Chinese Hypersonic Developments (HGVs/HCMs)

I think up to Mach 15, the highest in the world.

At that speeds instead of wind blowing continuously you essentially have a pressurised explosion of air lasting only milliseconds, and the power requirements are huge. It gets much harder as size of the wind tunnel design increases.

I believe China is actually a world leader when it comes to large high speed wind tunnels, it's just not much publicised.

I also remember seeing photos of complex aerodynamic designs being tested in wind tunnels from the 70s and 80s. Those designs were not realised because of technological bottlenecks in other areas, or just no in high enough priority due to limited funds. Hopefully today a lot more of the design potential can be realised.

Edit: I may have remembered incorrectly about the maximum speed of Mach 15 for Chinese wind tunnels. However below is a confirmed Mach 9 wind tunnel in China from 2012:



Ignore the second picture, the caption already stated that it is of a US wind tunnel example.

-The JF12 has a testing chamber diameter of 3.5 meters.

-265 meters length enable a testing time of 100ms, compared to about 30ms for related foreign wind tunnels. 60-70ms minimum is required when testing hypersonic engines.

-Maximum speed is Mach 9, enough to generate 3000 degrees Celsius and melt steel.

-It costed 4.6 billion RMB to build, which is still less than an equivalent facility would have costed outside China.

SamuraiBlue said:

Aughh, forerunner of avionics already adopted computer simulation and had done away with physical tests for modeling a long time ago. These days you utilize super computers and analyze wind sheers in millimeter grids which cannot be done with actual physical tests.

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Simulation is not comprehensive, and is used in conceptual stage. For example, aerodynamics produce thermal and mechanical stresses, deforming the airframe, which in turn causes changes in aerodynamics. That then causes different thermal and mechanical stresses, and the cycle repeats. But how do you know the initial deformation is correct, that it goes in the correct direction and the correct magnitude? You can't, and getting that wrong means the rest of the result is garbage. That is called butterfly effect, a nature of feedback system. So, beyond conceptual stage requires physical tests. There is no way around tests.

Engineer said:

Simulation is not comprehensive, and is used in conceptual stage. For example, aerodynamics produce thermal and mechanical stresses, deforming the airframe, which in turn causes changes in aerodynamics. That then causes different thermal and mechanical stresses, and the cycle repeats. But how do you know the initial deformation is correct, that it goes in the correct direction and the correct magnitude? You can't, and getting that wrong means the rest of the result is garbage. That is called butterfly effect, a nature of feedback system. So, beyond conceptual stage requires physical tests. There is no way around tests.

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Do a research on Boeing 777 and

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SamuraiBlue said:

Do a research on Boeing 777 and

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.

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So? Software being used does not mean physical tests are not being done. Quite the opposite, a few seconds search on 777 and 787 in wind tunnel testing give these:





Simulation isn't perfect, which is exactly why wind tunnel tests are absolutely necessary. And that is just for transonic speed. At hypersonic speed with a lot more unknowns, physical tests trump simulation.

No I never suggested that test will not be done entirely.
Digital mock-up is to do away with the trial and error in design in which it eliminates guess work where you develop a design, create a physical mock up and, test it in a wind tunnel to refine the design and go through the same process again until you obtain the optimum design.
With digital mock up you do away with the intermediate testing and go directly to final design for final testing.

SamuraiBlue said:

No I never suggested that test will not be done entirely.

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Good. We have no disagreement then.

SamuraiBlue said:

Digital mock-up is to do away with the trial and error in design in which it eliminates guess work where you develop a design, create a physical mock up and, test it in a wind tunnel to refine the design and go through the same process again until you obtain the optimum design.
With digital mock up you do away with the intermediate testing and go directly to final design for final testing.

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That is manufacturing related, and isn't relevant to the discussion of hypersonic research. I will leave it as that.

Engineer said:

That is manufacturing related, and isn't relevant to the discussion of hypersonic research. I will leave it as that.

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No it has very little with manufacturing and has all to do with optimum AIR FLOW.
The actual test flights has more to do with manufacturing though.

guys I think we have wondered so far away form the intended topic as to no longer see it.

I think we need to re-prioritize here. Currently we seem obsessed with the US program of record. However it should be noted that that is a grey program. We see the white aspects of it but like an iceberg that is only the tip of a very large program in the murky deep. Thus far the visible aspects have had limited success.


Fact The PRC has tested a Hyper-sonic glider,
Fact The PRC has the facilities to design and test Hyper sonic vehicles bodies,
Fact the PRC has from time to time shown an interest in space plane technology.

Hyper sonic aircraft and Space planes especially Single stage to orbit ones are very closely related.
Today we have a number of propulsion technologies that have transitioned from government space programs to commercial entities, like Reaction Engines Limited who have designed there Synergistic Air-Breathing Rocket Engine concept based on there founders previous work for the British government on the Horizontal Take-Off and Landing project. This means that The technologies to propel a huper sonic platform manned or unmanned are available through a verity of means both legitimate and illegitimate. IE There is no way to disprove that a Party like the PRC can have the propulsion tech to build a powered Hyper sonic vehicle either through work done in or done with out of the PRC.

Now the big question is are these recent rumored Hypersonic vehicles just father testing of the established WU-14 ( DF-ZF) platform which we know was last tested in or about August of 2015 or are they a totally new as yet unidentified powered platform?
Personally I could go to some degree either way one this, but with out hard evedence I favor the WU-14 as the source of the rumors.

Skywatcher said:

The Chinese hypersonic tunnel also goes to higher speeds, I think.

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Really? How much higher? Is there a creditable source for the claim?