Register Register

Author Topic: Primitive AMS  (Read 624 times)

DevianID

  • Master Sergeant
  • *
  • Posts: 254
Primitive AMS
« on: 11 February 2021, 01:19:46 »
Howdy.  The battletech lore always talks about missile miniaturization partly as an effect of AMS, but battlemech scale AMS didnt happen until the advanced tech AMS platform.  Thus, I figured I would design a Machine Gun trailer with an advanced fire control mount, and this item would be installed as both a trailer CIWS and vehicle weapon system.  The total system weighs 4 tons but is on a 5 ton chassis because below 5 tons we get into the infantry scale stuff that doesnt work. 

When installed as equipment, the CIWS AMS system takes up 4 tons and 2 spaces on a vehicle, or 4 tons and 5 criticals on a mech, but includes its own ammo which does not need to be accounted for.  The system has 9 rounds of ammunition, but otherwise functions as an AMS system.  A critical hit to the system causes the system to fail, but does not cause an ammunition explosion unless an 8+ is rolled.  Each point of ammunition does 3 points of damage in an ammo explosion.

The Heavy AMS system, which uses a Light Cannon or Light Missile as it's intercept weapon, weighs 6.5 tons, takes up 2 spaces on a vehicle, 7 criticals on a mech, and has 18 ammo.  It otherwise functions as an AMS system, and may explode on an 8+ like the CIWS AMS system if critically hit.

CIWS Trailer

Type: CIWS
Chassis Type: Tracked (Medium)
Technology Base: Inner Sphere (Standard)
Mass: 5,000 kg
Battle Value: 25
   
Equipment                                         Mass (kg)
Chassis/Controls                                  1500.0
Engine/Trans.                                       0.0
    Cruise MP:0
   Flank MP:0
Heat Sinks                    0                     0.0
Fuel                                                0.0
Turret                                            500.0
Armor Factor (BAR 5)          12                  500.0

                          Internal   Armor   
                          Structure  Value   
     Front                   1         5     
     R/L Side               1/1       2/2   
     Rear                    1         1     
     Turret                  1         2     
   

Weapons
and Ammo                 Location    Tonnage      
Machine Gun               Turret      500.0   
Machine Gun Ammo (200)     Body       1000.0   
   
Cargo
    None

Notes:
Features Trailer Chassis and Controls Modification
Advanced Fire Control(500 kg)
   

Sabelkatten

  • Major
  • *
  • Posts: 5899
Re: Primitive AMS
« Reply #1 on: 11 February 2021, 10:29:51 »
Way back when ('90s...) we added a house rule that let standard MGs be used as AMS. I think the rule was to make a range 1 attack with a +4 TMM to kill some number of missiles (might have been 2, 1d6 or 2d6).

DevianID

  • Master Sergeant
  • *
  • Posts: 254
Re: Primitive AMS
« Reply #2 on: 13 February 2021, 03:10:50 »
If I did mguns like warship mgun ams then each MGun in and mode would be -1 to a missile volley.

I like the idea of the trailer build since current CWIS systems have there own targeting system separate from the thing they are mounted on.

Atarlost

  • Warrant Officer
  • *
  • Posts: 400
Re: Primitive AMS
« Reply #3 on: 13 February 2021, 14:45:50 »
I'd be tempted to say that anything that isn't a missile or artillery or capital scale (and possibly some missiles with specialty ammo) should be able to be used against missiles across all rule sets. 

Throwing ideas at the wall:
Weapons must be declared reserved for AMS use for the next turn during the end phase (or before play starts for the first turn)
Machineguns, Autocannons, and energy weapons other than flamers may target missiles. 
Small guided missiles (SRM, LRM, ATM) may fire at capital and artillery missiles. 
Barracuda missiles may target other capital missiles*. 
No form of infantry nor any support vehicle without advanced targeting can make anti-missile attacks with non-AMS weapons.
non-AMS anti-missile attacks suffer secondary target penalties as appropriate to the unit mounting them unless fired by the primary target of the mounting unit's attacks or the mounting unit has declared no attacks. 
Missiles have a target modifier of tentatively +5 for small guided missiles, +4 for rockets and large guided missiles (Thunderbolts, Arrow IVs targeting TAG, and capital missiles), and +3 for artillery missiles not receiving TAG. 
Weapons under 1 ton and pulse weapons under 2 tons have an additional -1 modifier.
If the launcher is within your weapon's minimum range apply the penalty for their distance. 
Unless firing against an artillery missile use the short range bracket.  For artillery missiles use the range to the missile's target hex.  AMS hex coverage in aerospace is unchanged.
Missiles are treated as airborne targets for the purpose of the flak special.  The AA Targeting quirk applies only to artillery missiles and capital missiles. 
If firing on missiles with a cluster weapon roll on the cluster chart.  Break your damage into clusters normally. 
AMS does not engage missiles that have failed to hit on the cluster table (because missiles are usually a single column and I'd like to preserve that convenience)
Missiles have 1 standard HP per 10 standard damage or 1 capital damage rounded up (except nukes, see Stratops capital AMS rules).  If defending against 1 HP missiles (or using Barracudas against capital missile volleys) delete one missile per anti-missile cluster that hits.  Otherwise break multiple missile volleys into groups of 6 and apply damage as if they are BA squads.  Multiple missiles with more than 1 HP should only occur with large craft weapon bays. 

AMS fires last, always hits, and deals 3 damage per turn divided as the defender chooses with no restrictions.  AMS can engage single missiles from multiple salvos (eg. three Thunderbolt-5s) or multiple missiles from a single salvo (eg. three HE ATMs) or a mix (eg. a Thunderbolt-10 and two LRMs from an LRM-5 salvo) or even pick out specific already damaged missiles to finish off from a capital missile bay volley ignoring the BA squad abstraction. 

I think I've ticked all my AMS reform checkboxes except "simple" and I've tried to keep the complexity in the rarer matchups.  It is by design that using most weapons against missiles is not worth it most of the time so most of the messy bits can be ignored, but sometimes the other guy has a nuke or large cruise missile that it's worth throwing the kitchen sink at.  Warships with anti-fighter armaments but no AMS are the main intended beneficiaries followed by mechs and tanks with gratuitous small lasers and machineguns. 

* This is mostly for narrative reasons so that SLDF has a foolishly optimistic anti-nuke doctrine using AR-10 launchers rather than no anti-missile doctrine.  They still look stupid, but it's a more historically precedented level of stupid for a peacetime military than sticking their fingers in their ears and chanting "We'll never have to fight the Taurians again."

Daryk

  • Colonel
  • *
  • Posts: 19532
  • The Double Deuce II/II-σ
Re: Primitive AMS
« Reply #4 on: 13 February 2021, 15:44:53 »
Some good ideas in there!  :thumbsup:

Two things:
1) You missed sub-capital missiles.
2) Re: the HP concept: LRM-15s, LRM-20s, and SRM-6s?  ???

Atarlost

  • Warrant Officer
  • *
  • Posts: 400
Re: Primitive AMS
« Reply #5 on: 13 February 2021, 17:46:53 »
Some good ideas in there!  :thumbsup:

Two things:
1) You missed sub-capital missiles.
2) Re: the HP concept: LRM-15s, LRM-20s, and SRM-6s?  ???
1) I think subcapital weapons are a subset of capital weapons.  None of them have the improved accuracy of the Barracuda that I use to justify allowing those to hit other capital missiles.  Possibly being smaller than any ASF should prevent Barracudas from targeting subcapital missiles, but I'm not sure and I think small tracking missiles would still be able to go after them. 
2) I meant individual missile damage so all are 1 HP.  An LMG that hits will reduce any of them by 1 missile and an AMS will reduce by 3.  An LB-5X that hits with a median cluster role will also reduce by 3.  That's a nerf for AMS against large launchers, but the AMS rules creating yet another bias in favor of LRM-5s is one of the bugs I wanted to fix. 

The damage of AMS and missile damage to HP ratio are easily tunable if the initial numbers make capital and artillery missiles too vulnerable, but the missile damage to HP ratio shouldn't drop below 3 as that makes AMS vs HE ATM a major hassle that I'd tried to relegate to combats involving capital missiles or Thunderbolts mounted in large craft weapon bays or thunderbolts or A2A missiles fired by ASFs using the squadron rules. 

Daryk

  • Colonel
  • *
  • Posts: 19532
  • The Double Deuce II/II-σ
Re: Primitive AMS
« Reply #6 on: 13 February 2021, 18:01:44 »
Hmmm... I thought the Piranha did, but apparently it only has a longer range...

Daryk

  • Colonel
  • *
  • Posts: 19532
  • The Double Deuce II/II-σ
Re: Primitive AMS
« Reply #7 on: 13 February 2021, 18:28:21 »
Another thought just occurred to me: aren't sub-capital missiles designed to go after ASFs?   ???

idea weenie

  • Captain
  • *
  • Posts: 2839
Re: Primitive AMS
« Reply #8 on: 13 February 2021, 21:54:02 »
How about an earlier form of Reactive Armor?  It is essentially a claymore mounted on the armor that detonates when hit by a missile and attempts to wipe out other missiles in the salvo.  Advanced versions link the armor to a sensor system to detonate the claymore before the missile(s) hit.

Maybe a quarter ton each, each one destroys 2d6 missiles, but all other attacks destroy a number of these equal to half their damage (FRU).  They take up no spaces, but have to be mounted externally.  Detonating one of these also does 2d6 AI damage in the same hex as the mounting unit, this damage is done to all infantry units (including friendly).  Cannot be used underwater for vs torpedo attacks.  Activating/deactivating this system is done at the start of the round.

Comparison vs regular armor:
4 per ton, each ton will stop on average 28 pts of missile damage (unless the attacker uses small salvos to wear it down)
Effectively 8 pts per ton against other weapons (an AC/2 will take 4 shots to remove 1 ton of them)

DevianID

  • Master Sergeant
  • *
  • Posts: 254
Re: Primitive AMS
« Reply #9 on: 14 February 2021, 05:58:19 »
I like the idea of some variant armor for 3rd succession war play, but I also want the oh-so-pretty CIWS lighting up the sky.  As for using btech weapons like capital ams, I feel like doing anything other than ripping the warship rule with some penalty for a mechs worse detection system would be too complicated.

idea weenie

  • Captain
  • *
  • Posts: 2839
Re: Primitive AMS
« Reply #10 on: 14 February 2021, 20:28:45 »
I like the idea of some variant armor for 3rd succession war play, but I also want the oh-so-pretty CIWS lighting up the sky.  As for using btech weapons like capital ams, I feel like doing anything other than ripping the warship rule with some penalty for a mechs worse detection system would be too complicated.

So something like a Machine Gun Array, but set for AMS mode?

A single regular Machine Gun when used in AMS mode will shoot down 1d6 incoming missiles.  However, mounting them in an Array means all of the Machine Guns in that Array can be used against a single incoming missile salvo.

For each extra Machine Gun in the Array set up to shoot down missiles, it will shoot down +X missiles, where X is equal to the Machine gun's damage.

So you could put 6 MG into a single Array, and when it fires against an incoming missile salvo it will shoot down d6+10 missiles, using up 6 shots of ammo.

DevianID

  • Master Sergeant
  • *
  • Posts: 254
Re: Primitive AMS
« Reply #11 on: 15 February 2021, 12:04:35 »
My idea for primitive ams is kind of like a mgun array I guess.  I wanted sensors, a turret, structure and armor to be part of the "array" so the system was self contained--like on modern ships and trailers.

In battlespace, a mgun will shoot down 1 damage worth of missiles (damage/2) So my primitive ams would, instead of shooting down 1 missile damage, shoot down 3 using the ams rules, but it weighs more.
Also, on warships, an ams system can engage multiple attacks in the 1 minute turn, but mguns only fire once right?

In btech, I would use those rules as a base, so if ams is -4 on a cluster roll, an mgun would be -1.
« Last Edit: 15 February 2021, 12:18:47 by DevianID »

killfr3nzy

  • Recruit
  • *
  • Posts: 22
Re: Primitive AMS
« Reply #12 on: 13 March 2021, 22:15:27 »
Flamers would make a boss AMS - even if the fusion-powered version still shot in a stream like RL flamers, instead of a cone like cinematic ones, that's no worse than a machinegun's focus.

Plus, given the BT missile's sensitivity to heat, even a near-miss could set them off.

DevianID

  • Master Sergeant
  • *
  • Posts: 254
Re: Primitive AMS
« Reply #13 on: 14 March 2021, 17:40:13 »
Space flamers are pretty cool weapons I agree.  Real-world rules they would be direct energy microwave heat guns with their reach of 60ish km in space that are really good for cooking incoming warheads.  In the atmosphere they of course make streams of plasma due to all the air in the way, limiting the range to 120 meters max but giving them that splash effect versus dug in infantry.  We theoretically have these weapons already, just no fusion power source to make them weight economical.

My issue with flamers as a primitive AMS is that I am looking for the AMS's ability to engage multiple flights of incoming missiles at once on the space side.  So this 4 ton Primitive AMS+ammo, compared to the 1.5 ton actual AMS+Ammo, would use the AMS rules and shoot multiple times in a turn.  4 tons of flamers would do more damage to an incoming missile salvo (4 versus 3) and have 0 ammo worries, but the flamer array would only engage 1 salvo a turn.

 

Register