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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

#61

Post by coredog64 »

perrylaj wrote: post #58

Tyler Rogoway (formerly of Jalopnik's FoxtrotAlpha and now writing for TheDrive.com) had a take on China's goals(1). He seems to think that the plane's ability to act as a launch craft is a notable. I've found Rogoway to be a pretty good source of digestable and non-sensational military tech info. 1. http://www.thedrive.com/the-war-zone/5083/why-china-wants-to...

Air launch is an incredibly tricky operation. Even something as trivial as a 500 lb. bomb undergoes lots of trials before it is accepted for use.

The US Space Shuttle program only ever did glide testing of the orbiter off the back of the 747 carrier. A real launch of an orbital vehicle off the back of an AN-225 would mean serious envelope pushing and would be putting an extremely expensive aircraft at risk every time.

Re: China Will Resurrect the World's Largest Plane

#63

Post by k_lander »

wallace_f wrote: post #28
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…

Why is it difficult enough that not even a nation state as large and powerful as china has obstacles to develop a heavy turbofan? With respect to other tech they've developed I don't know what is technologically difficult here -- I'm asking genuinely as a layman, it's not a rhetorical statement of disagreement.

Also, how Ukraine, out of all countries?

Re: China Will Resurrect the World's Largest Plane

#64

Post by blakeyrat »

Const-me wrote: post #57
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?

This particular aircraft ain’t economical by today’s standards. Here’s some comparison to a popular modern cargo plane, based on public data: https://1drv.ms/x/s!AKpTxXHPN4XIj9tN As you see, fuel economy is somewhat worse compared to that Boeing. I don’t think the main problem is size or weight. I think the main one is age. AN-255 is 30 years old, Boeing 747-8 is 6. That’s almost 25 year or progress in aerodynamics a…

The unassembled one pictured towards the bottom of the article seems to have some refinements to the design, not being built with the requirement to haul the Buran around-- they mention a single tail specifically. It might not be as out-of-date as you'd assume.

Re: China Will Resurrect the World's Largest Plane

#65

Post by rayiner »

wallace_f wrote: post #28
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…

Why is it difficult enough that not even a nation state as large and powerful as china has obstacles to develop a heavy turbofan? With respect to other tech they've developed I don't know what is technologically difficult here -- I'm asking genuinely as a layman, it's not a rhetorical statement of disagreement.

Developing a modern turbofan engine requires deep expertise in numerous domains: fluid dynamics, metallurgy, etc. The basic principle is easy: increase temperature and pressure to increase efficiency. But just because you know that doesn't mean you know how to manufacture a single-crystal nickel alloy turbine blade that can actually work at those temperatures and pressures.

Re: China Will Resurrect the World's Largest Plane

#66

Post by rayiner »

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?

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.

Re: China Will Resurrect the World's Largest Plane

#67

Post by pcurve »

maxerickson wrote: post #9
to3m wrote: post #5

"84 meters ... 88 meters ... 250 tons ... 300,000 lbs"

The US also operates a fleet of larger cargo planes than the one chosen for the comparison. https://en.wikipedia.org/wiki/Lockheed_C-5_Galaxy (I think the typical reader will have little intuition for the cargo capacity of the C-17, so the more instructive comparison looks at the most capable operational US plane.)

side by side photo.

http://www.avionale.com/wp-content/uploads/2015/03/Lockheed_...

c5 Galaxy is massive.

Interestingly, Boeing 747-8F is even bigger, heavier, and carries more load.

Antonov 225?

Well, it can carry the same load as both of those planes combined, which really put things into perspective.

Re: China Will Resurrect the World's Largest Plane

#68

Post by stepik777 »

finid wrote: post #48
daurnimator wrote: post #10

Can't see the article. It redirects me to http://www.popsci.com.au/?src=redirect with an error: "Oops! Something went wrong. Please scroll down to find your content."

In cases like this, use Tor Browser.

Or Google Translate

Re: China Will Resurrect the World's Largest Plane

#69

Post by racecar789 »

icegreentea wrote: post #39
fma wrote: post #35

Earlier quoted context omitted.

This being China...what are the chances they can buy existing designs and reverse engineer them and improve then so they don't start from scratch. They've done it before...

Well, they've almost certainly been trying that. And as the OP said, it hasn't been paying off in a big way. If they've been doing it (I'm guessing they have), then they've probably benefitted, just not enough for the big win. Once you get into materials and fabrication, having a finished example to examine is rarely going to lead to a big win. If the secret sauce is in the fabrication (HOW do you make a single cryst…

Yep, sending the prints over is just getting started.

Similar to razor blades and little balls that go into writing pens. Few companies can make them well. China has to import little balls from Japan (at least for high quality pens).

Sending over work instructions will help (somewhat). China will need veterans of the process to work with local Chinese vendors, explaining how to do each step.

The Ukrainian staff will resist handing over their work babies. Also, the subcontractors (heat treaters, metal workers) will not hand over their secret sauce.

China will figure it out eventually. This will help. Still many years away from mastering it though. They will have to source from Ukraine for quite a while.

Re: China Will Resurrect the World's Largest Plane

#70

Post by PhantomGremlin »

Retric wrote: post #56
izacus wrote: post #41

Earlier quoted context omitted.

> Why would the Soviet's independently develop a highly flawed project? Probably a few reasons: * At the point of starting Shuttle operations, the flaws of the design weren't as apparent, especially not to general public. * Even though it LOOKS similar, it's actually not all that similar in design. The main difference is that it doesn't actually carry engines (which are the most expensive and problematic part of Shut…

It's not just rebuilding engines it's returning their weight that's a problem. The high temperatures are a result of pressure not friction. A smaller and or less dense craft has a vastly easier time during reentry. A shuttle actually works fairly well at around 1/5 the size. Lower thermal stress means no tiles. It would have a single ideally swappable engine large on board fuel and no external fuel tank. Still needs…

A shuttle actually works fairly well at around 1/5 the size

As I'm sure you know, the USA actually has an operational tiny "shuttle". But for others here, I wanted to link to it, because it's cute. It looks just like a baby shuttle.

I put the word "shuttle" in quotes, because it's actually not a shuttle, but an unmanned reusable orbital spy spaceplane. Or is it?

https://en.wikipedia.org/wiki/Boeing_X-37

http://phys.org/news/2016-05-super-secret-x-37b-space-plane-...

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