Thought this was interesting…
https://www.purdue.edu/newsroom/releases/2021/Q3/national-hypersonic-ground-test-facility-to-be-built-in-purdue-aerospace-district.html
Hypersonic wind tunnel testing? Yes, please!
HYPULSE? You betcha!
All this made me amused at the question, though, that popped into my brain uninvited: do they mean terrestrial-based testing facility for things moving at hypersonic (=>mach 5, or 3,705mph) speeds using the Earth’s frame of reference, or proving that any given chunk of Earth is traveling at hypersonic speeds through space?
Since the latter is largely considered proven, it makes it easier to consider the first. Also, the article supports the former.
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The speed of any object only has meaning, or can only be meaningfully measured, relative to another object or reference point in space (not so with acceleration, of course). Hence Mr. Einstein’s Special Theory of Relativity
I wasn’t aware of HYPULSE, though…thanks for today’s rabbit hole.
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But the Defense Department is turning its attention to hypersonic missiles to keep up with China and Russia…
Now we are trying to “keep up” with them.
All told, the Navy spent about $500 million on research and development,
I bet it was much more than that, all in.
God, what a depressing article.
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On the other hand - there was a lot of physics learned in the process. Will be interesting to see where the gained knowledge ends up.
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Agree. A lot of knowledge was gained: materials science, electronics, energy storage, etc. Info that will be used to improve other weapons.
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It’s electric-based. Maybe it can somehow be applied to car propulsion? You know…to be more green
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It very well may be possible since there will be a lot of BIG capacitors involved and some high high strength materials. Look how much came out of the space program that ended up in products that had nothing to do with it. The payback on that has been massive.
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I imagine that, ahem, conductor wear was the elephant in the corner that wouldn’t go away with the railgun prototypes. Materials science likely unable to come up with something that could handle that kind of current in addition to accelerating a slug up to several times the speed of sound in a millisecond or so.
Mass drivers on the lunar surface pumping tons of material into orbit for the construction of large space habitats? The idea has been around since the 1980’s and probably will take till the 2080’s to realize.
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One of the questions is how good is good enough. The 16 inch barrels on the Iowa class were only rated for a few hundred rounds when the class was introduced. I believe spare barrels were produced and some change outs were performed. Later, several techniques like lower pressure charges, and eventually a powder additive package increased barrel life to around a couple thousand rounds before the class was retired if my memory is correct. But anyway, the point is, for military purposes, you just have to get good enough life, and good enough doesn’t have to be numbers that make sense to the way we manage our finances.
I believe the railgun prototypes were hoping to get a tad more than single-digit round counts per barrel.
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I ran across these 2 videos on the subject of 16” guns(been watching naval ship videos over the past several months). 1 of them goes into better detail but the audio sucks.
The mid 80’s had a projected service life of 1500 rounds due to additives to the powder charge.
Warning the bad audio version
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OK, did a little digging and found a document on the subject. Since it’s light reading, here’s the money shot relevant passage:
So apparently they have somewhat addressed the conductor problem since I last looked into it. But that’s at fractional rounds per minute, suggesting that there are unmet challenges scaling that rate up more than an order of magnitude when the barrels won’t have pastoral whole minutes to cool.
The USS New Jersey Museum videos are interesting and informative, but their production values are unfortunately lacking. Get the feeling the curator has to squeeze them in between more urgent day job tasks and they lack the time to do multiple takes.
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It sounds like a wind tunnel that can do mach 8 which is very fast for a wind tunnel. Interesting tidbit there’s a wind tunnel in the area that can do mach 5.
This is a video about the conops of hypersonic weapons and how that changes things. The takeaway is hopefully these types of weapons don’t end up for sale to just anyone (and a treaty might help that).
This is about the organization that made the video.
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I wonder how fast the Men in Black would get here if we built a Mach 5 to Mach 8 High Speed Wind Tunnel at DMS… 
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About the only defense against these will be laser… and that won’t work against a kinetic energy warhead. Yuck.
I wouldn’t want to be anywhere near it if DMS built it. 
That high speed wind wants to go everywhere but the tunnel forces it in one direction. They’re incredibly powerful and dangerous machines. Very thick steel structures guide the wind. Here’s an example of a different one that illustrates the point.
Without those very thick steel structures to guide the wind it would blow up the building because there’s so much energy being dumped so quickly. The forces involved with that new one at Purdue must be incredible (like an ongoing rather than instantaneous explosion).