Dude exactly!!! I wanted to see the target!!! To me this just looked like an advertisement for requesting more money from the pentagon.

It was a firing test. if you notice, it's just shooting out over the water, so i don't think they were trying to hit anything, it was a test of the firing & reloading mechanisms.

Oh word

What makes you think none of those things are being measured?

Does not seeing a thing mean it doesn't exist?

Ok, so? There are other trailers and buildings all around it. You don't need to stand in front of it with a camera to track information, it's 2017. :P

I'd imagine that it's the burning projectile.

Speed and friction with the air, barrel, or other mechanism?

Because it's traveling at hypersonic speeds? Mach 6 in this case. That's ~7400 KPH. Shit burns when it goes that fast.

If it wasn't the projectile itself burning, there are a number of other things that will burn. Notably the air itself, as well as the internal metal shaft of the gun. One of the big problems with rail guns is that they wear themselves out just from use.

OK, you officially have no idea what you're talking about by saying that.

zero friction

You should spend five minutes with google and correct yourself on this subject. There's massive amounts of friction in rain guns. You seem to be confusing real life with science fiction.

I know enough about how railguns work to know that one of the main features is zero friction. They don't wear out the barrels unless there is a malfunction.

Actually barrel fatigue is one of the primary engineering challenges in designing a functional railgun. Molten metal from the round actually deposits on the barrel surface. The sabot is an armature that bridges the gap between the rails allowing the round to be accelerated. The smoke you see is the result of adiabatic compression of the air in front of the projectile as it is accelerated on the order of 1000g.

No.

I've built a rail gun, there's friction. Also electrical arcs form between projectile and rails, vaporizing some of both.

I like how the phenomenon is explained to you, but you keep acting like a child

Pressure, heat, and water vapor. Its vaporizing the air around it.

Small scale railguns do this as well but at a much smaller scale.

Could be the intense heat and pressure from shooting something that darn fast.

Heat and pressure affects air which has water vapor in it.

There's no such thing as electromagnetic pressure

Things moving fast in a small tube.

Not what you said. I think you need to research vapor pressure.

a cooling system for the magnets or other hardware?

commented before i watched the video. seems strange that there is any smoke at all wtf?

If i recall, rain guns of that size don't actually use magnets, but rather just massive electrical charges.

https://www.defensetech.org/2017/07/21/navys-railgun-will-get-faster-powerful-summer/

The system still has crucial issues that need to be resolved. The system sustains significant wear-and-tear when it’s fired because of the power behind the projectile, leading to worries that the gun will break down too fast. Beutner said that parts of the system are being developed for longevity.

The rails themselves take wear damage every time the device is used, and they have to be replaced or else it will damage the overall gun. Fortunately, they're relatively cheap and easy to replace.

so the electrical charge sets off that much smoke? still doesnt add up

The smoke is from vaporized metal from the projectile and the barrel as it gets fired. You don't see that happening on smaller rail guns because.. we.. they're smaller. This this is frigging massive, the largest most powerful rail gun ever created. Not even operating at full power yet. Literally needs a nuclear power plant to operate when in the field (on a boat).

hmm very interesting. so is the electric pulse moved from the interior of the gun to the tip bringing the projectile along with it? figured id ask before i go search it up

That sounds right but i'm not 100%.

very interesting. wonder if we could launch rockets this way

Not with our current level of tech, that's for sure. If it takes a nuclear power plant to shoot a few pounds of projectile, i think a multi-ton rocket is a way off. That and if anyone was inside it they'd be turned into jello. :D

at least with the tech they are willing to share

Fair.

Propelling something at that speed is going to cause heat and pressure fluctuations in the barrel. Those forces in turn are probably creating from air moisture.

I've seen videos of actual small scale railguns. They don't blow smoke or steam out the muzzle.

Scale matters in this case.

How do you know what looks right? Are you an expert on railguns?

Again. I know enough about railguns to know what makes sense what doesn't make sense.

How do you know you know enough to say that?

Except possibly friction of the projectile against the air. That may cause some effect. But there should be little or NO smoke or fire coming out the barrel or rail itself.

How do you know?

Tell me everything you know about Rail guns.

1:28 mark on this video is interesting.

https://youtu.be/hzxqw7bbA7c

https://www.reddit.com/r/explainlikeimfive/comments/2styo8/eli5_why_does_smoke_and_fire_come_out_the_end_of/

It's the armature and surface layer of the rails ablating (vaporizing) into a plasma as the armature (piece that pushed the projectile down the rail) travels down the barrel.

Fundamentally, the two rails and armature complete and electric circuit. The armature is the part you see falling away from the projectile once it leaves the barrel. The back of the armature is horseshoe shaped. The electric current enters one rail, crosses the armature and goes back down the other. This u-turn of current creates a force (Lorentz force) that pushes the armature (and projectile) down the rails (at the same time, the two rails are trying to push themselves away from each other and have to be incredibly strong and rigid).

In a big enough gun, there is literally 100,000's of amps flowing through the rails and armature. The armature could literally vaporize half its mass as it travels down the barrel. The metal turns into a plasma which is what you see coming out of the barrel as smoke and flame. The circuit connection between the armature and rail is basically a lightning bolt for most of the shot. The rails also lose some material during each shot and have to be replaced after a certain number of shots.

Most of the development in the last few decades has been on the barrel and get materials to stand up to the forces and conditions to make it feasible. Development now is mostly shifting to the power sources to operate it so that you can fire it repeatedly and not have to wait hours for the system to charge.

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To the top you go!

Perhaps they've found that a traditional explosive charge which accelerates the projectile before it enters the electromagnetic yields a higher rate of acceleration.

If you think about it, if the EM field is only limited by the amount of time over the distance, but it's acceleration is constant (like an electric car) the faster (greater starting speed) it enters the EM field, the more higher end speed it can realize.

Office of Naval Research (ONR) demonstrates the Navy's electromagnetic railgun initial rep-rate fires of multi-shot salvos at the Naval Surface Warfare Center Dahlgren Division. The revolutionary railgun relies on a massive electrical pulse, rather than gunpowder or other chemical propellants, to launch projectiles at distances over 100 nautical miles – and at speeds that exceed Mach 6.

My pellet gun creates smoke. Go learn what happens when you quickly decompress humid air.

Serious question, did you go to school for any science degree?

https://youtu.be/i737rM6FxqE?t=6m6s