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Author Topic: Sabot Artillery: thoughts on flinging your shoes?  (Read 2582 times)

Liam's Ghost

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Sabot Artillery: thoughts on flinging your shoes?
« on: 20 March 2020, 04:01:09 »
Basic idea: A saboted artillery shell is a smaller diameter shell fired from a larger diameter gun, with each shell fitted with a sabot to keep it centered in the barrel and make sure you don't waste any of those valuable exhaust gasses. This results in a higher muzzle velocity, and consequently range.

Rules: Saboted shells are available for the Long Tom and Sniper artillery piece for the duration of their existence, but not the Thumper artillery piece until the jihad era (smaller diameter shells aren't available until then).

A gun firing saboted shells increases its range by three map sheets (flight time is not decreased due to the arcing trajectory). However, impacts are resolved at though the gun was firing a shell one size category smaller (so the long tom is firing a sniper shell, the sniper a thumper shell, and the thumper a battle armor artillery shell). Shots per ton and cost is not changed from the gun's standard ammunition, to account for the extra weight and cost of the sabots. 

So... thoughts?

I'm also thinking about gauss artillery, just a straight improvement over standard artillery pieces using the power of SCIENCE!
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marcussmythe

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #1 on: 20 March 2020, 07:31:33 »
It likely wont come up much in standard play, but it would definitely make sense in the universe and Be A Thing.

Maybe a larger range increase, tbh?  Like 50% or 100%?  STILL wont come up much at the tactical layer, but would represent a thing thats actually a serious advantage at the operational level.

And I can see a version for arrow IV - more fuel, less payload.

Daryk

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #2 on: 20 March 2020, 14:55:25 »
I think Thumpers should totally have the smaller shell available earlier.  HE is not LosTech...

dgorsman

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #3 on: 20 March 2020, 17:10:55 »
I'd be more inclined to go with rocket-assist rounds myself.  Increase range, same payload.  Only rule changes would be larger scatter as range increases.
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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #4 on: 20 March 2020, 17:14:21 »
And fewer shots per ton... rocket assist motors are just that... assists to regular propellant.

marcussmythe

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #5 on: 20 March 2020, 17:52:48 »
Valid point on Rocket Assist.  Seems like could be own, separate, thing?

Liam's Ghost

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #6 on: 20 March 2020, 17:56:25 »
I think Thumpers should totally have the smaller shell available earlier.  HE is not LosTech...

My original concept was that the sabot artillery simply re-purposes existing munitions, and there wasn't a smaller munition than the thumper until battle armor artillery became available.

But I'm flexible. If someone is sufficiently committed to the extra range over hitting power, I suppose making new shells makes sense.

(will respond to more stuff after I get back from shopping).
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Daryk

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #7 on: 20 March 2020, 18:21:46 »
Honestly, there should be a smaller Artillery weapon than a Thumper in 3025 play.  That thing is a monster.

Liam's Ghost

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #8 on: 20 March 2020, 19:04:09 »
Honestly, there should be a smaller Artillery weapon than a Thumper in 3025 play.  That thing is a monster.

I don't disagree. I'm wondering if the intent was to prevent or at least restrict artillery spamming.

Since this is a thread for ideas, one idea I had was for a three ton gun based on a combination of the battle armor artillery and the man-portable davey crocket, just with conventional explosive instead of nuclear ordnance. Battle armor artillery damage, but allocated to infantry units as a field gun rather than field artillery, allowing them to utilize multiple guns. Say three tons and three critical slots for guns, five heat per gun, damage and ammo options of the battle armor artillery, thirty shots per ton of ammo, range equal to the man-portable davey crocket. Available any era, but not commonly used due to a general belief that such a tiny gun would be ineffective in this world of giant mechs and other impressive war machines (you know, the way the militia always gets shafted by generals with adequacy issues).

I'd be more inclined to go with rocket-assist rounds myself.  Increase range, same payload.  Only rule changes would be larger scatter as range increases.

I like it. Maybe a fifty percent range increase in exchange for only having half as many shells. Double the scatter distance for everything but direct fire?

Also, make them combinable. :) Saboted rocket assisted sniper!
Good news is the lab boys say the symptoms of asbestos poisoning show an immediate latency of 44.6 years. So if you're thirty or over you're laughing. Worst case scenario you miss out on a few rounds of canasta, plus you've forwarded the cause of science by three centuries. I punch those numbers into my calculator, it makes a happy face.

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Daryk

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #9 on: 20 March 2020, 19:07:11 »
Now that you've got me thinking about it, there should be a few steps below the Thumper, starting with 10 points of AOE damage in just the hex of impact, then stepping down to 5, then 3, then 1.  That should keep them sufficiently distinct from Mech Mortars to be worthwhile.

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #10 on: 20 March 2020, 21:33:40 »
Read up on Gerald Bull - sabot shells, with base bleed.  :thumbsup:
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Daryk

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #11 on: 21 March 2020, 03:25:19 »
Interesting read on Base Bleed: https://en.wikipedia.org/wiki/Base_bleed

I think the Gerald Bull page gets a bit close to Rule 4 though, so I won't link that.

Cannonshop

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #12 on: 21 March 2020, 11:07:42 »
I'd be more inclined to go with rocket-assist rounds myself.  Increase range, same payload.  Only rule changes would be larger scatter as range increases.

where are you putting your propellant?  You'd still be looking a either a reduced payload, or increase in shell weight.  (Sometime over a decade ago, when these boards were a few iterations back, I actually suggested RAP or 'rocket assisted projectile' rounds-the need to carry propellant meant a reduction in shell weight there as well.)

Thing is, I don't think Saboted rounds would necessarily increase effective range outside of specialist environments like vacuum, because saboted rounds tend to be MORE vulnerable to wind drift on high-angle applications.  (Lower mass to the surface area exposed, vs. higher sectional density of the projectile vs. lateral surface exposure and lower mass.)

Wind drift is influenced by your total mass vs. the exposed surface area.  Long, needle-like forms tend to be more vulnerable to wind drift than shorter projectiles of the same (Or greater) mass.  Artillery shells stop accelerating as soon as they've left the barrel-they're flying on inertia to the target (except with a 2nd stage rocket boost), and at apogee they start going down again because gravity has overcome velocity (they start accelerating again on that down-slope, but it's at or near terminal velocity in atmosphere for a given planform of projectile.)

Generally, sabot configurations are about relatively short to medium-range PRECISION.  (aka making the shell 'shoot flatter' to hit, say, a moving target).
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idea weenie

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #13 on: 21 March 2020, 14:31:35 »
Generally, sabot configurations are about relatively short to medium-range PRECISION.  (aka making the shell 'shoot flatter' to hit, say, a moving target).

Sabot style artillery rounds might be used with TAG, similar to Copperhead rounds.  But instead of going for damage like Copperhead, they trade off the damage for a better chance of critical?

Cannonshop

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #14 on: 21 March 2020, 15:53:17 »
Sabot style artillery rounds might be used with TAG, similar to Copperhead rounds.  But instead of going for damage like Copperhead, they trade off the damage for a better chance of critical?

I'd suggest mor of a concentrated punch with a SHORTER range.  (Similar to real-world examples), aka in the direct fire role, it doesn't do AOE damage (or does a drastically lowered AOE), but you gain "Gunnery plus movement plus target movement plus one" against any specific target out to the one-mapsheet range, no arty modifier and range is 'short' for determining to-hit.

aka a thumper "Sabot" round does 15 points of damage to the targeted unit, 0 dmage to any other unit in the hex, 1 or 2 damage to infantry, can pick off a single BA (but only one) out to 'direct fire' distances (1 or 2 mapsheets).

to prevent it from invalidating gauss rifles or ac/20s, each "Sabot" round is 5x the mass of a standard thumper round and you can only get them in 1 ton lots (aka 4 shots/ton of ammo) (the thumper carries 20 rounds/ton normally)

balancing existing weapons is an important aspect of any 'custom' proposals: It can't invalidate existing, widespread systems unless it's also a Clan exclusive weapon (because the Clans do everything, including things they don't want to do and that violate their doctrine and make no sense for them to be doing, better than the Inner Sphere-it's a rule.)

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RifleMech

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #15 on: 23 March 2020, 15:23:32 »
If I got this right, you're wanting to fire the smaller artillery rounds from the larger artillery cannons.  I can kind of see that to extend ammo supplies or simplify supply chains. What I'm not seeing is how the range would be extended. A Thumper round fired out of a Long Tom is still a Thumper round.

Or were you saying separate the shell from the propellant and firing the Thumper Shell with the Long Tom Propellant? I can see the range being extended this way. I think the accuracy would go down a little but I can see there being a few more rounds per ton to balance that out.

With Rocket Powered rounds, all the ones I've read about there ends up being fewer rounds but the range is more. A simple -50% for a +50% in range would seem workable to me.

The Base Bleed thing is cool. I'd just increase extend the range brackets on. Long Range becomes Medium. Extended Range becomes Long. Extended Range gets re figured to be further out. I would think reducing the damage a couple points would balance out.

Colt Ward

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #16 on: 24 April 2020, 14:23:54 »
If I got this right, you're wanting to fire the smaller artillery rounds from the larger artillery cannons.  I can kind of see that to extend ammo supplies or simplify supply chains. What I'm not seeing is how the range would be extended. A Thumper round fired out of a Long Tom is still a Thumper round.

Or were you saying separate the shell from the propellant and firing the Thumper Shell with the Long Tom Propellant? I can see the range being extended this way. I think the accuracy would go down a little but I can see there being a few more rounds per ton to balance that out.

With Rocket Powered rounds, all the ones I've read about there ends up being fewer rounds but the range is more. A simple -50% for a +50% in range would seem workable to me.

The Base Bleed thing is cool. I'd just increase extend the range brackets on. Long Range becomes Medium. Extended Range becomes Long. Extended Range gets re figured to be further out. I would think reducing the damage a couple points would balance out.

I never did tube but . . .

I have heard of what Liam is suggesting though some was involved with mortars.  My understanding is it gets into fancy math about bore size, ballistic co-efficients, propellant burn rates and diminishing returns . . . but basically comes down to the shell getting more force/acceleration and then when out the bore reducing the drag of surface area though I think some of the ones I heard did include BB.  The shell also accelerates down the barrel faster b/c the sabot & shell do not weight the same as a standard shell for that bore.  In fact the discussion of a theoretical system had BB, RA, RA-BB, and specials that combined them all along with laser guided.  Honestly, a sabot system could be even more accurate by having the sabot protect pop-out fins for stabilizing like some of the more recent MLRS rockets.

Modern shells do not have as many problems with wind-drift . . . to be honest, afaik they have not since the 60s or maybe earlier- its why we take met data for the layers to enter it into fire control computers.  IIRC mortars might . . . but mortars are lower velocity vs high velocity of artillery shells though mortar bombs weigh more than artillery shells.
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RifleMech

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #17 on: 25 April 2020, 10:24:32 »
So the smaller round fired from a bigger gun could get the range of the bigger gun? Cool. Thanks.  :thumbsup:

Colt Ward

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #18 on: 25 April 2020, 13:48:23 »
Its the theory I have heard thrown about . . . I am not sure any real world power put it into use, but the theory seemed solid and it seems it was tested but it would also not call for a buy of a new gun system, rather just some modifications of old guns and we know how procurement feels about new stuff.
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RifleMech

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #19 on: 26 April 2020, 06:45:01 »
Its the theory I have heard thrown about . . . I am not sure any real world power put it into use, but the theory seemed solid and it seems it was tested but it would also not call for a buy of a new gun system, rather just some modifications of old guns and we know how procurement feels about new stuff.

Would the modifications still allow the weapons normal ammo to be fired?

Colt Ward

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #20 on: 26 April 2020, 15:11:44 »
My understanding of the test system is they were rebored which may have to do with how spin is introduced.  For instance, modern tank main guns use smoothbores b/c they fire the tungsten penetrators at AT rounds, but they can also fire high explosive.  So they may have been rebored to get rid of the rifling grooves in the gun tube rather than to adjust the calibers.
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RifleMech

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #21 on: 26 April 2020, 21:54:48 »
I suppose that's work. I'd of thought smoothbore would reduce range but I guess with that much power propelling the round it doesn't matter.

Colt Ward

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #22 on: 27 April 2020, 09:02:51 »
Rifling and/or spin stabilization is about accuracy which indirectly aids range (effective vs maximum) but it does not change how much force is behind the shell.  Early (as in black powder days) difference between smoothbore & rifled barrels dealt more with the fact that the tolerances between the round and barrel- rifled shells were closer to the barrel and thus blocked more of the gases escaping (and losing out on that force) than smoothbores.
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Cannonshop

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #23 on: 27 April 2020, 09:16:38 »
Rifling and/or spin stabilization is about accuracy which indirectly aids range (effective vs maximum) but it does not change how much force is behind the shell.  Early (as in black powder days) difference between smoothbore & rifled barrels dealt more with the fact that the tolerances between the round and barrel- rifled shells were closer to the barrel and thus blocked more of the gases escaping (and losing out on that force) than smoothbores.

With the modern smoothbores, there's also a certain amount of friction reduction, letting a higher initial velocity with less wear on the barrel. (at least, in theory. I'm not sure the benefits actually accrue the way the sales brochures from thirty years ago claimed) and higher velocity from the same volume of propellant (assuming proper gas-seal via gas-checks on the sabot assembly).

One of the fun experiments NOT to try at home, is using shotgun powder in rifle shells. 

REally, don't do this.  Shotgun powders burn hotter AND faster than rifle powders.  you can blow up your rifle doing this.  same with many Pistol powders.

reason being both the placement and intensity of your pressure curve relative to the volume, surface area, and friction coefficient in your barrel. 
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Colt Ward

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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #24 on: 27 April 2020, 09:37:52 »
Gas seal!  THAT is the term I was forgetting for smoothbore vs rifled barrels back in the 1700s.
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Re: Sabot Artillery: thoughts on flinging your shoes?
« Reply #25 on: 13 May 2020, 14:00:13 »
What I was looking at for my own artillery ammo stuff was that Saboted shells were, as you say; less powerful in terms of their down-range effect and had longer range. What I did to mark them out though is kept them with the normal artillery scatter to reflect a smaller CEP (Circular Error Probable) than the contemporary FBBB (Full-Bore, Base-Bleed) Shells, which had all the power, plus the range, but for higher cost and more accuracy.

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