Slashdot Mirror
Australian Scramjet Launched
CaptainAlbert writes: "The University of Queensland, Australia is reporting the (possible) success of their "HyShot" scramjet test. The BBC have got this covered too. Apparently, they're now poring over the data loggers, trying to figure out if it actually flew under its own power." We had a story about these guys a while back.
I assume that it'll take a while to get up to full speed (not least because I don't think passengers would like being squished by a big acceleration). So if you were going, say, London to Paris you're not really going to have much time to get up to speed. What sort of distances do you need to cover before this option becomes worthwhile (i.e. more economical)? Would London to NYC be far enough? How about LA to Tokyo?
So, how is this supposed to work? Get in your plane, accelerate up to mach 5, wait for scramjet to kick in, cruise for a while, then land. At mach 5 it takes under an hour to fly across the Continental US. Of course, you need to accelerate up to mach 5, unless you want everyone tossing their cookies you can't do that too fast. It'll probably take 1000+ miles of the trip just to get up to speed. Another 1000+ to decelerate.
;)
Basically we've reduced this to those who fly half way around the world. And how many people do that often enough to make up for development costs? It aint ever going to happen. You're better off waiting for them to invent a transporter. The number of people with the desire for this kind of service is simply way too small.
That being said, its fun technology to watch, but you'll never see it used in the commercial airlines. And no, I didn't actually read the article
.. I remember when I studying at UQ, that they had built a hypersonic wind tunnel. The stream of gas could punch holes in sheets of steel.
A mate of mine was researching how to make a mass spectrometer that could work inside/with the wind tunnel. To do the scramjet research, given the speed of the gasses, they needed to know if they could achieve combustion inside the engine rather than several kilometers behind it!
Simon
The first German rocket scientists supposedly freaked out the same way you did, when they couldn't figure out why their guidance systems still left their rockets apparantly wobbling in all directions. It turned out not to be the guidance systems at all - just the wind. The rocket paths were straight, but shifting winds at different altitudes blew them into crazy lightning-strike looking things as the rocket was still aloft. I'd be surprised if the same phenomenon wasn't the explanation for that photo.
Wouldn't it possible to apply this technology to UAVs (an aircraft without any crew onboard) transporting cargo only, you would cut the acceleration and decelaration problem (unless the cargo can't take the pressure, but this problem would be much easier to solve anyway)... Of course, there would probably be a need for cargo that needs to be sent somewhere REALLY fast, to pay for the development cost.
Anyone reminded of those supercavitation torpedoes? Yet another area where those "technologically backward" russians are by far more advanced than the west...
Just how much brainwashing do we get?
Come on, they were first on orbit, their MiG-29 used to be considered better than their western counterparts - I think these facts are well known worldwide, so what brainwashing?
Soviet Union was technologicaly behind and as well is Russia if you don't stick to military technology. Go to an average Russian house and just look for a mobile, a PC - you probably won't find any unless you search in Moscow or Skt. Petersburg. And Russian TV sets were famous in the Eastern Block as "home explosive kits" because they tended to explode "just because". And these lovely Russian clocks famous as "the fastest in the world".
I come from Poland and I used a lot of these "far more advanced" Russian technology and I know how everyone counted their money because it was better to buy (extremely expensive for us then) no-brand western or Asian electronic equipement than to stick to Russian stuff.
And now even their military industry is falling behind due to fund reductions.
Rav
I bet it wouldn't be too hard to get that limit relaxed to something like no sonic booms below 15,000 feet (~4500m). A military plane once passed Mach 1 less than 2,000 feet (~600m) above the house of a friend of mine (at the time, he was living about forty miles west of Detroit in a rural area). He said it was really loud and shook the Earth, therein lies the problem. Moving it higher off the ground, is IMHO, a much better solution than an outright ban. In that regulatory environment, I can imagine the major hubs having regular supersonic connecting flights to each other, with conventional flights to all other airports. Think of it as a 'backbone network' for 'people packets'.
I like to play children's songs in minor keys.
"We're all sons of bitches now." --J. Robert Oppenheimer
many times
The US Space program used ordinary pencils in space throughout the Mercury and Gemini programs. Paul Fisher, founder of the Fisher Pen Company, spent over one million dollars of his own money developing the Fisher Space Pen before he came up with a working prototype in 1965, which he submitted to NASA for evaluation. NASA approved it for space flight in September 1965, and purchased 400 pens at $2.95 each in December 1967. The Soviet space program adopted them in 1968.
Why is it that the proponents of "one nation under God" are so eager to get rid of "liberty and justice for all"?
Accelerating at 1/10g (3.2 ft/sec/sec) to keep the passengers comfortable:
Mach 5 = 3000mph at high altitude = 4400 ft/sec
Time to reach this speed: 4400/3.2 = 1375 sec = 23 minutes
Distance covered while accelerating: 1/2(4400)(1375) = 3,025,000 feet = 573 miles
And your deceleration is going to be at least as long, so it's not worthwhile on trips much shorter than LA-NYC.
If the customers can be less comfortable, accelerate at 1g and your acceleration covers 57 miles in 137.5 seconds. But the ticket is going to be very expensive -- the plane has to go faster than most fighter jets BEFORE it can turn on the scramjets. So it needs ungodly big conventional engines, or else rockets. And the seats have to swivel around because you really don't want to hang from your seatbelt in 1g deceleration for 2 minutes.
Someone mentioned accelerating at 8g. This only takes 7 miles -- you could launch from an electromagnetic catapult to scramjet speed, IF the scramjets will run in thick air at low altitude. Of course, your passengers need a thorough physical, and there is still that deceleration issue.
Scramjets are not for airliners. The military applications should be obvious -- and you can use something like the space shuttle boosters in that case. Other than that, they might be useful for space launches -- get to Mach 5 with solid-fuel rockets, then use the scramjets to get to the outer fringes of the atmosphere at Mach 15 or so before you have to switch back to rockets. (The trouble with rockets is that they carry their own oxygen, which outweighs the fuel...)