.
    • What is the top theoretical speed of the current US fighter/and or/stealth aircraft?

      Current fighters top out at somewhat over Mach 2, perhaps Mach 2.5 for the F-15.

      The upcoming F-22's top speed is classified, but it might be as high as Mach 3 (this is purely a guess on my part). It is quite a bit higher performance than the F-15, and can cruise at supersonic speed (somewhere over Mach 1, again classified) without afterburner. It's the first aircraft ever to have this capability, dubbed "supercruise" (no

    • Fastest winged vessel the US has ever produced? 28,000km/h!

      Well, that was the orbiting velocity of the Space Shuttle. That's over Mach 20. It's rather easier to go fast in space - there isn't all that air you have to shove out of the way.

      The fastest combat jet is the MiG-25, which has been radar tracked at 3,395km/h.

    • Well, as other posters have pointed out, it's quite simple to achieve ludicrous speeds in space, and the space shuttle regularly goes WAY faster than mach 7. However, for atmospheric flight the current record is held by the NASA/AF X-15 program in the 60's. In 1967 it hit a top speed of mach 6.7 and had two flights to over 100 km altitude (that's high enough to win the X-prize). The program was a great success, but had two failures, one of which totaled on of the planes and killed its pilot. Humans haven't

    • Re:A hypothetical assumption. (Score:4, Informative)

      by egomaniac ( 105476 ) on Friday March 26, 2004 @12:58PM (#8681471) Homepage
      "Mach seven" really doesn't sound all that impressive.

      The SR-71 Blackbird has an official top speed of around Mach 3.5, and unofficially several pilots have reported taking the plane to substantially higher speeds. The plane's airspeed indicator goes up to Mach 5, if that means anything.

      At Mach 3.5, air resistance raises the plane's temperature to nearly a thousand degrees fahrenheit. Conventional aircraft aluminum would soften and lose its structural integrity at that temperature. For that reason, the SR-71's skin is made out of titanium. Thermal expansion causes the plane to be around six inches bigger while it's flying versus on the ground, which naturally caused nightmares for the plane's designers. The plane has a special cooling system which uses its jet fuel as a coolant liquid, circulated under the skin. After landing, ground crew must wait for a while before they can safely touch it, because the surface is so hot.

      And that's only Mach 3.5. Does Mach 7 still not sound impressive to you?

  • Obligatory Spaceballs comment (Score:5, Funny)

    by MalaclypseTheYounger ( 726934 ) on Friday March 26, 2004 @10:46AM (#8679967) Journal
    "Prepare ship for Ludicrous Speed! Fasten all seatbelts, seal all entrances and exits, close all shops in the mall, cancel the three ring circus, secure all animals in the zoo!"

    What have I DONE!?!?! MY BRAINS ARE GOING INTO MY FEEEET!!!

  • My sister did the logo! (Score:3, Interesting)

    by TheXerox ( 470814 ) on Friday March 26, 2004 @11:18AM (#8680331)
    My sister Caity died of cancer at 11 years old a couple years ago..

    Caity was out in California for proton radiation treatment, Joel (uncle in law / NASA engineer) held a party for his Engineering Section at his house and Caity drew a picture of the X43 plane's logo on the sidewalk in chalk.

    After Caity passed Joel took the picture of her sidewalk drawing and went to Nasa to have the plane named in Caity's honor and have her picture on the side of the plane.

    I hope this one does a lot better than the last time, it has a lot of sentimental value!

  • X-43C is cancelled, unfortunately (Score:3, Informative)

    by Maimun ( 631984 ) on Friday March 26, 2004 @11:19AM (#8680343)
    I already posted this in another discussion here, but probably it is worth mentioning again. The bigger cousin of X-43A, X-43C, is being cancelled [aviationnow.com] because it does not fit in the new space plans.

  • Is it just me... (Score:2, Insightful)

    by Jexx Dragon ( 733193 )
    or are prototype names getting stupider? Really Hyper-X? Sounds like the name for a fighter in a cheap sci-fi. Even Star Trek uses a letter(s) followed by numbers.

    Maybe since Sci-fi authors started using the normal system NASA felt they needed to distence themselves from the logical way of doing things so as to gain/keep credibility?

  • from the once-the-rockets-go-up-who-cares-where-they-come-d own dept.

    "That's not my department," said Wernher von Braun.

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