If You Could Own Just One Weapon

maggot SG

You are telling me that the electrical currents in our everyday life got recoil? Laughing

Why my electrical wires in my house and other people's houses don't jerk off and fell off?

Fingolfin_Noldor SG

Erm.... ok.. the main problems with railguns is wear and tear. These things have incredible wear and tear due to the projectile accelerating in the barrel at terrific speed. So yes, there is recoil but it is inflicted onto the barrel itself.

But that aside, the guns have relatively low recoil but in exchange you have low barrel life. I believe there have been attempts to increase the barrel life and they have been successful to an extent, but not as long as conventional weapons.

SingaporeTyrannosaur SG

You seem to have missed the whole point of my thought experiment.

It seems you are mixing up your electrical laws with the laws of motion.

What I am telling you is the quite obvious fact that while the transfer of electrons we know as electrcity is not related to mass and motion laws (on the macrolevel anyway), the projectile being accelerated creates very real recoil that has to be dealt with by the weapon, no matter by what method you use to propel it.

Electricity can be used to create motion in matter, and naturally that matter that is put into motion follows the classical motion laws and interact. For some reason you seem to think that railguns are recoiless, for reasons that do not seem to be consistent with any of the laws of physics.

And as I said, even if you don't believe what I say, at the very least listen to the quote on railguns from wikipedia, which I shall put again:

the rails need to survive the violence of an accelerating projectile, and heating due to the large currents and friction involved. The force exerted on the rails consists of a recoil force - equal and opposite to the force propelling the projectile, but along the length of the rails (which is their strongest axis) - and a sideways force caused by the rails being pushed by the magnetic field, just as the projectile is.

Actually from where do you get the idea that railguns were recoiless to begin with? It was never even stated to be that feature of such a system.

SingaporeTyrannosaur SG

http://www.iop.org/EJ/abstract/0022-3727/20/3/023

If you have the time to read, here is a study into the more complex nature of railgun physics, especially when operating (in theory) at near lightspeed muzzle velocities.

And as you can see, recoil force from firing the projectile is a very much part of it.

Abstract. In relativistic electromagnetism the recoil force of a railgun should act on the magnetic field and absorb field energy-momentum. The Ampere-Neumann electrodynamics, on the other hand, requires the recoil forces to reside in the railheads and push the rails back toward the gun breach. Experiment confirms the latter mechanism.

SingaporeTyrannosaur SG

Correct, but then again if you are talking about a personal hand-carried railgun, then quite obviously with current technology the user is going to experience a lot of recoil, especially when firing extremely high velocity projectiles, even if the projectiles are tiny.

In an emplaced railgun recoil is not really an issue, but it is certainly still there. I just don't get why some people think it's recoiless, which it certainly is not.

SingaporeTyrannosaur SG

http://www.physicsforums.com/showthread.php?t=58280

More discussion on the recoil of railguns, as one forumer put it:

The recoil is the result of the force require to accelerate a projectile - equal and opposite (reaction) forces.

The guns are much heavier than the projectiles, but the projectiles can be accelerated to very high velocities in short distances.

With the same projectile mass and muzzle velocity, the forces on the rail-gun and a normal gun would be the same. The response of the rail-gun/normal gun depends on their masses. The heavier the gun the less recoil acceleration (and lower momentum) if would experience.

If the normal gun and rail-gun had the same mass (and length over which the projectile is accelerated), they would experience the same recoil for the same projectile mass and acceleration.

However, the main advantage of railgun systems (especially in mass driver applications), is the ability to provide lower impulse then a conventional chemical energy gun system, which gives all of the impulse at the moment of firing. (Though if you are talking about accelerating projectiles to extremely high velocities close to c., then obviously the impulse of a railgun would be tremedous no matter how long the rails you have)

It's not necessarily something that gets gone over explictly in class, but:
Force * time = mass * velocity = momentum

The recoil is essentially the same.

In practice conventional (i.e. chemical propelled) artillery launches things other than the projectile (like some of the explosive gasses), and because conventional artillery does not have constant acceleration capability (conventional guns usually have most of the acceleration take place at the beginning of the shot), odds are that the conventional artillery piece would experience more recoil, both in the sense that the maximal force on the gun is higher, and in the sense that the total momentum change of the gun is higher. However, this is an practical efficiency issue, rather than some fundemental difference between the guns, and it's readily concievable that a rail gun that uses some kind of sled to accelerate a projectile could have more recoil per projectile mass than a conventional gun.

Clearly, if the acceleration of the chemically propelled charge is higher than the acceleration of the mass in the rail-gun, then the reaction force on the normal gun is higher. On the other hand, the force (pressure * area) of the normal-gun chamber falls off as the projectile moves forward in the chamber, so the acceleration, which is initially higher than that of the rail-gun, decreases to a level below - given the constraint on the problem that the muzzle velocity is the same for both cases.

Nowhere do you see them talking about railguns being recoiless... in fact they are just like any other gun system and have to deal with their generated recoil some way or another.

SingaporeTyrannosaur SG

http://www.newton.dep.anl.gov/newton/askasci/1993/physics/PHY24.HTM

felirox SG

Laughing

haha.a note that's super powerful! Twisted Evil

SingaporeTyrannosaur SG

http://hackedgadgets.com/2006/06/15/diy-coil-hand-gun/

Maybe to put it all into perspective here is a similar debate in which one dude thought that gauss based projectiles launchers were recoilless and he was pretty much shot down by everyone in there. An interesting read, if somewhat uncivil at times.

Ben Says:
January 5th, 2007
there would actually not be any kickback do to newtons law because newtons law says that every action has a reaction in a regular gun it is caused by gun powder exploding which creates a burst of expanding gases out of the tube, but in a coil gun there is not expanding air only electromagnetism that is dispersed out of the end of a wire after the projectile has been fired, it is also extremely feesable in the sense that it makes very little sound, you dont have to worry about gunpowder being wet or even having to carry the extra weight of it, also it can create more power, it can have greater range and as i said earlier, very little kick back

ACG Says:
January 23rd, 2007
Ben:
Nice words but unfortunately none are true.

Ben Says:
January 23rd, 2007
ive actually found that out haha, i still find it hard to understand, but could you explain it again?

Errant Says:
February 1st, 2007
Hi Ben,

yes its an easy concept to grab a hold of and assume - unfortunately recoil is a bad problem

Have you done much on electromagnetism? Thats not a dig just a question. You see it isnt so much that the projectile has a force applied by the electric field as the coil and the projectile repel each other. By holding the coil fairly still you make the projectile take the brunt of the force.

As in a normal handgun the gas pressure forces the gun and the projectile apart - this creates a recoil or a force backwards which you have to steady.

So unfortunately altho physically the electromagnetic waves do not give us recoil they force the coil itself back - which does

I am working on a project now with a friend from university to get some kind of blow back action similar to that of a normal handgun. It is an interesting Engineering problem

Fingolfin_Noldor SG

ST: That is pretty much it. The accelerating rails in the gun will inflict a force on the barrel by Newton's 3rd law and the law of conservation of momentum, not least that even though the Lorentz force (F = q (E + v x B) ) is used to drive the projectile forward and the projectile is in contact with the barrel although I believe that there are cooling fluids that are being tested to see if they can act as a lubricant while allowing high accelerating speeds. Also, we must recall Faraday's law and

The main difference between conventional guns and railguns is that conventional guns must provide provisions for a localised explosion within the gun because such high localised barrel pressures are deleterious to the barrel. Pretty much the early firearms suffered from this problem and it was only later with improvement in metallurgy techniques that guns with higher barrel pressure tolerances than older guns came along and we can use more propellant than before and achieve better range and weight of projectile hurled. Battleship guns pretty much epitomised this since Japanese, American, British and German guns are of varying quality. American 16" guns were the best if I recall and could hurl a larger projectile than even the 18" Japanese guns. One might think of them as rocket engines which fire short pulses.

Now comes the railgun. The Lorentz force drives the projectile which must certainly be a charge (otherwise the RF fields will have little effect on the projectile) and from basic electromagnetics, F = q E and this is an action reaction pair. From Lenz's law, we know that oscillating magnetic fields produce an action reaction force too. So the net result is a force that drives the projectile forward.

I am not so sure of a Gauss weapon, but regardless, even electrons carry momentum, thanks to de Broglie. Photons too, and do note that for laser weapons that start to reach terawatt or higher, you will start to see some palpable recoil.

maggot SG

Nice coil hand gun that can be DIY now everyone can make their own gun Twisted Evil

maggot SG

There is a system called "Dread" that says no recoil and electrically fired Mr. Green

http://www.sgforums.com/?action=thread_display&thread_id=245324

Fingolfin_Noldor SG

I won't quite call that recoilless. I suspect the company made provisions for it and designed it cleverly enough to minimise it possibly by allowing the recoil forces to say disintegrate the propellant canister. One should note that current guns use recoil in some meaningful way, such as reloading the rounds etc.

This Dread gun of yours is likely designed using similar tech designed this company: http://www.metalstorm.com/index.php. I am not sure if it has any relation to this gun.

Note: There will always be recoil. It is a question of management and clever design. The best firearms do not fight against recoil. They make use of it in a meaningful way that ensures that it does not adversely affect its operation.

SingaporeTyrannosaur SG

The Dread gun is (supposedly) a centrifugal weapon, that is spins projectiles around at insane speeds and then releases them at the target, like a hammer thrower.

And of course this system is as much affected by recoil as any other system that launches projectiles, just as a hammer thrower experiences forces the moment he releases his hammer. The Dread gun makers have found some way of reducing or canceling it out like other more conventional "recoiless" weapons (aka. your recoiless rifle).

I think maggot is mixing up the concepts of "recoiless" weapons with the physics concept of "recoiless".

An example would be our 84'. That recoiless rifle actually generates massive recoil forces when fired, but the inertial force created by the escaping propellant to the rear counters the recoil force of the main projectile and the net experienced force is zero (in theory, but in pratice it's never fully perfect).

In our Armbrust and MATAOR LAW the "recoiless" system is even more complex, using pistons and plastic countermass to allow firing of a projectile that would otherwise be quite difficult to fire without a proper recoil system.

But of course the fact that the weapon is effectively recoiless does not mean that it has no recoil, just that the recoil has been managed in some way or another.

There is no need to come up with bizzare, exotic and wrong physics solutions to understand the "recoiless" nature of some weapons when the solution is actually quite simple, and of course recoil is very much present.

In the case of a railgun, whatever the rails are secured to will experience the recoil of the weapon. If the gun is a fixed emplacement in some massive structure then the recoil is transfered to the earth or the mass of the structure and you might not observe anything at all. However it will be a different story the railgun was a personal weapon, or prehaps even mounted on a tank.

Actually it's basic logic leh, if the rails were not secured, the forces generated by the rail gun will make the projectile and rails fly off in opposite directions with opposite force (like magnets repelling).

And of course whatever is securing the rails will experience this force wanting to make the rails fly off as recoil and will have to deal with it some way or another. If Arnie really did manage to launch his projectiles in Eraser at just below lightspeed, even if they of the mass of 2 grams he would be subject to forces that would send him blasting back off his feet. Unless the weapon found some way to deal with it (highly unlikely).

maggot SG

84mm you think I never fire before meh? Laughing

84mm upon firing the stupid recoil push me back sia...shoulder pain... Sad

Armburst not recoiless...the jerk cost me to miss 2 shots Mr. Green

Not lah sometimes practical firing doesn't always tally with theory or else those weapon makers will "close shop"

maggot SG

I think it's magnetic repulsion or near those maglev theories or else how to shot so far with no flash? Mr. Green Rail or gauss got that visible plasma trails after the rounds

Nadare SG

i wanna own a Artic

SingaporeTyrannosaur SG

LOL, it's neither of these things that you mentioned... from what we know so far at least.

Why speculate when you can find some facts?

http://www.defensereview.com/modules.php?name=News&file=article&sid=539

And of course, some interesting talk in regards to the "recoil" of the system. The person pitching for the weapon in the main article makes some dodgy physics mumbo jumbo though.

SingaporeTyrannosaur SG

Armbrust you fire real HEAT or sub-caliber?

The sub-caliber has significant recoil, but the HEAT for all purposes works very well in being soft launch.

If you want to know what the recoil truly is like... try firing an 84 or Armbrust with the recoil soaking features disabled... and you will immediately understand the difference that their recoil-less features make.

If you survive that is.

X-men SG

This is a good one

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