10 Sci-Fi Weapons That Actually Exist

[RexMundi]

Re: 10 Sci-Fi Weapons That Actually Exist

 

Basically, turns the bullet into a ramjet engine. Doesn't need fuel because of the super sonic airflow physics behind it as the bullet is leaving the muzzle at well over twice the speed of sound to begin with. So it starts to accelerate, and remains stable do to spin etc ......

 

Now, combine THAT, with a bullet like the .408 CheyTac, which is deadly accurate already out to a range of 2500 yards. Depending on round and initial velocity, "slipperiness" of the bullet etc, you can get some Insane Ranges, and impact energy out of it potentially, while retaining even more accuracy (unlike a gyrojet round), then the bullet would already have (CheyTac's .408 is in a class by itself accuracy wise. 3 bullets within a smidge over 16 Inches at over 2300 yards, and not much more then 1 minute of angle for vertical dispersion for shots up to and over 3000 Yards. Even TV hosts were hitting man sized targets at over 2500 yards, with Kill Shot, and 3 out of 6, without spotter.

 

Remember, it wasn't very long ago, that folks thought making an Airplane that was smaller then a hummingbird on Radar was impossible or a gliding bomb that could steer itself for that matter, or Nuclear level exothermic reactions, without nuclear material. And that's all OLD tech. Just remember the sheer difference the Miniball round made in those pesky black powder days. There's still plenty of exponential leaps to be made in slug throwers.

 

~Rex

[BobGreenwade]

Re: 10 Sci-Fi Weapons That Actually Exist

 

Rubber Storm though' date=' would be kinda funner though at that velocity and rate of fire, Nerf Storm.[/quote']Okay, I just had to Rep this. And when Steve gets around to writing the Equipment book, I'm going to lobby for it.

[Kristopher]

Re: 10 Sci-Fi Weapons That Actually Exist

 

Basically, turns the bullet into a ramjet engine. Doesn't need fuel because of the super sonic airflow physics behind it as the bullet is leaving the muzzle at well over twice the speed of sound to begin with. So it starts to accelerate, and remains stable do to spin etc ......

 

Now, combine THAT, with a bullet like the .408 CheyTac, which is deadly accurate already out to a range of 2500 yards. Depending on round and initial velocity, "slipperiness" of the bullet etc, you can get some Insane Ranges, and impact energy out of it potentially, while retaining even more accuracy (unlike a gyrojet round), then the bullet would already have (CheyTac's .408 is in a class by itself accuracy wise. 3 bullets within a smidge over 16 Inches at over 2300 yards, and not much more then 1 minute of angle for vertical dispersion for shots up to and over 3000 Yards. Even TV hosts were hitting man sized targets at over 2500 yards, with Kill Shot, and 3 out of 6, without spotter.

 

Remember, it wasn't very long ago, that folks thought making an Airplane that was smaller then a hummingbird on Radar was impossible or a gliding bomb that could steer itself for that matter, or Nuclear level exothermic reactions, without nuclear material. And that's all OLD tech. Just remember the sheer difference the Miniball round made in those pesky black powder days. There's still plenty of exponential leaps to be made in slug throwers.

 

Turns the bullet into a ramjet, but with no fuel, which accelerates after leaving the barrel?

 

Cite?

[RexMundi]

Re: 10 Sci-Fi Weapons That Actually Exist

 

Basic principal of the function of super sonic airflow under compression, hmm, like the venturi effect for liquids. If it's fast enough to begin with, compression within the "engine" will speed up said air flow, and it leaves faster then it entered, providing additional thrust. It's made an appearance now in at least 3 separate Military sci fi books in the last year (the goofy ones written by real military people and real physicists not just handwavium folk), but it's a real fundamental principal that's been around as long as the Jet Engine.

 

You just have to START, really fast, to get away from having to have movie parts and exothermic additives. The Small Size, increases the efficiency of the process, and the muzzle velocity takes care of the rest (so the techno stuff says). It's not efficient enough to maintain much velocity, but per mass, it extends the range of the bullet considerably. If you could add a combustive fuel source (say, we get GREAT nanotech construction some day, and conversion fuels), you get a real little scramjet going and splat. Dead Target a long way away. Easiest novel to find it in now I believe would be Von Neumann's War, by John Ringo and Travis S. Taylor. Taylors work is interesting considering the guys background. Very much a return of the old school sci fi writer. Fun read with interesting concepts you can track all over the place for more info on.

 

~Rex

[Kristopher]

Re: 10 Sci-Fi Weapons That Actually Exist

 

I'd be interested in reading a more detailed explanation, if you can link to one.

[RexMundi]

Re: 10 Sci-Fi Weapons That Actually Exist

 

I'll see if I can find it. It's effectively the same principle as what you find when you look up Scram Jet or Venturi Tube on google ......They broke it down in the books though because the first question asked about the thing when it's presented is where is the fuel. Granted, it's not a Current thing we have now (At that SCALE ;D ), but we're talking future developments, and it's based on stuff we have now, so let me find the details for you, since from all apparent babble on it, it's possible. Just REALLY expensive. Still if you got to the point of automated Nano construction, then it would be a non issue, and far far more cost effective, then Hand Held energy weapons.

 

~Rex

[Kristopher]

Re: 10 Sci-Fi Weapons That Actually Exist

 

"Automated nano construction" of the type so beloved in SF is probably a pipe-dream if you don't ignore the practicalities.

 

Scramjets still need fuel.

 

The Venturi effect doesn't provide something for nothing.

[RexMundi]

Re: 10 Sci-Fi Weapons That Actually Exist

 

The basic principal of thrust doesn't change, because you add something that goes Kaboom, in the mixture. The fuel element, comes into play when you want continuous thrust and control to over come mass, as opposed to a brief boost, and a proper thrust vs mass situation, and the last I looked, Air, was still a Something. There is even a paper airplane you can build, that will accelerate away from you (up to a point, looks kind of like a flying ring/Cone kinda thing) based on that principal. It's the same principal as a garden hose. You toss the hose on the ground. Add water (or Air for an Air hose really either are interchangeable until you get to compression issues and even then if you compress far enough you end up with the same mechanics anyway, OR, you get combustion depending on what is being compressed.).

So long as the diameter at the END of the hose where said material exits the Hose most likely sits there. Decrease that Diameter, and Compress the flow of material (Venturi Process) and the Hose launches itself all over the place. Direct that thrust, and it can Launch You (Could you tube several things of that but I'm sure we've all seen it). You haven't, added anything to the mix at all. All you did was take what was entering at one end, compress it, and blow it out the other end, without any parts, or explosive additives.

 

The actual mechanics and terminology for the Ram Accelerator process, and things like the Light Gas Gun, and the all so fun sci fi Scram Cannon, better describe what the books illustrate. They also just incorporate, the same process, into the round itself. Does it boost Long? No, but long enough to give some extra legs down the track, without the squirrely control issues of the old gyrojets. If we still want to debate Ramjets having to Have Fuel. The Cold Ramjets used on the rotor tips of the old Djinn helicopter didn't use anything but air. This is all really Old Old Old technology. While both styles of ramjets (hot or cold) weren't very efficient back in the 50's, we've gone back to testing them again Nowadays, because we can do more with them, and the new materials we can make them out of, then what we did back then.

 

As for Automated Nano Construction? Why not? 20 Years ago we didn't have Automated Detailed Factories, Now we have them churning out Cars and Solar Panels. As for Fuel. Fuel, doesn't have to be self contained. At no time did we ever state, the Venturi Effect gives you something for nothing. I'm pretty sure I previously mentioned you are still firing this bullet out of a gun, so I should have explained, there's still a lot of explosion going on here in case that was over looked. Hells we're only steps away from having a dependable Combustion Light Gas gun if you want to talk Silly mean Awesome Slug Throwers (Or really over priced Potato Cannon), especially if one gets around to building said thrust boost into the round itself.

 

~Rex

[Kristopher]

Re: 10 Sci-Fi Weapons That Actually Exist

 

http://en.wikipedia.org/wiki/Tip_jet

 

There's an extranal power source pressurizing both the hose and the "tip jets". There's no special process going on there, it's just old-as-dirt Newtonian action/reaction.

[Captain Obvious]

Re: 10 Sci-Fi Weapons That Actually Exist

 

The only ramjet I've ever heard of that doesn't need fuel is the Bussard ramjet, which is a theoretical spacecraft engine. Other ramjets are desirable primarily because they don't have moving parts (which also makes them good for increasing bullet range, but they still need to carry some fuel along with them).

[RexMundi]

Re: 10 Sci-Fi Weapons That Actually Exist

 

Right. There's an external Power Source for the Bullets in Von Neumann's war as well. Gun powder. The contained explosive gas release within the barrel of the weapon as it's fired. The Air flow dynamics are the same, and once forward momentum starts, the velocity is maintained by the intake, and the forward motion Ram Effect. You've got, Initial Thrust, and a High Velocity in excess of what's needed to enforce a Ram Air effect inside the round, Said thrust need not continue long, and it's meant to be nothing more then an initial boot in the butt, and functions on the very simplistic principle that when you compress the volume the material will move Faster. If you can initiate a Ram effect, Air enters one end, compresses, and exits the other end faster and you generate Thrust. If you add a Combustive element to that, it will exit even faster generating more Thrust to actually Move the mass and greater amounts of mass. if the mass is SMALL, and already moving at significant super sonic speed, then you don't need much of a bump, to get it to go a little further. If you've already got Hot Air going in the front, and you compress it in the middle enough, it will get Hotter, and exit faster. So it's not just Newtonian Action Reaction. By that line of thinking, you wouldn't be able to have Sailboats, Go faster then the wind, and we do that All the time. It's doable. Probably not with metal much like the books, at least yet, but certainly doable.

 

That's before even getting into things like Nuclear and Laser Ramjets, and the sci fi fun Bussard Ram Jets so their little integral boost bullet in Von Neumann's War, is not far fetched at all. Far more close at hand then a man portable Laser Weapon that's for sure.

 

~Rex

[Captain Obvious]

Re: 10 Sci-Fi Weapons That Actually Exist

 

I'm not a physicist, so maybe I'm missing something, but it seems to me that without the combustive element, compressing air within the ramjet body will cause more loss of speed due to air friction than could possibly be obtained by the air jetting from the back. This looks like a perpetual motion claim to me.

[RexMundi]

Re: 10 Sci-Fi Weapons That Actually Exist

 

It's not perpetual motion, in the books it bled out pretty quick once all the factors balanced, but while it was in that initial launch phase from the explosive kick in the pants, it could add a little bit of it's own. I'll dig the exact description out of the book and post it, along with an idea someone that actually works in the ballistic field sent me, then the folks can pick the nits from it. I find it a far more possible avenue to go for a slug launcher, then say, a hand held Plasma Weapon (Though I did really like what the Battlelords folks called a Plasma gun heh).

 

~Rex

[Kristopher]

Re: 10 Sci-Fi Weapons That Actually Exist

 

I'm not a physicist' date=' so maybe I'm missing something, but it seems to me that without the combustive element, compressing air within the ramjet body will cause more loss of speed due to air friction than could possibly be obtained by the air jetting from the back. This looks like a perpetual motion claim to me.[/quote']

 

Bingo.

 

Additionally, what's going on in a ramjet or scramjet is not primarily the Venturi effect, AFAIK.

[Zeropoint]

Re: 10 Sci-Fi Weapons That Actually Exist

 

RexMundi, I hesitate to use the phrase "You Fail Physics Forever", but the effect you're describing cannot possibly exist because it violates conservation of energy. The paper airplane you mention does not; it converts gravitational potential energy to kinetic energy. The hose does not; the water utility provides energy in the form of water pressure, and that provides the thrust. Compressing air takes energy. Where does the energy come from in your fuel-less bullet? There's only one possible place: the kinetic energy of the bullet. The BEST case scenario, which is only even theoretically possible if you allow for 100% efficient processes, is that the ramjet effect would not slow the bullet down.

 

To put it more simply: if the bullet speeds up, its kinetic energy increases. Where is that energy coming from? In thermodynamics, there's no such thing as a free lunch.

[Old Man]

Re: 10 Sci-Fi Weapons That Actually Exist

 

It's not perpetual motion as long as fuel is added to the compressed ram-air and burned. A similar experimental projectile launch system is already being tested; the (very long) barrel is filled with a fuel-air mixture before launch, and as the projectile passes through it, it compresses the mixture to the point where it combusts directly behind the projectile. It's on YouTube somewhere, I'll have to look for it when I'm doing this from my phone.

[McCoy]

Re: 10 Sci-Fi Weapons That Actually Exist

 

I'm not a physicist' date=' so maybe I'm missing something, but it seems to me that without the combustive element, compressing air within the ramjet body will cause more loss of speed due to air friction than could possibly be obtained by the air jetting from the back. This looks like a perpetual motion claim to me.[/quote']

My degree's in biology, not physics or chemistry, but IIRC at high enough temperatures nitrogen does burn. Are we perhaps talking compressing the nitrogen-oxygen mixture to the point where it ignites?

[RexMundi]

Re: 10 Sci-Fi Weapons That Actually Exist

 

I don't fail Physics forever, though I may fail transcribing a process spoke of in a book on a game forum, for the period of a bit of sleep. The process used for the rounds in the book, is that of applying an intake to the bullet round, and a bit of creative engineering modeled around a converging/diverging nozzel at the opposite end of the round.

 

With initial supersonic Airflow, the Airflow Speed Increases as it passes through the Converging section (and compresses as well), through the throat, and into the diverging section, exiting faster (and providing thrust) then what it did when it entered.http://www.engapplets.vt.edu/fluids/CDnozzle/cdinfo.html if you want the basic math applet to play with.

 

The science gobbledegook in the novel comes courtesy of Travis S.Taylor, who's been pretty spot on for other such "could be done" science in other books http://www.doctravis.com/home (for credentials), and he doesn't seem to be in danger of Failing Physics Forever so I tend to give him the benefit of the doubt. I will do my best though to see if I can get him to give me the math and science behind it. I've had pretty good luck getting such things from brainy folk before.

 

 

 

~Rex

[Kristopher]

Re: 10 Sci-Fi Weapons That Actually Exist

 

I don't fail Physics forever, though I may fail transcribing a process spoke of in a book on a game forum, for the period of a bit of sleep. The process used for the rounds in the book, is that of applying an intake to the bullet round, and a bit of creative engineering modeled around a converging/diverging nozzel at the opposite end of the round.

 

With initial supersonic Airflow, the Airflow Increases as it passes through the Converging section, through the throat, and into the diverging section, exiting faster (and providing thrust) then what it did when it entered.http://www.engapplets.vt.edu/fluids/CDnozzle/cdinfo.html if you want the basic math applet to play with.

 

The science gobbledegook in the novel comes courtesy of Travis S.Taylor, who's been pretty spot on for other such "could be done" science in other books http://www.doctravis.com/home (for credentials), and he doesn't seem to be in danger of Failing Physics Forever so I tend to give him the benefit of the doubt. I will do my best though to see if I can get him to give me the math and science behind it. I've had pretty good luck getting such things from brainy folk before.

 

There's no free lunch. Forcing the air into the smaller section of the "tube" through the bullet takes energy, and it takes it from the bullet's kinetic energy.

 

And really, I have to question the utility of having a hole down the center of a projectile that's propelled by gas pressure from behind...

[RexMundi]

Re: 10 Sci-Fi Weapons That Actually Exist

 

It's not perpetual motion as long as fuel is added to the compressed ram-air and burned. A similar experimental projectile launch system is already being tested; the (very long) barrel is filled with a fuel-air mixture before launch' date=' and as the projectile passes through it, it compresses the mixture to the point where it combusts directly behind the projectile. It's on YouTube somewhere, I'll have to look for it when I'm doing this from my phone.[/quote']

 

Right, that's part of the Gas Cannon and Light Gas Cannon options I mentioned in a previous entry. If they can get stable results out of the gas mixtures for those (only a mater of time, valves, and math) those thing will be very very scary slug throwers. You can find the 45MM one on Youtube all over the place.

 

~Rex

[RexMundi]

Re: 10 Sci-Fi Weapons That Actually Exist

 

There's no free lunch. Forcing the air into the smaller section of the "tube" through the bullet takes energy, and it takes it from the bullet's kinetic energy.

 

And really, I have to question the utility of having a hole down the center of a projectile that's propelled by gas pressure from behind...

 

You mean something like These? Granted these are fueled but the divergent acceleration is still a principal that is part of their function.

 

 

~Rex

[Kristopher]

Re: 10 Sci-Fi Weapons That Actually Exist

 

Jet and rocket engines aren't propelled by gas pressure from behind the way a bullet or cannon projectile is.

[Zeropoint]

Re: 10 Sci-Fi Weapons That Actually Exist

 

Also, jet engines (rockets are sufficiently different from what's being described that I think we can leave them out of the discussion) have a critical difference: they carry with them an energy source to compress the gas. Furthermore, we don't need to get into any discussions of aerodynamics or fluid flow, because the bullet, as described, violates conservation of energy.

 

If the bullet is to accelerate, adding to its kinetic energy, there MUST be a corresponding loss of energy somewhere else. In a jet engine, it's the loss of chemical potential energy stored in the unburned fuel and unconsumed oxygen. As described, the bullet has nowhere to GET the energy that it adds to itself. Maybe the author got it wrong; maybe someone missed part of the description, but it simply CANNOT work as described here in this thread.

 

RexMundi, you may not fail physics "forever", but you DO need to brush up on your basics.

[RexMundi]

Re: 10 Sci-Fi Weapons That Actually Exist

 

I'm still working on getting an answer from the writer himself. Guys always been very approachable so no need to nail me to a Cross yet. I will point out though, the energy can be obtained without having to have a kaboom generating fuel source. If I take a bowling ball, and roll it down the street, it goes so far. If that street goes Uphill, it doesn't go so far, if it goes Downhill, it goes farther, and Faster, and in nowhere, did I add a fuel source, or give it something to give itself a boost.

 

It's use in the novel, simply boosts it up from it's initial muzzle velocity speed, to more velocity. That gives more range to the round. It can't do that very long, and in fact, the loss of energy rules do apply, eventually, enough friction and resistance and drag effects cancel out and over come the initial boost, just like they effect any other bullet, and once the airflow drops below the necessary minimum, the round can't benefit from it's design, and most likely at that point, is not a very good bullet. So it's not breaking any rules, and is following the converging/diverging nozzles rules to the T. So where, is it breaking laws?

 

It has a thrust source. It has a flow medium, a method to compress it, and a method to expel the accelerated thrust to get a kick. The energy source you describe doesn't compress the gas, it's what is used, to get it to move faster at lower compressions and slower speeds. The compression Chamber compresses the gas, not Hotter, Faster Moving Gas (Though compression does make things a lot warmer). Exothemic material compresses gives you even more thrust exiting the backside (more energy and more material per volume), and hence a higher specific impulse and a lot more "GO THAT WAY!"....Even as it was presented in the novel, they weren't very cost effective, or feasible. At that stage.

 

It doesn't invalidate the idea though, of the Von Neumann's War Jet Bullet. Certainly a better shot at THAT, then a man portable hand held, laser weapon. If we were able to make, Rocket Bullets back in the early 50's, I think something like this would not be stretching it. Wasn't long back, when the Metal Storm folks were told, No Way No How for their approach to slug throwers, or that balanced flight characteristics and very low drag bullets were impossible to make, or explosives chucked at people via artillery and gund were un-doable as well. It doesn't have to work continuously, in order to provide an advantage. Just for a bit, and it glides in like any other missile.

 

~Rex

[lemming]

Re: 10 Sci-Fi Weapons That Actually Exist

 

I'm still working on getting an answer from the writer himself. Guys always been very approachable so no need to nail me to a Cross yet. I will point out though' date=' the energy can be obtained without having to have a kaboom generating fuel source. If I take a bowling ball, and roll it down the street, it goes so far. If that street goes Uphill, it doesn't go so far, if it goes Downhill, it goes farther, and Faster, and in nowhere, did I add a fuel source, or give it something to give itself a boost.[/quote']

 

Gravity is a fuel source.

 

You need to add a fuel source for the ram jet to work and at current tech, a ram jet bullet isn't feasible since the gain is taken away by the act of having to add a propellant.

 

The propellant is normally ignited by the act of the air coming in being heated from the compression. The fact that the air is going thru at a faster speed is not adding to the speed of the bullet. Much like the water in a river goes faster thru a narrow canyon, doesn't make the canyon walls go any faster.