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China Will Resurrect the World's Largest Plane

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Re: China Will Resurrect the World's Largest Plane

#71

Post by semi-extrinsic »

rayiner wrote: post #66
vasili111 wrote: post #42

Earlier quoted context omitted.

Why not to just buy one aircraft and reverse engineer its engines? What is the problem with just copying exact copy of existing engine?

Modern turbofans only stand up to their extreme operating conditions because of the use of exotic alloys and elaborate cooling techniques. Just because you know what shape a turbine blade should be doesn't mean you can copy the exotic alloy and manufacture it in a way that results in the correct crystal structure.

Not only exotic alloys, but single crystal blades. That's right, the blade is machined out of a single atomistically perfect crystal with no defects what so ever. The main point is that this reduces thermal creep, meaning you can have tighter tolerances and more power/efficiency.

Re: China Will Resurrect the World's Largest Plane

#72

Post by ting_bu_dung »

ovi256 wrote: post #20

It's obvious to me that China doesn't care that much about the AN-225 design as for the design of the D-18 turbofan. They still can't design or manufacture a heavy turbofan domestically. This has seriously hampered their heavy airlift project (the Y-20, who first flew using Soviet-designed low-bypass 12-ton thrust D-30 fans, which killed its range). The domestic WS-20 turbofan design that was supposed to power the pr…

it seems China is starting to militarize under its one dictator Xi, what with the island building in south china sea, desire to build aircraft engines, voicing economic/military threats to other countries when it cannot buy critical infrastructures in those countries (UK, Australia) and continued trade support for north korea (with its bigger nuclear bomb capability). It must be preparing for some sort of external conflicts, what with the internal economy crashing, wto membership ending this year, capital outflows, manufacturing moving out.

Re: China Will Resurrect the World's Largest Plane

#73

Post by djrogers »

There is very little chance that story is even remotely true. The story had 2 sources - Saddam Hussein, and Mohammed Saeed al-Sahhaf aka 'Baghdad Bob' (if you don't remember him, look him up - he was a meme before the Internet made memes a thing). On top of that, the story changed from a farmer to a few peasants and back again depending on who was talking and when.

It was propaganda to make the US military look weak and ineffective - the same kind of propaganda that let us watch a split screen of al-Sahhaf's press conference saying the US hadn't taken Baghdad airport and US forces strolling around its tarmac.

Re: China Will Resurrect the World's Largest Plane

#74

Post by rayiner »

semi-extrinsic wrote: post #71
rayiner wrote: post #66

Earlier quoted context omitted.

Modern turbofans only stand up to their extreme operating conditions because of the use of exotic alloys and elaborate cooling techniques. Just because you know what shape a turbine blade should be doesn't mean you can copy the exotic alloy and manufacture it in a way that results in the correct crystal structure.

Not only exotic alloys, but single crystal blades. That's right, the blade is machined out of a single atomistically perfect crystal with no defects what so ever. The main point is that this reduces thermal creep, meaning you can have tighter tolerances and more power/efficiency.

Also, because combustion temperatures can exceed the melting point of the alloy, HPT blades often have a complex set of internal hollows and holes at the surface for cooling air. Air can be passed through to create a boundary layer on the surface that prevents the surface from heating up past the melting point of the alloy.

Re: China Will Resurrect the World's Largest Plane

#75

Post by Symmetry »

finid wrote: post #45
Symmetry wrote: post #25

Earlier quoted context omitted.

I don't see the author addressing that topic either and I reread the article twice.

Practically every single paragraph in that article, including image captions, either infer or directly address the economic reasons for why China would want the An-225 and its technologies.

Yes, nobody's disputing the idea that there are times when you need a single large cargo hold. The question is whether the plane would be economically competitive in terms of regular cargo. In other words is China going to build 3 of these and have them spend most of their lives sitting in hangers or are we going to be seeing hundreds of these flying all over China? That's something the article doesn't try to address.

Re: China Will Resurrect the World's Largest Plane

#76

Post by macintux »

djrogers wrote: post #73

There is very little chance that story is even remotely true. The story had 2 sources - Saddam Hussein, and Mohammed Saeed al-Sahhaf aka 'Baghdad Bob' (if you don't remember him, look him up - he was a meme before the Internet made memes a thing). On top of that, the story changed from a farmer to a few peasants and back again depending on who was talking and when. It was propaganda to make the US military look weak…

Curious to what in the world this is in reply.

Re: China Will Resurrect the World's Largest Plane

#77

Post by avmich »

chiph wrote: post #27
SideburnsOfDoom wrote: post #17

Is an aircraft of this size economical, or is it a fuel hog useful only for carrying huge single-piece cargos that smaller aircraft cannot? Is it useful, or is it sheer size-vanity?

I doubt there's enough heavy commercial cargo in the world that would support a fleet of these aircraft. While the current AN-225 is busy, it doesn't appear to be busy enough to financially justify restarting construction on the second airframe. I expect this is desired for a few reasons - heavy military airlift, to match what the US has had since Vietnam with the C-5 Galaxy. Access to licensed construction of the D-…

There is a known big problem of transporting big rocket stages from the place where they are manufactured to places where they are launched.

Saturn-5, one of the biggest rockets so far in the world, was manufactured near a river and transported by a big ship. This sidestepped the problem of roads.

Energiya, the Soviet heavy rocket which launched Buran, had its huge second stage flown by a plane to Baykonur.

In 1960-s, USSR was looking for a good solution to this problem. They considered building a huge canal to use ships; they were thinking about using an aircraft; they played with an idea of building an exceptional - biggest in the world, if I'm not mistaken - automobile to carry it over desert. Eventually they decided to build rocket near the launch complex - that's the reason N-1 has the unusual shape.

Today, SpaceX keeps lengthening Falcon-9 modules - but it can't make them wider, because existing roads won't allow it. Long stages have their share of problems - they could be less efficient by mass, they could have unwanted dynamic characteristics - imagine a long thin-walled container pushed from behind through the atmosphere, it way vibrate...

In short, just the rocket industry of the world alone - that's currently about under hundred launches per year - could provide the market for big planes. At least this is a possible option.

Re: China Will Resurrect the World's Largest Plane

#78

Post by dingaling »

SideburnsOfDoom wrote: post #17

Is an aircraft of this size economical, or is it a fuel hog useful only for carrying huge single-piece cargos that smaller aircraft cannot? Is it useful, or is it sheer size-vanity?

> Is an aircraft of this size economical

It's not just the size, it's also the shape of such airlifters that makes them non-economical for commercial use.

For example the USAF's own data shows that the C-17 burns more fuel per hour than the KC-10 but carries 20 tonnes less payload by weight, all because of the fat rear-loading-for-tanks fuselage ( that's seldom used for such ) and thick wing.

Both the C-17 and the C-5 were touted on the civil market but had zero uptake.

Re: China Will Resurrect the World's Largest Plane

#79

Post by hourislate »

vasili111 wrote: post #42
crawshaw wrote: post #31

Earlier quoted context omitted.

Fluid dynamics and combustion chambers. It's rocket science, a long, expensive trial-and-error development process. And unlike other sciences, most of the results are never published so each entity has to recreate the foundations themselves. It takes money, time, and dedicated careers.

Why not to just buy one aircraft and reverse engineer its engines? What is the problem with just copying exact copy of existing engine?

I'm not an expert in the field of reverse engineering but I have read in the past that it can be extremely difficult and end up costing more in time, effort, money than designing from scratch.

China has the luxury of being able to play catch up by purchasing technology. Why spend the next 20 years trying to develop it when you can pay Ukraine who already has the expertise/product and probably gave the Chinese a deal. It's just smart business.

China apparently did something similar with BMW. They bought a BMW factory in Brazil (I think) for a couple of billion and disassembled it piece by piece and moved it to China. It saved them years of figuring out the how to of high tech auto engine manufacturing.

Link to Story:

http://tech.mit.edu/V126/N4/4long4.html

Re: China Will Resurrect the World's Largest Plane

#80

Post by avmich »

qaq wrote: post #55
kostyash wrote: post #7

To make it possible Ukraine and Chine will need to redevelop many technologies that were used to build Mriya. The technologies were gone when USSR collapsed.

Not that many the bulk of manufacturing was done in Ukraine what was sourced externally can be sourced from subcontractors. For example engines are manufactured by Motor Sich (Ukraine based) which is still a fairly large engine manufacturer etc.

Hydrogen engines for Energiya, RD-0120, were made in Voronezh by KBKhA, which is still producing rocket engines. However this particular engine is practically lost - can't be recreated without extensive R&D program.

It's not enough to have the original manufacturer survive... Can Rocketdyne manufacture another F-1 today? So it's quite possible - though not certain - that Motor Sich wouldn't be able to create a unique enough engine, even if it did that in the past.

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