Tell me about...the Hypervelocity Autocannons

[UnLimiTeD]

I once built an Atlas for Megamech with 4 HVAC2s. Used two of them against a Bot.
For some reason, they fired twice a round, as if a UAC in permanent Ultra Mode, and at some point blew up on a 4.
Set a hex on fire and the smoke covered a third of the playing field...
Would they be useful if they'd practically be Ultras?
Also, would HVACs have any bracketing advantages in ASFs?
Namely the 2?

[Moonsword]

Since the HV ACs appear to have first shown up in Maximum Tech, it is possible they started designing the weapons, but once they got access to more reliable weaponry they set the idea aside.

They had access to more reliable weapons already.  The Gauss-armed Huron Warrior went into service in 3055, the same year HVAC research started.  The CTF-3L debuted in 3050 and was built in large numbers, meaning they had plenty of LB 10-Xs, too.

Also, would HVACs have any bracketing advantages in ASFs?
Namely the 2?

No.  LB 2-Xs are lighter and don't explode but already reach into extreme range.

[MoneyLovinOgre4Hire]

HVAC 2s do offer 2 points of damage rather than the 1 point dealt by LB-2Xs on ASFs, but I wouldn't say that exactly makes up for all their downsides.

[Maelwys]

So the rules for the HVAC say to inflict internal explosion damage equal to that of a single round, and destroy all of the HVAC's criticals. They also say to treat it as an ammo explosion.

So does that mean that on vehicles, all of the ammo cooks off, since that's what happens in ammo explosions for vehicles?

So on the Po, you roll a 2, inflict 10 points of damage to your structure (destroying the turret) and then have the remaining HVAC and Streak ammo explode, doing yet more damage to the turret?

Not only does the HVAC kill the tank just from firing the weapon, but it doesn't leave a crew or much to salvage.

I can see the Po (HVAC) being a limited production run during the Jihad if they were running low on regular Autocannons and had to make do, but it really stretches the imagination that these things went into regular production.

[Kotetsu]

Think the ammo explosion note is more for the two pilot hits it inflicts on a 'Mech pilot... and the crit check.

[YingJanshi]

Ok, what about the HVAC/20? Thoughts?

[MoneyLovinOgre4Hire]

What HVAC 20?  The gun only goes up to a size 10.

[Moonsword]

Ok, what about the HVAC/20? Thoughts?

Since it doesn't exist, any discussion of fan interpretations of such a weapon needs to take place in Fan Designs, not here.

Think the ammo explosion note is more for the two pilot hits it inflicts on a 'Mech pilot... and the crit check.

To my knowledge, yes.  It's treated like a Gauss rifle explosion and is handled the same way.  (Note the same ammunition explosion language is used in the Gauss rifle rules.)

HVAC 2s do offer 2 points of damage rather than the 1 point dealt by LB-2Xs on ASFs, but I wouldn't say that exactly makes up for all their downsides.

Nope.  ELRMs or LGRs are definitely better choices in that role.  Especially the LGR.  8 points is still enough to threshold the wings on a lot of fighters, even relatively large ones.

[YingJanshi]

Ok, what about the HVAC/20? Thoughts?

Since it doesn't exist, any discussion of fan interpretations of such a weapon needs to take place in Fan Designs, not here.

Oops, sorry, didn't realize it didn't exist (haven't looked over TacOps in awhile...).

[Orin J.]

it's too bad, the HVAC is rather obviously a prototype weapon of some potential they stopped developing because of the new tech influx of 3050 and is forever stuck in its awkward phase of being a "viable" weapon that has far too many problems to be useful. maybe someday they're get refined enough to be worthwhile, but they're too unstable.....

[Moonsword]

it's too bad, the HVAC is rather obviously a prototype weapon of some potential they stopped developing because of the new tech influx of 3050 and is forever stuck in its awkward phase of being a "viable" weapon that has far too many problems to be useful.

The HVAC research program didn't even start until 3055, something I already pointed out, and the prototypes weren't available until 3059.  Star League technology was already being deployed aggressively when the program started, with more of it reaching the field every day.  This isn't something the Capellans shelved because of the Helm Core.

It was shelved because as people have explained several times, the technology is dangerous and doesn't work very well compared to more common and less risky alternatives.  Even if you eliminate the tendency to explode, the performance of the HVAC/10 is miserable compared to the Gauss rifle and the LB 10-X, both of them weapons that have an established supply chain and maintenance capacity.  It's managing to take the worst features of ballistics (explosive ammo, weight) and the worst features of energy weapons (heat), then pile them together into a 14 ton pile of "Should Have Used A Gauss Rifle".

Not every research program winds up being a viable combat weapon.  The tragedy here isn't that HVACs aren't very good weapons.  Tough luck, better luck next time, and the AC/5 sent you a "Bad Autocannon Club" membership card.  It's the fact that someone at Lockheed was short-sighted or delusional enough to leave them on the RPR-300S instead of investing the time and money to properly rearm the plane with the Gauss rifles that would make it another entry in the Lyrans' panoply of terrifyingly deadly heavy fighters.  (That last part probably has something to do with why the decision wasn't made at CGL, mind you.)

[UnLimiTeD]

Heh, I'd have loved to have a review of that fighter model, what with it's armament being so 'quirky', but then stopping there.^^

[Thatguybil]

The crazy thing is that an LBX-10 costs more than a gauss rifle...?

[Gryphon]

It's like they looked at everything that in real life makes a caseless weapon non-viable, and then decided it needed to explode as well!

Amusingly, that Po with the HVAC 10, no CASE and Hardened Armor Basically means that in any real setting the tank may or may not survive the ten point hit but the super tough armor guarantees that the resulting explosion turns the inside of the tank into a chunky salsa room ala Shadow Run!

These really needed better range and the smoke effect with heavier weights and heat. Caseless rounds shouldn't take up more room than a standard round, any weapon that explodes at random is not fit for military use, and marginally better long range brackets is an insult to idea in general. Clearly this was never intended to be a viable weapon system, and having variants of standard combat units in even limited production shows that sometimes bribes will get anything through oversight!

[chanman]

The HVAC research program didn't even start until 3055, something I already pointed out, and the prototypes weren't available until 3059.  Star League technology was already being deployed aggressively when the program started, with more of it reaching the field every day.  This isn't something the Capellans shelved because of the Helm Core.

It was shelved because as people have explained several times, the technology is dangerous and doesn't work very well compared to more common and less risky alternatives.  Even if you eliminate the tendency to explode, the performance of the HVAC/10 is miserable compared to the Gauss rifle and the LB 10-X, both of them weapons that have an established supply chain and maintenance capacity.  It's managing to take the worst features of ballistics (explosive ammo, weight) and the worst features of energy weapons (heat), then pile them together into a 14 ton pile of "Should Have Used A Gauss Rifle".

Not every research program winds up being a viable combat weapon.  The tragedy here isn't that HVACs aren't very good weapons.  Tough luck, better luck next time, and the AC/5 sent you a "Bad Autocannon Club" membership card.  It's the fact that someone at Lockheed was short-sighted or delusional enough to leave them on the RPR-300S instead of investing the time and money to properly rearm the plane with the Gauss rifles that would make it another entry in the Lyrans' panoply of terrifyingly deadly heavy fighters.  (That last part probably has something to do with why the decision wasn't made at CGL, mind you.)

The Lyrans are oddly reluctant to use Gauss rifles on fighters. Production's probably sucked up by mechs and tanks. Off the top of my head, just the Eisensturm R3 and Prime and one of the Lightning variants are Gauss-armed. The Lyrans seem to actually have more HGR configurations/fighters.

[MoneyLovinOgre4Hire]

There's also the Royal Thunderbird, though strangely the MUL lists it as a FedSuns ASF.

[SCC]

These really needed better range and the smoke effect with heavier weights and heat. Caseless rounds shouldn't take up more room than a standard round, any weapon that explodes at random is not fit for military use, and marginally better long range brackets is an insult to idea in general. Clearly this was never intended to be a viable weapon system, and having variants of standard combat units in even limited production shows that sometimes bribes will get anything through oversight!

Except people did in real life, Cannons had a chance to explode, which goes up if you use a double charge, but there were ways to test for it (Proof with a quadruple charge). However in that case there wasn't another weapon that could be used in it's stead, that doesn't apply here

[Orin J.]

wait, four years? it was only four years from starting the program to "field-ready" prototypes? i thought they'd been worked on longer.....explains their current "pack in too much power so the slug will go further" design.  #P

[Nightsong]

The crazy thing is that an LBX-10 costs more than a gauss rifle...?

Bet it's the more complicated feed system. There's only one type of gauss slug, while the LB-x has to deal with standard and proximity fused rounds in separate bins.

[Moonsword]

That would be my bet if I were going to place one, yeah.

[SCC]

Not so much the feed system I'd say as the design of the barrel, I always got the impression that LB-X barrel's were different to normal AC's

[Moonsword]

I suspect that has much more to do with the materials it's made of (which probably have something to do with why the LAC/5 is costlier than the AC/5) than the fact it's a smooth-bore.  (Smooth-bores may actually be cheaper to manufacture from a little poking around but I'm not a firearms afficianado.)

[chanman]

I suspect that has much more to do with the materials it's made of (which probably have something to do with why the LAC/5 is costlier than the AC/5) than the fact it's a smooth-bore.  (Smooth-bores may actually be cheaper to manufacture from a little poking around but I'm not a firearms afficianado.)

They are. There are a variety of ways rifling can be added, but they all involve a lot of precise removal of material (by mechanical cutting or electro-chemical process) or some hardcore deformation of some very high-strength steel (button or cold-hammer forged rifling)

My take on on the LB-x is the added cost probably comes from the integral fire-control system. Cluster rounds aren't like shotgun rounds. They are a single cohesive round fused to release explosive submunitions near the target like some kind of mutant cross of a proximity-fused flak round and a cluster bomb (As the ammunition name kinda gives away). The simplest way to achieve this would be for the autocannon to use the mech's targeting data to set the appropriate burst distance for the fuses, but that's a bunch of electronics not required on standard ACs, and in CBT, electronics have a tendency to be heavy and expensive.

Programmable autocannon rounds, by the way, have existed for a while: http://www.youtube.com/watch?v=t7WqCbIpbjk
http://www.youtube.com/watch?v=rbWQjF2BJ0E

[A. Lurker]

So the rules for the HVAC say to inflict internal explosion damage equal to that of a single round, and destroy all of the HVAC's criticals. They also say to treat it as an ammo explosion.

So does that mean that on vehicles, all of the ammo cooks off, since that's what happens in ammo explosions for vehicles?

So on the Po, you roll a 2, inflict 10 points of damage to your structure (destroying the turret) and then have the remaining HVAC and Streak ammo explode, doing yet more damage to the turret?

Bit late to the party, but I remember asking more or less that question a good while ago and eventually finally getting an answer that seems to amount to "no, the ammo doesn't also brew up". Here you go.

Essentially, the idea seems to be that normally all ammo in a vehicle explodes at once on a critical hit because it's all stashed in the notional "Body" location, but since an exploding weapon will generally be located somewhere else (namely turret, front, side, or rear) that rule doesn't apply. CASE will still redirect all ammo-explosion-type damage to the rear armor, and it's probably best not to think too hard about the "Ammunition" critical hit slot on every turret. ;)