Heavy Tri-barrels

Weird Harold wrote:

Tenshinai wrote:And why would pods need to negate recoil?

Because unless the pod masses more than all of the missiles combined, "recoil" would accelerate the pod instead of the missiles.

kzt wrote:
Weird Harold wrote:Have you ever seen what happens to a cartridge that is fired without being contained in an appropriate firearm?


WTF does that have to do with a mass driver?

It is a graphic illustration of Newtonian physics -- which apply to mass drivers as well a firearms.

Theemile wrote:

kzt wrote:
Weird Harold wrote:Have you ever seen what happens to a cartridge that is fired without being contained in an appropriate firearm?


WTF does that have to do with a mass driver?

It is a graphic illustration of Newtonian physics -- which apply to mass drivers as well a firearms.

Grashtel & Lord Skimper wrote:

Tenshinai wrote:You realise that that can only manage at best about 1/3 of the rate of fire of the HV tri-barrel.

And can only do so from a vehicle that weighs SEVERAL tons.

Look at how the hummer moves from the recoil when firing sideways. That´s the 5ton version if i´m seeing right.

The PR folks says it has an "average" recoil force of 2.2kN. That´s 220kg worth of push. Or about a quarter of the power in the first generation engines of WWII jet fighters(i checked and it´s actually exactly 1/4 of the power of the Me-262 engines)...

You can also take notice that when they fire from the helicopter, there´s noticeable shaking, and the pilot has to turn against the recoil to compensate(notice what happens when it stops firing, it takes a moment for the pilot to stop compensating).

(that kind of gun should REALLY be in a spinal mount on a helicopter, sheesh!)

I'm glad someone else is as bad at Math as I am.

The idea that 2.5KG per Second is going to throw someone in battle armour is laughable. That is about the same as a 3/4 inch garden hose at 50 psi over 50 feet. As if that could throw anyone around let alone someone in battle armour.

I'll have to look up the link.

Skimper you don't get physics, stop trying to argue with people who do. The 2.2kN/220kg force is not per second (notice the lack of seconds in the units), its instantaneous, ie that force is being (on average) continuously applied while the gun is being fired. So if the person in battle armor and gun (and ammo ect) weigh less than 220kg and fire they can literally use it to take off and fly around by firing it downwards.

Tenshinai wrote:

Weird Harold wrote:There is a version of the minigun that fires BBs with compressed air.

I don't know of any version chambered for 5.56.

Some years ago i read about someone who did a working "minigun" using 9x19 ammo(ie pistol/SMG ammo), even with the much weaker ammo, it still needed someone very strong to carry the weapon and backpack with ammofeed and powerpack(batteries and a model engine for charging, with the weapon selfpowering after the first 10 or so shots).

A mostly absurd and useless weapon, but he made it work as it looked on movie and in games.

Weird Harold wrote:Honorverse grav accelerators don't have the kind of recoil problems 7.62x51 produces, but the physical size of a "Heavy Tribarrel" in 10mm would probably require contra-grav to make it man-portable. The 25mm version would require even more contra-grav and recoil suppression to be man portable.

All that aside, with three calibers available, and contra-grav to make them man portable, I would expect the designations to be Light, Medium, and Heavy for 5mm, 10mm and 25mm respectively.

25mm as manportable? Even with a seriously powerful powersuit/battle armour, that is waaaaayy too much.



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MaxxQ wrote:Edit: On further thinking, since one doesn't have to worry about tiny little things like Pyrodex exploding in the casing/chamber, the barrels and other parts do not necessarily need to be made of metal - high-strength and lightweight composites should be sufficient, so the weapon may be lighter than you might think. I still think you'd need to be in battle armor (or the civilian equivalent) to handle one though. I suppose the battery pack probably weighs a hell of a lot... but that's just a guess on my part.

The barrels can be lighter yes, but you still need a little something to accelerate those wee little darts, that´s going to put much of the weight back again.

And at a hundred shots per second? Even if the shots are a puny 5g each(since they´re explosive that´s not entirely unrealistic even for a larger weapon), that´s half a kg of shots per SECOND.

I don´t remember the stated V0, but even if it´s just close to current rifles, the amount of energy is still absurdly high.

A 25mm gun would weigh MUCH more.

Historical 20mm cannons had shells commonly ranging from 80-150g, adjusting for much less metal and more explosives, we MIGHT be able to get a 25mm dart down to maybe 50g(unlikely but...), then lets guess that the weapon has 1/2 the rate of fire from the 5mm one(again probably too "nice")...

That´s 50*50= 2.5kg per second. That´s going to throw someone even wearing a HUGE battle armour.

50g at a (probably too low)guess V0 of ~1000m/s, that makes each shot vaugely similar to the most extreme 12.7mm ammo available for regular HMGs or Russian 14.5mm.

Doesn´t sound so bad until you figure out that you´re trying to shoot at least twice the rate of fire common for those weapons, probably far more, and with a lighter weapon (which means less weight to absorb recoil before affecting the shooter).

And the fact that even those weapons produce about 10 times more joule per shot than is considered tolerable for a regular infantryman without power assist to be effective with autofire.

So while a battle armour should add quite a bit, i rather doubt it allows quite that much of a bonus.

Basically, 25mm manportable? Not a chance. Not even with wildly optimistic and unrealistic numbers. Would be completely uncontrollable weapons that would actually manage to push or even throw people back when fired.

Of course, there's also the possibility that the rounds may be *less* than 10mm. Anthing above what the OP quoted as 4-5mm would likely be considered "heavy", so maybe 7.5mm?

That sounds a lot more possible yes. But probably needs plenty of tech assist to deal with the recoil.




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kzt wrote:The one in the movie was the 5.56mm version. Didn't go into wide use, but there was a 5.56mm version. I've seen some comments about what they needed to just run the gun in the movie, and it was kind of excessive for a gun that had no recoil (due to shooting blanks). It's not exactly surprising that it didn't go into common infantry use...

Ehm, blanks doesn´t mean zero recoil. Even movie blanks have some recoil. And at the rate of fire involved, it quickly adds up.

I recall they required a water hose for cooling as well as a powercable for the spin engine. Both hidden on the ground and going up through his trouser leg.

Weird Harold wrote:Have you ever seen what happens to a cartridge that is fired without being contained in an appropriate firearm?

kzt wrote:
WTF does that have to do with a mass driver?

Weird Harold wrote:It is a graphic illustration of Newtonian physics -- which apply to mass drivers as well a firearms.

Theemile wrote:
Actually, Newtonian physics dictates that BOTH move in relation to the mass of each, ...

Weird Harold wrote:Which is sort of the point of asking about a cartridge fired without containment -- like a very early Mythbusters episode about using 22LR cartridges as (old style) substitute auto fuses.

The bullet, the most massive part of a cartridge barely moves, while the cartridge case move away at dangerous, possible lethal in some cases, speeds.

Theemile wrote:As KZT points out - the total mass of a Pod is 2x or more than that of the missiles. So if no handwavium were involved, the Pod would be move backward with at most the same velocity as the missiles.

dreamrider wrote:
I DID NOT write the quote above. I know better.

Please be careful who you cite.

...

And FWIW, although firing the full up .50 MG ball ammo from a 'small' handgun would be a ... challenge, I feel quite sure some fool with a good hobby gunshop HAS done it! <grin>

Note that the .50 MG round is almost a standard round for heavy 'shoulder fired' (usually bipod) sniper rifles/extreme range target rifles.

None of which should really pertain to this discussion, because those are chemical explosive, contained compression firearms, NOT the linear accelerators of HV pulsers. Totally different physics.

Theemile wrote:
Actually, Newtonian physics dictates that BOTH move in relation to the mass of each, with the firing point as the centroid of the momentum. The pod (should it be lighter) would just have more velocity than the missiles. Or vice versa if the mass ratio was reversed.

m1*|v1| = m2*|v2|

Remember - Equal and Opposite reactions

Tenshinai wrote:

dreamrider wrote:I thought I would just remind everyone that for the HV heavy tri-barrel, we are talking about a tri-barrel pulser, basically using rail gun type physics, not chemical propellant physics.

And railguns have EXACTLY as much recoil as chemically powered guns if the forces involved are the same.

Please keep in mind that to the current military planners and designers of this world, "man portable" means a weapon breaks down into loads of 25 to 60 pounds for a crew of 2 to 5 operators and assistants.

Most machine guns ever made were in some version "man-portable", including the M2 .50 (although, having humped a portion of that load, I'd say that one is pushing it.)

"Man-portable" does NOT mean carried and operated by 1 man. At the least, it usually means 1 guy carries the unitary weapon as his extra load, and 1 helper carries the basic load of ammo as his extra. Some so-called "man-portable" weapons (the 81mm mortar comes to mind) might need a crew of 5-6 to hump all their components and a useful bit of ammo.

Quite true, sorry i should have been more specific on what i was talking about, as heavy tri-barrels have been specifically stated to be used by single persons, i guess man-operable is the correct definition?

I say again,
"Remember to adjust for 2000 years of development...", etc.

Sure, but do recall that physics still apply. You may be able to cheat physics more or less, but you can´t remove it.

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Pulsers aren't exactly rail guns.

Whether recoil negation is designed into Pulsers or an inherent feature of grav drivers, the fact remains that Honorverse Tech minimizes recoil in a way that would drive Sir Isaac crazy.

I´m not so sure about that, I recall textevs suggesting the recoil is still there. Or at least some of it.

I real world terms, the XM214 cited by kzt is probably pushing the limits of man portable, but the real world doesn't have San Martinos, Ndebelese, sphinxians, or other heavy worlders in powered battle armor to compensate for recoil and weight.

Seriously, you do not wish to try and have a XM214 used by a single person off-mount.
It´s potentially backbreaking in the literal sense.

Just as a wag, the Honorverse should be able to support five or ten times the weight and recoil -- 27.8mm to 55.6mm through handwavium anti-recoil tech and unobtainium weight reduction.

No, just no.


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I don't think you could readily fire a 50 cal from a small handgun due to recoil, so the technology must limit recoil.

You can, but not nicely so and not on auto.

Vince wrote:

Tenshinai wrote:{quote="dreamrider"}
I don't think you could readily fire a 50 cal from a small handgun due to recoil, so the technology must limit recoil.{/quote}
You can, but not nicely so and not on auto.

I think that would be the .50 caliber pistol round,

{images removed to conserve space - dr}

[Edit] For a rough idea of the size comparison, consider the fact that a US Dollar bill will almost entirely cover my hand. And I have what I think are average size hands for a man. Since the pistol's grip is held by your hand, consider that the height of the machine gun / rifle round alone is taller than the pistol grip of the .50 caliber pistol. And the ammunition for the pistol is stacked laying horizontally in the ammunition magazine, which fits into the magazine well of the pistol grip. [End Edit]

I don't even want to think what the recoil would be even from firing one round [Edit] even two-handed while standing [End Edit] if someone somehow managed to design and build a pistol that was able to fire the machine gun / rifle round.

This animation shows the difference in size of various ammunition calibers. The largest pistol round shown is .50 caliber. The .50 caliber machine gun / rifle round is the third largest shown in the second group.

Edited to correct punctuation and to add comparison points.