Size based modifiers to space detection/combat

[Spartan159]

I could swear that somewhere I saw a table of modifiers based on size, I remember that 9- tons was -2, 10 to something99 tons was -1, etc etc. Ring any bells with anyone? Driving me nuts trying to find it. I don't think it was a mongoose product, as they don't seem to have smaller than 10 dTon small craft and I seem to recall wanting to adapt/steal the chart. Also now that I think about it, that could affect damage in that the effect of the hit roll affects damage in MgT...

To me it seems logical that target size would affect detection and raw to hit. Am I off on this?

Oh, and heretic that I am, I decided to make Rampart Fighters IMTU 9 dTons because 1) fighters seem to be made of paper in MgT in that any hit penetrating armor is probably going to destroy the craft, 2) I saw that chart and thought it was worth going down a dTon (or 6 dTons depending on version) for survivability, and 3) I was redoing the AHL IMTU to more closely match the original deckplans. I'm still having to handwave some stuff to fit but the overall scheme seems to work.

 

[flykiller]

yeah, straight out of little black book 5, hg2. 1-99, -2. 100-1999, -1. 2000-19999, 0. I think P is +1, R is +2. those were for general to-hit, I use them for sensor detections too.

 

[Spartan159]

Thanks! That was not the one I saw but works for me well enough.

 

[kilemall]

yeah, straight out of little black book 5, hg2. 1-99, -2. 100-1999, -1. 2000-19999, 0. I think P is +1, R is +2. those were for general to-hit, I use them for sensor detections too.

Me too- AND as a modifier for the sensor ship, not just the target ship, or datalinked fleets added together.

Concept being VLA type hull mounted sensor tech would be of more use rather then largish dishes/domes.

 

[AnotherDilbert]

Oh, and heretic that I am, I decided to make Rampart Fighters IMTU 9 dTons because 1) fighters seem to be made of paper in MgT in that any hit penetrating armor is probably going to destroy the craft,

Smaller targets should be more difficult to see and hit.

[MgT2] Light fighters can only carry one turret weapon that will struggle to penetrate high tech armour. Medium, 35 dT, fighters can carry barbettes with much higher lethality, they can also take some hits.

If you want to hurt enemy warships you may find 35 dT fighters necessary. Hence removing the one hit = kill problem.

 

[Spartan159]

Smaller targets should be more difficult to see and hit.

[MgT2] Light fighters can only carry one turret weapon that will struggle to penetrate high tech armour. Medium, 35 dT, fighters can carry barbettes with much higher lethality, they can also take some hits.

If you want to hurt enemy warships you may find 35 dT fighters necessary. Hence removing the one hit = kill problem.

I was looking at that, I did do a 35 ton attack fighter. with hull reinforcement it has 15 hull, given the 10% hull damage rule that means a critical hit every 2 points of damage. This particular design has armored bulkheads for everything and I will continue to use the 1e rule about ignoring the first crit to an armored system, but still, paper.

I am house ruling various aspects of the game per tradition IMTU craft can be as small as 1 ton (basically a drone) and modifying the information from B5 I am going to use the following chart for sensor detection/lock on and to hit:


TARGET SIZE DM (To Hit/Sensor Detection)
Size dTons Die Modification
1 to 9 -3
10 to 99 -2
100 to 999 -1
1,000 to 9,999 none
10,000 to 74,999 +1
75,000+ +2
Do not add mod to effect of a hit for damage.


Depending on how this works of course I will rethink this aspect. Regarding the ability of turret weapons to penetrate armor I need to study the fleet combat rules, but my first instinct is to allow turrets to be in batteries that fire as one unit, all hit or all miss, and add total damage dice in 1 roll. For fighters that would mean they would have to be in formation, ie a "squadron" and thus more vulnerable, I was picturing the finger-four fighter formation as a minimum.

 

[flykiller]

if you want to include ship aspect, in addition to the hg2 mods you can implement similar mods based on hull shape. for example the hg2 mods apply for a spherical target of that dtonnage. a cylindrical hull type, viewed bow- or tail-on, gets an additional -2, while if viewed laterally gets a +1. etc.

 

[AnotherDilbert]

I was looking at that, I did do a 35 ton attack fighter. with hull reinforcement it has 15 hull, given the 10% hull damage rule that means a critical hit every 2 points of damage. This particular design has armored bulkheads for everything and I will continue to use the 1e rule about ignoring the first crit to an armored system, but still, paper.

It takes a few hits to kill, much better than a light fighter. Yes, still fragile, but it is a fighter...

I am house ruling various aspects of the game per tradition IMTU craft can be as small as 1 ton (basically a drone) and modifying the information from B5 I am going to use the following chart for sensor detection/lock on and to hit:

Depending on how this works of course I will rethink this aspect. Regarding the ability of turret weapons to penetrate armor I need to study the fleet combat rules, but my first instinct is to allow turrets to be in batteries that fire as one unit, all hit or all miss, and add total damage dice in 1 roll. For fighters that would mean they would have to be in formation, ie a "squadron" and thus more vulnerable, I was picturing the finger-four fighter formation as a minimum.

Interesting. That will make fighters much better, which I'm not sure they need. Dogfights...

In the fleet system you just add up all damage and subtract a percentage for armour, no penetration needed. In the fleet system fighters could probably use a boost.

Thanks for the idea and the table.

 

[aramis]

Smaller targets should be more difficult to see and hit.

[MgT2] Light fighters can only carry one turret weapon that will struggle to penetrate high tech armour. Medium, 35 dT, fighters can carry barbettes with much higher lethality, they can also take some hits.

If you want to hurt enemy warships you may find 35 dT fighters necessary. Hence removing the one hit = kill problem.

the median signature change between 15Td and 9Td is a reduction of 6.1 to 4.3 m^2...
so about 65% of the cross-sectional area outside near axis. But, given realistic pulse rates, and such, a laser shouldn't miss until about 0.2LS anyway, even against that small a target.

 

[AnotherDilbert]

the median signature change between 15Td and 9Td is a reduction of 6.1 to 4.3 m^2...
so about 65% of the cross-sectional area outside near axis.

Well, yes the size difference between a 9 dT and a 11 dT object is not very great, but we have to draw the line between DMs somewhere?

But, given realistic pulse rates, and such, a laser shouldn't miss until about 0.2LS anyway, even against that small a target.

The laser might hit what it is aimed at, but neither the mount system nor the sensor targeting solution is likely to be perfect. Even with a perfect sensor solution, there is at least a half second delay between radar bounce and incoming laser beam; the target is manoeuvring during that time.

Compare with a Phalanx system. It's targets are slow, do not manoeuvre, and are much bigger as seen from the targeting radar. Yet the Phalanx finds it necessary to fire a very high rate of fire stream of rounds to hit its target at a range of 2 km, a single round has very little chance of hitting.

In conclusion I do not think even lasers are likely to unfailingly hit any highly manoeuvrable target at 60000 km range

 

[aramis]

Well, yes the size difference between a 9 dT and a 11 dT object is not very great, but we have to draw the line between DMs somewhere?


The laser might hit what it is aimed at, but neither the mount system nor the sensor targeting solution is likely to be perfect. Even with a perfect sensor solution, there is at least a half second delay between radar bounce and incoming laser beam; the target is manoeuvring during that time.

Compare with a Phalanx system. It's targets are slow, do not manoeuvre, and are much bigger as seen from the targeting radar. Yet the Phalanx finds it necessary to fire a very high rate of fire stream of rounds to hit its target at a range of 2 km, a single round has very little chance of hitting.

In conclusion I do not think even lasers are likely to unfailingly hit any highly manoeuvrable target at 60000 km range

The phalax, with a 50rd burst, has a pretty damned good accuracy. 2cm at 1 km. With a bullet with a length under 10cm.

The laser has a bullet kilometers long, and the target, at 0.2 LS, can't move more than a meter (given canonical limits on G-comp), and pointing accuracy of current long range lasers is pretty damned high - >99% on a 2m target at about 1.28 LS.
Even allowing for a full 0.1 second to bring things to bear, that puts the location variance only 2.5 m per G. Given a battery of 10, you fire at the predicted spot and a bunch around it. At 0.1 LS, it's 40 cm or so, and so if it can adjust the angle in 0.1 sec, you cannot miss a 6G fighter except for programming or sensor errors.

 

[kilemall]

AD, I highly disagree with that assertion.

Let's take a full agility 6G target.

In that half second even with full burn that vehicle is only going to move 30 meters.

And it's not a round bubble of probable movement in any direction, the radar bounce will also reveal ship attitude and therefore only have to deal with known momentum plus that 30 meters forward of the ship the main M-drive may impart in that half second.

Large enough target, it's not even getting out of it's own way.

And of course anything short of 6G is that much less running room.

The difficulty is not hitting, but justifying NOT hitting at 60000 km.

I do so largely on the idea that sideways thrust equal to 10% G rating is constantly pitching and yawing the ship around and seeking to move the ship a few meters so the incoming hits along the edge of the target ship. Superior target computer rating yields an advantage in calcs for such maneuvers and incidental EW.

Agility negatives should probably be greater for smaller ships, and a non-factor for larger ones, or at least require that much greater range to have effect.

 

[AnotherDilbert]

The phalax, with a 50rd burst, has a pretty damned good accuracy. 2cm at 1 km. With a bullet with a length under 10cm.

±2 cm at 1 km is something like ±1,2 km at 60000 km, so barely better than a shotgun for our purposes. With a 50 round burst that is steered on target by a feedback loop. What is the accuracy of a single round?

The laser has a bullet kilometers long, and the target, at 0.2 LS, can't move more than a meter (given canonical limits on G-comp), and pointing accuracy of current long range lasers is pretty damned high - >99% on a 2m target at about 1.28 LS.
Even allowing for a full 0.1 second to bring things to bear, that puts the location variance only 2.5 m per G. Given a battery of 10, you fire at the predicted spot and a bunch around it. At 0.1 LS, it's 40 cm or so, and so if it can adjust the angle in 0.1 sec, you cannot miss a 6G fighter except for programming or sensor errors.

Sorry, I do not understand most of that. Care to uncompress a bit?

Some comments that might have a bearing on what you said:
MgT2 fighters are now up to 25 G, max 6G is retconned away (since TNE and definitely in MgT).
Sensors are not perfect.
Weapon mounts are not perfect.
A beam laser has to be kept on target, just touching the target for a fraction of a second is not enough.


A disc of a few meters at 60000 km is an angle of about 0,000005°, what sensor system, and what weapon mount, can reach that accuracy in 0.1 s?

Current radars seems to have an accuracy of about 0,1°, or about ±100 km at 60000 km?

The weapon mount would need to point a metre long laser weapon with an accuracy of less than 100 nm. What weapon mount can come even close to that?

 

[mike wightman]

The bullets from a phalanx have a lot more variables affecting their flight path than a laser beam firing through the vacuum of space...

The main drawback to laser weapons in a space combat game should be how to deal with the waste heat they generate - but Traveller has some magic mechanism for dealing with thermodynamics so it's a moot point.

Oh, and the authors of MgT have taken it upon themselves to produce a cinematic version of space combat that owes more to Star Wars then Newton.

Fighters that can blast across space at 25G but somehow magically dump their velocity vector to allow them to engage in dogfighting - which they get a unique bonus for because of the rule of kool rather than any semi-realistic reason.

I would be very careful bringing 2eMgT space combat paradigm to a discussion about Traveller space combat.

 

[aramis]

Simple...

If at distance D in LS, time to intercept (T_i) is equal to 2D+T_A
If you can't move at least your smallest dimension in T_i, and my mechanical accuracy is sufficient to hit that spot (and lasers currently can be aimed to fractions of an arc-second, and 1" arc = (1/3600)°)... I cannot miss unless the turret has a mechanical or programming failure.

At 0.1 LS, each G changes your position by less than 0.441m
Average side length on 9 Td is 126^1/3 or 5m

Given the G-Gompensator limits of 6G at TL 15, maximum distance you can go is about 9G's at 0.3 sec or about 3.96 m.
Also, maximum rotation is 340° per second, for about 102° maximum rotation, but given that that would require reducing your velocity change to near 0, I can concentrate effectively on the forward ±45°...

But, Canon also says (at least, the canon list Marc sent me midsummer) SSOM is still canon. SSOM says T-plates have a 25% 90° off-axis thrust, and a 10% reverse thrust. So, unless mounting a separate high thrust reaction thruster, G's at moment is 1/4 that, for 25.5° in that 0.3 second. I now have a 51° wedge, with both sides curved in.

So, given 9 G's forward and 25.5°, I've an area 3.96m radius and 3.5m long, with a ship radius of about 2.5m. I am for the center of this thrust bell, as offset by your prior speed, and BANG. I can't miss.

Unless the turret fails somehow.

 

[AnotherDilbert]

The bullets from a phalanx have a lot more variables affecting their flight path than a laser beam firing through the vacuum of space...

It was, like all analogies, perhaps not perfect. My point was that we currently have a problem hitting what is comparatively a big, slow, barely manoeuvring target at very short ranges. We can, but it takes a lot of ammo.

Oh, and the authors of MgT have taken it upon themselves to produce a cinematic version of space combat that owes more to Star Wars then Newton.

Fighters that can blast across space at 25G but somehow magically dump their velocity vector to allow them to engage in dogfighting - which they get a unique bonus for because of the rule of kool rather than any semi-realistic reason.

I would be very careful bringing 2eMgT space combat paradigm to a discussion about Traveller space combat.

It is, according to Mongoose, not Mongoose's idea with more than 6G M-drives. They received instructions...

The lack of vector-based movement has no bearing on the magnitude of agility of spacecraft.

 

[kilemall]

The bullets from a phalanx have a lot more variables affecting their flight path than a laser beam firing through the vacuum of space...

The main drawback to laser weapons in a space combat game should be how to deal with the waste heat they generate - but Traveller has some magic mechanism for dealing with thermodynamics so it's a moot point.

Oh, and the authors of MgT have taken it upon themselves to produce a cinematic version of space combat that owes more to Star Wars then Newton.

Fighters that can blast across space at 25G but somehow magically dump their velocity vector to allow them to engage in dogfighting - which they get a unique bonus for because of the rule of kool rather than any semi-realistic reason.

I would be very careful bringing 2eMgT space combat paradigm to a discussion about Traveller space combat.

Nothing wrong with cinematic combat as an entertainment choice. Just don't get confused that it's anything but.

 

[AnotherDilbert]

Simple...

If at distance D in LS, time to intercept (T_i) is equal to 2D+T_A

We were talking about 0.2 ls range:

... the target, at 0.2 LS, ...

In 0.5 s with an acceleration of 9 G ≈ 90 m/s² (much less than the possible 25 G) we can achieve a speed of 45 m/s and move 11 m during that half second, plenty enough to deny the enemy a pinpoint location.

You are assuming the front of the fighter is pointing directly at the firing ship, but we don't know that.

Even if the target could only move 2,5 m in a random direction we would not be sure to hit it. If the target moved 2,5 m the target would be a 5 m circle somewhere inside a 10 m circle we knew of. Even if we could pinpoint the 10 m circle exactly, and hit it unerringly, we would still only have 25% chance of hitting the target.

(and lasers currently can be aimed to fractions of an arc-second, and 1" arc = (1/3600)°)

What laser specifically can be aimed with an accuracy of 0,02 arc second (≈ the needed 0,000005°) in less than 0.1 s and unfailingly hit the target in one try?


You are also assuming that we have a perfect sensor solution. What sensor system can follow a manoeuvring target, from a manoeuvring platform, with an accuracy of 0,000005°?


As far as I can see we have three problems:
We don't know exactly where the target were (sensor accuracy).
We don't know how much it moved between measurement and incoming fire (target agility).
We have a problem aiming that precisely (mount accuracy).
Even if we discount agility (which I don't) we are still not assured of hitting.


Since canon (many different versions of canon even) provides a hit chance that is often not 100% it would seem that canon disagrees with you.

 

[AnotherDilbert]

The main drawback to laser weapons in a space combat game should be how to deal with the waste heat they generate - but Traveller has some magic mechanism for dealing with thermodynamics so it's a moot point.

That is true for all ship's systems.

But is that any worse than reaction-less drives or inertial compensators?

 

[Spartan159]

Speaking of magic I've always wondered why gravitic drives are at the rear of the ship and have exhausts, why jump drives are not in the center of the ship if generating a bubble, and why meson guns have openings in various ship drawings. Since they shoot through matter I'd hide their presence internal to the ship. /meh