China’s hypersonic jet shatters Mach 6.5 speed in Gobi desert test (interestingengineering.com)
from yogthos@lemmy.ml to technology@lemmy.ml on 13 Dec 19:02
https://lemmy.ml/post/23546149

#technology

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cygnus@lemmy.ca on 13 Dec 19:49 next collapse

Uhh OK, they’ve matched something the X-15 was doing 65 years ago. What’s the endgame here? Build a ludicrously inefficient passenger aircraft?

catloaf@lemm.ee on 13 Dec 19:53 next collapse

Seems like it. No mention of the fuel efficiency either, which leads me to assume it’s significantly worse than existing flights.

alcoholicorn@lemmy.ml on 13 Dec 20:10 collapse

It probably is, the whole reason supersonic passenger flight looked feasible for a bit was that turbine technology hadn’t caught up so slower jets weren’t that much less efficient than supersonic jets.

But fuel concerns aside, it’s kinda silly to compare a billion dollar fighter jet built with 60s technology to a 747-sized aircraft built for passenger flight with modern technology. Just wildly different environments, purposes, and resources.

cygnus@lemmy.ca on 13 Dec 20:29 collapse

Based on the renderings (as there are no actual photos of this thing, other than the blurry-ass pic of what appears to be a rocket taking off vertically) it’s nowhere near the size of a 747. It actually looks rather like an elongated SR-71, which makes me very skeptical that it can actually hit Mach 6.5 because ramjet engines have a hard limit due to something called “physics”. That fact, plus the rocket-like takeoff, are why I think this is more like the X-15 and can’t sustain its top speed for long.

alcoholicorn@lemmy.ml on 13 Dec 21:26 collapse

The rendering in interestingengineering article is a stock image. An older SCMP article gives a much weirder rendering which matches the whitepaper the lead researcher published on I-shaped hypersonic configurations.

So I have no idea what the blurry ass rocket pic is supposed to be, maybe it was a test vehicle for just the engine, maybe SCMP misattributed it, maybe the team dumped the whole “I-shaped configuration” thing.

Presumably any ram or scram-jet engine will require a rocket engine or other assist, assuming it’s not a hybrid like the SR-71.

cygnus@lemmy.ca on 13 Dec 21:37 collapse

Nice, thanks for this extra background! My first thought was scramjet too, but it would be nice of them to mention how it takes off and lands.

The original rendering looks awesome, in a bonkers sci-fi kind of way.

Eezyville@sh.itjust.works on 14 Dec 02:09 collapse

The X-15 was a rocket propelled aircraft. This is an air breathing aircraft.

goatsarah@thegoatery.dyndns.org on 13 Dec 21:28 next collapse

@yogthos Did it though?

yogthos@lemmy.ml on 13 Dec 21:44 collapse

It did

goatsarah@thegoatery.dyndns.org on 13 Dec 21:50 collapse

@yogthos And I'm the queen of England.

yogthos@lemmy.ml on 13 Dec 21:51 collapse

Just a sad racist.

goatsarah@thegoatery.dyndns.org on 13 Dec 21:58 collapse

@yogthos No, just someone who can smell obvious bullshit. SCRAMjets basically don't work for any real world application, and can't. They inherently have utterly useless power to weight performance.

None of this shit works on anything that's not a scale model.

yogthos@lemmy.ml on 13 Dec 22:24 collapse

I guess we’ll see won’t we. Pretty much same thing was confidently said about lots of technology in modern use, like the high speed train network in China. Plenty of western geniuses derided it as not being cost effective.

goatsarah@thegoatery.dyndns.org on 13 Dec 22:26 next collapse

@yogthos Oh, their rail network is impressive and I wish it was being copied elsewhere.

But this ... is not credible.

yogthos@lemmy.ml on 13 Dec 22:51 collapse

Well since you obviously must be an aeronautics engineering expert, perhaps you can explain what aspects of the paper aren’t credible for a dumdum like me

www.researchgate.net/publication/…/download

goatsarah@thegoatery.dyndns.org on 13 Dec 22:59 collapse

@yogthos plenty of published stuff on why scramjets aren’t practical and air breathing hypersonic transport is basically a white elephant even if you’re able to do it.

I’m not your butler

goatsarah@thegoatery.dyndns.org on 13 Dec 23:06 collapse

@yogthos the tl;dr is that you basically have super high energy air coming in at Mach 5. You then have to take all that energy away to get your fuel to burn in it, which barely gets you past break even. They create massive amounts of drag too and in order to function need to stay in the part of the atmosphere that’s thick enough to breathe, thus prolonging the drag and problematic heat generation.

Given the point of a scramjet is to get you into a suborbital trajectory for a rapid glide to your destination, the fact that they have inherently terrible thrust performance and only work when you’re in the bit of the atmosphere you desperately don’t want to be in, they’re uniquely terrible at it.

Turborockets solve these problems. Get up to Mach 5 on air, close the intakes, run on liquid oxygen, and CLIMB.

They’re lighter, more efficient, and faster than hypersonic air breathers. You wanna go that fast, use a rocket, and get away from the nasty draggy burny stuff. As enticing as the idea of “free oxidiser” is, it’s a sucker bet.

yogthos@lemmy.ml on 14 Dec 00:28 collapse

Again, go ahead and explain what the paper about this specific jet gets wrong. Also, nobody is asking your to be anybody’s butler. You made a claim, so now it’s up to you to substantiate it.

I find it absolutely hilarious how arm chair aeronautics engineers such as yourself just assume that people building this stuff aren’t aware of obvious arguments that even a layman such as yourself understands. Like it took your galaxy brain to figure this out, but the people actually making the jet aren’t aware of this.

goatsarah@thegoatery.dyndns.org on 14 Dec 01:33 collapse

@yogthos I did.

Scramjets are fundamentally fighting Newton’s 3rd law. Slow air down by Mach 5 only to speed if back up to Mach 5 again. You’re burning tonnes of fuel to accomplish almost nothing.

If they have a practical scramjet vehicle (they don’t), then they should feel free to show the world, rather than posting vacuous bullshit on the Internet.

yogthos@lemmy.ml on 14 Dec 02:38 collapse

Nowhere in the paper does it say that this is a scramjet. Meanwhile, obvious solution for a hypersonic vehicle would be to go to upper atmosphere at a lower speed, and then achieve speeds over Mach 5 where there is low atmospheric density. You really think that you’re smarter than literally everybody working on this project, and it’s absolutely hilarious.

Maybe take your own advice and stop posting vacuous bullshit on the internet pretending that you’re an expert on things you have little understanding of.

goatsarah@thegoatery.dyndns.org on 14 Dec 03:00 collapse

@yogthos “The paper”.

This isn’t a paper. It’s a blog post.

It’s no more a “paper” that is subject to any kind of scientific debate than some rando who said they made cold fusion in their microwave.

“Jumbo jet prototype”. Bless.

yogthos@lemmy.ml on 14 Dec 03:51 next collapse

Nothing more adorable than internet randos acting like they’re bonafied rocket scientists. Bless.

Eezyville@sh.itjust.works on 14 Dec 04:10 collapse

The “paper” that OP is referring to is the one they posted a few levels up. It links to a researchgate paper that I believe is associated with the article. Just from a quick look at the paper, which is only 3 pages, they are talking about the design the aircraft uses to mitigate the negative effects that occur at hypersonic speeds. They refer to the Waverider design and modified it by including a High-Pressure Capturing Wing to improve lift. Waveriders are designed to conform to the shockwaves the vehicle produces at hypersonic speeds to reduce the drag from those shockwaves. When designing high speed aircraft you have to design around the shockwaves it will produce. This enhancement seems to improve the lift the vehicle creates at those speeds.

Also you aren’t getting everything right in your arguments. Earlier you stated that scramjets are fighting Newton’s 3rd law which states, “For every action, there is an equal and opposite reaction”. You do understand that all air-breathing engines slows the air down before it gets to the engine. This is usually done during a compression cycle to increase the pressure and density of the air. Turbojet and Turbofan engines do this using compression fans, Ramjets uses a normal shockwave, and scramjets uses a series of oblique shockwaves called a “shock train”. The difference between a scramjet and the other engines is the airflow is subsonic in Turbojet, Turbofan, Ramjet, etc while the air enters the engine at supersonic speeds for scramjets. That’s why its called a SCRamjet, Supersonic Combustion Ramjet. But like OP said the paper doesn’t mention what type of engine was used, only that it was a hypersonic vehicle so it could be a rocket.

How do I understand this? I actually have a degree in aerospace engineering, I’ve worked on scramjets (X-51) for the USAF, and I designed engines for GE Aviation. Your arguments are all wrong.

FleetingTit@feddit.org on 14 Dec 14:28 next collapse

Their high speed train network is impressive, but none of it was new technology when they built it. The first train sets they bought were Siemens Velaro D, a mature high speed train system that has been around in Europe for almost a decade prior.

It ISN’T cost effective, but in China that doesn’t matter: what the state wants the state gets. No matter the cost. And I’m willing to bet that in 10 years time a lot of the stuff just doesn’t work anymore, line speeds get reduced and stops cancelled due to infrastructure not being maintained.

We have seen chinese prestige projects fall into disrepair time and again, and their extensive transport network will see the same fate.

yogthos@lemmy.ml on 14 Dec 18:10 collapse

China absolutely has done a lot of innovation in HSR tech. Building stuff is how we develop and improve technology. It’s absolutely incredible that you think China hasn’t innovated in this area.

It ISN’T cost effective, but in China that doesn’t matter: what the state wants the state gets. No matter the cost. And I’m willing to bet that in 10 years time a lot of the stuff just doesn’t work anymore, line speeds get reduced and stops cancelled due to infrastructure not being maintained.

That shows just how utterly clueless you are. The reason China wants to have the whole country connected by rail is because it stimulates the economy. It makes it easy to transport goods across the country, and for people to move around. To suggest that China would abandon its rail network is sheer idiocy.

We have seen chinese prestige projects fall into disrepair time and again, and their extensive transport network will see the same fate.

It’s not a prestige project, it’s critical infrastructure. You’re gonna be doing a lot seething and coping in your future.

geneva_convenience@lemmy.ml on 14 Dec 17:37 collapse

High speed rail can be cost effective. High speed planes however cannot.

The amount of air resistance at higher speeds is insane. Instead of relying on wing lift for efficiency the entire aircraft has to remove all wings and it literally becomes a missile.

Efficient planes have long wings to create lift and cruise at lower speeds. This is the opposite where all lift is generated from the fuel.

yogthos@lemmy.ml on 14 Dec 18:06 collapse

Given that China has high speed rail all across the country, I suspect that there’s going to be little market for short flights. I would expect this sort of a plane would go all the way to the edge of space where it doesn’t need to worry about air density.

geneva_convenience@lemmy.ml on 15 Dec 00:28 collapse

That’s going to cost a lot of fuel, maintenance and spare parts. Rebranding an ICBM as a passenger plane is not that big an invention.

The high spees rail is much more impressive as it can be used by the general population. Whereas these top speed planes will only be for the elites.

yogthos@lemmy.ml on 15 Dec 12:50 collapse

It’s not really an ICBM, it’s likely a hypersonic glide vehicle. I imagine people building this stuff have thought of obvious things like cost of fuel and parts before trying to build it. Maybe it will work or maybe it won’t, I think we’ll learn something interesting one way or another.

I also don’t think it’ll just be for elites. All successful technology becomes cheaper over time, and it sounds like they’re explicitly building a large capacity vehicle here. I imagine it’s going to be a long haul vehicle that could go anywhere in the world in about an hour.

sp3tr4l@lemmy.zip on 14 Dec 00:45 collapse

I am willing to believe that this may have actually been developed…

But a better source sure would be neat.

Interesting/Wonderful Engineering both claim this was posted on ‘Social Media’ by the Chinese Academy of Sciences… with no link.

South China Morning Post also claims a video posted by CAS on social media… with no link, no video.

The english version of the CAS website is updated every couple of days, but this isn’t on it.

Granted, they could be taking their time doing a proper translation.

Does anybody know where to see this video?

yogthos@lemmy.ml on 14 Dec 01:37 collapse

www.researchgate.net/publication/…/download

sp3tr4l@lemmy.zip on 14 Dec 09:37 collapse

I mean sure, thats a related research paper, but that isn’t the same thing as an official press announcement or video saying ‘Hey we actually built this thing, it works, take a look.’

I know that the CAS has specifically been researching/developing a hypersonic, passenger liner sized craft for around a decade… and the US has been doing the same with the SR 72, both attempting to develop … something like turbo ramjet that transitions to scramjet at high speeds/altitudes.

But a link to a research paper from 6 years ago is not actually a primary source to what your original link claims, but does not actually source.

yogthos@lemmy.ml on 14 Dec 12:34 collapse

Sure, and if it works I’m sure we’ll get videos and announcements at some point.

sp3tr4l@lemmy.zip on 16 Dec 01:08 collapse

Ok so 24+ hours later and I now see a few different websites I’ve never heard of before that basically have the same article as this:

scienceinfo.net/chinese-hypersonic-aircraft-proto…

Still no actual link to the apparently original source somewhere on some social media site.

Now whats being said is that this was a flight test that actually occured 3 years ago, and was classified until now.

And they do provide an image, and credit it to CAS (without an actual link, I still can’t find this on CAS’ english site, but again maybe they are still writing a proper English post?)

<img alt="" src="https://lemmy.zip/pictrs/image/0bee9f0e-635c-4e15-807f-ed64c1fe3fa6.webp">

This is a test article, that doesn’t appear to have any intakes for scramjet. I think I can make out two small rocket bells inside the thing, but the image quality is very low.

It’s just a test article, launched by a rocket, that Inwould guesstimate to have a wingspan of about… 4 meters, ish?

This new article also mentions that Cui, the team lead, did not mention anything about the current status of the hypersonic passenger jet which this was a test article for.

So… this test article got up to mach 6.5, 3 years ago.

Absolutely nothing about whether or not a successful test flight of a passenger jet sized craft achieved hypersonic speeds with an air breathing turbo ramjet / scram jet or something like that.

Completely different than the originally report.

… This is why I wanted an actual source.

If this very poorly sourced article from this random, clickbait style website is more accurate than the OP article (another poorly sourced article from another clickbait style website) is more accurate, that would mean SCMP, and everyone in this thread saying China has built an air breathing hypersonic jet liner is wrong, and everyone saying that this is basically comparable to the X15 is correct.

(Differences being the X15 was carried up to 45 thousand feet by a B52 instead of a rocket, and the X15 was manned, and this test article is presumably unmanned.)

yogthos@lemmy.ml on 16 Dec 03:55 collapse

Yeah, if they’re reporting on the test from three years ago then it is basically similar tech to X15.

sp3tr4l@lemmy.zip on 16 Dec 13:05 collapse

So… then… you agree that this entire Interesting Engineering article you posted is wrong?

Are you going to apologize to Sarah Brown for calling her a ‘sad racist’ when she expressed doubt as to the veracity of the dubious article you posted?

yogthos@lemmy.ml on 16 Dec 13:08 collapse

That’s assuming that the random article you found is correct, the veracity of which I can’t verify any more than the interesting engineering article, and assuming they’re talking about the same test. Sarah Brown didn’t substantiate the doubts in any meaningful way, so no I’m not going to apologize for my assumption on what those doubts are based on.

sp3tr4l@lemmy.zip on 16 Dec 14:04 collapse

So, you just assumed a unsourced, unverified story is true because you have a bias in favor of China, and put the burden of proof onto the other person to disprove it, and are completely fine with calling the other person a ‘sad racist’, despite now admitting that the veracity of the claim they are skeptical of is in fact not well established.

This is the argument/personality style of a fanatic, a religious fundamentalist, a QAnon adherent, an Elon Musk simp.

This is how we got ‘the Trump assasination attempt was staged!’

Please stop posting trash tier misinformation as ‘technology news’, please stop jumping to ‘everyone who disagrees with me is rascist’, this level of unjustified vitriol only makes you appear manic.

yogthos@lemmy.ml on 16 Dec 14:20 collapse

So, to sum up, you found a completely unsourced article, and on that basis you’re attacking the article I posted. The fact that you don’t see the irony in that is really a cherry on top. However, you, unlike Sarah Brown, at least went to the trouble to attempt to substantiate your position.

sp3tr4l@lemmy.zip on 16 Dec 15:00 collapse

Neither of the two articles are well sourced.

But you acted like yours was credible, until I presented another one, whereupon you admitted they are both equally valid.

That’s assuming that the random article you found is correct, the veracity of which I can’t verify any more than the interesting engineering article…

That is to say, you cannot verify either of these articles at all, ie, they are both of dubious legitimacy.

You accused someone of being racist based of an article you admit you cannot verify, posted a bunch of related research papers that indicate, sure, they’re trying to develop the thing your article claimed they did… but doesn’t indicate that they actually developed it.

I can link you a patent for a triangular shaped aircraft, listed as filed by a US Navy Scientist that claims to outline how to create an electromagnetic, gravity negating field around the craft.

That would not be evidence that the US Navy officially announced that they basically built a UFO, that it works, and there’s a video of it, all officially documented and released.

But to you, it would be, if China had done all those things.

I am not saying China certainly has or has not developed a hypersonic passenger liner.

I am saying your source for this claim is dubious.

I am saying that you believe(d?) it credulously, without any skepticism, got very hostile with people who doubted its claim less tactfully than I did, and now you admit you got hostile based on a claim that you now admit is dubious, and shifted the burden of proof from the article making the claim to the skeptic questioning it.

Again, this is the logic of a fanatic.

If we just pick which dubiously sourced claims we believe based on vibes, truth stops existing.

yogthos@lemmy.ml on 16 Dec 15:17 collapse

But you acted like yours was credible, until I presented another one, whereupon you admitted they are both equally valid.

Every article I’ve seen aside from the one you found says the same thing. These articles come from fairly mainstream sources, so if somebody is arguing that this is impossible then they can at least provide some evidence for the claim.

You went through the effort of finding something that makes different claims, but it’s in no way authoritative. I was just giving you the benefit of the doubt saying that it’s plausible.

You accused someone of being racist based of an article you admit you cannot verify, posted a bunch of related research papers that indicate, sure, they’re trying to develop the thing your article claimed they did… but doesn’t indicate that they actually developed it.

I accused someone of being a racist based on their vacuous comment that dismissed the claim without substantiating their position in any way. My reaction would’ve been quite different had Sarah said something along the lines of I don’t find the source convincing, here’s another source claiming something different.

But to you, it would be, if China had done all those things.

No it wouldn’t, but if a mainstream US publication came out and said that the US built an aircraft like that my first reaction wouldn’t be to just dismiss it as impossible as Sarah did.

I am saying that you believe(d?) it credulously, without any skepticism, got very hostile with people who doubted its claim less tactfully than I did, and now you admit you got hostile based on a claim that you now admit is dubious, and shifted the burden of proof from the article making the claim to the skeptic questioning it.

Again, I had a hostile reaction to the style of argument. The same way you’re having a hostile reaction to my style of argument.

Again, this is the logic of a fanatic.

Certainly would be, but that’s not my actual position. My whole point from the start is that it is plausible that China may have developed what they say they developed. You’re seemingly intentionally misrepresenting what I actually said to make me sound like a deranged lunatic.

If we just pick which dubiously sourced claims we believe based on vibes, truth stops existing.

And nobody is actually doing this.