Fighters/PT Boats in the Traveller Universe

[Carlobrand]

This comes out of something McPerth mentioned which, due to my unfamiliarity with this new forum, I find myself unable to quote when starting a thread except this way:

There are also other points, of course. Do we want fighters to be decisive (as in BG or SW), from decisive to irrelevant depending on TL (HG) or inexistent (ST)? And sure there are others I cannot thing about now…

Fighters are probably better imagined as PT boats for Space inasmuch as they use most of the same design rules as larger craft, have similar Newtonian performance characteristics (there being no air to be used for more agile performance), and mostly deliver "torpedoes", i.e. nuclear-weapon-tipped missiles. Most fighter mentions I've encountered are CT Book-2 related; they're an important element of the small ship setting, where they can have a significant impact. I don't recall much mention of fighters and their performance in canon related to the big-ship setting other than what's in Book 9, some bits in the games like Azhanti High Lighting, and I think there was some in MegaTraveller; can't speak for other systems, and my knowledge of CT canon is by no means complete.

The general rule of thumb with fighters/PT boats is the higher the tech level, the less relevant they become to CT Book-5 combat as it becomes increasingly less cost effective to field fighters that can influence the battle: providing adequate electronics becomes prohibitively expensive as tech levels rise, and they are obsolescent at TL 12 when nuclear dampers appear and obsolete at TL14+ except in roles in which they're unlikely to be opposed by a nuclear damper. I'm good with that as I see their primary role as ground attack, sensor pickets around a fleet, scouts to search and gather intelligence in star systems, and raiders to harry merchant shipping and frontier settlements to force the opponent to disperse assets to protect those targets. However, I know from past experience that there are those with a strong interest in seeing fighters play a role in big ship combat.

So, if we want fighters to play a bigger role in big ship combat, how can we achieve that in CT Book 5 - and possibly other settings - without rendering the game unduly complex or inadvertently nerfing the big ships?

 

[AnotherDilbert]

It's entirely dependent on edition: LBB2 had questionable (I believe?) laser fighters, LBB5/MT had inefficient missile fighters, MgT1 had battleship-killing PA fighters, MgT2'16 had battleship-killing PA/Fusion barbette fighters.


If we want cinematic fighters I think MgT2 has a decent start. They have to get in close, and have some special privileges when doing so (dogfight), basically replacing the need for a massive computer. Difficult to balance...


Another idea is letting larger ships harassed by fighters have a negative DM to their attacks. The fighters don't do much on their own, but creates problems for the enemy. A force multiplier. They will not replace warships, but compliment them.

 

[mike wightman]

A capital ship can carry multiple sensors larger than the fighter. It can see further and achieve target lock at a greater range.

A capital ship can mount a weapon bay larger than the fighter, such a bay should instantly destroy a fighter.

Note that the energy a capital ship can dedicate to a weapon bay or massed battery is an order of magnitude or two greater than the fighter.

A capital ship can carry enough armour to make a fighter's weapons useless, assuming it can make it to a range at which it can fire.

 

[mike wightman]

Now how I would make the fighter a bit more useful

The manned fighter controls a swarm of chatGPT AI drones the same size as the fighter. The drones are there to act as decoys and also to carry big nukes or better yet a derivative of the battlefield meson gun.

The carrier provides the long range sensor data to the fighters.

Some of the drones are designed to detonate to produce a sensor white out, others carry short range ECM and ECCM

 

[Condottiere]

Depends on what roles and missions you want them to undertake, whether they are optimized for those or not.

Ultralite fighters can be drone hunters.

 

[kilemall]

The way I have them involves several use cases, many of which are heroic/suicidal. This is within the context of my CT/HG maneuver hybrid.

I have them able to carry 1-2 bay missiles, which means they can get off one bay missile attack.


I have armor be absolute, so most fighters cannot even scratch seriously armored warships. But the fighters can close to sub-100000 km range at which point they are close enough to overcome computer differences and burn through the armor.

I have the computer EW line/reserve mechanic which adds up all the line computers as a negative DM to hit ships in the reserve. Many fighters have just the model/1 computer, but 80 fighters would be -80 DM to hit, requiring most to be disabled/destroyed to get at the reserve. This functionality alone makes them worth protecting a key big ship to avoid damage or buy time to repair.

An ugly mechanic I haven’t delved into is fighters kinetically impacting enemy ships, unmanned or otherwise. Expensive but almost guaranteed wreckage of any major ship.

Fighters can build up big vee quickly, potentially giving little missile swarms they fire big kinetic impact and enough to penetrate the heaviest armor.

Giving missiles integral higher computer power so they get higher computer DMs. Very expensive but what price admiralty?

My sensor rules give most low model computer small craft poor sensor fits and bad lock ons due to smaller hull arrays. So they can be used for cheap fleet patrol/detection, just not great scouting.

But a shuttle or the like can mount a serious computer, be given a full ship size bridge and act as a little pocket AWACS.

I have serious stealth rules which make it prohibitive to apply them to anything but small craft. So a small stealth gig can get that spec ops crew through, or a stealth AWACS can get the detection and narrow beam the alert to the fleet.

So, all about the special equipment/action/heroism/annoying big ships stuff. But they die in droves and/or cost a lot.

 

[TheDark]

A potential use for a light fighter screen that I don't think I've seen used is as a way to thin out a missile/torpedo launch before it gets within range of the capital ships. Even on large vessels, point defense emplacements are limited by various rules regarding the number of installations on a vessel. When engagements are at extreme range, being able to put a fighter screen between two flotillas/fleets reduces the number of targets the point defense systems have to engage and helps the larger ships maintain combat effectiveness longer. If the opponents choose to focus missile fire on the fighters instead, it becomes costly in crew losses but keeps the main fleet from taking damage during the time that the fighters are being engaged.

 

[mike wightman]

This actually makes a lot of sense since a 10t CT fighter is basically an additional mobile turret.

 

[McPerth]

This comes out of something McPerth mentioned which, due to my unfamiliarity with this new forum, I find myself unable to quote when starting a thread except this way:

Fixed that. I hope you don't mind

 

[Spinward Flow]

So, if we want fighters to play a bigger role in big ship combat, how can we achieve that in CT Book 5 - and possibly other settings

You really need to determine what mission role your fighters are intended to fill.
Capital ship torpedo squadron is a very different mission set from a system defense patrol asset doing policing work.

Are the fighters intended to be able to harass and take down cruisers, battleships and dreadnoughts?
Or are the fighters intended for "beat cop" roles in the local constabulary, keeping pirates and other unwanted riff raff at bay?

Another question is ... how destructive are fighters supposed to be?
Are they meant to be armed with nuclear missiles ... or are (simple) lasers adequate for what they're supposed to be doing?
If you're arming your fighters with HE missiles or lasers, then nuclear dampeners become irrelevant and fighters can "remain in the fight" beyond TL=12+.

If you're dealing with civilian policing/patrol mission tasking, you usually won't need the "latest+greatest" bleeding edge technology in your fighters, because they aren't intended for major fleet on fleet actions. No need to let the "perfect" be the enemy of the "good enough" for the local constabulary role. Additionally, in a policing role you probably aren't wanting to resort to every Min/Max Gamer Favorite ... there's no kill like OVERKILL!!!! ... because Use Of Excessive Force can lead to unintended and unwanted consequences (even if Law Levels are obscene).

I prefer to think of small craft fighters (as opposed to big craft fighters) ... as being something of a military fad/fashion that peaks by about TL=10-11 before being overtaken by increasingly advanced technologies. However, in civilian and paramilitary roles, fighters can "hang on" a bit longer into the TL=12-15 range when put into secondary and supporting roles, including patrol and recon missions, so as to spare the "Big Iron" from needing to go check out each and every single little thing for themselves. Cheap fighters make for a relatively decent sensor/intel network to support other craft while on maneuvers, offering screening services "on the cheap" relative to other heavier options.

 

[WizWom]

JTAS early on had an article trying to make fighters useful. I think the best option was to let a squadron (up to 10) fighters fire in salvo as a single battery. 10 fighters with TL13+ beam lasers would then be able to have 30 lasers, a factor 9 battery for HG, now that's likely to hit and penetrate.

Another idea was to let them close a range over the general battle range in HG; so they could be as short if the range was long, and at close if short. Give all fighter weapons +2 at close, and now they have a good chance of dogfighting with other fighters, and maybe enough will hit a capital ship to get through or use up their sandcasters.

 

[Carlobrand]

Fixed that. I hope you don't mind

Not at all. Thanks!

 

[kilemall]

A potential use for a light fighter screen that I don't think I've seen used is as a way to thin out a missile/torpedo launch before it gets within range of the capital ships. Even on large vessels, point defense emplacements are limited by various rules regarding the number of installations on a vessel. When engagements are at extreme range, being able to put a fighter screen between two flotillas/fleets reduces the number of targets the point defense systems have to engage and helps the larger ships maintain combat effectiveness longer. If the opponents choose to focus missile fire on the fighters instead, it becomes costly in crew losses but keeps the main fleet from taking damage during the time that the fighters are being engaged.

That use depends on your conception of what point defense fire is.

I conceive of it as a low power shot in the terminal phases of a missile flight, when the missile has to commit to its target and the problem to solve hitting incoming is greatly simplified because it’s only got one way to go.

As such I would only really see acting as point defense if the fighter was datalinked into the defending ship, using its computer DM, and was within 1000 km on the same heading and vee of the defending ship.

The other winnowing out the crazy missile horde is firing preemptively at full range, with anyone able to fire at any incoming missile attack as though they were ships. Agility could be an issue although that would reduce velocity and thus damage.

But I classify them as one size class below small craft for a -3 DM to hit. This also applies to detection and lock on, including the missile’s terminal seeker in case th firing ship is destroyed.

 

[chipla]

I use small craft as a mix of both fighters and PT boats.

I tend to divide them into two types:
Light - essentially a ten dton fighter with pulse laser and light ground attack weapons (wing mounted missile-pods). In fleet actions light fighters perform an interception role, targeting missiles and heavy fighters.

Outside of fleet actions they perform a coac or customs role, a fighter’s pulse laser is enough of a threat to get them to submit to another craft boarding them.

In ground combat they operate as interface capable multi-role fighters able to gain air superiority and perform ground attacks/CAS.


50dton Heavy fighters on the other hand operate more like PT boats carrying torpedoes for attacking shipping and a pulse laser for defence. They can’t do much against a battleship but they can mess with the escorts and screens and most importantly the logistical element of any fleet. I tend to house rule that the torpedoes can be swapped out with bomb racks with a few hours work to allow them to be used as interface capable tactical/strategic bombers.

 

[Carlobrand]

A capital ship can carry multiple sensors larger than the fighter. It can see further and achieve target lock at a greater range.

A capital ship can mount a weapon bay larger than the fighter, such a bay should instantly destroy a fighter.

Note that the energy a capital ship can dedicate to a weapon bay or massed battery is an order of magnitude or two greater than the fighter.

A capital ship can carry enough armour to make a fighter's weapons useless, assuming it can make it to a range at which it can fire.

That sums up the challenges for fighters, and I actually think it would be worse if not for a quirk of the armor rules. That percentage based armor system means the fighter has a thinner shell but gets the same level of protection as a battleship.

 

[Spinward Flow]

Light - essentially a ten dton fighter

10 ton fighters ... are pretty gimptacular ... as far as performance goes.

Just going by "minimum 1 ton" for drives (maneuver, power plant), fuel, model/1 computer and turret ... you're already up to 5 tons minimum before doing anything that can be occupied by a crew. If you add a bridge, you're up to 9 tons (under LBB5.80) and have 2 acceleration couches (good for pilot, gunner). At most you can upgrade the computer to a model/2 before you run out of internal displacement at a total of 10 tons.

However, with custom drives ... a 10 ton small craft needs 1.1 tons (11%) to reach 4G maneuver.
Spoiler alert: ALL fighters need 6G/Agility=6 if they want to "live" beyond their first combat round.



Assuming TL=15 for maximum power plant size efficiency, Maneuver-6 is going to cost 1.7 tons (17%) and Power Plant-A will cost 1 ton (10%, because 1 ton minimum) in a 10 ton hull.

• Maneuver-6 = 1.7 tons (-0.6 EP for Agility=6)
• Power Plant-10 = 1 ton (+1 EP)
• Fuel = 1 ton
• Model/1 computer = 1 ton
• Turret = 1 ton
• Bridge = 4 tons (minimum)

1.7+1+1+1+1+4=9.7 tons required, minimum

No point going with a model/2 computer but no bridge (to save tonnage), because you just wind up with a "smaller but MUCH more expensive model/1 computer" for your troubles (because without a bridge, your computer is -1 model number).

A show of hands for anyone who thinks a model/1 computer is going to "cut it" in combat with anything more fearsome than a Fat Trader?



My point being that a 10 ton fighter is simply "too small" to be capable of anything "serious combat relevant" aside from offering warning shots and harassing fire. It can't even power a single laser without reducing its Agility from 6 to zero ... which would seem to be counterproductive. At best you've got a "minimalist missile launcher" and that's about it.



Move up to 20 tons displacement for a Light Fighter, however ... and you've got room for a "useful loadout" of equipment.

• Maneuver-6 = 3.4 tons (-1.2 EP for Agility=6)
• Power Plant-6 = 1.2 tons (+1.2 EP)
• Fuel = 1 ton
• Model/2 computer = 2 tons
• Turret = 1 ton
• Bridge = 4 tons (minimum)
• Small Craft Stateroom = 2 tons

3.4+1.2+1+2+1+4+2=14.6 tons

If you want to add a single laser, you're going to want +1EP ... which at TL=15 means +1 ton of power plant (15.6 tons allocated).
If you want a model/4 computer, you're going to want +2EP ... which at TL=15 means +2 tons of power plant and +2 tons of computer (19.6 tons allocated).

A model/4 computer installed on a Light Fighter with Maneuver-6, Power Plant-21 and Agility=6 is going to be a "decent" performer against most "low end threats" but isn't going to be anything other than trivial to deal with for any craft with a Model/8-9 computer installed.



This is why Heavy Fighters tend to congregate around 50 tons so that you can attempt to fit a model/6+bridge or a model/7+no bridge into a hull. Those computers demand a LOT of EPs for a small craft power plant, so there's a practical upper limit to how far you can go (technologically speaking) before small craft fighters become relatively uncompetitive.

Fun side note ... what's the smallest hull displacement you can fit a model/9 computer + turret(s) into so as to create a big craft fighter, rather than a small craft fighter?
Note: a model/9 computer requires TL=15, so ...

 

[chipla]

Entirely dependent on your system.

I use mgt2.

I’ll break down my drinaxi Peregine fast (aka light) fighter which is represented by an imperial guard Valkyrie on my tabletop (and was somewhat designed to match).

Hull: 10dtons
Armour: Bonded super-dense 6pts (0.48dton)
M-drive 8 (.72dton)
TL 15 Fusion plant 26 power (1.3dton)
1ton fuel
Cockpit (1.5dton)
Computer/30 - 0dton
Military sensors (2dton)
Small weapons mounts (1dton)
Fixed mount pulse laser (0dton)
Acceleration Benches (2dton allowing eight troopers in armour to sit in a space roughly the size of a Huey cabin)

Cost before software is purchased is MCr 28.1

Cost if all the various software is maxed is something like MCr 115 but that’s the same with basically all Mongoose Hoghguard designs

 

[kilemall]

That sums up the challenges for fighters, and I actually think it would be worse if not for a quirk of the armor rules. That percentage based armor system means the fighter has a thinner shell but gets the same level of protection as a battleship.

That’s why I have an armor multiplier rule by size code.

If it’s -1 ACS sized, armor tonnage doubles. If it’s -2 small craft sized, it’s tripled.

Justifiable due to much smaller surface area to volume. All that heavy metal has to go somewhere.

 

[TamsinP]

@chipla makes a very good point about the COAC role of fighters, which would still be a major role for them at high TLs where they are no longer as viable in a ship attack role. The major space combat roles for them at higher TLs would be acting as an extended sensor net for the fleet, as a screen against incoming missiles (and possibly enemy fighters) and as a missile barrage platform which can launch from a closer range than you would want the capital ships to be at.

 

[McPerth]

A capital ship can carry multiple sensors larger than the fighter. It can see further and achieve target lock at a greater range.

A capital ship can mount a weapon bay larger than the fighter, such a bay should instantly destroy a fighter.

Note that the energy a capital ship can dedicate to a weapon bay or massed battery is an order of magnitude or two greater than the fighter.

A capital ship can carry enough armour to make a fighter's weapons useless, assuming it can make it to a range at which it can fire.

All of this can also be said from a WWII (or current, for what's worth) Capital ship and an airplane...