I'm really afraid...

My entire party has the skills and influence...

They want to build a Chimera.

There are two issues I would like to address in this subject.

1. Building time and cost: My group will need to requisition all the parts and an imprint of the STC. How many requisition tests should this take? How available are the parts? Should they just requisition once for a kit (like a kit car)? As well as the actual building. It will require a special workshop, no? How long will the building take? Days, Weeks, Months? Will there be any modifiers to the tests?

2.How should I begin to modify my campaigns to avoid this thing just rolling over everything save for a greater daemon? Environmental, saboteurs, other tanks?

What ... why ... how would ...?

I mean, obviously it would not be impossible - a number of crazy hobbyists around the world have spent tons of cash and many months into building functional military vehicles - but if you are in the position of requisitioning the relevant parts, especially stuff like a turreted multilaser, why would they not just requisition a ready-made vehicle off the assembly line of some plant?

And perhaps more importantly, why are these people wasting the time the Emperor has granted them with such a hobby project instead of hunting heretics?

How should I begin to modify my campaigns to avoid this thing just rolling over everything save for a greater daemon? Environmental, saboteurs, other tanks?

Do your players even have a plan of how they'd want to get this thing off whatever rock they want to "build" it on? It's not exactly going to fit into the baggage compartment of the local transit shuttle.

Also, there's nothing wrong with a militant approach to Dark Heresy, but at the same time I have a feeling that they won't get a lot of investigation done if they cower in METAL BAWKSES all the time. Not that this thing would be particularly difficult to immobilise if you know how, anyways. I have a feeling both you as well as your players are overestimating the usefulness of an APC.

I feel the very first question to consider would be "Are you comfortable with letting your players roam around in a Chimera?" Hesitating to answer means that the answer is probably "no" and that it would be wise to tell your players the same.

[Lynata] brings up some great and important points.

Like my previous speakers wrote, it is important, if you want to include tanks and the like in your game.

On the other side I guess your players are very excited about the idea of having their own chimera. If the group majority wants to play DH as a frontal assault kind of acolyte group, I don't know, if I would try to stop them. Best would be to have a talk about it.

In it's core DH is designed to be an investigative game with small, but nasty fights...or at least that is my opinion. But you can also play it more Eisenhorn style, with your own flying cannon boat and imperial army support...

To your questions about building a chimera by yourself. Most things would depend on the world they want to build it on, unless you say they are on board of an navy space ship which has it's own forges for such small vessels like standard tanks and the like I think you cannot just build your own tank, without at least a very good stacked workshop and an inquisitor who is quite casual about working hours. But let's say they want to build it all by themselves. To build a tank and you have all the parts and a super shop, I would say is a job of a month full time work, if you "just" need to assembly the spare parts. Then again you can strech the period to as long as you want. Simply use the infamous imperial bureaucracy...^^

Then again maybe you can form a small campaign for building this thing. You could plant the seed in their head, that they want to have a special chimera, which needs special parts, like a sanctioned hull plating or a holy heavy flamer instead of a multilaser. These need to be obtained before the forge will assembly the chimera. Addionally they might want or need the blessing of the Magos in charge?

I'm really afraid...

My entire party has the skills and influence...

They want to build a Chimera.

There are two issues I would like to address in this subject.

1. Building time and cost: My group will need to requisition all the parts and an imprint of the STC. How many requisition tests should this take? How available are the parts? Should they just requisition once for a kit (like a kit car)? As well as the actual building. It will require a special workshop, no? How long will the building take? Days, Weeks, Months? Will there be any modifiers to the tests?

2.How should I begin to modify my campaigns to avoid this thing just rolling over everything save for a greater daemon? Environmental, saboteurs, other tanks?

1. I guess they should requisition for a whole Chimera, then rebuild it. It isn't a rare or hard-to-access vehicle at all, you can probably find at least a few dozen of them on every planet (maybe even on feudal and feral planets). Getting one is almost like buying a truck in our world. Also, it isn't a very complicated piece of machinery either by design . Anyone with Rank 3-4 in Tech-Use/related Lore/related Trade should be able to rebuild a Chimera no problem within a few days.

2. Narrow spaces and obstacles. Unless the players are building an anti-grav Chimera .

Requisitioning an STC...if they don't have a tech priest I'd say they need to garner the Mechanicus's favor rather than make a requisition test.

If they do then that tech priest really needs to prove himself. Event then heavily negative influence roll.

There's this game called Only War where the party can actually start with a Chimera that it sounds like your group would rather be playing. Which is fine because you're actually already playing it.

Which is fine because you're actually already playing it.

Let's not start this here too.

Id recommend taking a look at the vehicular repair rules for only war.

Just gonna say...

Acolyte 1: "Alright we're gonna cruise down the street and wipe out these Heretics in our new Chimera."

Acolyte 2: "You don't think this is a little obvious?"

Acolyte 1: "Who cares, what are they gonna do about i-- oh Holy Emperor on Terra, they saw us coming and brought out their Las Cannons. If only we had a mode of transport they couldn't hear coming three hours away."

Scenario 2:

Acolyte 1: "Curses! Small alleyways! Our one weakness!"

------

In short? I'd let them be able to have it since you can easily control when and where it's practical. Obviously, it's nice to let the Acolytes have a ball in their new tank once in awhile but you can very quickly make them regret bringing it, or just make them have to ditch it.

Also. Supplying it with ammunition and fuel might be a minor thing. I know that Gelt's not a thing anymore, but hell, passing Influence tests everytime the Chimera's fuel tank starts to run low or the Acolytes are running out of ammo for its guns might start becoming a pain in the ass.

In short? I'd let them be able to have it since you can easily control when and where it's practical. Obviously, it's nice to let the Acolytes have a ball in their new tank once in awhile but you can very quickly make them regret bringing it, or just make them have to ditch it.

... although I'd generally advise against inserting obvious obstacles just for the tank. In my opinion, a setting should feel like a living, breathing world, not a scripted track hand-tailored to the party's ideas and tactics. In cases where an APC would be an advantage, they should be able to make full use of it. In cases where problems could be expected, on the other hand, they should regularly run into them. With any luck, you can thus train your players when to make use of that vehicle, and when they ought to leave it in the garage.

Just no "rocks fall" GMing, please.

Also. Supplying it with ammunition and fuel might be a minor thing. I know that Gelt's not a thing anymore, but hell, passing Influence tests everytime the Chimera's fuel tank starts to run low or the Acolytes are running out of ammo for its guns might start becoming a pain in the ass.

It is a very minor thing. The multi-laser feeds from the vehicle's power plant, so it won't run out of ammo, the heavy bolter/heavy flamer is nothing special, and the vehicle can run on any kind of fuel (even on wood, if needed).

It is a very minor thing. The multi-laser feeds from the vehicle's power plant, so it won't run out of ammo, the heavy bolter/heavy flamer is nothing special, and the vehicle can run on any kind of fuel (even on wood, if needed).

Depends on how far the GM is willing to push this...

• The "any kind of fuel" is just fluff (from an old codex iirc?), and as we all know, it could simply be discarded and replaced. The official writers do it all the time; no reason to hold yourself to different standards.

• Even if you take the "any kind of fuel" as a fact for your campaign, it is up to you to set the ratio of energy conversion. Simple combustion is not very effective, so your players may need to gather lots of fuel to power the vehicle.

• Even if your players spend half an hour looking for enough dry wood or coal to cram into the vehicle's tank, it may well only be enough to drive a few kilometers, without lights or power to the weapons. Alternatively, they may opt to charge the multilaser for two shots.

My apologies, I forgot to explain how this group works...

Step 1: Kill every NPC and GMPC in sight.

Step 2: Investigate corpses and surroundings.

Repeat steps 1-2 until the entire campaign is complete.

For some miraculous reason they are always able to find the end-game by accident

In that case you should outfit their chimera with loudspeakers facing every direction that blare the A-Team theme song.

That sounds quite appropriate for their Modus Operandi.

Perhaps I should have them air-dropped inside the tank...

I just knew some 40k player would have done something in this direction ...

My apologies, I forgot to explain how this group works...

Step 1: Kill every NPC and GMPC in sight.

Step 2: Investigate corpses and surroundings.

Repeat steps 1-2 until the entire campaign is complete.

For some miraculous reason they are always able to find the end-game by accident

They are clearly Adeptus Munchkinum

That sounds quite appropriate for their Modus Operandi.

Perhaps I should have them air-dropped inside the tank...

Airdrop them inside a Baneblade!!!

I just knew some 40k player would have done something in this direction ...

/)^ ε ^(\ So AWESOME!

They are clearly Adeptus Munchkinum

Half the party.

The Chimera sounds like an excuse to have a look at the Subtlety mechanics:

Cultist 1: "Some heavily armed people are driving around town in a Chimera, do you think our nefarious plots have been compromised?"
Cultist 2: "Better not to take any chances, let's kill the hostages, dispose of the witnesses, incinerate the papers and relocate immediately."
Cultist 1: "Why not just detonate the warhead? That should handle most of the loose ends."
Cultist 2: "Great idea! How many of our brethren can we get out on an one-hour fuse?"

I seriously reworked my planning style when my group solved an investigation by literally shooting every NPC I put before them in the knee. The one that survived (being shot, run over, fragged and beaten up by two arbitrators and an assassin) was recruited to the Inquisition for his tenacity. He is now the longest surviving Acolyte of my campaign.
Vary your adventures; everyone loves an opportunity to go full-on Rosette-and-Bolter, especially when backed up by imperial armor such as a Chimera, but it will make more sense when not every scenario can be solved with excessive force. Give your players amble opportunities to use any non-combat related skill, connection or background element to further their investigation, give them other tools than the hammer and your world will slowly turn into something else than a game of Whack-a-Heretic ^TM

Also, if it makes sense that too much noise would compromise an investigation and make the bad guys spook and disappear, let them. Even when the group leaves no witnesses, one can be certain that somewhere, someone will start talking about how an entire house full of people were killed by unknown assailants and that Foul Ol' Ron in the back alley behind the chapel swore that he saw a chimera speeding away from the scene, and that this information at some point will arrive at the ears of the naturally paranoid kind that is at the receiving end of inquisitorial investigations.
Your players do not have to win every time. This is player agency at its core. If their mistakes have consequences, their successes will feel more deserved and meaningful. This also means that you'll have to avoid tailor-made PC killers, such as lascannons suddenly appearing in the hands of every cult, gang conspiracy, and knitting club two hours after the Chimera is done.

I'm really surprised that things like Chimera's are available for acolytes on a permanent basis, and I would probably house rule that they're shared assets that can be requisitioned for a period of time, but no longer than a week or two, unless the warband was operating in a certain area that Interrogators or Inquisitors deem such a long term deployment prudent. Much like the CIA and FBI have APC's as well, but undercover and field agents don't ride them from interview to interview. They do, however have up-armored SUV's and even MRAP's that they ride around in places like Libya, Iraq and Afghanistan. Not to mention that in a millennium that is dominated byt the 'only war' theme, there probably isn't a whole lot of old or extra APC's laying around on the open market.

My experience with demilitarization of vehicles and vessels for divestment leads me to a few conclusions on how a warband might acquire a piece of equipment such as a Chimera. The first step is to remove all sensitive equipment. This includes all hardware and software that communicates with other military systems, vehicles or satellites such as radios, FBCB2, blueforce tracker and any other similar systems. Next any weapon systems are removed; permanently mounted weapons are removed and stored or destroyed, coaxial or pintle mounted weapon systems are removed. Smoke launchers or generators are removed as well. Next, any components that are still useful are removed to put back into the supply system for repairs to vehicles/vessels still in service. This includes winches, rare or obsolete pumps and other accessories. Finally, all military markings must be removed. Any markings that identify the hull as being associated with the army, navy or coast guard must be ground off and/or painted over so they cannot be read. Hull numbers and names are left on to preserve the legacy of the vessel, and so it can be tracked by safety and environmental protection regulators back to it's date of commissioning. Only after everything useful is taken off, including Basic Issue Items, weapons have been removed, and the vehicle/vessel can only be traced back to military service through research, and not casual observation*, will it be released for sale on the open market.

This means that it is theoretically possible to obtain a working vehicle like a Chimera. It also means, however that it would be extremely unlikely that one would be available that has any weapons or equipment on board, and it might not even have everything it needs to run properly. Replacement parts might be Just as rare or difficult to find as the hull itself. Really obvious things might not work, like the motor that makes the turret traverse might be missing, or the back ramp might be welded shut with the hydraulic mechanism that raises and lowers it might be gone. Maintaining an APC is a lot of work, and phenomenally expensive item. It should require a lot of attention from a tech priest character. Trade (technomat) would not be sufficient to maintain such a complex piece of equipment.

Another concern is that IRL, really common APC's are difficult to obtain, not because of their expense, but because of their usefulness. M113's are the most common APC in use, and are almost never up for sale because they are so versatile and so useful. Entities that posess them tend to hold on to them, and I imagine that as common and as useful as Chimera's are, they would probably be pretty difficult to find, but also there would be a lot of competing interested parties. Demand would almost always outpace supply.

All this being said, it would be pretty rad to have one for those particularly well defended nests of cultists, and if my players wanted one I'd probably try to find a way to make one available, even if only for a certain period of time.

*This pertains mostly to vessels. No one would mistake an APC for anything other than military origin.

If their inquisitor knowingly allows them to do this, have him send them on a mission where they can use the tank. Something like putting them on a world that's already lost to Xenos/chaos to recover something important.

If the inquisitor doesn't know, they get a mission to find out who is getting the parts for a tank and take them out. Have it turn out that another group of heretics has ceased rhino APCs and is pretending like they have tanks. They've got decommissioned weapons but that's it. Give the players an opportunity to pin everything on these guys and also have a battle with their tank against the group. After you do this, have the inquisitor send them on the above mission.

And in general, if you want your players to not just kill everyone, first give the NPCs some more character and personality so they become characters more than just targets. Make them more than just people who order players around or tell them no. Give the players some friendly NPCs who have goals beyond just killing everything. Basically, if you want to do different things with your players than just combats, give them the carrot rather than the stick. Keep in mind that the gameplay for non-combat is inherently pretty boring, so you're going to have to rely a lot more on story to get them involved.

Something like putting them on a world that's already lost to Xenos/chaos to recover something important.

Or just a planet whose environmental conditions make trips without protective equipment - or sealed vehicles - hazardous, either due to toxic atmosphere, radiation, or really bad weather.

Remember, the Space Marines' Rhino APC was originally a scouting vehicle for human colonists!