What are the best arcs of fire to use to represent a ground based, direct
fire, beam weapon? I like 180 degrees (3 arc), horizon to horizon, but a
friend has suggested 270 degrees (I don;t understand how or why) or even 360
degrees.
I think the problem lies with whatever model you use to represent a 3-D
planet on a 2-D map. If the table is the plane of the eliptic (which I
suspect we all subconsciously assume) the a polar base would be able to fire
360 degrees unless the ships came too close, then the curve of the planet
would block the guns. Alternativly an equitorial base would only have a 180
degree arc of fire. What do you think?
Well, layout of the ships are in two dimensions, so I'd say the planet's
defenses should be likewise. I think of the batteries on the edge of the
planet, and maybe only 60 degrees. I've never liked the 'rolling over' ship
option to bring new batteries to bear, but rolling a planet is difficult to
imagine. On the other hand, the battery should only take damage from it's arc
of fire. Getting over 180 degrees seems like it should be in NEO.
Also, I don't recall, but I'd say construction of any thing, including large
planet defense batteries, should be cheaper on a planet rather than in orbit.
Free fall makes many things easier, but getting the goodies to put together is
always a problem. YMMV.
The_Beast
> What are the best arcs of fire to use to represent a ground based,
[snippage]
180 is reasonable. Even if you do have 3D, however, there's no reason to
increase is. It's 180 in any given plane.
The only argument I could see for a greater arc would be if you mounted it on
a mountain, or if the planert were very small.
> What are the best arcs of fire to use to represent a ground based,
I would be more inclined to a 120-degree arc, personally. It does,
though, depend on how far you plan on abstracting things. Now if the planet
had an atmosphere, I would strongly argue *against* anything greater than a
120 degree arc of fire due to atmospheric interference and distortions.
To the original poster: for ship bombardment on your target planet, where does
your ship(s) have to be in order to hit your target? Directly overhead, or can
they be off at an angle? I would then use that as a guideline for planetary
defense battery fire (if the ship cannot hit it, it can't hit the ship).
*shrug* Makes sense to me.
My $0.02 worth; on to wading through the other 100 msgs... (boy you guys were
busy over the weekend!)
Mk
The man with the technicolor id sed:
I would be more inclined to a 120-degree arc, personally. It does,
though, depend on how far you plan on abstracting things. Now if the planet
had an atmosphere, I would strongly argue *against* anything greater than a
120 degree arc of fire due to atmospheric interference and distortions.
***
Interference and distortion crossed my mind, though there is plenty of PSB why
this won't be a concern in 10 yrs, much more the future we're talking about. I
figure we're trying to also stay in the FB-style fire arcs, so
60/120/180/240/300/360 are the choices. We might even throw in hardening
of sites, with regular being 180, hardened 120 or less...
Also, what is the 'down' angle to the horizon of an Earth-style planet,
say at 100 feet above the surface, assuming a really tall PDB? Five mi? Seven
mi? Top of Everest without other mountains to worry about? Top of Mons
Olympus? Near as much as the 30 degrees required for going to 240?
Definitely, though, what the enemy ship can target on sites should match what
the sites can target back.
The_Beast
> Michael Blair wrote:
...Snip...JTL
> I like 180 degrees (3 arc), horizon to horizon, but a friend has
...Snip...JTL
> What do you think?
Micheal, I am rather against the concept of having 'beams' on planets.
An orbital battle station/s is better for the 'space' aspect of
FT. Another reason, perhaps more valid in game justification
terms, would be: Ortillery has no reason to exist if the beams can reach the
ground.
Bye for now,
> On Mon, 1 Feb 1999, John Leary wrote:
[snip]
> Micheal,
Well, ground-based defense systems that can reach orbit should be
allowed to
exist - there are just too many good (and bad!) Sci-Fi books that use
this concept. You can rationalize it in that the installations of
ground-based
defenses aren't size/weight limited like a shipboard system is, but that
power
limitations and/or atmospheric/weather/gravitic/whatever effects of the
planet
prevent them from reaching beyond near-orbit.
That would still preserve the need for ortillery, yet allow a "well defended"
planet to install both OWPs (orbital weapons platforms, which can be attacked
from space), and GDSs (ground defense systems) that must be attacked by
ortillery.
Beams might be able to reach the ground, but ortillery is more efficient &
does more damage against surface targets (or underground bunkers). The old MT
has beam armed ships able to do 1 surface strike per class,
while ortillery is 1 per weapon & double the diameter (in SG/DS terms).
Personally, I abstract planetary defences into a Sa'Vasku vessel with
1/2 PF & 6" range bands. This tends to randomise what weapons are
available to fire (planetary curve, atmospheric attenuation, etc, etc) but
gives a place for surface batteries. Ships need to enter orbit & only gain 1d
per 5d of normal beam fire, but ortillery acts as an
anti-surface submunition pack (3d). This gives a good 'feel' to a
planetery assault, as you need to suppress the defences before sending in
assault shuttles, or the PDS will wipe them out in the upper atmosphere.
PS: I'm baaaaccckkkk..... from holidays.
'Neath Southern Skies
http://users.mcmedia.com.au/~denian/
*****
They seek him here, they seek him there; Those Frenchies seek him everywhere.
Is he in heaven or is he in hell? That damned elusive, Pimpernel.
- 'The Scarlet Pimpernel', Baroness Emma Orkzy
[quoted original message omitted]
> Robertson, Brendan wrote:
> PS: I'm baaaaccckkkk..... from holidays.
A very good thing that, the 'T-verse' is changing as we speak!!
Bye for now,
> devans@uneb.edu wrote:
> Interference and distortion crossed my mind, though there is plenty of
If the Planetary Defence Facility (PDF) is on an earthlike planet, I'd suggest
60 degree arcs. Consider the effect of a beam hot enough to punch through the
atmosphere and zap spacecraft a zillion clicks away. Now imagine, say 1% of
that energy being wasted in the atmosphere.
Can you say "ecologically Unsound"?
Maybe I can believe that a Multi-Gigajoule pulse directed nearly
straight up would be merely equivalent of a multiple lightning strike or pony
nuke ie no effect on the neighbours. But to have such a beam at a shallow
grazing angle would be disruptive to the local area to say the least.
I see PDFs as being of two types: Those in Orbit, which are essentially
thrustless spaceships, armed conventionally (and which can be "Weapons Free"),
and those huge facilities parked on convenient areas, such as
> From MT (the Orty support section) it states that beam batts can fire
(what ever that is, as I don't have DS2, but that will change by the end of
the week, I hope) to be placed at the impact point. I would say that it would
not be good for the environ. For more info you might want to check out
Cardinal of the Kremlin, it deals with HELs (as does the FCS set of articles
from Armor Mag at Fort Knox). As for the rules I would say that the area that
it coupide would have the same things happen as if a Ortilary had landed, alto
I would have it be narrow at the bottom (smaller than the temp for Orty) and
get larger at the top (this would be a very good way to kills VTOLs).
-Stephen
In a message dated 99-02-01 20:10:07 EST, you write:
<< Personally, I abstract planetary defences into a Sa'Vasku vessel with
1/2 PF & 6" range bands. This tends to randomise what weapons are
available to fire (planetary curve, atmospheric attenuation, etc, etc) but
gives a place for surface batteries. Ships need to enter orbit & only gain 1d
per 5d of normal beam fire, but ortillery acts as an
anti-surface submunition pack (3d). This gives a good 'feel' to a
planetery assault, as you need to suppress the defences before sending in
assault shuttles, or the PDS will wipe them out in the upper atmosphere.
> [quoted text omitted]
With the Gawain Assault that I'm hoping to kill I have worked out that there
will be A/S Def Towers (think of the missile towers from Dune2k) but the
idea of a S'V like def system for the entire planet is interestesting, how
would you do an assault on sites? The NAC smugled a group of Mercs on planet.
-Stephen
Well, the CF of the PDF only represents ground forces _immediately_
available as base defence personnel, rapid reaction forces etc, not the full
military available.
In FT scale, any ground assault (boarding action) initiated would be just to
establish the planethead & suppress air defences for the full invasion force
to land. If you wanted to strike a specific objective, agree on a CF & hull
for the facility, or organise a GM to plan this sort of detail.
'Neath Southern Skies
http://users.mcmedia.com.au/~denian/
*****
They seek him here, they seek him there; Those Frenchies seek him everywhere.
Is he in heaven or is he in hell? That damned elusive, Pimpernel.
- 'The Scarlet Pimpernel', Baroness Emma Orkzy
[quoted original message omitted]
> devans@uneb.edu wrote:
> Also, what is the 'down' angle to the horizon of an Earth-style
Laying myself open to corrections by better mathematicians, the following are
what
I reckon the total arcs of fire (horizon-to-horizon) would be for the
specified altitudes on an Earth sized planet:
Planetary Radius 6500km
Altitude (m) Arc Horizon (km)
0 180.00 0.00 10 180.20 11.40 50 180.45 25.50 100 180.64 36.06 250 181.01
57.01 500 181.42 80.62
1000 182.01 114.02
2000 182.84 161.26
5000 184.49 255.00
8000 185.68 322.59
10000 186.35 360.69
1000000 239.85 3741.66
The above all assume a perfectly spherical planet with a smooth surface.
So, to get to four FT fire arcs we need to be 1000km above the planet's
surface, a fairly substantial orbital altitude! Ignoring atmospheric effects,
surface obstructions etc we can pretty conclusively say that a Planetary
Defence Battery
has a 180 degree fire-arc.
> On Tue, 2 Feb 1999, Tony Francis wrote:
> devans@uneb.edu wrote:
Seven mi? Top
> > of Everest without other mountains to worry about? Top of Mons
well, i can only think of one way to do that (other than a satellite in
LEO).
SPACE ELEVATOR!
a beanstalk extends from the surface to 40 000 km, and you can build
things part-way up, if it is built strongly enough. you could run
superconductors and ammo lifts up the elevator to supply it. it might be
rather neat, in fact.
since most people now consider that a beanstalk would be made from a cluster
of independent but interlinked fibres to minimise impact damage, the firebase
would have to be strung from them, much like a gondola is from a balloon, with
weapons muzzles poking out between the fibres. it would look very odd, but
it'd be cool.
Tom