Talk:Heavy Cannon vs Auto Cannon

From UFOpaedia
Jump to navigation Jump to search

Jasonred: During the early part of the game, the most common enemies (the only enemies?) are Sectoids. Since a sectoid is so very delicate, even a near miss from a AC-HE round can kill it, thus changing the kill probabilities a bit. The HC has higher firepower per shot, but a great deal is "overkill" in this case.

I don't think the above is true so I've moved it here for discussion.

For direct fire / direct hits, there is no overkill. Because direct fire damage is 0-200%, for unarmoured targets the kill probability is linearly proportional to base damage (where Health < 2*Dmg). For armoured targets, kill probability rises better than linearly with base damage. So there is no overkill.

But you are talking about HE area damage (near misses). I actually did not model near miss effects in my firepower calculations. In theory there is an overkill factor in area damage, whenever 0.5 * Base Damage is > (Armour + Health). But in practice, even weedy Sectoids are not this weak. Keep in mind a near miss is 10 or 20 base damage less than a direct hit. So in practice, area HE kill probability for these weapons has no overkill and is better than linear with base damage.

If we compare AC and HC as HE area weapons, the HC has a greater lethality over a greater area with a greater accuracy. I have not done the sums but my gut feel is that it will outweigh the better fire rate of AC auto.

By the way, the firepower advantage I'm quoting is not per-shot but per unit of time or per TU. Also, Floaters are quite common in the early game, and the terror units associated with both Floaters and Sectoids will be encountered toward the end of the first month, when AC and HC are still state-of-the-art weapons.

Spike 06:13, 27 February 2009 (CST)

Overkill limit

Quick calculation: With health of 30 and under armour of 2, you need an explosive power at least > 75 to get any overkill on a Sectoid with a near miss. AC-HE is 44, HC-HE is 52, Grenade is 50. By overkill I mean that the minimum damage is enough to kill, therefore the kill probability stops rising with the base damage because it is already 100%. Spike 06:51, 27 February 2009 (CST)

Kill Modelling

Well, that's why I rely on you guys who have all this software which can be used for kill modelling and such. MY proposal: test and compare Autofire and snap shot for both AC and HC. I'm not certain, but I'm under the impression that the the AC-HE on autofire has the best chance of killing a medium distance sectoid in one attack. And also the best chance of killing in 1 turn.

The high tech software we use generally involves pen, paper and maybe a calculator. But I guess those with access to spreadsheets and other analytical software do certainly have a clear advantage! Heh.
For highly inaccurate attacks over a great range, auto attacks tend to be more reliable compared to single attacks in general. Even if you were firing at a resulting accuracy level of 10%, your chances of hitting at least once tend to be greater with an auto attack than a snap or aim shot. Snap an aimed shots on the other hand work best at high accuracy levels for medium to long ranges. That's where both of the cannon types lever their advantage.
The AC-HE on auto does have one thing that goes heavily against it though: Loot destruction. Assume that the alien was killed on the first hit, the remaining two hits would then blow up the items on the ground unless they missed, which can happen with the first or second direct hit on the first three primary alien races you encounter.
The lower damage of the auto-cannon is an advantage later on once you get power suit or flying suits. -NKF 11:29, 27 February 2009 (CST)
NKF: The most valuable part of any alien's gear is their weapon, which the Autocannon-HE lacks the power to destroy. It can destroy clips, grenades, the corpse, and either of the launcher weapons, but a GZ hit from the AC-HE does 44 damage against objects on the ground; the Plasma Pistol needs 45 damage to be destroyed, and the Plasma Rifle and Heavy Plasma need 50 damage. The Blaster Launcher needs 40 damage, so is safe if you botch the shot by one, and the alien corpse(26 damage or more) is safe if you botch by two or more. The rest of their gear survives at 3 or more spaces off. Arrow Quivershaft 12:12, 27 February 2009 (CST)
Except for Blaster Bombs, which IMHO are each worth much more than several Heavy Plasmas put together. Elerium is pretty important as well, usually.
Monetary value wise though, yes, the alien weapons are the bulk of the spoils of war. BUT, note that blowing up 1 corpse+1ammo+1clip+1alien grenade= around $40,000... about the same as hiring a rookie. Jasonred 14:38, 27 February 2009 (CST)
In my opinion, if you are facing aliens packing Blaster Launchers armed with nothing better than AC-HE, its usually early in the game and you're generally a lot more concerned about making sure the alien with the BL is dead than how much loot you're going to pick up off his corpse. ;) And if you do have better weapons, what's the AC-HE being used for against aliens weilding Blaster Launchers? Arrow Quivershaft 20:51, 27 February 2009 (CST)
No argument there - but if you're just starting out, loot's fairly necessary to get you up to speed so you don't want to reduce it too much. You may even want some ammo and alien grenades on hand when you do start using them. In general, a few bursts of AC-HE wiping out some equipment isn't really that big an issue, since your non-explosive weapons and the one-off explosives like grenades and rockets will secure plenty to sell off. At least, not unless you've armed the entire squad with autocannons! (I tried this once - a literal blast). You do have to be extra mindful of elerium pods - they aren't as forgiving. -NKF 14:31, 27 February 2009 (CST)

AQ posts a strong argument in favour of the AC-HE, this ability to kill enemies but leave loot unharmed (anybody remember the Neutron Bomb?). Increased weapon firepower/lethality will win the tactical game and save lives, but loot is what wins the strategic game. Its well worth sacrificing lives - rookie lives particularly - in order to collect more loot. Interesting!

I'll post some preliminary stats on area firepower later. Up until now in my Firepower Tables I have only ever modelled the area effect damage on the 3 adjacent squares of a 4-square terror unit after a direct hit.

But basically, whether AC area fire is better than HC area fire hinges on the tactical situation: how much inaccuracy can be tolerated, and how much you need extra TUs for maneuver. Spike 12:54, 27 February 2009 (CST)

HC vs AC, direct and area effect damage

Adjusted after reviewing the Explosions page: AC-HE and HC-HE are both "crimped" to radius=3. This benefits the AC, as otherwise the HC would have a much bigger total area of effect and more total damage. As it is, HC does not affect any more area per shell than AC - though the damage level is more intense within the affected area.

Kill and damage modelling of area fire and auto fire is difficult enough. Modelling automatic area fire takes the biscuit. (I know. However, not taking AOE damage into account affects HE SEVERELY... BTW, to make your calculations EVEN MORE difficult? How about multiple targets? EEK!!!Jasonred 15:09, 28 February 2009 (CST)) However, here's some starting data:

Auto Cannon:

  • 44 HE warhead, best mode is auto: 40% TUs per burst, 32% accuracy
  • 716 average total area damage per shot, over 29 map squares (radius=3).
  • Max RoF: 6/turn (auto - 20% TUs left over)
  • Gross total area damage per turn: 4296
  • Accuracy-adjusted RoF (hits per turn): 0.93 (at FA=50)
  • Accuracy-adjusted total area damage per turn: 666
  • Direct fire HE kill probability vs Sectoid... per hit: 77%; per shot: 12%; per turn: >>55% (at FA=50)
  • Possible area kill vs Sectoid (32 dmg) out to GZ+2 = 21 squares (24 avg, 36 max damage at GZ+2).
  • Direct fire HE kill probability vs Floater... per hit: 43%; per shot: 6.9%; per turn: >>35% (at FA=50)
  • Possible area kill vs Floater (47 dmg) out to GZ+1 = 9 squares (34 avg, 51 max damage at GZ+1)
  • Avg TUs per kill (at Firing Accuracy=50)
    • vs Sectoid: 60% (66% using AP)
    • vs Floater: 91% (85% using AP)
    • vs Reaper: 95% (AP is 6x less effective)
    • vs Cyberdisc: 1219% (if using AP: HE is 13x less effective)
    • vs Muton: 306% (AP is 3-4x less effective)

Heavy Cannon:

  • 52 HE warhead, best mode is snap: 33% TUs per snap shot, 60% accuracy
  • 948 average total area damage per shot, over 29 map squares (radius=3).
  • Max RoF: 3/turn (snap - 1% TUs left over)
  • Gross total area damage per turn: 2844
  • Accuracy-adjusted RoF (hits per turn): 0.9 (at FA=50)
  • Accuracy-adjusted total area damage per turn: 853
  • Direct fire HE kill probability vs Sectoid... per hit: 88%; per shot: 26%; per turn: >>60% (at FA=50)
  • Possible area kill vs Sectoid (32-34 dmg) out to GZ+2 = 21 squares (32 avg, 48 max damage at GZ+2).
  • Direct fire HE kill probability vs Floater... per hit: 60%; per shot: 18%; per turn: >>45% (at FA=50)
  • Possible area kill vs Floater (47-43 dmg) out to GZ+2 = 21 squares (32 avg, 48 max damage at GZ+2)
  • Avg TUs per kill (at Firing Accuracy=50)
    • vs Sectoid: 66% (63% using AP)
    • vs Floater: 96% (80% using AP)
    • vs Reaper: 100% (AP is 5x less effective)
    • vs Cyberdisc: 765% (if using AP: HE is 7x less effective)
    • vs Muton: 327% (AP is 2-3x less effective)


Floaters have strong underarmour, a value of 12, which is good protection against indirect HE. Past GZ+1 the explosion does not hit under armour; the other armour is weaker. Also, airborne Floaters can only be killed by a direct hit, unless there is a nearby wall or another airbourne object on the same level.

In Snap mode the AC is slightly less accurate than the HC, with the same rate of fire (Accuracy-adjusted RoF = 1.56 hits per turn). So in Snap mode the AC is clearly the inferior weapon (in firepower terms), though with more than double the ammo capacity.

If accuracy is relatively unimportant, the gross damage levels are most relevant, and this favours the AC-HE. This might be the case when firing downward from an elevation - misses tend to go into the ground on a nearby square, rather than flying past the target altogether.

If maneuverability is important, a fairer comparison would be to assume RoF of 2 for the HC, but still RoF 6 (2 x 3) for the AC. In which case the firepower measures for HC fall by one third, and the per turn kill probabilities are >>33% vs Floater, >>46% vs Sectoid - making the AC-HE more lethal than the HC-HE.

Note that the AC-HE auto rounds will tend to bunch up in the same area. Depending on the tactical situation, this may be a good thing (cumulative damage) or a bad thing (wasted rounds). If a greater spread is desirable, degrade accuracy by carrying an item in the other hand, standing, etc.


Notes: ">>" should be read as "significantly greater than". The number I give is the product of the kill probabilities per shot, but it completely ignores any effects from cumulative damage. "FA" means Firing Accuracy skill.

Spike 14:28, 27 February 2009 (CST)

Close-combat Use

Not to pound on the poor Heavy Cannon any more, but in the late game, one remaining use for both the HC and AC is to load it with HE rounds amongst troops of soldiers in Power or Flying Suits and wander around, since the armor renders you invulnerable to damage from the HE. In practice, this doesn't quite work. The maximum damage at ground zero for an AC-HE shell is 66 damage; the max for a HC-HE shell is 78.

It is pointless to hit yourself with a ground zero explosion from a projectile weapon; so a soldier in a Flying Suit is immune to his own HE shots from either the HC or AC. However, in a friendly fire incident that results in the soldier being at GZ, the FS's underarmor of 70 is enough to protect against the AC round...but not quite against the HC round(though the chance of penetration is fairly low.)

A soldier in a Power Suit, on the other hand, is still vulnerable to an HC-HE explosion that detonates adjacent to him...and vulnerable at GZ to both the HC and the AC. None of these attacks are particularly wounding, not enough to kill the soldier if it happens once, but it's something to be aware of. In fact, if a soldier in a Power Suit is hit at GZ with all three shots from an AC-HE auto-burst, he could take up to 21 damage(due to armor damage), whereas being hit by a single HC-HE will only deal 18 damage to him. Arrow Quivershaft 15:41, 28 February 2009 (CST)

Queries

  1. What is meant by "121 accuracy"?
  2. 3 targets within a 90 degree firing arc? Surely not. That is a huge arc. Also, it's totally dependent on range. At point blank, maybe. At 10 squares, no way.

Spike 18:25, 22 July 2009 (EDT)

Retrieved from "https://www.ufopaedia.org/index.php?title=Talk:Heavy_Cannon_vs_Auto_Cannon&oldid=22024"