Wednesday, August 22, 2018

Dogfighting Revisited


I looked at David Pulver’s Dogfighting article, from Pyramid#3/53, way back in Iteration 3 and dismissed it as inappropriate for what I was trying to do, and in some sense that’s probably still true. Dogfighting won’t cover everything and misses a lot of elements key to space combat, especially how capital ships interact, or things like power management. Even so, Dogfighting is close to “chases,” and I find it easiest to handle gameplay when all the rules match. Broadly speaking, the space combat scenes from Star Wars do not differ dramatically from the chase scenes from Star Wars, and in at least one case, the space combat scene was a chase scene!

Furthermore, as I step away from GURPS Spaceships as the driving mechanics behind my vehicles, I find that I need to look elsewhere for rules governing how they fight. I do still believe that GURPS Spaceships includes lots of interesting concepts for space combat, but it’s also clear to me that Psi-Wars space combat more closely resembles naval and aerial combat than it does space combat, which means we need more aerial and naval forms of combat.


I have no doubt that the final version of these rules will likely integrate elements from GURPS Action, GURPS Spaceships and GURPS Vehicles (especially as the first two are generally simplifications of the third). But if I have to choose a base, it looks like Dogfighting might be the ideal foundation from which the rest of my system will flow.


Walking through the Rules

We’ll be using the Dogfighting article straight today, but I want to see how well I understand it. The intention here is that when we get to our space combat, we port as much of it over as we can, with only a few tweaks here and there, either to accommodate the characteristics of Psi-Wars space combat, or to account for any additional cinematic twists I want to add. But before I can do that, I need to know how everything works.


Movement

The basic rules are out of GURPS Action 2, which is explicitly for chases. It assumes a pursuer and a quarry. Dogfighting, of course, doesn’t have this. It has two vehicles attacking one another. In principle, they are two people attempting to pursue one another. On the other hand, we might get a quarry if you’re attempting to “lose” the other fighter, either because you want to escape combat, or because you’re trying to regain the upper-hand. However, the rules for chases are sufficiently generic that this isn’t necessarily the problem. “Move” or “Move and Attack” can be done by quarry or pursuer, and the winner decides we “close” range by a band or two, or “open” range by a band or two. Dogfighting also states that only the person who won the contest by “0 or more” can fire on the other because all dogfighting vehicles have forward facing mounts. I’m curious how one can “win by 0” given that this is a tie, but this presumably means succeeding where the other failed; I think I’ll also give ties to the person who won the previous round (that is, once someone is on your tail, they remain there until you “shake” them).

The roll for our movement portion of the dogfight is Pilot (of course), modified by handling and a “speed bonus.” The speed bonus is interesting for Psi-Wars. Currently capital ships will move at between 200-300 miles per hour (+10 to maximum +11) while grav drives and ion thrusters cap out at 600 (+12 to max +13) and plasma thruster equipped fighters move as fast as modern fighters (about +14). This means the difference between a starfighter and a capital ship, setting handling aside, is only about +3, while a fighter vs something like the Millennium Falcon is only +1 to +2, something easily exceeded by a top-notch pilot. Interesting! Perhaps I can/should revise the maximum speeds for capital ships, and this also means that “slow” Ion Thruster fighters aren’t so bad off, especially if they have a high handling.

Note that we get an additional bonus for “Radar.” That will be something else in Psi-Wars, but it’ll stand for now.

Dogfighting action clarifies some additional ranges, and states that fighters rarely get closer than 500 yards. That might be worth looking into more closely.


Attack

GURPS Action says that one can “attack” if one is static (not possible on a fighter, I think), and Move and Attack otherwise. I’m not sure if the Chase rules are explicitly covering vehicle-mounted weapons, or if Gunslinger refers to your own guns; I’m inclined to treat it that way!
Dogfighting Action states that you must “win” your contest to attack, that you can ignore your bulk penalties due to “bracing and sighting systems” and you get +3 with a radar lock. The +3 is a standard rule, but the ignoring bulk is interesting. On what physical mechanism is that based? How can we “build” a fighter that has the same advantage?

GURPS Campaigns offers several modifiers for moving and firing for air vehicles: you’re at -1 if using a handheld weapon, but that’s never going to come up. You’re at +0 otherwise, so far so good. It also hits you with a penalty to all shots equal to -4 if you dodged last turn, and with a penalty equal to how much you failed a control roll last turn. “Vehicular Targeting Systems” add +1 to +3 if the shooter took a turn to aim. If we dig a little deeper, we find several interesting rules. First, a typical optical sight will give +2 while a TL 8 fire-control system will give a +3 (but this might be part of radar). A fixed mount requires you to roll the lower of your gunner or pilot skill to hit (same with hardpoints, but you’re at -1 Acc). GURPS Vehicles offers a +2 to fire with a fixed mount (which is borrowed by GURPS Spaceships). Gyrostabilization seems to offer some bonuses, but mainly to turrets to “reduce the penalties for firing on the move.” These penalty reductions are handled in the Ranged Attack Modifiers section, which state that bonuses from Accuracy, Aim, bracing and targeting systems cannot exceed stability unless stabilized, and that (for example) a water vehicle in rought-water is at -1 to hit if moving and attcking with a stabilized mount, -2 with a fixed mount, and so on but no rules on the penalty for attacking with an unstabilized turret).

Move and Attack on B365 states that you lose all Aim bonuses, which makes me wonder why everything is discussing Accuracy at all! After careful hunting, the only rule I can find that negates this seems to be “Weapon Fire from a Moving Vehicle” on B469, which discusses aiming from a moving vehicle.

So the intent here seems to be that the “bracing” of weaponry (the +2 from fixed mounts and hardpoints), the accuracy of the weapons themselves and any “scopes” that they might have are being simplified into “ignore the bulk value.” It might be worth looking into that more closely, since both this and Space Combat seem to just toss aside quite a few rules by suggesting that other modifiers make up the difference, but this might cause a problem if we don’t know what modifiers still apply and which do not. In this case, it seems clear that the weapons don’t gain the +2 from fixed mounts, or from any “scopes,” but this might not be the case with our ultra-tech vehicles, so we’ll need to return to this topic.


It should be noted that even with all of these rules, we have a -15 to hit at Extreme range, which is the closest the article says we can get. The highest ROF cannon, the 20mm autocannon, fires 100 rounds, which is +7 to hit, and our radar gives us a +3, and the size of the vehicles gives us another +5 to +6, which is, altogether, a +0 or +1 to hit. It’s not clear to me if and how I should apply the speed penalty, but a close reading suggest that I only apply the worst of the two; the simplest way to handle this is to apply the worse or range or their speed modifier. Given that their speed penalty is -14 and the closest range penalty is -15, then range seems the greater concern, at least for now.

That leaves us with the homing weapons from before, which is where everything went south fast (well, at least one of the issues). The problem I had here was the ROF and how to handle it. The rules state that you roll Artillery with the missile’s Accuracy as a bonus, and a penalty equal to the ECM modifier. “All usual attack roll modifiers apply” except we ignore range and apply only have the speed penalty. Setting aside accuracy and ECM, “half speed modifiers” will be -7 on average, Size modifier is +5, the ROF of 100+ is +7, which means we have a +5 to hit with a Rcl of “--” (I presume 1?), which means we’ll hit with an average of 6 fragments; the accuracy of a TL 8 missile is +5 while our ECM is typically -3, so we’re looking at another +2 for a total of +7 or 8 fragments per missile, and even if we dodge or manage to make it a little harder for our opponent to hit us, we just reduce the number of fragments.


Psi-Wars isn’t going to use those sorts of fragments, because I have no way to design them, so in the interest of moving this along, I’m going to replace those rules with an explosive round that deals 6dx10. It can “airburst” for +4 to hit and be close enough to apply full damage. If you miss by 1, you still hit but you do 1/3 damage, and if your opponent successfully dodges, but only by 0 or 1, he’s still hit, but only takes 1/3 damage (unless he was already going to take 1/3 damage, in which case he dodged the shot). This is to simulate the Plasma Missiles our ships will be using. This means that we have an average of -7 for speed, +4 for airburst, +5 for accuracy and -3 for ECM, or -1 on average to hit.

The Dogfight

Part 1: The Fighter-Craft and Pilots

So, we’ve got our basic rules. What will the fight look like? For our fighters, let’s put a skilled “underdog” against a less-skilled “brute.” In Team America, we’ll take a “Viper,” and treat it as an “advanced” fighter, perhaps something like an F-18. It’ll have the standard stats, including a 20mm gatling cannon +6 ROF), six a2a missiles, and we’ll treat it as a later model with 75+ mile radar and ECM -3. Our pilot, Maverick, will have Pilot-18, Gunnery-16, Artillery (Guided Missile)-16, and HT 12. I don’t think any other stats are relevant.

On Team Bad Guy, we’ll use a lower-tech Phantom as a stand in for a Mig-28 (The Mig-28 is a fictional aircraft that Top Gun depicted with an F-5, which is close to a F-4, and thus a Phantom is appropriate). I’ve chosen a 30mm cannon (+6 ROF) to reflect the fact that Russian craft depicted tend to have heavier guns than American fighters, 8 air-to-air missiles, 50 mile radar, and ECM -2. Our nameless pilot will have all appropriate skills at 15 and HT 11.

The first thing that jumps off the page is that we don’t see much difference in stats. I had wanted to see what it would look like with a Flanker vs a Viper, but they’re really, really close, so if I really want a difference between the vehicles, I need some sort of difference, and this should give us a good idea. It is interesting to see that most vehicles won’t differ substantially, however; a point of handling here and there, a minor weapon difference, etc.

Part 2: Engagement details

Both craft have radar, so we can start Beyond Visual, which means they’re only picking up one another as bogies.

Weather is clear, terrain isn’t particularly special (but, say, a big rocky and mountainous below). Neither can be reached by the other side’s support, so they’ll both be alone.

Part 3: The Fight

Turn 1: Beyond Visual: Encounter


Step 1: Quarry chooses his chase maneuver

Step 2: Pursuer chooses his chase maneuver

Well, it’s not clear at this point who is quarry and who is pursuer. The rules suggest that if its not clear, both pick blindly. So, all we have is a radar ping on both (or so? We don’t really get into sensor checks here). So, I think the reasonable thing for our Russian to do would be to Move closer to investigate. For Maverick, let’s go ahead and fire a missile: his superior radar was picking up the Mig from a lot farther off, so he has a better idea.

A note: rules on whether you detect someone would be nice here. The fact that one guy has 75+ mile range and the other doesn’t doesn’t seem to make much of a difference at this point. I’m also curious about how facing would work. Perhaps if you detect someone first, or you happen to be behind them, that you are automatically the pursuer?

Step 3: Pursuer resolves any attack rolls for his manuever

Well, Maverick is attacking, so he’s surely the pursuer at this point.
  • His Artillery is 16;
  • his missile has an accuracy of +5 (he’s using the TL 8 version);
  • The Russian’s SM is +6;
  • our missile airbursts for +4;
  • we’re not worried about range;
  • his opponent has an ECM of -2;
  • his opponent has a speed modifier of +15; we halve it (round down) for -7.
So, we have a total of...22 or less. We roll a 10 and hit, no problem!

The Russian needs to dodge now. He has a skill of 15, which is a 7 or less to dodge, plus his handling of +1, so 8 or less. If we assume combat reflexes, he has a 9 or less. We can boost that by +1 more if we take a high-G defense, which requires him to make an HT roll. Let’s do this. We roll a 9, which beats our 10 by enough to get rattled by the missile, which deals 80 damage (after reducing for distance). That’s enough to “stun” the jet and possibly set it on fire (11 or less to avoid being disabled, 8 or less to avoid being on fire). We roll a 14 and an 8, which means we’re not on fire, but we’re falling out of the sky. We roll 8 on our HT roll, which means we can handle the intense Gs just fine.

Note: For the sake of the fight, let’s call that attack a miss, but it’s interesting that’s very hard to dodge a missile and very easy to hit with it from such a long range. It’s also arguable that Maverick couldn’t make this attack at all: we’ve not established who the pursuer is, and he has won no particular contest yet. Still, the extreme effectiveness of the missile is potentially a problem.


Step 4: Quarry resolves their roll

The Russian has no special rolls

Step 5: Resolve the Chase quick contest.


Maverick is at -2 for his Move and Attack maneuver, has +14 speed and +3 handling. Paired with his 18 piloting, he’s got a total of 33. The Russian has Skill 15, +15 speed, and +1 handling, for a total of 31. Both can make an electronics operation (sensors) roll to get a boost. Maverick rolls an 11 on his electronics roll and gains a +1 to his chase roll (34) and rolls an 11, passing by 23. The Russian rolls a 13 on his electronics roll and passes, gaining a +1 (32) and rolls a 7, passing by 25.
The Russian wins. He can fire on Maverick, but not vice versa.

Step 6: Adjust range band and continue to next round

No range band change is allowed.

Note: Dogfighting Action states that one can only attack if he succeeded by 0 or more on the previous chase roll. But what about the initial check? A couple of options are possible: you roll off to see who senses who first, or you just state that neither can fire or both can fire.

It’s also interesting how painfully accurate the missile is. It looks like Dodge is your only real option! That said, while I’m not sure, I know that 160mm missiles typically have an accuracy of +6, while TL 11 jammers tend to have a ECM penalty of -6, so it’ll be harder to hit a Psi-Wars fighter with a missle, but not by much.


Round 2: Beyond Visual; The Russian Pursues; Russian has full ammo; Maverick has 5 missiles and full cannon.

Step 1: Quarry chooses his chase maneuver

Well, Maverick is definitely in the hot seat now. His radar is going nuts, showing his enemy has a lock and, likely, is pissed. He needs to turn things around fast. He chooses a Reverse.

Step 2: Pursuer chooses his chase maneuver

The pursuer chooses second so he can adapt, but the Russian doesn’t need to. He chooses to Move and Attack.

Step 3: Pursuer resolves any attack rolls for his manuever

The Russian is attacking with a missile:
  • His Artillery is 15;
  • his missile has an accuracy of +5 (he’s using the TL 8 version);
  • The Maverick’s SM is +5;
  • our missile airbursts for +4;
  • we’re not worried about range;
  • his opponent has an ECM of -3;
  • his opponent has a speed modifier of +14; we halve it (round down) for -7.
So, we have a total of...19 or less. He rolls an 8, and hits, of course. It’s almost impossible not to.
Maverick has a dodge of 13, with +1 for a High G maneuver. We roll a 7 to dodge (easy) and a 10 for High G (Out of our 12), so we’re fine. Whew!


Step 4: Quarry resolves their roll

Maverick has no special rolls.

Step 5: Resolve the Chase quick contest.

Maverick is at -10 for his Reverse maneuver, has +14 speed and +3 handling. Paired with his 18 piloting, he’s got a total of 25. The Russian has Skill 15, -2 from move and attack, +15 speed, and +1 handling, for a total of 29. Maverick rolls a 9 (being his skill by 16) and the Russian rolls a 14, which beats his skill by 15.

Maverick wins by 1. He closes from Beyond Visual to Distant.

Note: Reverse is… weird in this version, and I’m not sure I like it. It’s much more difficult than a Stunt, and roughly equivalent to adding a +5 to your chase roll, which is an average of +1 or -1 range band, which is exactly what Maverick got here. It’s possible to get 2 range bands out of it, so I suppose there is that, but I’m not sure that’s better: it means that if you want to close in a dog fight, it’s always better than a stunt. What’s also weird about it is that it’s just part of your “chase” roll, as opposed to a separate roll, as in a stunt. This means that extremely fast craft are less likely to “wipe-out,” thanks to their high speed bonus, than a slower vehicle. That’s… counter-intuitive, and I’m not sure it’s a good rule.

Round 3: Distant; Maverick Pursues; Russian has 7 missiles and full cannon; Maverick has 5 missiles and full cannon.


Step 1: Quarry chooses his chase maneuver

The Russian is now on the run, and he can turn around to SEE Maverick, who has managed to close in on him. He pushes to go as fast as he can to escape. He chooses Move.

Step 2: Pursuer chooses his chase maneuver

Maverick almost hit the Russian last time, but it almost lost him the race. So let’s complete our close with a Stunt at -4.

Step 3: Pursuer resolves any attack rolls for his maneuver

Maverick needs to roll against Pilot -4, so a 14 or less. He rolls… a 15. Man, what are the chances! He’s got a stability of 4 so he’s more-or-less fine and can participate in the chase, but he’s in trouble next round.


Step 4: Quarry resolves their roll

The Russian has no special rules.

Step 5: Resolve the Chase quick contest.

Maverick is at +0 for his stunt, has +14 speed and +3 handling. Paired with his 18 piloting, he’s got a total of 35. The Russian has Skill 15, +0 for move, +15 speed, and +1 handling, for a total of 31. Maverick rolls a 12 (success by 23) and the Russian rolls a 7 (success by 24).
The Russian wins by 1.

Note: I’d almost rather see Maverick win with the stunt. That would have given him enough to continue to hold his advantage, but not so much that he could choose to gain ground. Gaining ground is hard! Harder than I expected. Also, this fight is far more dynamic than I thought it would be. This is actually kind of dramatic!


Step 6: Adjust range band and continue to next round

The Russian becomes pursuer. He cannot close range.

Round 4: Distant; The Russian Pursues; Russian has 7 missiles and full cannon; Maverick has 5 missiles and full cannon, and must make an emergency action.


Step 1: Quarry chooses his chase maneuver

Maverick must make an Emergency action.

Step 2: Pursuer chooses his chase maneuver

The Russian could simply move. That might give him enough speed to close in for a kill with his superior cannon, and Maverick is at a penalty for the chase. So let’s do that. Seeing Maverick flaming out, the Russian dives after him, pushing to get as close as he can.

Step 3: Pursuer resolves any attack rolls for his maneuver

The Russian needs to make no special roll.

Step 4: Quarry resolves their roll

Maverick makes no special roll and recovers his craft.

Step 5: Resolve the Chase quick contest.

Maverick is at -5 to recover, has +14 speed and +3 handling. Paired with his 18 piloting, he’s got a total of 30. The Russian has Skill 15, +0 for move, +15 speed, and +1 handling, for a total of 31. Maverick rolls a 14 (success by 16) and the Russian rolls a 12 (success by 19).


The Russian wins by 3, which is not enough to close range. Man, that’s hard!

Note: Maverick is just a better pilot and in a more nimble jet. It’s really the only thing keeping him alive now. An emergency action, at -5, averages a free band of movement, so he’s lucky he was able to hold the Russian at bay.


Step 6: Adjust range band and continue to next round

The Russian remains pursuer. No closed range is possible.

Round 5: Distant; The Russian Pursues; Russian has 7 missiles and full cannon; Maverick has 5 missiles and full cannon.


Step 1: Quarry chooses his chase maneuver

Maverick makes a Stunt at -4 again. Surely problems can’t happen twice in a row!

Step 2: Pursuer chooses his chase maneuver

The Russian simply can’t catch up to Maverick. He’ll fire a missile.

Step 3: Pursuer resolves any attack rolls for his maneuver

The Russian still needs a 19 or less to hit. He rolls a 12, and hits. Maverick has a dodge of 13, with +1 for a High G maneuver. We roll a 9 to dodge and a 13 for High G (Out of our 12); he doesn’t pass out but he loses 1 fatigue!

Step 4: Quarry resolves their roll

Maverick needs a 14 or less and rolls a 13 (man, his rolls are not great today, but it’s enough). I think it’s a shame that he can’t use a High-G “stunt.” And why not? Perhaps a +2 if you’re willing to risk blacking out!

Step 5: Resolve the Chase quick contest.

Maverick is at +2 for his stunt, has +14 speed and +3 handling. Paired with his 18 piloting, he’s got a total of 37. The Russian has Skill 15, +0 for move, +15 speed, and +1 handling, for a total of 31. Maverick rolls an 8 (success by 29) and the Russian rolls a 12 (success by 19); success by 10!

Maverick succeeds by 10; he can close two bands.

Note: Nothing says you can’t close by to less than Extreme, just that jets rarely do. Let’s say that they do, but immediately revert to Extreme on the next round.


Step 6: Adjust range band and continue to next round

Maverick leads and they are at long (-11)

Round 6: Long; Maverick Pursues; Russian has 6 missiles and full cannon; Maverick has 5 missiles and full cannon and 11 fatigue left.


Step 1: Quarry chooses his chase maneuver

The Russian needs to get out of this. He’ll stunt for -2.

Step 2: Pursuer chooses his chase maneuver

Move and attack! Kill the Russian with cannons!

Step 3: Pursuer resolves any attack rolls for his maneuver

Maverick fires his cannon:
  • He has gunnery 16
  • He has a radar lock (+3)
  • He’s at Long Range (-11)
  • His quarry is SM +6
  • He has ROF 100 for +7
He needs a 21 or less to hit (this close range is helping a lot!). He rolls a 13 to hit, which will hit a total of 5 times!

The Russian needs to dodge, again with a High G manuever. He dodges on a 9 or less and rolls… a 14. Well, that’s not good. Maverick hits dead on 5 times for (after DR 5) 30, 48, 45, 45 and 51, for a total of 219 damage against an HP of 125. That’s a stun check (11), a fire check (8), and a disabled check every second after this one. With an 11, the vehicle can still fly, but with a 16, it is on fire. But he passes his HT check for high-G! At least he has that.

Note: Given that speed now exceeds range, I could replace range with speed. That feels like an added complexity, and likely why David Pulver mutters about never getting closer than Extreme, as that means the -15 is always worse than the -14 for speed. It also means that there’s no point in getting closer. I’ve avoided that complexity for now, but it’s worth bearing in mind.


Step 4: Quarry resolves their roll

The Russian, I remind you, was in the midst of a stunt. He needs a 13 or better to pass, and rolls a 14. Oh… bother.

Step 5: Resolve the Chase quick contest.

Maverick is at -2 for move and attack, has +14 speed and +3 handling. Paired with his 18 piloting, he’s got a total of 33. The Russian has Skill 15, -4 for damage this turn, +0 for move, +15 speed, and +1 handling, for a total of 27. Maverick rolls an 8 and the Russian rolls a 12; Obviously, Maverick maintains the lead; we’ll keep to Extreme, rather than Long.

Note: There’s no rules her for reduced handling when you’re below 0 HP, but maybe there should be. GURPS Basic talks about it, but Action doesn’t. Might be a good rule to import from Spaceships!
Step 6: Adjust range band and continue to next round
Maverick leads and they are at Extreme (-15).

Post-Script

After this, the Russian needs to make an HT roll every turn to keep from wrecking and a critical failure results in an explosion because he’s on fire. It’s not clear what, if anything else, the fire does. Perhaps continues to do damage? I think that’s fair! In any case, on the next turn, the Russian would be at -5 from needing to make an emergency action, so even if his plane survived, Maverick would retain his advantage and get to fire again, probably hitting again, and forcing more HT rolls. The Russian could make a DX roll to bail before he crashed, which looks inevitable at this point.
And I have to admit, with a few minor changes, this isn’t bad. It feels more dynamic than the space combat, and easier to remember. It’s pretty fast paced and dramatic and can turn on a few bad rolls. I honestly thought this was a bad pairing, because Maverick would clearly win, but the dogfighting system keeps the rolls pretty close, overall. This might cause some problems with other sorts of ships (capital ships aren’t as “slow” in this form of combat as I might like).

There are a few things I’m concerned about, but we can look at those in more detail later. They are mainly:
  • Why not High-G stunts? Too many rolls?
  • Are reverses worth keeping in at all?
  • Rules for who detects who first?
  • Missiles seem really unlikely to miss.

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