[FT] Railgun Goals

52 posts ยท Nov 25 1998 to Nov 30 1998

From: Sean Bayan Schoonmaker <schoon@a...>

Date: Wed, 25 Nov 1998 08:17:35 -0800

Subject: [FT] Railgun Goals

Perhaps before we get too far along any one trail for our K'V weapons
discussion, we should establish some general goals. These are the one that I
think are important:

1) The "To-Hit" mechanic should reflect a projectile flavor. In my eyes,
that means performance should be relatively constant out to a given range and
then drop off quickly.

2) Damage should be constant, without regard to range.

3) Firing arcs should be very limited to preserve the K'V "feel."

4) Mass should be relatively low, and point cost should be relatively high.

Please refute these if you don't agree; they're just a starting point. Once
we agree on some goals, then we can get down to the nitty-gritty of the
specific mechanics to achieve them.

From: Tom Sullivan <starkfist@h...>

Date: Wed, 25 Nov 1998 08:32:02 PST

Subject: Re: [FT] Railgun Goals

> Perhaps before we get too far along any one trail for our K'V weapons

Agreed, all three.

> 4) Mass should be relatively low, and point cost should be relatively

Agree with the point cost, but not with the mass. After all, you have
everything that a beam battery has, plus ammo! And you have to throw a *lot*
of metal around to hit anything at these distances.

> Please refute these if you don't agree; they're just a starting point.
Once
> we agree on some goals, then we can get down to the nitty-gritty of the

Where's the chaos in that?

> Schoon

From: Thomas Barclay <Thomas.Barclay@s...>

Date: Wed, 25 Nov 1998 11:47:00 -0500

Subject: Re: [FT] Railgun Goals

Sean spake thusly upon matters weighty:

> Perhaps before we get too far along any one trail for our K'V weapons

Don't necessarily agree. Depends on the one shot vs. multishot theory. At
close range, multiple shots could well give you a better chance of a hit. At
close range, I'd want a rapid fire mode for my railguns to up my chance of
hitting. At long range, this would just be a waste of ammo.

> 2) Damage should be constant, without regard to range.

Agreed. Except again multiple shots could well give you more hits.

> 3) Firing arcs should be very limited to preserve the K'V "feel."

Yep, although I liked the wider arcs for small guns (they don't need the big
runup that a large gun does... ergo they should be able to slew around a bit).

> 4) Mass should be relatively low, and point cost should be relatively

Sure. At least I agree on point cost.

> Please refute these if you don't agree; they're just a starting point.
Once
> we agree on some goals, then we can get down to the nitty-gritty of

Here would be my take on RGs 1. There should be some type or mode that fires
one large projectile at high speed for a long range hammerblow. There should
be some mode or type that fires lots of smaller projectiles at slower
individual velocities, but at a much higher cyclic. The mechanics of these
must integrate smoothly.
2. They are alien - they don't necessarily have to balance in mass,
but definitely in points, with human weaponry. 3. Maybe (unlike other weapons
systems using energy) they can jam. Maybe a counterbalance for a powerful
salvo capability is the
possibliity of a jam - which takes a round or two to clear.
4. I think small rapid fire railguns would make good PDS (ADAF/PDAF).
Maybe not quite as good as lasers, but a darn sight better than nothing. 5. A
high energy single shot type or RG (or mode) should have a low chance to hit,
and a fairly linear drop off (since projectiles won't just drop off odds to
hit in space, but will tend to drop off with sensor and targetting accuracy
which will probably decline linearly or perhaps even as a squared function of
range, rather than declining
ast some set point - which is why the 'beat the range' roll sounded
good). But when a round hits, regardless of range, damage should be the same.
6. Rapid fire shots (a mode or a type of RG) should have a higher chance to
hit, a more limited range, and drop off in a much more pronounced pattern
since this type of attack relies more on volume of fire than on single shots
from sensor data. And volume increases as a cubic function or increased range.
So these should be shorter range (effectively) and should be capable of high
damage raking fire and PDS functions. Damage here should be widely variable,
but increasing as range closes (at closer range, more projectiles on target).

My 0.02.

Tom.
/************************************************

From: Michael Brown <mwbrown@s...>

Date: Wed, 25 Nov 1998 09:01:00 -0800

Subject: RE: [FT] Railgun Goals

Quick comment:

[quoted original message omitted]

From: Indy Kochte <kochte@s...>

Date: Wed, 25 Nov 1998 12:13:02 -0500 (EST)

Subject: Re: [FT] Railgun Goals

> Quick comment:

[raises hand from somewhere in the back of the room]

Question: how is gravity going to affect high-speed projectiles, in the
time/distance scales we are discussing? If you are near (near!!!) a
high-
gravity mass (Jupiter and larger), your onboard combat computers ought to
be able to easily compensate for *that*, at least. I see range drop-off
accuracy as the inability to accurately predict where your opponent will be
when you fire at their ship(s).

From: Sean Bayan Schoonmaker <schoon@a...>

Date: Wed, 25 Nov 1998 09:28:06 -0800

Subject: Re: [FT] Railgun Goals

> Question: how is gravity going to affect high-speed projectiles, in the

The drop off of which I speak is the predictability variety - not
gravity. To be a little more specific, it should drop off like and inverse log
function.

From: John Leary <john_t_leary@y...>

Date: Wed, 25 Nov 1998 09:37:47 -0800

Subject: Re: [FT] Railgun Goals

> Tom Sullivan wrote:

Hi All, Tom has a very valid point in what he is saying.

My concept of the 'K' railgun.

The 'K' rail gun is a device that throws a stream of small dense
'BBs' across the path of the target ship.   (thus the 'swiss cheese'
comments in the rules) The primary difference between each of the
three types is the addition of power storage/charging units on the
larger railguns.
Type 1 = railgun + charger
Type 2 = railgun + charger + charger
Type 3 = railgun + charger + charger + charger
The increased damage function of the guns is due to the following shot being
more compact (shot pattern) and of increased accuracy due to the tracking of
the preceding shot placement.

Now this is all PSB, but it works for me.

The 'garbage can' projectile concept would require sensors far superior to the
'standard' sensors of the Kra'Vak. (Now to scuttle my own concept: If the
'garbage can' was similar to a SML projectile, I.E. a proximity device, the
sensors do not need to be as good, but the damage should be more varied.)

At one point in time, I started to look at the possibility of inverting the
'to hit' scale and decreasing damage vs range. (like a shotgun pattern) At
short range: big 'to hit' number and big damage. At long rang: small 'to hit'
number and small damage. This concept offsets the scattergun short range
abilities.(in Part)

Bye for now,

From: John Leary <john_t_leary@y...>

Date: Wed, 25 Nov 1998 09:54:38 -0800

Subject: Re: [FT] Railgun Goals

> Michael Brown wrote:
...Snip...JTL
> Subject: [FT] Railgun Goals
XXX Disagree here, the range is limited by to ability of the target to detect
and correctly plot the locations of the projectile. Also by the ability of the
target to alter its direction after the projectile course has been determined.
(Reaction time) JTL XXX
> 2) Damage should be constant, without regard to range.
XXX True, if dealing with a garbage can, not true if shotgun. JTL XX
> 3) Firing arcs should be very limited to preserve the K'V "feel."
XXX Agree. JTL XXX
> 4) Mass should be relatively low, and point cost should be relatively
XXX Depends on the overall concept. JTL XXX
> Please refute these if you don't agree; they're just a starting point.
Once
> we agree on some goals, then we can get down to the nitty-gritty of

Bye for now,

From: Jeff Lyon <jefflyon@m...>

Date: Wed, 25 Nov 1998 11:54:42 -0600

Subject: Re: [FT] Railgun Goals

Another thing that needs to be cleared up IMO is what exactly do we mean when
we say "railguns"?

We can build prototype railguns today and will probably be fielding early
field models within a decade (probably less).

Some of the weapons in DS2 and SG2 (such as the MDC and gauss rifle) might
arguably be classed as railguns. So might PDS systems.

I've heard KV railguns described as accelerating projectiles to "near
relativistic" velocities, but can't seem to find that in the descriptions in
MT. (Personally, I think such a weapon would be more like the
"C-plus"
cannon in Saberhagen's Berserker novels; it would probably destroy any ship it
hit.) I've also seem some back and forth over whether they are the
electromagnetic accelerators we are familiar with or some sort of gravitic
accelerator instead. If true, they clearly aren't "your granddaddy's railguns"
anymore.

I think we need to ask what general guideline we expect them to conform to;
are these the products of technology that is similar to, slightly superior to
or significantly superior to that of humanity in the official GZG universe.

And while we are at it, why not hammer out some general guidelines for
incorporating advanced technologies into FT?  I think the low mass/high
cost payoff makes a lot of sense and should be fleshed out so that those of us
who don't play in the official sandbox can have a truly generic system for
designing balanced ships for any alien race rather than getting too caught up
in the care and feeding of Kra'Vak specifically. That way you can have your
"advanced drives" race, your "advanced material science" race, etc. in
addition to your special weapons X, Y, and Z races. For
example, I'd like to use railguns for the "low-tech" humans in my
universe.

In the case of the official universe I think one should ask why humans did not
develop them as a primary weapon system when we are clearly on that path
today.

Who knows?  You might find that the Kra'Vak are actually _less_ advanced
in some areas and use RGs because they are the best thing they could think of.
Perhaps with the new FB designs, we'll find that railguns are really only
effective against fleets that have "over specialized" in their defenses
against beam weapons.

I guess, in summary, I'm saying lets re-evaluate what they are and how
they work as part of an integrated ship design system that will continue to
work for any universe. Perhaps we'll end up with two (or more) different types
of weapons; call 'em railguns and gauss cannons or whatever.

Just some thoughts.

From: Jeff Lyon <jefflyon@m...>

Date: Wed, 25 Nov 1998 12:07:18 -0600

Subject: Re: [FT] Railgun Goals

> At 09:37 AM 11/25/98 -0800, you wrote:

One point in favor of larger projectiles; small caliber HiVeloc rounds tend to
vaporize on impact. We use a layer of metal foil to protect satellites and
space stations against micrometeors today. Tanks in WWII used thin metal
plates and spacers to deflect small caliber AP rounds. A similar defense would
seem to work against your swarm of pellets idea, while a large caliber round
would be more like to blow through one side of the ship and out the other.

From: Thomas Anderson <thomas.anderson@u...>

Date: Wed, 25 Nov 1998 18:18:10 +0000 (GMT)

Subject: Re: [FT] Railgun Goals

> On Wed, 25 Nov 1998, Sean Bayan Schoonmaker wrote:

very sensible. a pre-argument argument!

> 1) The "To-Hit" mechanic should reflect a projectile flavor. In my

this may play well, but as physics it is pretty groundless.

WARNING: what follows is fairly simple algebra etc, but it is
probably badly-though out and deeply incorrect. it also makes lots of
unjustifiable assumptions which are never clearly defined.

hitting a target with a single round / burst means putting them in the
same place at the same time. since the position of the burst is trivial to
predict, the difficulty lies in finding the target. at range r, the time taken
for a scanner pulse to get there and back (assume active firecon) is:

        t       time
r range c speed of light

        t       =       2r/c

in this time, a ship with acceleration a can change its velocity by

a acceleration v velocity d change in. i can't do capital delta, sorry!

dv = at
                =       2ar/c

since that velocity change can be in any direction (well, it can't, but
this is really hard if it is not - assume a spherical chicken and all
that), the target can be anywhere in a sphere of radius (size)

s radius of target envelope

s = t.dv
                =       2r/c . 2ar/c
                =       4arr/cc

given that the railgun round crosses the sphere, the target is a circle, and
so the probability of hitting the target is given by the
probability-sum of the cross-sectional areas of the burst and the target
as fractions of the potential target area:

	[p(a)	probability of a occurring]
p hit probability p1 p( burst in right place) p2 p( target in right place) x
radius of burst (circular) y square root of (area of target divided by pi)

        p       =       p1 + p2 - p1.p2
        p1      =       xx/ss
        p2      =       yy/ss
        p       =       ( xx + yy - xxyy/ss ) / ss

for very small values of x and y relative to s (as they will be at large
range):

% is proportional to (damn this ascii!)

        p       ~=      (xx + yy)/ss
                %       1/ss
                %       cccc/16aarrrr
                %       1/rrrr

the hit probability should fall off with the fourth power of range.

> 2) Damage should be constant, without regard to range.

right - no drag to slow down the round. otoh, if you use a burst, the
number of rounds which hit will fall with range, so damage will fall.

> 3) Firing arcs should be very limited to preserve the K'V "feel."

spot on.

> 4) Mass should be relatively low, and point cost should be relatively

i don't see why massdrivers should be smaller than beam batteries; if
anything, i would say they are larger but cheaper.

> Please refute these if you don't agree; they're just a starting point.
Once
> we agree on some goals, then we can get down to the nitty-gritty of

excellent methodology. maybe we should submit the list for ISO 9000 process
quality certification?

Tom

From: Dean Gundberg <dean.gundberg@n...>

Date: Wed, 25 Nov 1998 12:25:09 -0600

Subject: RE: [FT] Railgun Goals

> Schoon wrote:

Aaaah, good thought, start at the beginning

> 1) The "To-Hit" mechanic should reflect a projectile flavor. In my
Why drop off quickly? The projectile is at a constant velocity so wouldn't
the drop off rate for the to-hit roll be constant?  I like the PSB that
the projectile (one big one not a lot of BBs) is of similar size on all
railguns, but the larger guns are able to accelerate it to higher velocities
resulting in more damage and larger range bands (a reason to mount larger
railguns).  I still like the 4/6/8 progression (I did work with Matt to
get
the figures he posted ;) more than the 3/6/9 progression which seems to
vary the range too much (beam ranges vary a lot but less variation for
railguns make them different).

> 2) Damage should be constant, without regard to range.
Yup

> 3) Firing arcs should be very limited to preserve the K'V "feel."
Yup, though I would allow the R1s to have a couple arcs so they can have some
weapon coverage in all arcs on cruisers and larger.

> 4) Mass should be relatively low, and point cost should be
Yup

On re-rolls, when the FB was being worked on, weapons that got re-rolls
were subject to screens (beams) but weapons that ignored screens (PTs) did not
get the reroll. This seemed to balance out since they all had the same cost
per point of mass.

Railguns, as they were in MT should have a higher cost per mass than the basic
weapons (due to their extended range, high average damage, ignored screens).
Once we get the FT2.5 versions, allowing railguns to have
re-rolls in addition to ignoring screens and their other benefits would
call
for an even higher point cost.  I could live with re-roll on railguns
but don't see a real need for it. In the end I just want them costed according
to their abilities.

Also on armor, why not let the K'V have their own type of armor, different
from the human alabative armor. K'V armor would stay as it was in MT, acting
like screens but without the possibility of it going down due to thresholds.
It would talk up a percentage of mass very similar to screens but increase the
cost per mass used a point. Then the basic hull integrity classes can stay and
don't need modification for the K'V.

From: Thomas Barclay <Thomas.Barclay@s...>

Date: Wed, 25 Nov 1998 14:18:21 -0500

Subject: Re: [FT] Railgun Goals

Thomas spake thusly upon matters weighty:

> On Wed, 25 Nov 1998, Sean Bayan Schoonmaker wrote:

I'm skeptical about some of the math on the way here. But it seems to be on
the order of magnitude I'd expect.

In truth, if your target envelope is a sphere, and your railgun burst through
it has a spherical cross section (an approximation of sorts),
is seems likely the burst will  generate a truncated-tip conical path
volume through the volume of space we call the target envelope. The ratio of
the volume of this conical path to the total size of the
target envelope volume may be something that defines the hit-miss
result. It isn't that obvious though, because it isn't strictly a relation of
these two volumes. But your intial work seems to assume no spread.

Even beams gravitically focused will have spread. In the FFS (Traveller)
construction system, gravitic focus was postulated for beams as a requirement
as no mechanical focus was of sufficient accuracy. So the spread of the
pattern may have something to do with changing the area of the shot pattern.
And that is an *unplanned*
variance - let's call that modified choke. You may be able to control
the choke of your shot pattern to make it very wide at close range, for PDS
and for good hit probs.

Gaming Note: Interesting trade would be a mechanic that lets you palsy the
damage in exchange for better hit probs.

> > 4) Mass should be relatively low, and point cost should be

Depends on relative energy requirements. Which I can't begin to caculate...

> excellent methodology. maybe we should submit the list for ISO 9000

I'm in the middle of a 9001 Audit. You don't want that - you'll never
rest comfortably again....

/************************************************

From: John Leary <john_t_leary@y...>

Date: Wed, 25 Nov 1998 11:34:40 -0800

Subject: Re: [FT] Railgun Goals

> Jeff Lyon wrote:

I must disagree here, the concept that a 'big' round has better penetration
than a 'small' round is not valid. All of the DS2 people will agree, I am
certain.

or: Penetration equals force per unit area. (KE=mass X velosity) or: APFSDSDU
(I think I got the letters in the right order.)

It is an unstated premise of the railgun discussion that it can, reguardless
of actual projectile size, penetrate ships to at least half if not all the way
through the target.

While it is completely your choice as to what 'flavor' of PSB your going to
have, I am quite happy with mine.

Reasons: 1) BBs do not require advanced sensors, in our current campaign
setting this is important, since sensor types are important. 2) BBs justify an
almost unlimited ammo supply. 3) BBs would be easier to accelerate to some
high value of speed. 4) BBs could have multiple 'rounds' going down the 'tube'
at the same time.

I have no doubt that these can be countered with real or PSB concepts, but the
botton line is: Do what works for you.

Bye for now,

From: Indy Kochte <kochte@s...>

Date: Wed, 25 Nov 1998 15:44:19 -0500 (EST)

Subject: Re: [FT] Railgun Goals

> My concept of the 'K' railgun.

Slightly different things, these layers of foil (MLIs) and tank armor plates.

Aside from that, the MLIs are not used for micrometeor protection. Rather,
they are anti-radiation shielding and assist with temperature control.

(MLI = multi-layer insulation; this is the stuff that is deteriorating
on
the Hubble after 7+ years in space that the astronauts on the last
Servicing Mission [Feb'97] had to fashion bandaids for using their onboard
repair kits)

Mk

From: PsyWraith@a...

Date: Wed, 25 Nov 1998 17:35:42 EST

Subject: Re: [FT] Railgun Goals

In a message dated 11/25/98 12:49:34 PM Pacific Standard Time,
> KOCHTE@stsci.edu writes:

> >>My concept of the 'K' railgun.

Also keep in mind that if we go with the burst railgun concept these clusters
of "BB's" could very well be bundles of 20-40mm penetrator rods at the
scale envisoned for Kra'Vak railguns.

From: Michael Brown <mwbrown@s...>

Date: Wed, 25 Nov 1998 14:40:31 -0800

Subject: RE: [FT] Railgun Goals

I thought I was clear. Fire control is the ability to predict and target.
Gravity and other effects are what we see on planets.

Mike

Snip

[quoted original message omitted]

From: Indy Kochte <kochte@s...>

Date: Wed, 25 Nov 1998 18:54:21 -0500 (EST)

Subject: Re: [FT] Railgun Goals

> In a message dated 11/25/98 12:49:34 PM Pacific Standard Time,

PsyWraith, just for the record, that's not me you're quoting up there.
;-)

Mk

From: trapper <trapper@n...>

Date: Wed, 25 Nov 1998 17:11:22 -0800 (PST)

Subject: Re: [FT] Railgun Goals

> At 06:18 PM 11/25/98 +0000, Thomas Anderson wrote:

> WARNING: what follows is fairly simple algebra etc, but it is

LOL, I think I'm going to start writing this at the top of all my math exams
from now on!:)

From: Jeff Lyon <jefflyon@m...>

Date: Wed, 25 Nov 1998 20:23:17 -0600

Subject: Re: [FT] Railgun Goals

> At 05:35 PM 11/25/98 EST, Chris Ruhl wrote:

Quite a bit more reasonable.

From: John Leary <john_t_leary@y...>

Date: Wed, 25 Nov 1998 18:38:57 -0800

Subject: Re: [FT] Railgun Goals

> Jeff Lyon wrote:

Or depleted uranium ball bearings. (BBs)

:-)

Bye for now,

From: Jeff Lyon <jefflyon@m...>

Date: Wed, 25 Nov 1998 20:43:42 -0600

Subject: Re: [FT] Railgun Goals

> At 02:18 PM 11/25/98 -0500, you wrote:

That's a neat idea.

From: Jeff Lyon <jefflyon@m...>

Date: Wed, 25 Nov 1998 20:57:44 -0600

Subject: Re: [FT] Railgun Goals

> At 11:34 AM 11/25/98 -0800, you wrote:

A penetrator rod is not a BB. The rod gives the best of both worlds; is has
higher mass than a sphere of the same diameter and a lower diameter than a
sphere of the same mass.

> or: APFSDSDU (I think I got the letters in the right order.)

Of which 2 to 4 are of questionable utility in a vacuum.

:)

From: John Leary <john_t_leary@y...>

Date: Wed, 25 Nov 1998 19:54:41 -0800

Subject: Re: [FT] Railgun Goals

> Jeff Lyon wrote:
is
> has higher mass than a sphere of the same diameter and a lower

Pickey, Pickey, Pickey.

:-)

Bye for now,

From: Sean Bayan Schoonmaker <schoon@a...>

Date: Wed, 25 Nov 1998 21:22:06 -0800

Subject: Re: [FT] Railgun Goals

> John and Roxanne Leary <realjtl@sj.bigger.net> wrote:

> The 'K' rail gun is a device that throws a stream of small dense

I'm not sure I agree with this concept. I think that the size of the BBs will
also vary with class, assuming we go with the BB model. Even though the class
3 uses the same basic railgun system, it's a bigger one.

The idea of a superdense spindle blowing through another ship, regardless of
the realism involved, sings to me.

My personal preference is for a middle ground - a handfull of larger
projectiles. Not one big one or millions of small ones.

From: Sean Bayan Schoonmaker <schoon@a...>

Date: Wed, 25 Nov 1998 21:23:48 -0800

Subject: Re: [FT] Railgun Goals

> John and Roxanne Leary <realjtl@sj.bigger.net> wrote:

> The 'K' rail gun is a device that throws a stream of small dense

I'm not sure I agree with this concept. I think that the size of the BBs will
also vary with class, assuming we go with the BB model. Even though the class
3 uses the same basic railgun system, it's a bigger one.

The idea of a superdense spindle blowing through another ship, regardless of
the realism involved, sings to me.

My personal preference is for a middle ground - a handfull of larger
projectiles. Not one big one or millions of small ones.

From: Andrew Martin <Al.Bri@x...>

Date: Thu, 26 Nov 1998 21:50:14 +1300

Subject: Re: [FT] Railgun Goals

> Jeff Lyon <jefflyon@mail.utexas.edu> wrote:
is
> has higher mass than a sphere of the same diameter and a lower diameter
Armour Piercing, Fin Stabilised, Discarding Sabot, Depleted Uranium.

> Of which 2 to 4 are of questionable utility in a vacuum.
Sorry, only Fin Stabilised is of no use in space. Armour Piercing allows
penetration of target armour. Discarding Sabot allows the use of a short,
large diameter barrel to propel
target - even if using a electro-magnetic rail gun.
Depeleted Uranium allows higher projectile density - more damage done to
target.

From: John Crimmins <johncrim@v...>

Date: Thu, 26 Nov 1998 09:34:52 -0500

Subject: Re: [FT] Railgun Goals

> At 09:22 PM 11/25/98 -0800, you wrote:
I have to agree. The shotgun approach seems MUCH more sensable...but I like
the thought of one big shot a lot better. It's much more visually appealing,
somehow. However, as another option....

"The spotlight tracked the packet for visual confirmation of deployment, which
came at once as eight small shaped charges burst. Each threw a fifty meter
length of iron chain away from the center. "As the pinwheel unfurled, she
thought, *They should call it a
spiderweb--that's what it really looks like.*
"...Even a torpedo that burst exactly where desired would probably not do
significant damage. On a ship like [the target] nothing was close to anything.
     "But a chain-link spiderweb 100 meters in diameter had to hit
something...they would slash through like grapeshot."
        Kevin O'Donnell, Jr--"Fire on The Border",pps. 21-22.

I think that the big spiderweb has both visual appeal, and makes sense. It
lets you cover a large area, while still presenting a small target for area
defense. Just a thought, that's all.

From: Doug Evans <devans@n...>

Date: Thu, 26 Nov 1998 08:36:25 -0600

Subject: Re: [FT] Railgun Goals

At last, something I can comment on... ;->=

***Discarding Sabot allows the use of a short, large diameter
barrel...***

Well, the discarding part is probably 'useless', as the idea is to make a
large diameter shot-in-the-barrel a small diameter projectile-in-air to
reduce drag. No drag in space. And, the discarded sabot is discarded mass,
probably off target. On the other hand, you might want the projectile of small
diameter to punch through the exterior of the ship.

EM railguns always assume ferrous rings for the induced magnetic charge, but
I'm not familiar with the electrical properties of uranium. Would depleted
uranium (a metal) be similar to iron as far as magnetism? Would
there BE depleted uranium in a fusion powered world? ;->= Aren't some of
the rare earths near uranium in density, and near iron vis-a-vis
magnetism?

In fact, DO inquiring minds want to know? Is this still giving ideas for
Kra'vak rg's, or has it gone to far off topic?

The_Beast

From: Thomas Anderson <thomas.anderson@u...>

Date: Thu, 26 Nov 1998 15:43:53 +0000 (GMT)

Subject: RE: [FT] Railgun Goals

> On Wed, 25 Nov 1998, Dean Gundberg wrote:

hey! not so much of the 'pseudo' - that is certified weapons-grade
_authentic_ scientific bulls**t! it's a serious idea; it explains things
and fits in with physics as we know it.

> Also on armor, why not let the K'V have their own type of armor,

nice idea; it certainly has a different feel to ablat. however, the fact that
it does not change with damage should make it costlier.

Tom

From: Thomas Anderson <thomas.anderson@u...>

Date: Thu, 26 Nov 1998 16:56:40 +0000 (GMT)

Subject: Re: [FT] Railgun Goals

> On Wed, 25 Nov 1998, Jeff Lyon wrote:

i doubt this. relativistic is, like 25% lightspeed minimum. to accelerate a
kilogram of matter to 0.25 c, not accounting for mass increase at high
v, takes about 3e15 joules -three thousand terajoules. this is a bit
much for a tactical weapon, i would say. how much energy is there in a
megatonne nuke?

Tom

From: Thomas Barclay <Thomas.Barclay@s...>

Date: Thu, 26 Nov 1998 11:59:48 -0500

Subject: Re: [FT] Railgun Goals

Sean spake thusly upon matters weighty:

> My personal preference is for a middle ground - a handfull of larger

How about multiple modes? A Raking/Volume mode which gives you good
hit/damage potential, but spreads the damage so armour acts more
effectively (more lower energy projectiles) and a Piercing/Impact
mode which gives you long range, good one-hit penetration vs armour,
but less aggregate damage?

Tom.
/************************************************

From: Thomas Anderson <thomas.anderson@u...>

Date: Thu, 26 Nov 1998 17:12:17 +0000 (GMT)

Subject: Re: [FT] Railgun Goals

> On Wed, 25 Nov 1998, Thomas Barclay wrote:

> I'm skeptical about some of the math on the way here.

excellent! skepticism is the soul of rationality. or something. perhaps the
spleen.

> In truth, if your target envelope is a sphere, and your railgun burst

> But your intial work seems to assume

one of those unwritten assumptions, i'm afraid. at extreme range, the spread
will not be very much.

> > i don't see why massdrivers should be smaller than beam batteries;
if
> > anything, i would say they are larger but cheaper.

[rolls up sleeves] old hat; relativity is vital in fudging physics
experiment results!

E kinetic energy m mass M rest mass v speed c speed of light k relativistic
coefficient

E       =       mvv/2
m       =       M/k
k       =       (1 - vv/cc) ^ 1/2

E       =       mvv/2
        =       Mvv/2k
        =       Mvv/2((1 - vv/cc) ^ 1/2)

for a projectile travelling at half lightspeed (1.5 e 8 m.s), the kinetic
energy is 13e5 joules per kilogram (if i have done the algebra and arithmetic
correctly, which, given past form, is unlikely).

Tom

From: John Leary <john_t_leary@y...>

Date: Thu, 26 Nov 1998 09:29:47 -0800

Subject: Re: [FT] Railgun Goals

...Snip...JTL
> I think that the big spiderweb has both visual appeal, and makes

From: John Leary <john_t_leary@y...>

Date: Thu, 26 Nov 1998 11:00:48 -0800

Subject: Re: [FT] Railgun Goals

> Thomas Barclay wrote:

Oh ya, Oh ya!	This will keep everybody happy.   Shotgun and
Trashcan lovers unite, now all we need to do is make it work.

Shotgun mode at short range allows the 'K' to 'scrub' the armor off the target
and have a low 'to hit' number. Trashcan mode at long range allows AP effects
against armor (1 point to armor and rest internal) and a higher 'to hit'
number.

As far as 'K' vs 'K' simply subtract the armor level from the damage done per
hit and apply the remainder per the above.

Bye for now,

From: Andrew Martin <Al.Bri@x...>

Date: Fri, 27 Nov 1998 10:14:03 +1300

Subject: Re: [FT] Railgun Goals

> ***Discarding Sabot allows the use of a short, large diameter
Nope.

> No drag in space. And, the discarded sabot is discarded mass,
Would
> there BE depleted uranium in a fusion powered world? ;->= Aren't some

A discarding sabot made of the appropriate materials allows the most efficient
"push" to the projectile, regardless of what the projectile is made of. Which
is why they are used. A short, large diameter barrel is easier to manufacture
and aim than a long, thin barrel.

From: Thomas Barclay <Thomas.Barclay@s...>

Date: Thu, 26 Nov 1998 16:54:35 -0500

Subject: Re: [FT] Railgun Goals

> A discarding sabot made of the appropriate materials allows the

Agreed. But I think you'll agree also that a railgun (by nature) requires such
a long thin barrell. And the pressure accelerating the round is not an
expanding fuel air mixture such as in a CPR (HV) gun, but instead is either
gravitic acceleration or electromagnetic acceleration. I'm not sure the sabot
has as much use.

> Andrew Martin

/************************************************

From: Andrew Martin <Al.Bri@x...>

Date: Fri, 27 Nov 1998 15:05:44 +1300

Subject: Re: [FT] Railgun Goals

> Thomas Barclay wrote:
Ah, but you misunderstand the nature of the sabot. It's designed to be easy to
drive along the barrel while holding the penetrator. That's so the penetrator
can be designed solely to penetrate the target. The sabot divides the problem
into two parts. Of course, if you've got projected gravitic accleration at 10
to 1000 Gs, you don't really need a sabot, projectile or barrel. Just call the
system a tractor or pressor beam.

From: Sean Bayan Schoonmaker <schoon@a...>

Date: Thu, 26 Nov 1998 19:19:56 -0800

Subject: Re: [FT] Railgun Goals

> Thomas Barclay <Thomas.Barclay@sofkin.ca> wrote:

> How about multiple modes? A Raking/Volume mode which gives you good

A very interesting idea, but can it be done without overcomplicating the
entire thing?

From: Tim Jones <Tim.Jones@S...>

Date: Fri, 27 Nov 1998 08:16:18 -0000

Subject: RE: [FT] Railgun Goals

> My personal preference is for a middle ground - a handfull of larger

I too think this is an unrequired over complication. In MT it clearly states
it works as a hyper velocity penetrator in
bursts - analagous to a machine gun burst, Dacca Dacca Dacca.

The class just changes the calibre of the bullet/projectile
so here its analgous to:

class 1 is a.22 class 2 is a.303 class 3 is a.50.

And the damage done reflects the larger calibre round having more energy when
it hits the target.

Its not analagous to a shotgun or artillery (AKA trash can)

From: Thomas Anderson <thomas.anderson@u...>

Date: Fri, 27 Nov 1998 14:51:47 +0000 (GMT)

Subject: Re: [FT] Railgun Goals

> On Fri, 27 Nov 1998, Andrew & Alex wrote:

one of the problems with big powerful electromagnets is this: electromagnets
use a coil of wire with current in it it generate a magnetic field. a current
flowing in a magnetic field experiences a force. in the case of coils, this
force is outwards. hence, at large fields, electromagnets tend to explode. the
research group down the road here at oxfurd builds such things, and half of
the coil is carbon fibre for strength. they still have to run the tests at
night in case the explosion annoys other labs.

if you use a smaller diameter coil, you have less length of wire per turn (and
it is turns which determine field strength), and so less outward force. i'm
not sure exactly how the physics work out (and i'm not inclined to figure it
out right now, i have DNA to macerate back in the lab), you might find that
smaller diameter barrels have less radial force per unit field strength, and
so can operate at higher field levels. of course, you might also find that
larger barrels spread the stress wider and so it makes no difference. unless
someone wants to run the algebra on this, we'll leave it as PSBable.

just my 20 m$

Tom

From: Thomas Barclay <Thomas.Barclay@s...>

Date: Fri, 27 Nov 1998 10:58:52 -0500

Subject: Re: [FT] Railgun Goals

Sean spake thusly upon matters weighty:

Well, here is an example

Say we went with roll to beat range (trashcan mode) with whatever multiplier
(double?) we thought sensible, allowing rerolls on damage and range. This kind
of railgun fire is only half blocked by armour. Class Fire Damage Arcs Class 1
1d6 1d6 2 usable for PDS Class 2 2d6 2d6 1 not Class 3 3d6 3d6 1 not

Now, i'd suggest for a raking mode, roll to beat range, use the same
multiplier, but for the larger RGs (Class 2+), roll double the
above # of dice separately, thus making multiple class 1 shots effectively and
DON'T give the rerolls for damage (lower energy projectiles) or range. This
kind of railgun fire may be totally blocked by armour.

So, you can fire your class 2 as a trashcan shot out to say 24" barring
rerolls, but will average 14". It'll do 2d6 damage (an average of 3.5 to
armour and 3.5 past armour). Fire the same gun in a raking fire mode at close
range, your average range will be 7" (since you are rolling d6 individually),
a maximum range of 12", but your damage could be as much as 6d6, but it will
all be applied
against armour and won't get re-rolls for damage.

What thinkest thou? Note: I am not speculating on point cost or on
mass - these are matters for the more constructionally inclined.

> Thomas Barclay <Thomas.Barclay@sofkin.ca> wrote:
/************************************************

From: Tim Jones <Tim.Jones@S...>

Date: Fri, 27 Nov 1998 16:31:05 -0000

Subject: RE: [FT] Railgun Goals

> Now, i'd suggest for a raking mode, roll to beat range, use the same

The mode you describe is more like 'double shotting' than 'raking', firing two
cannon balls or HVP's out at the same time. More mass in projectiles, lower
velocity and range.

Its behaviour profile should be lower range limit large damage multiplier.

If you rake and double shot at close range its usually game over for a sailing
ship or in our setting spaceship.

I don't buy this trashcan/shotgun concept but we'll agree to disagree.

From: Thomas Barclay <Thomas.Barclay@s...>

Date: Fri, 27 Nov 1998 11:55:25 -0500

Subject: RE: [FT] Railgun Goals

Tim spake thusly upon matters weighty:

> >Now, i'd suggest for a raking mode, roll to beat range, use the same

yes, that is roughly it. Rolling the dice individually limits your range to 6"
(since you deny the rerolls on range also in this mode). large damage would be
getting hits on all the dice. (Since there are twice as many)

> Its behaviour profile should be lower range limit large damage

That makes sense.

> I don't buy this trashcan/shotgun concept but we'll agree to disagree.

It supports an interesting close in/far out mechanic mix. Call it
shotgun, call it high volume rapid fire, and as for the trashcan,
call it lower-volume higher velocity fire. And (as always) YMMV, and
you can do what you like.:)

/************************************************

From: Thomas Barclay <Thomas.Barclay@s...>

Date: Fri, 27 Nov 1998 12:57:23 -0500

Subject: Re: [FT] Railgun Goals

Andrew spake thusly upon matters weighty:

> >Agreed. But I think you'll agree also that a railgun (by nature)

Sure, and I reiterate that this has a point for CPR guns like HVs. It may or
may not have a point for railguns. It may be that my projectile can be as
easily driven along if it is a small sharp tungsten penetrator as if it was
encased in a larger casing.

/************************************************

From: John Leary <john_t_leary@y...>

Date: Fri, 27 Nov 1998 10:23:13 -0800

Subject: Re: [FT] Railgun Goals

> Thomas Barclay wrote:
...Snip...JTL
> So, you can fire your class 2 as a trashcan shot out to say 24"
...snip...JTL

Please note, reguarding the division of damage between the armor and the first
damage box row

Please don't bother, as the action is a POINTLESS WASTE OF TIME.

The best way to look at 'armor' is to consider the armor to be an extension of
the first row of damage boxes, nothing more. Unless we create an 'official'
method to bypass the armor, (I.E. one point to armor and the rest internal)
all the different modes, (Shotgun, Trash can, Penetrator, ect) have no
meaning. (Beyond a feel good effect)

Shotgun mode: scrubs off armor (all) and then first damage box row (all)
causing a threshold check. Trashcan mode: divides damage between armor and
first damage row untill armor (all) and damage boxes (all) have been marked
off causing a threshold check.

There is no difference between the two modes, both cause a threshold check
after all armor and all damage boxes have been marked off.

Now to trash my concept, it would be possible to design a ship with an very
large amount of armor on a fragile hull, but I really cannot see this being
done with any regularity.

Just thoughts, Bye for now,

From: Steven Arrowsmith <arrowjr@u...>

Date: Fri, 27 Nov 1998 13:36:02 -0500 (EST)

Subject: Re: [FT] Railgun Goals

> On Fri, 27 Nov 1998, John and Roxanne Leary wrote:
<snip>
> Please note, reguarding the division of damage between the
<snip>
> Just thoughts,
John,

In the Fleet Book, both Enhanced Pulse Torpdpes and Salvo Missiles use a
variation of this system. Half damage to amour, the rest to the hull boxs, so
I do not see a problem with idea..

SA

From: Robin Paul <Robin.Paul@t...>

Date: Fri, 27 Nov 1998 19:11:08 +0000

Subject: [FT] Railgun Goals

Yet another way to differentiate the RG sizes would be to give them the same
basic damage but different multipliers e.g.
RG1 Base damage 1, Multipliers 0 (die roll 1-3) or 1 (4-6)
RG2 Base damage 1, Multipliers 1 (1-3)         and 2 (4-6)
RG3 Base damage 1, Multipliers 2 (1-3)         and 3 (4-6)

The Base damage could be doubled in the closest range band to reflect the
likely impact of more penetrators at point blank range.

I still hate the idea of multi-arc railguns.

From: Sean Bayan Schoonmaker <schoon@a...>

Date: Fri, 27 Nov 1998 20:06:41 -0800

Subject: Re: [FT] Railgun Goals

> Yet another way to differentiate the RG sizes would be to give them the

You might want to adjust this to get the full spectrum from the larger RGs, so
they all go from 0 to something, or 1 to something.

From: Ground Zero Games <jon@g...>

Date: Sat, 28 Nov 1998 07:56:35 +0000

Subject: Re: [FT] Railgun Goals

> On Fri, 27 Nov 1998, John and Roxanne Leary wrote:

Ahh, Love takes a battering again....
<Heh! Sorry, first rule of comedy - NEVER pass up a Straight Line,
(especially at this time of night)....:)>

> , the rest to the hull boxs,

It only really makes a difference when the target has an armour row longer
than its hull box rows - then split penetrating damage can force a
threshold before all the armour is gone.

Jon (GZG)
> SA

From: John Leary <john_t_leary@y...>

Date: Sat, 28 Nov 1998 10:08:45 -0800

Subject: Re: [FT] Railgun Goals

> Ground Zero Games wrote:

> >John,

I did make a point of saying that this was a possibility. Since the PT and SML
do not exist in a (other) weapons vacuum, I still feel that the exercise is of
extremely limited value (at its Best). If the List developes a true
'Penetrator' round for the 'K' (one point to armor and the rest internal),
then the concept will have a valid reason the exist.

Rationalization can get us anywhere we want to be!

Bye for now, John L.
> >

From: Jeff Lyon <jefflyon@m...>

Date: Mon, 30 Nov 1998 08:33:22 -0600

Subject: Re: [FT] Railgun Goals

> At 09:50 PM 11/26/98 +1300, you wrote:

That was the other one I was not sure about. Hence the 2 to 4 comment. But
then, why would you necessarily want a short, large diameter barrel?
Wouldn't the KV-style RGs be long accelerators?

> Depeleted Uranium allows higher projectile density - more damage done