Scramjet Success in Australia

glengyron writes "Australia's ABC reports today that a University of Queensland team have successfully tested a supersonic scramjet (air-breathing supersonic combustion ramjet engine). Read more here or here. Great to see after previous problems. Does the future of air travel still include those breakfast egg-roll things?"

Comments

A little more info

[Bastian]

A diagram of the difference in design between a ramjet and a scramjet engine can be found here.

For more information, check out the HyShot homepage.

Re:A little more info

[ender81b]

A little more info from Encylopedia Astronautica. A scramjet is vastly more efficent than standard chemical rockets because only half the fuel has to be carried (hydrogen). Also scramjets have a greater ISP than most regular chemical engines and have no moving parts, unlike the hundreds of parts on moden rocket engines.

Taken from here

air/LH2 (scramjet) ISP=1,550

Space Shuttle Main Engines

ISP = 453

Obviously scramjets are vastly more efficent. Of course ION engines have ISP values of roughly 5,000-6,000 and fusion another magnitude greater, etc. Still lots of room for improvement.

Re:A little more info

[tony_gardner]

Unfortunately, the diagram is not totally correct. It's possible to have scramjets with duct convergences, and ramjets without duct convergences. The difference lies in the fact that in a ramjet the air becomes subsonic, and in a scramjet the air does not become subsonic.
Making the air subsonic provides a great deal of control over the combustion process, thus the problem with scramjets.

Re:A little more info

[JimPooley]

Obviously scramjets are vastly more efficent.
In an atmosphere, yes. Once you get outside the atmosphere, they're useless.

Re:A little more info

[Yazeran]

Of course, we could build a fusion pulse rocket right now. Just get a huge bowl, with shock absorbers and a spaceship above it, and explode a few hydrogen bombs underneath.

Actually, this is an old concept known as Daedalus and was invented by the British Interplanetary Society.

Yours Yazeran

Plan: To go to mars one day with a hammer.

Re:A little more info

[WolfWithoutAClause]

Also scramjets have a greater ISP than most regular chemical engines and have no moving parts, unlike the hundreds of parts on moden rocket engines.

In its simplest form rocket engine has no moving parts either (ok, there's usually a few valves, but scramjet would need them also.)

The Space Shuttle Main Engines have complicated turbopumps, but I wouldn't exactly hold that up as a shining example of rocket engineering; but the SRBs don't have any moving parts.

ISP is not everything- it's recently been realised that fuels that have lower ISP can give more payload to orbit than hydrogen/LOX. Reaching orbit is much more subtle than you would expect. Scramjets actually look like a bad idea for reaching orbit; they're too heavy- but may be good for a first stage, where the weight doesn't matter nearly so much.

Re:A little more info

[Dyolf Knip]

As an analogy imagine this: Currently your car uses one engine to do 0-60mph. Use of scramjets is like somebody offering to add a 700lb, $3000 solar powered motor to your car so that from 10-30mph you can use solar power instead of gasoline.

What you neglect to mention is that your existing engine (i.e., the rocket) is 2000 lbs, costs $10000 to buy, must be taken into the shop every week for another $5000 worth of repairs, and is so fuel inefficient that 99% of your car is gas tank.

Rockets are working technology & the most efficient power source known to man

Rockets are barely working technology. I find it ironic that the failure of both NASA's and Australia's previous scramjet tests were due to the rocket booster screwing up. They are insanely complicated and expensive beyond all reason. And they do not even come close to being the most efficient. As was pointed out, in the atmosphere Scramjets are 3 times more efficient. Outside the atmosphere, ion drives and even a simple pulsedrive are orders of magnitude more efficient. Rockets' only saving grace is that they can be used in both.

And where'd you get the idea that scramjets peter out at mach 10? There's nothing in the theory that keeps them from going as fast as you want. Your biggest problem is that heat from air friction melts your plane at these speeds.

Re:A little more info

[kzinti]

Of course, we could build a fusion pulse rocket right now. Just get a huge bowl, with shock absorbers and a spaceship above it, and explode a few hydrogen bombs underneath.

Actually, this is an old concept known as Daedalus and was invented by the British Interplanetary Society...

Readers of Niven/Pournelle's Footfall will recognize this as Orion, which was used as part (first stage?) of the Daedalus project's craft.

--Jim

Re:A little more info

[Dyolf Knip]

Good rocket engines weigh about 1/15 as much as jet engines with similar sea-level thrust & scramjets weigh even more than jets.

Regarding jet engines: got a link? Regarding scramjets: so you mean this technology they've spent billions of dollars on is further along than the one that got virtually no funding at all? What a surprise.

Terrier-Orion sounding rockets (from surplus military stocks) can be obtained on a university budget

Can you get to orbit in them?

The dev costs on scramjets are easily in the billions

And, what, orbital rockets were developed in someone's backyard on a shoestring budget? They spent billions on them, too.

Finally, who cares how much is tanking. Fuel costs are negligable compared to the rest.

What we're interested in here is mass. To get to orbit, a rocket has to take thousands of tons of oxidizer along with it. A scramjet could leave most of it behind.

(hint: they weren't. Scramjets will be subject to the same guidance problems).

What, you mean the guidance problem of having all your thrust at the very bottom of the vehicle, which is basically a requirement for rockets?

As was pointed out != as has been proven. Please point me to your real-world proofs or stop presenting "I hope" as "It has been proven".

Oh, I do apologize. Shuttle engines specific impulse in a vacuum of 452. And let's see, here's an experimental air-breathing jet engine with a specific impulse in the atmosphere of around 2000. Or this one, from NASA themselves. In particular note the specific impulse of ion engines at 20000 which, if I'm not mistaken is higher than 400. Also it specifically states, "The chemical rocket engine is a fairly lightweight device. However, the specific impulse is not high. Solid and liquid propellants in present use deliver an impulse of around 250 seconds. The best liquid propellants so far conceived and evaluated yield an impulse of about 350 seconds." And of, course, there's this one, also at NASA, stating that Scramjets' specific impulse varies over the Mach range from 1000 to 1500. Want more?

Before stating that scramjets can accelerate to mach25 in the atmosphere you are going to have to solve the materiels problem

Gee, I seem to recall saying that very same thing. How kind of you to tell me what I already knew and act like you are all-knowing in the process.

scramjets by definition cannot [throttle back]

Eh? They have to accelerate constantly the whole time? Can't slow down, can't cruise, can't do anything except go faster? Do explain to me where you learned this.

Until then, kindly refrain from proposing theoretical yet unachievable limits.

You're the one proposing limits pal, not me.

Re:A little more info

[Dyolf Knip]

The 15/1 weight difference between rockets & jets is a direct cite from a post by henry spencer in sci.space.tech. You want a specific cite, ask henry

Excuse me? You ask me for proof and I cite four references. I ask you for proof and you tell me, "Go see Bob. Bob knows all."?

Scramjets cannot replace rockets

And you know this how? Oh, right, Henry told you.

Nice links. None of them give proof of a real-world scramjet showing positive thrust, though. You tried to point out that scramjets are 3X more efficient than rockets.

You are unbelievable. So because the second working prototype doesn't outperform the technology that has had billions dumped into it already, you say, "Throw it away"?

Furthermore, there has been a scramjet test that produced net acceleration. Exhibit A. Not much, but it worked.

[Scramjets can't not accelerate]

Drag does decrease the higher you go. I realize that with anything air-breathing, that also limits your thrust, but it does allow for higher speeds. And I'm not suggesting they try to reach orbital velocity in the atmosphere. I'm well aware that it's stupid to try with air around anyway. Rocket assists can be used for the last bit.

scramjets have materiel limits imposed on them that rockets do not

I think fuel qualifies as a material. Rockets have fuel efficiency limits imposed on them that scramjets do not, at least not to the low level of rockets.

Do you contend that systems failures will dissapear because scramjets are used?

Rockets just don't scale well. Sure, for fireworks (or adding the last 1 or 2 kps to a launch vehicle) they're fine. But if you want to rocket any significant payload, especially to orbit, the mass of the fuel has to exceed the mass of the payload by orders of magnitude. You're right, cost of fuel isn't a problem, but mass and space is. To make a rocket vehicle capable carrying enough fuel to get to orbit and the fuel needed to get this huge mass of fuel up(true for even scramjets, but less fuel and oxidizer), it's gotta be absolutely huge. And insanely complex. And expensive. Chemical rockets are about as fuel efficient as they will ever get. Find the cheapest per-kilo rocket-based booster we've ever built and that's about it. A scramjet, needing less fuel, doesn't have to be built to even close to the same scale and can end up being simpler. Simpler systems usually mean less systems failures. Also, rockets are fairly unique regarding guidance in that your thrust is taking place entirely at the bottom of the vehicle. This is not just a 'systems failure'. This is a fundamental, inescapable problem of rockets that makes guidance very difficult, and therefore more failure-prone than something that is air-breathing and thrusts from closer to the center of mass.

Scramjets can be better than rockets. That we don't have a working orbit-capable one yet is irrelevant. We know this because aerospace engineers are bright guys and have done the math.

You propose spending billions to "solve" reliability problems in rockets by using scramjets made out of unobtainium.

Never said anything of the sort. I said that rockets were nowhere near as efficient as scramjets and that rockets suck for getting to orbit. I've provided links for the former and today's $10k/kilo pricetag on launches demonstrates the latter. Will scramjets be cheaper? If we can get them to work, the theory says they will be. No way to know for sure without trying.

I'd prefer spending the money on something with a reasonable chance of being useful and feasible

I'm all for it. But the guys with money have spent 50 years putting everything into rockets. That they are even considering something else is an achievement. Laser boosters, beanstalks, whatever. Never said that scramjets were the best, simply that, if they can be made to get to orbit, they'll likely do so more cheaply than any straight-up rocket launcher. I have explained why rockets are so pitiful. I realize the materials problem for scramjets is really, really difficult. But hey, so were the problems with rockets.

Lastly, NASA is the one that spends billions of dollars on programs. Hyshot put this thing together for 1 million. Not exactly chump change, but NASA's test was many times more than that and they have yet to try again.

Successfully tested???

[Ratface]

How come the site says this then?
"Dr Paull said although the signs so far have been positive, it is still too early to say the scramjet experiment has succeeded. The scramjet experiment took place within only the last few seconds of the flight, lasting almost 10 minutes."

(OK - I'm hair splitting, it looks positive, but jumping the gun like this doesn't help anyone if it turns out that everything was just a fluke ;-)

Re:Successfully tested???

[squaretorus]

But hey! Who wants to read THIS story?:

"Scramjet tests looked positive in Australia"

Hey! Wait a minute! That IS the story we're reading. Call a shit Lola and its still a shit!

Re:Successfully tested???

[tony_gardner]

Mainly because last time, the rocket veered off course and crashed into the ground before the test could be conducted. This time, the rocked stayed on path, they received telemetry from the package, and nothing spectacular went wrong. It is still very possible for something non-spectacular to go wrong, and clearly they're avoiding talking before thinking (an increasingly rare occurrence).

Better information at :

[EvilBastard]

Little bit less of a press release, little bit more information including a better explanation of the flight profile at

http://www.mech.uq.edu.au/hyper/hyshot/

confused as usual (big surprise)

[Em Emalb]

OK first off, the abc.au news piece was an abomination of English:
"In South Australia's outback history has been made with a team from the University of Queensland successfully flight testing their supersonic air-breathing scramjet engine atop a rocket.

How about:
A University of Queensland team made history today when they launched their super-sonic airbreathing scramjet engine atop a rocket. The test was conducted in the outback and was the first successful one of it's kind.

Yech, even that one sucks, easier to read though.

Anyhow, on to the point. Later in the article, it said data was recorded from the descent. Is that descent back to earth or what? Was it controlled or did it just crash land? The other page has almost as little information too, unfortunately.

Re:confused as usual (big surprise)

[marcsiry]

Later in the article, it said data was recorded from the descent. Is that descent back to earth or what? Was it controlled or did it just crash land?

The descending flight plan was intentional; the speed needed to ignite the motor is quite high, and a gravity assist helped to attain it. The scramjet fired during the last portion of a parabolic flight.

Plus, I bet they didn't want to risk the vehicle flying off in an unintended direction if it worked too well; with the chosen flight path it was stopped directly after the experiment concluded :-)

Re:confused as usual (big surprise)

[tony_gardner]

Yes it was controlled, and yes it did crash land (Why should the two be exclusive?) The rocket has a ballistic trajectory, and the experiment is performed on the way back into the atmosphere (between 32km and 22km altitude), for about 4 seconds, you can work out the speed yourself. It then has about 10 seconds before it hits earth. When the payload of the last attempt was found, the nosecone was buried about 1 meter below ground, and it only flew upward for about 10 seconds. The current experiment goes upward for 5 minutes.

Suffice to say, that this is an unmanned experiment.

Woomera is the place to be in Australia...

[v8interceptor]

Successful scramjet tests, crazy Japanese rocket flops - I don't know what the refugees are complaining about, look at all the entertainment they get!

Russians?

[4im]

Didn't the russians already test ScramJets (brought up to speed by rockets, just like this one) a couple of years back? IIRC it was even successful. Definitely not a first here in Australia, then...

Re:Russians?

[tony_gardner]

There was a joint flight experiment between NASA and CIAM (Central Institute of Aviation Motors, Moscow), in 1998. There were three tests. they were launched on modified Russian SA5 missiles. One failed outright. One tested the engine in subsonic mode, and the third did not achieve supersonic combustion in the engine.

I think that the outcome from these experiments could be summarised as that no working scramjet was flown. As a note though, the main objective was to prove the Hypersonic flying laboratory, "Kholod", which is a package with fuel and telemetry to attach to a rocket so that any experiment can be easily flown on a rocket. This package was successfully tested (ie fuel, power and telemetry were provided to the model)

Australia's inventing all the cool stuff.

[marcsiry]

First the Metal Storm, now this!

Soon Australians will be able to fly up to anyone, anywhere in the world, within minutes, and then cut them to ribbons.

I wish I was Australian.

Re:Australia's inventing all the cool stuff.

[Muad'Dave]

errr next one - Americans also invented the Second Amendment - what a great invention that was!

At least it has kept our government from forcibly disarming its citizens, making them into subjects instead of members of the government "of, for, and by the people." Note that your crime rate climbed after the confiscation that was supposed to stop all that crime. Guess what? Your crooks now have free rein to rob and pillage, since they're the only ones with firearms. You've fallen for the old liberal crap that disarming everyone will prevent crime. Here in the US, when the states passed "shall issue" laws that required states to issue concealed carry permits to anyone who was eligible, the liberals predicted blood running in the streets. In fact, in every single state that enacted such laws, the crime rates dropped, while the rates in other states continued to climb. Don't give me your holier-than-thou liberal bs - look at the facts before you spout rhetoric.

Re:Australia's inventing all the cool stuff.

[Goonie]

I see this quoted again and again and again, but it's just horribly misleading.

Firstly, gun ownership in urban Australia has *always* been quite low, and pistols are extremely rare (except for police and security guards who carry them whilst at work). It is unheard of for women to carry guns for self-defence here, and always has been. Additionally, the definition of self-defence justifying the use of deadly force is much narrower here. So, the changing of gun laws had virtually no effect on the risk a criminal was taking when committing a crime.

Very few offences committed against "ordinary people" (muggings, burglaries, rapes etc) involved criminals with firearms. The career crooks have them, but they very rarely attack "civilians".

Violent crime rates have been largely steady over the past few years. Property crime went up over the last couple, basically because of an explosion of heroin availability which had nothing to do with guns.

And, finally, I've noticed that yanks don't like being told what to do by foriegners who don't understand their culture and the actual situation on the ground. Guess what? We feel the same. We like our current gun laws just fine, and don't appreciate the NRA funding loony friggin' shooters parties.

Re:Australia's inventing all the cool stuff.

[e40]

I wish I was Australian.

If you want to be an honorary Australian, follow these simple rules:

• Say crikey at least 5 times a day.
  Good Australians say it early and often.
• Pretend your dog is a 'roo. And for crikey's sake, man, watch out for
  those hind legs! They can gore a man!
• Refer to Americans as yanks.
• Above all, make fun of the English.

If you follow these rules, you too can attain that Australian aura.

Re:Australia's inventing all the cool stuff.

[ceejayoz]

Shitty beer

Comment of a friend who visited Oz - "WTF no one drinks Fosters! I thought Fosters was Australian for beer!" Quite amusing.

Re:Australia's inventing all the cool stuff.

[Jester99]

Hrm. Assume the average bullet weighs 10 grams. 1,000,000 bullets/minute * 10 g/bullet = 10,000,000 grams of lead per minute; that's 10,000 Kg... Given 2.2 lbs/ Kg, that's 4,500 lbs of lead, or about as much weight as a minivan.

So my question is... what good is this thing, if the battle lasts more than 10 seconds?
You'd have to have an ammo depot the size of a house sitting right next to the thing.

Any more detailed images of the HyShot?

[RyanFenton]

No goatse links, thanks.

I'd be interested in seeing what this implimentation of a scramjet looks like on the actual craft.

I've done the usual google search and found this (which was very nice, but is a little video, not a good image), and this,but was wondering if anyone has found anything more detailed. :^)

Ryan Fenton

Re:Any more detailed images of the HyShot?

[RyanFenton]

Of course, that's why I posted that link, as opposed to a half dozen links to all the different pages they had. All images shown on those pages either cropped off the interesting bits, or had someone's big mug in front of the schematics I'd love to see. I'm sure everyone here has had such frustrations finding images they are *interested in* before.

Again, I must reiterate: No goatse links. Thank you. ;^)

Ryan Fenton

Slashdot *making* the news?

[KFury]

Let's see: First news link was DOA. Second one says "University of Queensland researchers say they are receiving data from the rocket, but it is too early to say whether the experiment has been a success." which /. interprets as "Successfully tested."

Salshdot editors must feel pretty giddy with their manifest-destiny powers, if writing a headline can make something so...

Re:Slashdot *making* the news?

[ceejayoz]

Wouldn't it be quite easy...

Yes. It could be done in PHP in about 30 seconds, I'm sure it's just as easy in Perl.

Re:Southern California sure has strange earthquake

[Bastian]

I doubt it.

The donuts on a rope phenomenon has, to the best of my knowledge, not been fully explainet yet (i.e., nobody is fessing up as to what plane is making those contrails).

The most plausible explanations I can see for it require some sort of pulsejet engine. I'd expect scramjet engines to generate contrails similar to ramjet engines, since the shift to supersonic speeds doesn't turn any other supersonic engine's contrails into donuts on a rope.

"Successfully tested"

[Hitokage_Nishino]

Well, considering the feat of testing was accomplished instead of the plane exploding and crashing on unaware kangaroos... one could say they had "successfully tested".

Re:"Successfully tested"

[tony_gardner]

Exactly, a siren was sounded so that the kangarooy were not takes unawares this time.

Re:"Successfully tested"

[leviramsey]

Yes, they only crashed on three unaware koalas, and an indeterminately large number of wombats and emus.

DARPA appear to have done it already

[sambo99]

Looks like will have faster bombs, way before we have faster airliners ...

http://216.239.39.100/search?q=cache:MKgyf6-JQS0 C: www.darpa.mil/body/NewsItems/pdf/hyfly.pdf+scramje t++Defense+Advanced+Research+Projects+&hl=en&ie=UT F-8

Re:DARPA appear to have done it already

[PhxBlue]

Hrm. For some reason, copy-paste puts a few unwanted spaces in the link. Oh, well--here's a link, maybe that'll work.

Anyway, I think 11 September really kinda blurred the line between airliners and bombs. A faster airliner is a bomb in the wrong hands.

First link broken...

[phunhippy]

The page or file you've requested, "http://www.abc.net.au/news/justin/nat/newsnat-30j ul2002-53.htm" doesn't seem to exist on this server.

hmmm you'd think after so many people on slashdot complaining to slashdot editors to check links before they post articles... they would!!... then again... these are slashdot editors...

Stupid Error Message Tricks

[Bastian]

A bit offtopic, but I thought I'd share the error message popup Mozilla gave me when I tried to follow this link:

This page contains information of a type
(text/plain) that can only be viewed with
the appropriate Plug-in.

Of course, there is no appropriate plugin =)

At least this time...

[NewtonsLaw]

At least this time those clever scientist types remembered to bolt the test vehicle to the rocket engine.

Anyone remember the poor Japanese SSTV model a few weeks ago?

But seriously (did I just say that?), one of the problems with SCRAMJETs is their gobsmackingly high fuel consumption.

This is one of the reasons that scientists are also exploring pulse detonation engines as an alternative super/hypersonic propulsion engine.

It is rumored that the PDE-powered craft are responsible for those "donut on a rope" contrails seen by some high above the USA.

Re:At least this time...

[tony_gardner]

Depends that you mean by high fuel consumption. They go fast, and this creates drag, thus fuel must be expended. It you mean low efficiency, then you are half right: No scramjet achieves good fuel efficiency at the moment. However, since there are not really any working scramjets that should come as no particular surprise.
Generally, Scramjets should work in the range Mach 6 to 20. I've never seen an upper limit on pulse detonation engine operation, but I can't remember ever seeing one that worked over Mach 8, even in theory.

Confusion Part II

[Em Emalb]

I know less than nothing about this technology, nor what it would be used for, therefore I must post to this topic ;) Mod me -1 dumb if you must, but here are my questions:

1) What is this engine useful for?

2) What industries would this apply to?

3a) Is there video anywhere of the launch/flight?

3b) How bout the crash landing, I'm more interested in that. Any video on that?

Thanks.

Corrected ABC.NET.AU link

[caveman]

Another route to what would seem to be the right page is here: http://www.abc.net.au/news/2002/07/item20020730140 728_1.htm

Uses of a scramjet

[tony_gardner]

Firstly, it is not really useful for passenger aircraft. The high G to get up to speed is not really sellable.

The main use is as a secondary engine for rocket propulsion. Since atmospheric air is used, the scramjet theoretically can lift more payload for a given engine weight, and it is hoped that this will translate into launch cost savings for light payloads (I've seen one estimate that put the saving at a factor of 10 for a 1-10 tonne payload), however nothing really beats rockets for very large payloads.

The biggest advantage, in a launch to orbit is that, since the engine will be going sideways to pick up speed, the cost difference between a polar and equatorial orbit is negligible.

Next week on TV

[__aahlyu4518]

A brand new series of Roger Scramjet !

*THUD*

[TheSHAD0W]

Until this morning no organisation, including NASA in the United States, has been able to successfully test fly a scramjet - an air-breathing supersonic engine.

Umm, I'm sorry, but in my humble opinion, heading straight down and digging a crater in the ground does not constitute "flying". Please be more accurate in your description.

Re:Southern California sure has strange earthquake

[TheSHAD0W]

"Donuts on a rope" are caused by shock waves in the stream of a jet engine; they'll show up in nearly any high-output jet engine, much less one meant for supersonic travel.

If you're thinking of the neat light display behind the engines of a SR-71 Blackhawk, those engines are indeed for supersonic flight -- but they aren't ramjets. They're turbofans. They are configurable, though; the cone on front adjusts the position of a shockwave that slows the air down to the point where it will work in that type of engine.

The difference is that a scramjet, having no turbine and only basic moving parts, can operate at a much higher velocity than a turbojet. The SR-71 was limited to the supersonic realm, while a scramjet-powered vehicle can reach hypersonic speeds, above Mach 10.

Re:That's one large, deep hole

[WolfWithoutAClause]

133km/s would be mighty impressive!

Hint: 11.2 km/s is escape velocity (mach 25 or so).

So 133km/s would be more than mach 250 ;-)

Link into Mama (ABC) seems to be broken, so...

[leonbrooks]

The hyperlink into Mama appears to be broken, try this one instead.

Re:Southern California sure has strange earthquake

[phayes]

"Donuts on a rope" is the characterisation given to the contrail of a secret US program thought to use pulsed detonation to achieve high mach.

"shock waves in the stream of a jet engine" are better known as shock diamonds and are the results of shock waves producing visible artifacts in the flaming exhaust of aircraft using afterburners.

Finally, as has already been stated in another post, the SR-71's engines fonction in both ramjet & turbojet modes. The inlet cone slows the air down to subsonic speeds so that it can be used in the ramjet part of the engine profile -- using hypersonic air is the definition of scramjet.

HoveRoc destroyer decoy, Jindalee OTH Radar, ...

[leonbrooks]

...LCA2003, and now working scramjet engines! Australia seems to invent the best of everything. (-:

Yes, and we know exactly where to cut, too (-:

[leonbrooks]

This could do air traffic control in the USA if we wanted it to. (-:

This can't see quite as far, but does pick out nearby* stealth aircraft in stark relief without any apparent effort (`bombers flying at low altitude' includes B1s and B2s). And there are about 70 Chinese in China for every Australian in Australia...

* on the first bounce, ie, out to just shy of 1000km away.

Yes, there is!

[leonbrooks]

EMACS will display text/plain just dandy.

Re:Yes, there is!

[Pig Hogger]

EMACS will display text/plain just dandy.

EMACS? What a dog! Nothing's better than a cat!!!

Re:Southern California sure has strange earthquake

[drwho]

"Donuts on a rope" HAS been explained. It is produced by PDW (Pulse Detonation Wave) engines. What hasn't been explained is what is making them, as there are no PDW engines officially in use yet. Much speculation is that the ultra-secret US spy plane Aurora is what's creating these. Some spy plane, if it leaves such a distinctive signature!

So... the engine worked, then? (-:

[leonbrooks]

...and now they're scanning the desert looking for pieces of Woomera...?

Re:Is it just me?

[Howzer]

No, not just you! Glass Elevator was my favourite of the two....

Piss poor pedant

[A nonymous Coward]

of it's kind

Apostrophe not needed for this possesive....

As for Is that descent back to earth, where else if not descent to the earth? You think this was done on Mars or somewhere?

Re:Southern California sure has strange earthquake

[smagoun]

There's speculation that the donuts-on-a-rope photos that were in Aviation Leak a few years back were created by a Pulse Detonation Wave engine. The donuts imply distinct combustion pulses (like in an internal combustion engine, only much slower), as opposed to continuous combustion (turbine).

Another theory is that the donuts are some sort of weapon; the "rope" is the contrail left by the aircraft's engines, and the donuts are exhaust pulses from a gun or something.

What it comes down to is that like you said, nobody knows what created the phenomenon.

Re:SR71 engines

[smagoun]

Do they really contain ramjets as well as turbojets?

Yup - sort of.Studies have shown that less than 20 percent of the total thrust used to fly at Mach 3 is produced by the basic engine itself. The balance of the total thrust is produced by the unique design of the engine inlet and "moveable spike" system at the front of the engine nacelles and by the ejector nozzles at the exhaust which burn air compressed in the engine bypass system.

That link is a quick overview of the Blackbird, including a bit of info about the engines. Ram air definitely plays a big part. Anyone know if those "ejector nozzles" are what I'd call an afterburner, or is the afterburner included in the "basic engine itself?" It sounds like they're the ramjet portion, but...

Re:Southern California sure has strange earthquake

[ceejayoz]

Spy planes don't necessarily have to be stealthy - the SR-71 and U2 survived not by stealth (the Russians could easily detect them on radar) but by flying too high for Soviet interceptor aircraft and SAMs to reach them (and in the case of the SR-71, it also flew faster than anything they could throw at it).

Gun Strangeness + Woomera = spear thrower

[Mandelbrute]

At least it has kept our government from forcibly disarming

I don't recall there being any force involved - lots of grumbling but no force.

Note that your crime rate climbed after the confiscation that was supposed to stop all that crime

Yes, I saw "Mad Max/road Warrior" too - but it is just a movie. Sadly for the US gun lobby the crime rate hasn't done anything noticable.

Your crooks now have free rein to rob and pillage, since they're the only ones with firearms.

Hasn't happened, and the robbery weapon of choice has been sawn off shotguns for years (illegal for decades), instead of semi-automatics which are now restricted to the military after the changes in the laws. Fully automatic weapons have always been military weapons here. Handguns have been restricted for at least fifty years and are fairly rare in this country. Rifles and shotguns can be easily obtained, just not semi or fully automatic versions. The well armed militia is the army reserve, which I suspect is what the US constitution was talking about instead of masses of gun clubs calling themselves citizens militias.

Back on topic - Woomera is named after a koori spear throwing device, the rocket range and town were built in the late 1940s to test rockets in the middle of the desert. The scramjet project has been going for a while - I saw a model which closely resembles the current version in December 1989. It's just now that they are finally getting to put the things on rockets instead of helium filled testing tunnels (simulating mach 8 and thereabouts).

Re:Gun Strangeness + Woomera = spear thrower

[Muad'Dave]

I don't recall there being any force involved - lots of grumbling but no force.

Had anyone refused, do you doubt there would have been force? I don't.

Yes, I saw "Mad Max/road Warrior" too - but it is just a movie.

I wasn't referring to any movie. Did you read the 100's of articles I referenced?

and the robbery weapon of choice has been sawn off shotguns for years (illegal for decades),

So gun control hasn't worked "for decades", but you let your gov't pass more worthless laws? What made you think anything would be different this time around? It didn't work then, it won't work now or ever.

Re:Successful... Maybe

[ceejayoz]

OMG! A misleading title on Slashdot? How will they ever live with themselves?

Re:Southern California sure has strange earthquake

[Pig Hogger]

"Donuts on a rope" HAS been explained. It is produced by PDW (Pulse Detonation Wave) engines. What hasn't been explained is what is making them, as there are no PDW engines officially in use yet. Much speculation is that the ultra- secret US spy plane Aurora is what's creating these. Some spy plane, if it leaves such a distinctive signature!

Makes sense. An explosion (a high-pressure squirt of gas) funnelled through a narrow exhaust pipe will most likely produce a torus, like a smoker blowing rings of smoke, or a diver making ring-bubbles at his decompression stop...

Re:What is this good for?

[Creepy]

I'm not an Aussie, or an expert, but I recall from old Popular Science's (Space Planes issue) that Scramjet engines use much less fuel because they don't go straight up (ascend more like a plane) and use the atmosphere as part of their combustion, unlike rockets, which use liquified propellents. The major problem with scramjets was accelerating to a speed where they become efficient. The airline industry abandoned the idea because they couldn't carry enough passengers to make a profit (one of the Concorde's problems, as well) and the US military abandoned it because they didn't have an immediate need and it was an easy way to save money. Since I haven't heard much about them for a number of years, I'd guess that other militaries abandoned them, as well (at least for combat uses).

There probably won't be much of a market for passengers in the near future, unless someone builds a space casino, mainly because the cost is too high, at least compared to conventional aircraft. There is a market for cheap satellite delivery, though, which conventional aircraft can't do (the plane or the satellite would need to be rocket assisted to get into the proper orbit, and orbit velocity, I'd think).

Re:SR71 engines

[jafac]

Pretty much any supersonic plane uses a technique of shock-wave deflection. Look at the F4, where the intakes meet the fuselage. The deflectors are clearly visable.

Vegemite

[leonbrooks]

Vegemite has an interesting history; it was actually invented by a Seventh-day Adventist named John Harvey Kellog (Kellog company of cereal fame was started by a relative of his), Catholic-owned Kraft then stole the recipe and after manufacturing it for a while, turned around and sued JHK's company for using `their' recipe. Yes, JHK was a Yank. (-:

I actually prefer Promite, but will accept Marmite as a fallback. Then again, I'm a weird Aussie, I don't like beer or watermelon.

In answer to the tourist questions, the only kangaroos hopping down the main street are bronze, prawns on the barbie are very rare (and a bad idea) - usually it's steak and/or `snaggers' (sausages), and it takes over two days of nonstop (except for fuel) driving at the speed limit (110km/h in WA, 100km/h SA and NSW) to get to Sydney from here in a taxi (sorry about all the parentheses).

Table wines

[leonbrooks]

I prefer the juice before it goes rotten. Ambrosia!

The French or people near them actually invented most kinds of wine, but it took Australians to get the recipe right... (-:

Yep, and I wonder...

[leonbrooks]

...whether `decoding' the position of a `stealth' aircraft constitutes a DMCA violation.

The Chinese antennas look very similar for a variety of reasons. One obvious one is that there are only so many reasonable configurations that work well, another is that some of Jindalee's technology was public while the Chinese were building theirs. While I don't think conspiracy is necessary explanation, it wouldn't shock me if the Chinese picked up some other information covertly.

Their OTH performs differently to Jindalee (some things better, some worse), but never mind, either installation sees much more than countries like the USA, Russia or Germany are happy about. (-:

One thing that neither site makes clear is that multiple bounces are routine. Jindalee can actually see itself by looking around the globe, and IIRC in practice has enough range/resolution to see around 2 and a half times. When I mentioned diong ATC in the US, I wasn't kidding. The resolution is good enough to manage (for example) JFK's traffic, although I imagine many pilots would be startled by the Aussie accents.

Re:DARPA test was a Ground Test

[aebrain]

The Americans appear to have beaten the aussies in this race.
link to darpa press release [216.239.39.100]

Not quite. That was a Ground Test. DARPA and others - like the Uni of Queensland - have had scramjets in the labs for a while. This is the first time that one has been successfully flown. It may or may not have worked - we'll see in a day or two.

Way offtopic gun strangeness

[Mandelbrute]

I wasn't referring to any movie. Did you read the 100's of articles I referenced?

No I glanced at a few and gave up - nothing appeared to have been written by anyone that has even been to Australia. I have read a magazine called "lock stock and barrel" which expounded the exact same views, written in Australia in 1994 (before the gun laws) and talked about how we needed to arm so that we could overthrow the government at will, shoot Indonesian invaders (the Javanese are happier in Java anyway instead of annexing a lot of desert) and kill members of the "Jewish Conspiricy" (there are almost no jews at all in Australia - the writer lived in his own little world). That sort of publication would appear to have been the only Australian source of material for those articles. The murder rate here was low, so three loonies with armalite semi-automatic rifles raised the murder rate considerably - hence the ban on semi-automatics.

So gun control hasn't worked "for decades", but you let your gov't pass more worthless laws?

But it has worked - violent crime here mostly involves blunt instruments, single shot rifles, syringes, or fists. The violent crime rate in large cities in Australia is very low in comparison to the middle states of the USA, and of course even Belfast (Ireland) has a much lower violent crime rate than Liousiana, Washington DC and New York.

I can own a gun if I want to (I don't have a criminal record so I can get a licence), just not an easily concealable weapon (and I'm glad that no-one is likely to ever point a pistol at my head either) or a miltary weapon (fully or semi-automatic). My granny's shotgun is legal, the .22 rifle I first fired when I seven is legal, and the one inch bore "Brown Bess" style musket that a friend made is legal. The semi-automatic that my uncle got to deal with animals that ate his fruit trees wasn't, so he had a few months to sell it back to the government. A lot of firearms on the banned list are still out there - hence the proposal to have a second gun amnesty - it looks like the "forcible disarming" has only happened in a few minds across the Pacific. The previous posters "doubts" or fluffy feelings don't really hold up against reality.

It's a difference of culture - when the USA revolted the right to bear arms was a big issue. When Australia was made independant most people in rural areas had firearms anyway, and as colonies each area had it's own volenteer army. The miliary still reserved the right to be the only ones with artillery, and now the only ones with automatic weapons. Hence the second amendment in the USA, and other countries looking on and saying "only in America" when someone uses that amendment as a flimsy excuse to own a .45 automatic or similar military sidearm. The problem, as in the national parks, is not the bears, but the huge numbers of guns carried in fear of the bears.

There are a lot of things wrong with Australia, but the gun laws have no impact on any of them. The worst thing an Austalian leader has been hit with is a cricket ball (during a game) - and we didn't even have a federal police force until someone threw an egg at a prime minister.