Beta
×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

How We Might Have Scramjets Sooner than Expected

Zonk posted more than 6 years ago | from the zooom-zippy-fast dept.

Transportation 674

loralai writes "Recent breakthroughs in scramjet engines could mean two-hour flights from New York to Tokyo. This technology, decades in the making, could redefine our understanding of air travel and military encounters. 'To put things in context, the world's fastest jet, the Air Force's SR-71 Blackbird spy plane, set a speed record of Mach 3.3 in 1990 when it flew from Los Angeles to Washington, D.C., in just over an hour. That's about the limit for jet engines; the fastest fighter planes barely crack Mach 1.6. Scramjets, on the other hand, can theoretically fly as fast as Mach 15--nearly 10,000 mph.'"

cancel ×

674 comments

Sorry! There are no comments related to the filter you selected.

SR-71 Blackbird (5, Informative)

wilder_card (774631) | more than 6 years ago | (#21690050)

"set a speed record of Mach 3.3 in 1990 when it flew from Los Angeles to Washington, D.C., in just over an hour."

I feel compelled to point out that's the unclassified speed record. Its actual top speed is still speculative.

Re:SR-71 Blackbird (5, Interesting)

Miltazar (1100457) | more than 6 years ago | (#21690164)

Yes, infact I knew someone who use to fly those things and they weren't allowed to fully throttle up. He also said that during normal missions the plane would damage itself when going the faster speeds. Now of course this is all at someones word, so I have no written proof. Also there would be a slight correction, the SR-71 didn't have "normal" jet engines. SR-71 used ramjet engines, scramjets employ similar but much more advanced technology.

Re:SR-71 Blackbird (5, Informative)

Hamilton Lovecraft (993413) | more than 6 years ago | (#21690224)

Hybrid turbojet-ramjet, according to wikipedia [wikipedia.org] :

The J58 was unique in that it was a hybrid jet engine. It could operate as a regular turbojet at low speeds, but at high speeds it became a ramjet. The engine can be thought of as a turbojet engine inside a ramjet engine. At lower speeds, the turbojet provided most of the compression and most of the energy from fuel combustion. At higher speeds, the turbojet throttled back and just sat in the middle of the engine as air bypassed around it, having been compressed by the shock cones and only burning fuel in the afterburner.

Re:SR-71 Blackbird (5, Interesting)

DaedalusHKX (660194) | more than 6 years ago | (#21690370)

Of course materials will have to advance further, and not just structural components (which might well strip off the plane or warp at speeds too far past a few Mach) but new fuel mixtures will have to be worked out. This was similar to the requirement to add Cesium to current fighter plane fuel along with a few other rare elements to raise its flash point. Experimental planes blowing up because the fuel overheated or certain electronics received more heat than they could tolerate is nothing new, but the production models will obviously have to have gotten past that point when they roll out :)

I wager this technology has been near perfected sometime ago, but as with all things, it was probably kept back to be used in case of sagging sales due to rights abuses at airports (Atlas has Shrugged, and it is visible in that people are avoiding airports now because of the downright abusive behaviors of the TSA and federal shock troops there to protect us from incompetent unshaven twits with box cutters and toothpaste.

Seriously, this will be the carrot on a stick to dissuade people from using other less regulated means of transportation. Obviously L.O.S.T. was ratified recently in Congress to restrict private sea travel... now only warships and those with "permission papers" will be "allowed" to travel, and who knows what else is coming. Free travel is becoming far less so.

Re:SR-71 Blackbird (3, Insightful)

turgid (580780) | more than 6 years ago | (#21690510)

And it was designed 50 years ago.

Re:SR-71 Blackbird (1)

myrdos2 (989497) | more than 6 years ago | (#21690292)

At the speeds they're talking about in the article, Mach 6 and above, would it be feasible to use a scramjet to reach low earth orbit? At a certain elevation the atmosphere would no longer be dense enough to power the scramjet's air intake. But by that time, could it have gained enough velocity to enter a stable orbit?

If so, it seems to me that scramjets would pave the way for cheap, re-useable spacecraft.

Re:SR-71 Blackbird (2, Informative)

Gospodin (547743) | more than 6 years ago | (#21690420)

Well, let's think about that for a second. Mach 6 at high altitude is (roughly) 2,000 mph. Orbital velocity at LEO is around 17,500 mph. It's really hard to get into orbit.

Re:SR-71 Blackbird (2, Informative)

Dr_Banzai (111657) | more than 6 years ago | (#21690430)

You need about 7 km/s to reach orbit, which is above Mach 25. You could have rockets which would kick in at the maximum altitude of the scramjet to give the final push to orbit.

Re:SR-71 Blackbird (1)

flibbajobber (949499) | more than 6 years ago | (#21690462)

Sadly escape velocity is about Mach 25.

Re:SR-71 Blackbird (1)

SatanicPuppy (611928) | more than 6 years ago | (#21690518)

The drag of atmosphere will doom any LEO below ~300km...You'll come right back down. The highest flights (for air-breathing planes) to date were done by the X-15 rocket planes, and they made it to about 100km.

They didn't make it to the theoretical scramjet velocity of Mach 15, but they did break Mach 6. I think it's pretty doubtful that a scramjet could cross that additional 200km where the atmosphere is so thin as to be useless for the engines...Remember the X-15 was powered by a liquid-fuel rocket engine...The scramjet might not even be able to beat its performance.
 

Re:SR-71 Blackbird (3, Interesting)

Fry-kun (619632) | more than 6 years ago | (#21690340)

Agreed.
I've heard stories that imply that the true top speed of SR-71 is somewhere closer to M5 or M8 - as tested "unofficially" by the military sector.
Most likely such speeds are attainable but not sustainable (fuel runs out, plane breaks in mid-air, ..?).
Maybe they used some experimental (or nonstandard) fuel -- then again, it may be a bunch of bullshit.

Re:SR-71 Blackbird (3, Funny)

Hamilton Lovecraft (993413) | more than 6 years ago | (#21690388)

I've heard stories that imply that the true top speed of SR-71 is somewhere closer to M5 or M8

I've heard stories that UFOs are real.

Re:SR-71 Blackbird (1)

Brett Buck (811747) | more than 6 years ago | (#21690484)

That's about the max for the SR-71. In operational use, they were limited to around Mach 2.8. The highest speed recorded for any of the A-12 family was ~mach 3.56, in an A-12.

          Brett

2 hours flight time, 10 hours airport time (5, Funny)

AuMatar (183847) | more than 6 years ago | (#21690056)

Don't worry, between the security line, customs, delays, and waiting on the tarmac, you'll still be garunteed at least 10 hours at the airport for any trip.

Re:2 hours flight time, 10 hours airport time (1)

secPM_MS (1081961) | more than 6 years ago | (#21690288)

I would not expect to see this in the aerospace transport market. Too expensive. The military and space arena is different. The military could use this for some purposes and the higher specific impulse associated with not having to carry your O2 would suggest that this could be used to replace the lower stage of a rocket, reducing the cost of lifting stuff. This would be useful in both civilian and military orbital lifting.

Re:2 hours flight time, 10 hours airport time (3, Insightful)

Breakfast Pants (323698) | more than 6 years ago | (#21690312)

Since drags is non-linear with respect to velocity.. you'll also pay a huge fuel bill (e.g. this is just for the military for the foreseeable future).

Re:2 hours flight time, 10 hours airport time (1)

Pendersempai (625351) | more than 6 years ago | (#21690498)

Except that you can reduce drag by flying higher where the atmosphere is thinner. My understanding was that scramjets didn't work much lower than near-space anyway.

Re:2 hours flight time, 10 hours airport time (1)

Jeff DeMaagd (2015) | more than 6 years ago | (#21690364)

Another issue is that the article doesn't mention the amount of power needed to maintain such a speed. Drag in a fluid (like air) goes up polynomially, I think it's related to the fourth power. A seat on the Concorde was priced at $10,000, and that's despite the airliner getting the plane for free, fuel costs are just enormous.

Re:2 hours flight time, 10 hours airport time (1)

zakezuke (229119) | more than 6 years ago | (#21690396)

Don't worry, between the security line, customs, delays, and waiting on the tarmac, you'll still be garunteed at least 10 hours at the airport for any trip.
Hey 12 hours from NY to Tokyo. 2 hours of flight, 10 hours of latency. That's a 2 hour improvement over current airtime not including customs, delays, waiting on the tarmac.

Scramjets are only a small piece of the puzzle (2, Interesting)

EmbeddedJanitor (597831) | more than 6 years ago | (#21690540)

Designing a commercial airframe that will survive these speeds and be commercially viable (ie. cheap enough to build and maintain) is a far greater challenge. That definitely won't take "a couple of years".

Re:2 hours flight time, 10 hours airport time (1)

mrmeval (662166) | more than 6 years ago | (#21690552)

You're right and there's been bitching about putting down more concrete and doing so in areas away from urban blight creating many smaller airports. But then NIMBY, Sierra Club, Greanpeas and others start howling....

10000mph! (1, Interesting)

Dogers (446369) | more than 6 years ago | (#21690074)

But until we get forcefields to protect against bird strikes at 10000mph, don't expect to see it in passenger jets any time soon.

Re:10000mph! (0)

Anonymous Coward | more than 6 years ago | (#21690140)

There aren't a lot of birds at 40,000 feet.

Re:10000mph! (0)

Anonymous Coward | more than 6 years ago | (#21690178)

To say nothing of 140,000 feet.

Re:10000mph! (5, Insightful)

cplusplus (782679) | more than 6 years ago | (#21690170)

Birds aren't usually a problem @ 100,000 feet ;-)

Re:10000mph! (4, Funny)

Kenshin (43036) | more than 6 years ago | (#21690404)

Maybe where YOU come from.

Re:10000mph! (2, Informative)

Deadstick (535032) | more than 6 years ago | (#21690222)

Scramjets have the potential to do their high-speed cruise at 100,000 feet. Until we get birds that can go that high, don't be too worried.

rj

Re:10000mph! (0)

GregPK (991973) | more than 6 years ago | (#21690232)

Oh, it'll be a passenger jet soon enough. You just have to pass through the retina scan, hand scan, voice scan, background check. That's before they do the strip search at the airport. Then, when you are on the plane they use something equivalent to the strap downs that you see at a theme park roller coaster ride to hold you in your seat. Bathroom: a stewardess with a bowl will be happy to help you. Your laptop must be connected to the airplane dock where they can monitor all keystrokes. If at any time they feel you enter the wrong sequence of keystrokes the seat has a built-in high voltage stun gun that puts you out till the end of the flight. Say bad about anyone in the Bush family(Stun) Say bad about the US lovermint(Stun) Talk about the constitution(Stun). oh the number of scenarios they will be happy to stun you with.

Re:10000mph! (2, Informative)

Cecil (37810) | more than 6 years ago | (#21690358)

You pretty much need forcefields to protect you from air particles at that speed. The SR-71 expanded so much during flight due to frictional heating that even the fuel tanks needed to be built with expansion joints (so the fuel would leak out until it reached operating temperature at altitude). The fuselage would be about 300 degrees Celsius by the time it landed. Getting out of the plane was apparently a bit of a challenge.

Re:10000mph! (1)

TheDukePatio (621176) | more than 6 years ago | (#21690482)

Great, now we're going to need a scramjet powered canon to launch the frozen birds @ 10k mph just to test the windshields. We've almost gotten back to the chicken and egg problem.

"Well folks, the scramjet works perfectly. The only problem is that we don't have a windshield strong enough to install on the aircraft, hence, we're going to have to scrap the whole project."

We'll have scramjets in a couple years (4, Funny)

SpeedyGonz (771424) | more than 6 years ago | (#21690086)

. . . and fusion power in 10 . . .

That's nothing! (1)

spun (1352) | more than 6 years ago | (#21690492)

The entertainment systems in the back seat of our flying cars will run Linux on the desktop and play Duke Nukem Forever, next year!

Re:We'll have scramjets in a couple years (1)

cyfer2000 (548592) | more than 6 years ago | (#21690548)

Don't lemme start the Duke Nukem For...

can we harness this technology (1, Funny)

circletimessquare (444983) | more than 6 years ago | (#21690090)

for the intertubes, and move the information superhighway faster down the series of tubes, perhaps an advanced vacuum tube technology?

senators from alaska want to know

We could, but should we? (1)

CellBlock (856082) | more than 6 years ago | (#21690094)

Would flying at that velocity be at all safe or comfortable? I mean, getting halfway around the world in an hour would be a great convenience, but not if you break your neck in the process.

Re:We could, but should we? (1)

yincrash (854885) | more than 6 years ago | (#21690134)

It's not the velocity that would hurt us, it's the acceleration.

Re:We could, but should we? (1)

WaKall (461142) | more than 6 years ago | (#21690174)

Velocity != Acceleration

Considering that current planes exert not very much acceleration, and have long periods of flight at constant speed, surely there is some time to be trimmed with only slightly higher acceleration but much higher top speeds?

Re:We could, but should we? (1)

$random_var (919061) | more than 6 years ago | (#21690512)

surely there is some time to be trimmed with only slightly higher acceleration but much higher top speeds
Yes - but with high fuel costs: [from wikipedia]

Assuming a constant drag coefficient, drag will vary as the square of velocity. Thus, the resultant power needed to overcome this drag will vary as the cube of velocity.

I think that we can get a much better bang for our buck improving airport logistics than airplane topspeed. Waiting two hours in lines only to have your flight be an hour late or get canceled is a much bigger time sink than practical topspeeds of conventional jet technology.

Re:We could, but should we? (1)

Sciros (986030) | more than 6 years ago | (#21690194)

I imagine that like maglev trains in Shanghai, the planes would spend the entire trip speeding up and then slowing down, probably never reaching their "max" speed.

Re:We could, but should we? (1)

SeekerDarksteel (896422) | more than 6 years ago | (#21690200)

Why would the velocity matter at all? It's the acceleration that is uncomfortable, but at the acceleration planes normally undergo 10,000 mph is easily reachable in a few minutes of constant acceleration.

Just too late (1, Offtopic)

Colin Smith (2679) | more than 6 years ago | (#21690102)

As we trip over the peak of oil production...

 

Re:Just too late (0)

Anonymous Coward | more than 6 years ago | (#21690456)

IIRC, scramjets operate at a temperature too high for conventional fuels and instead use hydrogen. So the only part of the flight that could require conventional fuels would be while accelerating to the speed required to start using the scramjet engine.

Now producing the hydrogen in the first place...

yeah and.... (0)

Anonymous Coward | more than 6 years ago | (#21690108)

so is fusion. pie in teh sky projects that have been promising for decades. like moller skycars.. actual delivery ? nah.

2 seconds of research reveals... (5, Interesting)

Anonymous Coward | more than 6 years ago | (#21690122)

F-16 top speed at altitude: Mach 2+
F-22 top speed at altitude: Mach 2.42 (officially...it's reported it can exceed Mach 4)
F-18 top speed at altitude: Mach 1.8+

I actually couldn't find a modern jet fighter that COULDN'T exceed 1.6 (at least within my aforementioned 2 seconds of research)

Of course, that doesn't diminish the insanity of Mach-15, but still.

Oh yeah, if you turn, your heart will forcibly exit your body via your anus before exploding. Have fun.

Re:2 seconds of research reveals... (1)

tcolberg (998885) | more than 6 years ago | (#21690270)

Are those with or without afterburners? They tend to use up all available fuel in short amount of time. And the extra thrust happens outside the jet engine.

Re:2 seconds of research reveals... (1)

spaceyhackerlady (462530) | more than 6 years ago | (#21690536)

The Concorde could also cruise supersonic, though it needed afterburners to accelerate to supersonic speed. What I have read in the past is that turbojets run out of breath at about Mach 3. But those words were written a while ago, and there may be developments that cannot yet be published.

Secrecy issues aside (e.g. SR-71 top speed, U-2 ceiling, etc.), is there a need for a fighter to go much faster than about Mach 2? If there was, fighters would indeed be designed to go faster. If radar can't see them (low, stealthy), and humans can't hear them coming (supersonic, though Mach 1.1 would do), how much faster do they need to be?

...laura

Re:2 seconds of research reveals... (1)

tlhIngan (30335) | more than 6 years ago | (#21690294)

F-16 top speed at altitude: Mach 2+
F-22 top speed at altitude: Mach 2.42 (officially...it's reported it can exceed Mach 4)
F-18 top speed at altitude: Mach 1.8+

I actually couldn't find a modern jet fighter that COULDN'T exceed 1.6 (at least within my aforementioned 2 seconds of research)


Don't forget the aging F-15, which can do apparently Mach 2.5. Of course, the F-22 has the advantage that it can cruise at supersonic speeds without engaging afterburners (supercruise) like the others you mention do (and the F-15 is a gas guzzler supersonic).

But yeah, Mach 1.6 is low. Maybe in the '50s?

(ObTF - Of course, if your jets happen to actually use Energon, who knows how fast they can really go...)

Re:2 seconds of research reveals... (0)

Anonymous Coward | more than 6 years ago | (#21690326)

Add the Russians; the MIG-25 is either 2.5 or 3.2, depending on who's publishing. The mig-29 which doesn't need that speed has a published top speed of Mach 2.4

Re:2 seconds of research reveals... (1)

snl2587 (1177409) | more than 6 years ago | (#21690464)

Oh yeah, if you turn, your heart will forcibly exit your body via your anus before exploding. Have fun.

If you were to try to turn at those speeds, I think the force on the wings would tear the plane apart. Your heart popping out of your anus would be the least of your worries and may even be a little better than burning alive while falling 100,000 feet.

we're the bottleneck (1)

Romancer (19668) | more than 6 years ago | (#21690138)

I don't think we can handle the instant jump to mach 15

Wrong, wrong, wrong (0)

Sciros (986030) | more than 6 years ago | (#21690144)

1) Mach 3.3 speed record by SR-71 -> official speed record. NASA's X-15 set an unofficial one of Mach 6.7.

2) So.. 3.3 is NOWHERE NEAR the limit for jet engines.

3) Fighter jets don't "barely crack" Mach 1.6. The F-22 in cruise mode goes something like 1.7, is max speed generally known as being well above Mach 2, the actual maximum being, naturally, secret.

Fact-checking is your friend, people.

Re:Wrong, wrong, wrong (4, Informative)

jdhutchins (559010) | more than 6 years ago | (#21690256)

1) Mach 3.3 speed record by SR-71 -> official speed record. NASA's X-15 set an unofficial one of Mach 6.7.
2) So.. 3.3 is NOWHERE NEAR the limit for jet engines.

Neither the SR-71 or the X-15 have conventional jet engines- the X-15 had a rocket and the SR-71 has ramjets

Re:Wrong, wrong, wrong (5, Funny)

Sciros (986030) | more than 6 years ago | (#21690398)

Well, I said fact-checking was *your* friend. Not mine. :P

Re:Wrong, wrong, wrong (1)

Hamilton Lovecraft (993413) | more than 6 years ago | (#21690258)

X-15 is a rocket, not a jet. SR-71's official mach 3.3 probably isn't dramatically less than its actual top speed.

Not so wrong (1)

tomthegeek (1145233) | more than 6 years ago | (#21690260)

They were talking about jet aircraft. From Wikipedia [wikipedia.org] :

Powerplant: 1× Thiokol XLR99-RM-2 liquid-fuel rocket engine, 70,400 lbf at 30 km (313 kN)

What was that about research?

Re:Wrong, wrong, wrong (1)

TheOrquithVagrant (582340) | more than 6 years ago | (#21690266)

The X-15 was not a jet plane, it was a _rocket_ plane.

Re:Wrong, wrong, wrong (1)

hondo77 (324058) | more than 6 years ago | (#21690280)

NASA's X-15 set an unofficial one of Mach 6.7.

Are we talking about the rocket-powered X-15 [wikipedia.org] ?

Re:Wrong, wrong, wrong (0)

Anonymous Coward | more than 6 years ago | (#21690282)

Speaking of fact checking, three seconds of it would have told you that the X-15 was rocket powered, and so its speed records do not affect the records set by airbreathing aircraft, which are considered in a separate category. It also did not take off under its own power, further changing the speed record category.

More wrong! (0)

Anonymous Coward | more than 6 years ago | (#21690284)

The X-15 had a rocket engine, not a jet.

Fact checking is your friend.

X-15 was ROCKET-powered (0)

Anonymous Coward | more than 6 years ago | (#21690302)

Since X-15 was a rocket-powered and not jet-powered, your second point isn't valid. (Note, it may well be true that jet engines can go faster than Mach 3.3; that's not for me to say. I'm just saying that the X-15 doesn't prove this.)

You also didn't mention the XB-70 Valkyrie bomber prototype, which reached Mach 3 during test flights.

Re:X-15 was ROCKET-powered (1)

LabRat (8054) | more than 6 years ago | (#21690444)

And the MiG 25 would be another example :)

Re:Wrong, wrong, wrong (1)

PlatinumCursor (611961) | more than 6 years ago | (#21690324)

1) The X-15 was not a jet engine, it was powered by a Ammonia/LOX rocket engine.

2) And while mach 3.3 was set by the SR-71, its worth noting that it was not a pure jet engine, but at high speeds utilized a bypass to effectively become about 80% ramjet.

Really? Really? Really? (1)

TransEurope (889206) | more than 6 years ago | (#21690354)

Sorry, but how many F22's are flying around these days? I think the few dozen machines are less then 1% of the world's fighter jets. So, the average fighter jet is a design from the 1960s, 1970s and early 1980s. No supercruisy F22.

Re:Really? Really? Really? (1)

Sciros (986030) | more than 6 years ago | (#21690474)

Right but by that logic we should say that the max speed of an internal-combustion-powered automobile is like 140 mph or something since there's "way too few" Lambos and other exotics around. This article isn't from the 1980s is it?

Re:Wrong, wrong, wrong (2, Informative)

LabRat (8054) | more than 6 years ago | (#21690366)

I'll agree for the most part..though I'll respectfully point out that the X-15 was rocket powered, not jet-powered ;)

Everything else is spot-on for the most part...even the venerable F-15 has a "public" top-speed of Mach 2.5 :) Although getting upwards of Mach 4 is a practical limit for turbojets due to the drag issues of slowing down the stream to subsonic via a "tuned" shockwave ala the SR-71 "cones". That's where SCRAMjets come in...they can sustain combustion with a supersonic stream flowing through the engine from inlet to outlet, thus they don't have the same "upper" limit.

Re:Wrong, wrong, wrong (1, Informative)

Anonymous Coward | more than 6 years ago | (#21690374)

Fact-checking is YOUR friend, too, buddy. The X-15 [wikipedia.org] was rocket powered, not jet powered.

Re:Wrong, wrong, wrong (0)

Anonymous Coward | more than 6 years ago | (#21690414)

The X-15 engine was an XLR-99 single chamber rocket

Re:Wrong, wrong, wrong (1)

barakn (641218) | more than 6 years ago | (#21690486)

NASA's X-15 set an unofficial one of Mach 6.7.... Fact-checking is your friend, people
Yeah, maybe if you had actually tried fact checking you'd have found that the X-15 was rocket-powered, so no jet engine.

Re:Wrong, wrong, wrong (1)

Brett Buck (811747) | more than 6 years ago | (#21690526)

The X-15 did not have a jet engine.

Sooner than expected? (4, Funny)

Chris Burke (6130) | more than 6 years ago | (#21690150)

Nobody expects the scramjet engine!

Re:Sooner than expected? (1)

davester666 (731373) | more than 6 years ago | (#21690522)

Until now. Now I expect one next week.

Re:Sooner than expected? (1)

spun (1352) | more than 6 years ago | (#21690532)

Nobody expects the scramjet engine!
We will definitely need the comfy chair, though.

Just need some Unobtainium (2, Insightful)

Stele (9443) | more than 6 years ago | (#21690154)

Now we just need some Unobtainium for the wings+fuselage so it doesn't fly apart when it hits 5000 mph.

Sure, the Space Shuttle is doing 16K mph on reentry, but no scramjet is going to get a plane built like that off the ground.

Re:Just need some Unobtainium (1)

Hawkeye05 (1056362) | more than 6 years ago | (#21690448)

Modded up for the "The Core" reference, one of the worst movies in recent memory. Kudos.

Skyborne Catamaran (2)

TheLazySci-FiAuthor (1089561) | more than 6 years ago | (#21690156)

While I am a huge fan of aerospace tech in general, I cannot help but feel that the technology has begun to flat line. I feel as though we are ship-builders, and that we are excited about the newest interceptor-class sea vessel.

While this new technology is remarkable, it still lays within the same paradigm as it has for over one hundred years: air goes in, air goes out (be it prop, turbine or scramjet), wings generate lift, shape minimizes drag.

I don't know of any other way to do it, so I don't mean to demean these mind-blowing advances. I only mean to make a point that while our speed is increasing, the paradigm will hit a wall.

Are we not seeing smaller advances as the decades roll-on?

I wonder, what other transportation paradigm could allow us the kind of advances that air had as compared to sea?

Re:Skyborne Catamaran (1)

interiot (50685) | more than 6 years ago | (#21690500)

We've been doing the water thing for at least 45,000 years [wikipedia.org] , aviation for perhaps 250 years, spaceflight for ~60 years. Next would be... Interstellar travel? Spelunking about the mantle?

Sonic Boom - Bust (3, Insightful)

tcolberg (998885) | more than 6 years ago | (#21690158)

The Concorde didn't have many routes because there was a NiMBY problem. Nobody wanted the plane flying out of their airports because of the sonic booms. Opposition to airport expansion is already bad as it is. I can't imagine how hard it will be to convince people to allow these scramjets on commercial flights, even if they were limited to trans-oceanic flights.

Re:Sonic Boom - Bust (1)

eggfoolr (999317) | more than 6 years ago | (#21690304)

Put the airports 15 hours drive away from civilisation. Problem solved!

Re:Sonic Boom - Bust (1)

Hawkeye05 (1056362) | more than 6 years ago | (#21690530)

There are ways to eliminate the sonic boom, or GREATLY reduce it, i cant find a site but it was in Popular Mechanics a few years back, just rounding the bottom of the plane seems to greatly help it.

Re:Sonic Boom - Bust (0)

Anonymous Coward | more than 6 years ago | (#21690534)

if they were limited to trans-oceanic flights.
Ah! You see! You're not thinking of the ocean life!

We need to contact Greenpeace asap! Progress must be stopped!

Amazingly . . . (4, Funny)

StefanJ (88986) | more than 6 years ago | (#21690168)

The incredible cost of fuel required to slam one of these puppies through the atmosphere is more than compensated for by the savings to the airline due to not having to serve more than one round of beverages.

F-22 Raptor is almost certainly faster than that (1)

tomthegeek (1145233) | more than 6 years ago | (#21690204)

"the fastest fighter planes barely crack Mach 1.6"

Or so they tell us. I'm pretty sure that the actual, classified, top speed of the F-22 is above Mach 2.

Vote for Hillary (0, Offtopic)

Anonymous Coward | more than 6 years ago | (#21690226)

And the chinese will be given the technology too!

summary a bit misleading (1)

weighn (578357) | more than 6 years ago | (#21690236)

There hasn't been a eureka moment, the "recent breakthroughs" have come over the past few years.:
The HyShot [wikipedia.org] project demonstrated scramjet combustion in July 30, 2002 and had further tests in March [bbc.co.uk] ;
A DSTO/USAF program had successful tests this past June [slashdot.org] . Search /. [slashdot.org] for some other mentions.

If you were a bird (0)

Anonymous Coward | more than 6 years ago | (#21690242)

If you were a bird, would you rather be hit by a jet going Mach 3.3 or Mach 15? I'm personally guessing that it wouldn't matter.

Mach 1.6 is speed without afterburners (0)

Anonymous Coward | more than 6 years ago | (#21690290)

The F-15 can reach at least Mach 2.5 and it's emphisis is on manuverability. The MiG based of the F-15 with larger engines can reach Mach 3, but it's more of a dedicated intercepter than actual 'fighter."

Re:Mach 1.6 is speed without afterburners (2, Informative)

vought (160908) | more than 6 years ago | (#21690468)

The MiG based of the F-15 with larger engines can reach Mach 3

What are you talking about? There's a MiG based on the F-15?

If you're talking about the MiG-25 Foxbat, it was flying well ahead of the F-15 (which itself was a response to the development of the MiG-25), and was designed to intercept bombers like the XB-70, which were never made operational.

10K MPH? (1, Funny)

ROU Nuisance Value (253171) | more than 6 years ago | (#21690328)

"Scramjets, on the other hand, can theoretically fly as fast as Mach 15--nearly 10,000 mph"

Not in an atmosphere, they don't. Unless you think flying droplets of metal and scorched fragments of composites still counts as a "scramjet".

Really? (1)

TubeSteak (669689) | more than 6 years ago | (#21690338)

'To put things in context, the world's fastest jet, the Air Force's SR-71 Blackbird spy plane, set a speed record of Mach 3.3 in 1990 when it flew from Los Angeles to Washington, D.C., in just over an hour. That's about the limit for jet engines
That's the 'official' top speed of the Blackbird.

The CIA had their hands on the A-12, YF-12 and SR-71 since the early to mid 1960s. It is widely assumed that the CIA took those planes higher and faster than the official records indicate.

Cost? (2, Interesting)

Hacksaw (3678) | more than 6 years ago | (#21690342)

Sure, that's cool and stuff, and I'm sure we'll eventually overcome the other technological problems, but the energy is a gigantic factor in this. How much would the fuel cost jump to have a two hour flight from NYC to Tokyo? Would it be worth it? Remember that ten times faster might mean 1000 times more costly!

hitting a duck (2, Funny)

bl8n8r (649187) | more than 6 years ago | (#21690344)

I wonder what hitting a duck at 10,000 mph would be like.

Re:hitting a duck (1, Funny)

Anonymous Coward | more than 6 years ago | (#21690470)

Quack.

Re:hitting a duck (1)

eagl (86459) | more than 6 years ago | (#21690508)

I wonder what a duck would be doing up at 80,000 ft where we'd find a plane travelling at 10,000 mph.

Changing the scope of local again (2, Interesting)

Baddas (243852) | more than 6 years ago | (#21690382)

Horses and humans can run 20 miles a day...

Trains changed it to 400-600 miles a day...

Cars made it routine to drive 100 miles a day...

Planes made it routine to fly 3000 miles for a vacation...

I really can't wait until it's routine to nip out to Luna for a weekend.

2 hours, eh? (2, Interesting)

pizzach (1011925) | more than 6 years ago | (#21690394)

Does that 2 hour flight time from New York to Japan include the time to accelerate and slow down from the 10,000 miles an hour speed? Somehow I am skeptical. Speaking of which, I wonder what the ideal acceleration speed is for plane so that it gets to max speed relatively quickly without endangering the health of it's passengers.

Pffft!! (1)

fatmal (920123) | more than 6 years ago | (#21690408)

New York to Tokyo in 2 hours? With all the airport security delays I'll just wait for my flying car and drive there!

Fast fighters barely crack Mach 1.6? Since when? (4, Informative)

DragonWriter (970822) | more than 6 years ago | (#21690416)

the fastest fighter planes barely crack Mach 1.6.


Huh?

MiG 29 [fas.org] - Mach 2.3
F-14 [fas.org] - Mach 2.5+
Kfir [fas.org] - Mach 2.3
JAS 39 Gripen [fas.org] - Mach 2.0

Current speeds grossly incorrect (5, Insightful)

eagl (86459) | more than 6 years ago | (#21690458)

The original poster is grossly incorrect regarding the max speeds of current fighters. The venerable F-15 has a very achievable basic airframe limit of mach 2.5. It is rarely flown at that speeds for various reasons, however the engines and basic aircraft are quite capable of reaching that speed. One of the biggest limiting factors, as with all high speed aircraft, is heat buildup. Stuff simply starts melting when you get going that fast and sustain it.

Keep in mind that the mach 1.6 speed quoted is generally tied to the F-16, not the F-15, even though both aircraft use essentially the same engines. The difference is that the F-15 uses a complex variable geometry inlet design while the F-16 uses a fixed inlet. There are very good reasons why each aircraft uses one design or the other, but it has nothing to do with the available technology. It has to do mostly with how much cost we are willing to put up with in order to get the plane to perform up to requirements. The F-15, as our primary air superiority fighter, needed to be able to go very fast yet retain good performance at all speeds and altitudes. So the cost and weight penalty of a complex inlet design was warranted. The F-16 on the other hand, was designed from the start to be a lower cost multi-role fighter, and the cost and weight associated with a variable inlet was not justified by the performance requirements for that aircraft's role.

A similar tradeoff was made with the B-1 design. One of the big differences between the original B-1A design and the production B-1B design was the elimination of the costly and complex engine inlets that were needed to make the B-1 a high supersonic design. The B-1B has much simpler inlets and is therefore speed restricted below the original design specs.

Again, this has nothing to do with the available technology. Rather, it's the result of the basic truism that any speed freak knows, even in automotive racing, that going faster costs more. Almost any design can be pushed to a higher speed, but it's going to cost you and at some point you're throwing a whole lot of money to get marginal speed increases.

The original post's point that we haven't seen a breakthrough in this area in a long time is valid, but anyone following hypersonic technology research knows that in the last few years there have been multiple programs flying actual demonstration hardware with some success. The progress is fairly slow in part because this is considered low priority research since there simply isn't much firm demand for faster air-breathing vehicles (expecially ones that burn petrochemicals and therefore create more pollution than slower, more mature, and more efficient designs) however the research continues in the face of the harsh fact that speed is expensive.

one problem... (1)

Jarik C-Bol (894741) | more than 6 years ago | (#21690528)

that I see, is that at these speeds, you're on the verge of your passengers needing to pass a nasa physical to be able to take the flight without suffering a heart attack or some other problem. its one thing to go fast, its another to be able to go fast comfortably. your average 50+ CEO (the sort of person who can afford a flight like that) most likely will not be able to handle the stress of the flight.
Load More Comments
Slashdot Login

Need an Account?

Forgot your password?