4WheelSword
The original N-body Problem
- Pronouns
- It/She/They
That is correct. I like them though, hence keeping them.
Traveller, The Rise of Empire: A Naval Design, Procurement and Command Quest
- Thread starter 4WheelSword
- Start date
- Original Art Quest Sci-Fi
Coyote Niff
the most transbian obligate scavenger on the 'net!
- Location
- Misery!
- Pronouns
- She/Her
@Pyrelight thanks for the drop tank info-that's making me more sure that it's the right choice for the Lancer to have that J4 ability. In IRL, drop tanks on aircraft are for the flight out, and internals for the trip home, so it makes sense that a Lancer escorting DSSs or Scouts would jump two out, then purge the tanks and jump two back.
Because, with enough fuel for 4 jumps, there's just 60% tonnage left for other stuff, in contrast to fuel enough for 2 jumps leaving 80%. It's less efficient. Plus, with multiple small scouts and cruisers, we want our pilots to crew a bit bigger ships.
Rat King
Izutsumi-pilled
Fuel for two of the jumps comes from drop tanks on the Lancer IIRC, so your tonnage estimate is off. It's 80% (2,400 tons) for armor, weapons, engines, etc., plus two drop tanks (which is the advantage of said drop tanks; you get more range while maintaining "actual" payload at the cost of logistic trickiness). With maybe a bit of tonnage loss to fuel feeding systems and clamps, but not much.
Even if your calcs weren't off, they'd still have double the tonnage of weapons, armor, engines than the "Interstellar Cruiser" (800 tons vs 1800). But as it is, they're at 3x (which I expect, considering they're three times the size).
If we wanna go back to size, I'll point back to the construction limitations we're looking at and how we should consider economics of scale and how we will want to maintain slack / parallel construction capability. I think 4k is really the biggest we should be looking at for designs we intend to build a lot of, until we can expand our tonnage capacity.
Last edited:
Coyote Niff
the most transbian obligate scavenger on the 'net!
- Location
- Misery!
- Pronouns
- She/Her
@4WheelSword I know we don't have the yard space for it right now, but we still in-universe have the fully-drawn-up Lancer "in our back pocket" for building, correct?
I was talking about ships without drop tanks. I maintain that we ought to not put them on ships that we expect to be able to operate on longer missions further away from our bases. If we wanted to conduct an extended operation without returning Home, such as war against distant power, we'd be limited to just 2 jumps within enemy territory because we wouldn't have the infrastructure needed to reattach the tanks.
Eh, I can go with 4K with internal fuel storage for 4 jumps. Or... internal fuel storages for 4 jumps and extra drop tanks? 6 jumps total. That has much better potential for longer-term use.
Wiadi
Uncompromising Radical Leftist
- Location
- Something Clever
- Pronouns
- She/Her
Hm. @4WheelSword what level of infrastructure actually is required to attach fresh drop tanks? Would that be something our current logistics ship could manage, something that would require a new design but could be achieved, or something that's entirely impractical outside a dedicated shipyard?
Rat King
Izutsumi-pilled
I think that's just straight out true of everything we build though. Unless we dedicate a lot of internal space to fuel all of our ships are going to be limited. We'll need extensive support for any long range missions into enemy territory anyway - the drop tanks are supposed to allow for extended range so it seems a little weird to object to them because they don't allow the right kind of operational independence? They do allow for a longer range than the cruisers currently.
Trying to cram four jumps worth of fuel into a hull is gonna require tradeoffs in armor and guns. A 4k hull with four jumps internal is basically carrying the same tonnage as the 3k with drop tanks in terms of weaponry. And a 6k with four jumps internal is only 50% more effective in terms of weapons and armor for a 100% increase in tonnage.
Yes, but that's hardly an achievement given that ICs were our first warship design.
Sure, but remember that you guys want them to be multi-roles. Jack of all trades, master of none. We don't expect them to stand up to dedicated warships.
Rat King
Izutsumi-pilled
Yes, but that's hardly an achievement given that ICs were our first warship design.
Sure, but remember that you guys want them to be multi-roles. Jack of all trades, master of none. We don't expect them to stand up to dedicated warships.
Yeah we do, they're still warships. I don't know where you got the idea the multirole *wasn't* a warship design.
Strictly speaking 2 jumps is fine. This is what tankers are for. Everyone we might currently want to shoot is one jump away.
Options will really open up once we have two logistics ships and can Black Buck it, having one stick with the fleet heading out and the other one head back to get fuel for the return trip.
Whether an interstellar enemy can track your jumps and follow you back or hit your tankers is another matter.
The tanks are used one at a time and dropped when you jump, and each tank has to have the extra fuel to carry the tanks for future jumps.
The math I've come up with is:
A 1000t J2 ship has 800t of usable displacement and 200t of fuel.
Each jump is 100t since displacement doesn't change, it's a unitary hull.
One droptank is 1000t + 100t tank, 100t/jump, 300t total.
That presumes the tank is discarded on jump. If it's kept instead, the ship has to use 110t of fuel to squeeze the jump field wider. Which means it still only has two jumps of range since it will then come up 30t short for the third.
The second droptank is 1100 + 110, 410t fuel. If it's kept on jump, the ship now needs 121 fuel/jump and has three jumps of effective range.
So it's J4, if it ditches tanks as it goes. Otherwise J3.
Or it can travel together with a fleet tender and top up before doing a 2 out, 2 back lunge. With one tank being left behind in thst first hex as it goes, to be refilled and refitted. Admittedly a wrong-size tank.
But a true J4 with equivalent non-fuel displacement would be 1333t. Idk how the actual payload goes. I think that ship would also have 3 more weapons.
and so on. I think for the third tank it still has 3 jumps but might be able to round to 4 if it pours in some reactor fuel.
So all in all it depends on whether you're willing to have less maximum range after the mission or expect to have a fuel ship. And having done that range-4 lunge, it can't do another one until it gets a replacement for the missing fuel tank or the fuel tanker moves to catch up on the way back. So it's good for quick response, but has issues with turnaround. (I think they have to return to a proper spaceport to get tanks refitted? That might have been houseruled too)
So you're carrying the fuel tanks on the outside, but if you don't dump them like a staging rocket they change how much fuel you need per jump and you need another source to make up the difference, if that makes sense?
Also also I think the "real" mass of droptanks includes "dry" mass which I have no clue about. So don't use these calcs for a long range far trader expedition across a rift.
It's entirely possible this is incoherent nonsense, my sleep schedule is especially shit lately.
Had math a bit wrong before, was dividing by .9. About the same for practical purposes.
Some other potential uses:
- attach drop tanks to a cargo ship to boost range, use bladders in some internal cargo space to make the numbers work
- jump 0 space station using external tanks and fuel tenders to be jumped out to another system
Edit: so in the context of a Lancer escorting DSSes, it can keep up with them, but once the mission is done it has to go home. It can't just top up at an outpost and head out for another run, the way they can.
But if you only bring the Lancer along when you suspect trouble it's fine. Or if you don't use the whole four hexes of maximum range and have a tanker meet you on the return.
Options will really open up once we have two logistics ships and can Black Buck it, having one stick with the fleet heading out and the other one head back to get fuel for the return trip.
Whether an interstellar enemy can track your jumps and follow you back or hit your tankers is another matter.
Just to clarify because it's a bit weird:
The tanks are used one at a time and dropped when you jump, and each tank has to have the extra fuel to carry the tanks for future jumps.
The math I've come up with is:
A 1000t J2 ship has 800t of usable displacement and 200t of fuel.
Each jump is 100t since displacement doesn't change, it's a unitary hull.
One droptank is 1000t + 100t tank, 100t/jump, 300t total.
That presumes the tank is discarded on jump. If it's kept instead, the ship has to use 110t of fuel to squeeze the jump field wider. Which means it still only has two jumps of range since it will then come up 30t short for the third.
The second droptank is 1100 + 110, 410t fuel. If it's kept on jump, the ship now needs 121 fuel/jump and has three jumps of effective range.
So it's J4, if it ditches tanks as it goes. Otherwise J3.
Or it can travel together with a fleet tender and top up before doing a 2 out, 2 back lunge. With one tank being left behind in thst first hex as it goes, to be refilled and refitted. Admittedly a wrong-size tank.
But a true J4 with equivalent non-fuel displacement would be 1333t. Idk how the actual payload goes. I think that ship would also have 3 more weapons.
and so on. I think for the third tank it still has 3 jumps but might be able to round to 4 if it pours in some reactor fuel.
So all in all it depends on whether you're willing to have less maximum range after the mission or expect to have a fuel ship. And having done that range-4 lunge, it can't do another one until it gets a replacement for the missing fuel tank or the fuel tanker moves to catch up on the way back. So it's good for quick response, but has issues with turnaround. (I think they have to return to a proper spaceport to get tanks refitted? That might have been houseruled too)
So you're carrying the fuel tanks on the outside, but if you don't dump them like a staging rocket they change how much fuel you need per jump and you need another source to make up the difference, if that makes sense?
Also also I think the "real" mass of droptanks includes "dry" mass which I have no clue about. So don't use these calcs for a long range far trader expedition across a rift.
It's entirely possible this is incoherent nonsense, my sleep schedule is especially shit lately.
Had math a bit wrong before, was dividing by .9. About the same for practical purposes.
Some other potential uses:
- attach drop tanks to a cargo ship to boost range, use bladders in some internal cargo space to make the numbers work
- jump 0 space station using external tanks and fuel tenders to be jumped out to another system
Edit: so in the context of a Lancer escorting DSSes, it can keep up with them, but once the mission is done it has to go home. It can't just top up at an outpost and head out for another run, the way they can.
But if you only bring the Lancer along when you suspect trouble it's fine. Or if you don't use the whole four hexes of maximum range and have a tanker meet you on the return.
Last edited:
grimely
Twink Death Sufferer
The easiest, simplest, most scaleable, most reusuable, and all around best way to use drop tanks as formal doctrine is that they give you +1 jump when leaving from a system with refueling infrastructure. That's it. You leave them at the gas station and don't think about them any harder.
4WheelSword
The original N-body Problem
- Pronouns
- It/She/They
Yeah, absolutely. Designs are only really going to become outdated when tech actually goes beyond them.
I *think* you want a friendly dock that is connected to your supply network. So you could do it in Deep Hope or S'Taxu, for instance.
Understood. In that case, grimely said it best:
Aside from dedicated long-range explorers, we can fit our future design with one drop tank to serve as spring-board. That way we're never losing drop-tanks in hexes where its hard to recover them and so we don't need to replace them. Let's redesign the Lancer with either 3+1 or 4+1 jumps at 4K tonnes and I'm OK with building one of them alongside an additional flotilla supply ship the next time there's we've got yard space to spare.
4WheelSword
The original N-body Problem
- Pronouns
- It/She/They
My current read of the fleets (prospective) use of drop tanks is:
DSS - 2 jumps internal - 100 tons of drop-tanked fuel (50/50) and 5 tons of cargo fuel, giving two external jumps.
MMV - 2 jumps internal - 630 tons of drop-tanked fuel (300/330), giving two external jumps.
Now, none of these have been used yet. The DSS has only flown 2-jump trips, and so hasn't bothered with the drop tanks. The MMV (Lancer) of course, doesn't exist.
ETA: The DSS tanks cost 100,000Cr. (NOT MCr.) per tank, the MMV tanks would cost 600-650kCr. per tank.
DSS - 2 jumps internal - 100 tons of drop-tanked fuel (50/50) and 5 tons of cargo fuel, giving two external jumps.
MMV - 2 jumps internal - 630 tons of drop-tanked fuel (300/330), giving two external jumps.
Now, none of these have been used yet. The DSS has only flown 2-jump trips, and so hasn't bothered with the drop tanks. The MMV (Lancer) of course, doesn't exist.
ETA: The DSS tanks cost 100,000Cr. (NOT MCr.) per tank, the MMV tanks would cost 600-650kCr. per tank.
Last edited:
Coyote Niff
the most transbian obligate scavenger on the 'net!
- Location
- Misery!
- Pronouns
- She/Her
I'd rather keep the design as it is for the Lancer MMV-it's a fine craft and drop tanks are designed to be "lost." Heck, we could even attach simple beacons for SAR and tracking a fleet's progress.
Nah, these tanks cost over half a MCr for the Lancer. It's going to add up over long use. Let's make it so we can always recover them. In addition, remember that the current Lancer has just M-3 engines. It needs at least M-4 to keep up with our other ships and not trail behind them. To add to that, it has armaments that are split between torpedoes and particle beams and so its enemies can engage both kinds of countermeasures against it rather than just sand-casters. If we want diverse weapons, then I'd rather see particle beams to cover long range and, say, mass drivers to cover short range. The Lancer can stand to be improved and at this point I'm OK with doing it at 4K with a single drop tank if just so we can have other topics to argue about in the thread.
Only using droptanks in home systems makes them seem moderately pointless, since that first jump is also the easiest to "fake" using a fuel tanker (even a borrowed civilian cargo ship)
I do not think the Lancer would survive trying to use a mass driver. For that matter I'm not sure it would be able to get into range.
Edit: in any case less droptanks suggests a bigger market for tankers. Both big ones and something smaller that can boost surveyors. Though whether that's more economical than bigger surveyors idk.
Also pilot need seems to be linear with tonnage?
I do not think the Lancer would survive trying to use a mass driver. For that matter I'm not sure it would be able to get into range.
Edit: in any case less droptanks suggests a bigger market for tankers. Both big ones and something smaller that can boost surveyors. Though whether that's more economical than bigger surveyors idk.
Also pilot need seems to be linear with tonnage?
Last edited:
You mean the idea where we dock the tanker to another ship, jump them both and have the tanker return to base? It works fine if we're moving just one ship at once, but drop tanks would be better at scale.
Meaning? I'm not opposed to packing it with just particle beams.
You're right about it having problems of maintaining proper range, it does need to have M-4 drives at least. Perhaps more.
Dunno about docking. Thinking more jump out in company with a freighter full of fuel, have it top you up, fly on and meet it again with more fuel on the way back.
Mass drivers are short range weapons and iirc the Lancer is very thinly armoured, so it would have to get in close and presumably long range weapons are more accurate the closer you get.
Ah, so basically what we're doing now? Yes, we'll continue to do that.
Oh, that's true, I forgot about Lancer's armor. It has 4 in comparison to the humble Interstellar Cruiser's 8. I'd be fine if we expected non-combat roles for it, but since it's expected to serve as a warship it needs to be improved before it gets into production.
Last edited:
Alas, can't be done. Conveyer has no UNREP equipment, it can't refuel other ships in space.
Rat King
Izutsumi-pilled
Guys, half a mill for a droptank is a rounding error in our budget. We've got something like 9 billion credits to spend annually. 1% of our annual budget is $90,000,000. A tenth of a percent pays for roughly 18 drop tanks.
It's not worth worrying about that sort of line item expense.
It's not worth worrying about that sort of line item expense.
Coyote Niff
the most transbian obligate scavenger on the 'net!
- Location
- Misery!
- Pronouns
- She/Her
What @Rat King said. If a B-58 could run on drop tanks, so can the Lancer. Also? I'm not giving up on the torps. We need kinetic stand-off yesterday; particle beams are fine for deep-space, long range work but we need a BVR kill that they, by dint of being a beam of linear c speed energy, simply don't offer.