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US Navy's Railgun Now Undergoing Tests in New Mexico

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Re: US Navy's Railgun Now Undergoing Tests in New Mexico

#101

Post by DuskStar »

charlesju wrote: post #97
ChuckMcM wrote: post #44

I find the physics of rail guns pretty fascinating. For something nominally invented in world war 1 (1918) which is now "only a few years" away from possible deployment. We are talking literally a 100 years later. We went from powered flight to flying in orbit in less time, think about that. Is it a compelling weapons concept? Of course it is, you don't need explosives to shoot things that is pretty huge. Are wars ba…

I think the interesting use case would be to put things into space for a lot less money. Imagine putting one or many of those new Space X internet satellites into a rail gun that goes straight up. It doesn't need to go all the way into space, it just needs to get pretty high, then the cost to break into orbit can require a lot less fuel and make it a lot more cost effective to do space stuff.

> Imagine putting one or many of those new Space X internet satellites into a rail gun that goes straight up.

Orbit doesn't work like that. Getting 200, 300 miles up is the easy part - the vast majority of the required energy comes from going sideways at 7800m/s.

Re: US Navy's Railgun Now Undergoing Tests in New Mexico

#102

Post by ChuckMcM »

derefr wrote: post #49
ChuckMcM wrote: post #44

I find the physics of rail guns pretty fascinating. For something nominally invented in world war 1 (1918) which is now "only a few years" away from possible deployment. We are talking literally a 100 years later. We went from powered flight to flying in orbit in less time, think about that. Is it a compelling weapons concept? Of course it is, you don't need explosives to shoot things that is pretty huge. Are wars ba…

It's not like the technology behind railguns hasn't been stable and ready to use for decades now. It's just that, until the more recent invention of ancillary technologies like supercapacitors, it's been so costly to fire them that there was no logical place for them on the battlefield, so we never bothered to operationalize them.

I can't agree with this: "It's not like the technology behind railguns hasn't been stable and ready to use for decades now.", at least not in terms of practicality. I did a bit more research on flight and found a similar comment from Wilbur Wright[1] about George Cayley.

It is very different to be able to demonstrate a principle in physics (such as flight, or accelerating a piece of metal with electricity) and building a practical application of that principle. In many ways the time it takes between those two points is likely a good indicator of just how difficult it is to reduce the principle to practice.

You yourself mention super capacitors, another comment mentions the rails, then there are the switching devices themselves, the wiring harnesses, the control system. That is why I'm pretty awestruck at the fact that they were able to make it work and get this close to being something they can field test.

[1] "About 100 years ago, an Englishman, Sir George Cayley[2], carried the science of flight to a point which it had never reached before and which it scarcely reached again during the last century." -— Wilbur Wright, 1909 --- http://www.ctie.monash.edu.au/hargrave/cayley.html

[2] https://en.wikipedia.org/wiki/George_Cayley

Re: US Navy's Railgun Now Undergoing Tests in New Mexico

#103

Post by haneefmubarak »

PhasmaFelis wrote: post #96
qball wrote: post #66

Earlier quoted context omitted.

A railgun, while its mechanism is electromagnetic, works on a base level by causing a massive high-current electrical short. As a side effect (as in most electrical shorts), both the rails and some of the projectile are vaporized when the gun is fired due to both friction and electric arcing; and that's the smoke and fire you see. This wear (which is signifcant per shot) is also the main obstacle to actually using ra…

Why is no one developing coilguns? I've been wondering.

Coil guns require a lot more precision and accuracy in both manufacture and timing than rail guns, because you have to sequence the pulsing of the coils (compared to one massive burst of sustained power on a rail gun).

In a nutshell, you need to deal with most of the rail gun hard problems and then also deal with the added coil gun problems.

Re: US Navy's Railgun Now Undergoing Tests in New Mexico

#104

Post by [deleted] »

ijpoijpoihpiuoh wrote: post #94
derefr wrote: post #49

Earlier quoted context omitted.

It's not like the technology behind railguns hasn't been stable and ready to use for decades now. It's just that, until the more recent invention of ancillary technologies like supercapacitors, it's been so costly to fire them that there was no logical place for them on the battlefield, so we never bothered to operationalize them.

To me, it's not entirely clear why we're bothering. Do we actually envision shore bombardment as a useful combat modality going forward? IIRC the types of ships that can mount this weapon are the same types that are currently vulnerable to hypersonic anti-ship missiles. All our potential equiv-tech adversaries have those, to my understanding. So wouldn't the railgun only be useful against lower tech opponents? And ag…

[deleted]

Re: US Navy's Railgun Now Undergoing Tests in New Mexico

#105

Post by greedo »

ijpoijpoihpiuoh wrote: post #94
derefr wrote: post #49

Earlier quoted context omitted.

It's not like the technology behind railguns hasn't been stable and ready to use for decades now. It's just that, until the more recent invention of ancillary technologies like supercapacitors, it's been so costly to fire them that there was no logical place for them on the battlefield, so we never bothered to operationalize them.

To me, it's not entirely clear why we're bothering. Do we actually envision shore bombardment as a useful combat modality going forward? IIRC the types of ships that can mount this weapon are the same types that are currently vulnerable to hypersonic anti-ship missiles. All our potential equiv-tech adversaries have those, to my understanding. So wouldn't the railgun only be useful against lower tech opponents? And ag…

Railguns have potential for ship defense and missile defense.

Re: US Navy's Railgun Now Undergoing Tests in New Mexico

#106

Post by TimTheTinker »

losteric wrote: post #79
minikites wrote: post #41

Earlier quoted context omitted.

Do you genuinely see the same virtue in the engineering of a bridge and the engineering of a cruise missile?

Virtue? For me, it's much more basal than that. Railguns, rockets, explosions, lasers... fast cars, fighter jets, massive supercomputers... all impressive engineering "magic" that spark some childish awe in a certain type of person. As an adult, I know the why behind the technology. That "awe" grows into "awesome" or "awful"... but it always starts awe.

There is something awe-inspiring about raw power in action -- whether it's a power that creates or a power that destroys.

Re: US Navy's Railgun Now Undergoing Tests in New Mexico

#107

Post by ars »

antpls wrote: post #63

Could the same technology be used to help the lift off of Falcon9-sized space rockets from a deep vertical tunnel ?

See here: https://en.wikipedia.org/wiki/Mass_driver

You actually want horizontal velocity, not vertical. Getting "up" is easy (it's only a few miles), it's the horizontal speed that keeps you there.

The only reason rockets launch straight up is to avoid the thick air as quickly as possible, then they turn and accelerate sideways the rest of the way.

Re: US Navy's Railgun Now Undergoing Tests in New Mexico

#110

Post by ars »

godelski wrote: post #31
travisporter wrote: post #9

Is there any active research on this technology for non-rocket launch systems?

Do you mean like going to space? There's some research but after everyone figured it that all humans inside would be instantly squished they started researching other avenues. The g forces are pretty large and would damage a lot of cargo too.

> would be instantly squished

Not so. That's only for a very short launch. You would actually have a track a few miles long (probably up the side of a mountain) and launch using that. The g-forces would be very mild.

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