TL9 Heavy Tank

[mr beer]

Originally Posted by Fred Brackin

Oh! I just remembered something about the OP's design. If a strong incendiary weapon hit the fuel tank filled with aluminum slurry for the engine I would be worried about that turning into a thermobaric bomb.

Definitely not an expert but IIRC thermobaric weapons are finicky in their aerolisation requirements e.g. WW2 Germany tried and failed to develop effective thermobaric bombs. So my guess is this wouldn't create a thermobaric bomb.

Of course, the difference between "explosively igniting aluminium and fuel mix inside your tank" vs. "real thermobaric bomb" is probably a trivial distinction to the unfortunate crew of said tank.

[Polydamas]

One of the troubles with the Peruns and Nicholars Morans and Bernhard Kasts producing videos rather than essays is that its hard to track down things like "which Soviet tank has a vulnerability low on the side towards the back which lets autocannon fire reach the ammunition storage." But that is design error + vehicles being used long after their intended lifetime + vehicles being used in close quarters without supporting infantry so the other fellow can get a close-ranged shot at the side hull.

[weby]

Originally Posted by Nightrider_88

Main armament: It's a massive 15cm/60cal high pressure composite barrel gun made from a carbon fiber tube impregnated in a titanium matrix with its bore nitrided about a third its way through,

Does not sound like a likely armament. The early TL 9 will likely still use 120mm guns, then maybe, a bit larger like a 130mm or 140mm and then more likely some other technology.

The problems with a larger gun are many:
-Larger gun ammo is heavier and more bulky, if the proportions stay the same in the ammo, the 150mm ammo would be twice the mass and more importantly volume, so you could carry less ammo.
-Larger gun is longer to get the same length rating and a 120mm/L50 gun is already annoyingly long.
-autoloader: see below

Then the actual proposed technology:
Having carbon tubes as a contact surface to a projectile sounds unlikely as such construction is really not very abrasion resistant and thus would not last many shots.

firing a 20kg semi-segmented, sleeved, telescoping, uranium alloy penetrator at 2400m/s using a powerful propellant based on CL-20 and ADN (plus additives, mostly to reduce combustion speed).

A 20kg uranium penetrator that is more than four times the typical DU projectile today and about three times to heaviest DU penetrators. In the most extreme cases you are talking about 32 to 1 diameter to length ratio for penetrators instead of the more traditional say 27:1.

As you want as long as possible penetrator that does not shatter and with better alloys I guess thus that your gun would likely thus fire a say 40:1 penetrator to give it best possible penetration. Thus the penetrator would be about 1.3 meters long.


You want a 2400m/s muzzle velocity. Estimating that the sabot would need to be close to current 50% of projectile mass due to the huge bore you want to fire the 32mm diameter dart. Thus you are around 86 mj muzzle energy. That is about 6-7 times 120mm apfsdsdu ammo. Basically your gun would need to contain that in about double the volume of 120mm gun. That is some interesting pressures and would require quite sturdy design.

Making it telescoping would require a much sturdier sabot as the uranium rod is very fragile to sideways effects given how thin it is. So that sounds like an "interesting" development path to get it all working.. I would expect a lot of snapped penetrators in the process.

The resulting rod can go through over 2mRHAe with approximately twice the spalling of a modern one. It uses combustible casings and a super-lightweight sabot made from fancy carbon-carbon composite, which makes the gun very efficient overall and an easy job for the autoloader.

Just no. The penetrator is only 1.3 meters long and thus it will not penetrate that far until it is ablated away.

Your super lightweight sabot cannot survive the explosion that is the thing needed to reach that muzzle velocity, specially if you go for the telescoping case.

As for autoleader handling easily the at least 1.5 meter long and 15cm diameter object. Well, way less handily than the 12cm diameter 1 meter long 120mm ammo of today.

The gun can also fire missiles for indirect fire, including kinetic and chemical warheads, as well as other specialist shots as the gun can double as artillery if needed Its not wholly segmented, but the rod is internally shaped in a similar way, with a pattern of ductile and stiff alloy that reduces mushrooming.

You do not want your tanks to act as artillery if it can be avoided. A high pressure tank gun has low maximum number of short that can be fired.

Yes, tanks do and should act in direct fire role to support other forces, but using them for indirect fire is wasting the lifespan of the gun in tasks better done by other platforms.

It's all uranium except for a very thin sleeve of TWIP steel around the penetrator to protect it from shearing. A cool thing is that the projectile does not suffer too hard from overpen as the wide and mushrooming sleeve spalls a lot in the first third or so of the penetration.

Uuh? TWIP? no idea what you are talking about so cannot comment, but sounds..

Should carry 40 rounds, more is not impossible but neither likely, less would be used if needed. It can carry missiles split between two pieces too. All of the ammo spaces are isolated from the crew and each other, covered by panels, armored and fireproofed with a wet gel that may or may not be a horrible ozone depleter
There's two ammo spaces separated by a bulkhead with the loader in the middle, and also a buffer in the turret for rapid fire, tho it should only be filled when the firepower is needed, which us rarely as the tank is designed to one hit kill

Why a buffer? An unmanned turret is the likely solution and building an autoloader for such that pulls from the hull under the turret does not sound very difficult. Obviously such ammo bins would need to have the blow out panels and so on.

Secondary armament: Its main secondary weapon is a heavy armored autocannon on top of the autoloader part of the turret. It has good elevation and depression and a very high fire rate, with enough power to shred IVF and incapacitate tanks; however it has relatively little ammo. It can target independently from the main turret and traverses fast...

An autocannon does make some sense, but historically it has been seen better to put the autocannon in a separate vehicle(the IFV) as giving more roles to an MBT is normally not a good idea as they are heavy enough already and busy enough for the crew.

If used you would likely want a fairly high load of ammo to deal with drones, autonomous ground combat units and such.

Also regardless you want a machinegun, as you will also likely meet infantry unless the enemy is totally incompetent. If all infantry is in bodyarmor it would likely be something larger like a 12.7mm, but else a normal 7.62 or similar would do the job.

The idea is that it's able to swap barrels for a smaller one if the low ammo proves a weakness (e.g. urban combat), but so far I've had trouble designing such a loading mechanism...

Not likely.. weapons of war should be as simple as possible, thus you add the MG as separate weapon not a fancy and easy to break change thing.

It also has canisters for loitering munitions

Programmable ammunition is much more likely. That is the ammunition explodes at the distance set when fired. That could be used against drones, against troops behind cover and so on. But really drones should be engaged by other units not the MBT.

A laser for drone defense that could be used as a weapon too

A very possible development.

An automatically aimed 20mm cannon which, depending on the version of the tank is mounted in various places, on top of the cannon, coaxial to it, to the gun or on the back of the tank, and it's a bit of another layer of point defense plus ****ing infantry. The 50cal is pretty boring but the 2cm has two rounds: a high velocity incendiary sabot and a big fat timed fuze shrapnel, with AHEAD-like design, but the casing is a continuous rod and the beads are long and made of a flammable uranium alloy.

A 20mm is a bit small autocannon for explosive payload, in most casees you would much prefer the 30mm/40mm rounds from the accompanying IFV. So in case of a 20mm, no autocannon would likely be better for the tank.

Front hull armor: ERA followed by a complex composite armor mostly based on tiled NXRA, using PE/PE as rubber with a bit of explosive mixed in. The plates contain fancy **** like nanocrystalline titanium with various treatments, TWIP steel or superplastic CMC

Likely more vehicles would also use some development of the later Leopard 2 tank turrets with space to snap long rod penetrators that do not hit square on.

Side armor: two layer ERA, one shaped charge the other flier plate based, angled in a sight V, triggered early by magnetic detectors, followed by a tightly packed composite of fancy ceramics and stupidly ductile steels, in thick plates separated by rubber and glassed titanium foam spacers. The side armor is less weight efficient but incredibly space efficient, and it saves weight from ERA.

Hard kill active protection systems would be a likely in use instead of the proximity fuse ERA.

Powerplant: Also there's a variant using aluminum fuel, <snip>It also could run underwater (wirming out the how) and has no exhaust.<snip>

Aluminium is indeed a possible fuel, but the underwater use is questionable at best. Historically the idea has come up every now and then but the number of times it has been used is minuscule. Besides the battery part likely hydrid power train should be enough for any such.

The interesting question on the powertrain would be the balance of the powerplant and the batteries.

60 tons.

Not realistic. Already today we have some tanks over 70 tons and you want to add a bigger gun and an extra weapon system.

Unmanned turret.

Very likely.

RHA equivalent of the hull armor should be about meter.

Against what? Modern armors are not uniform against different attack types.

Nothing in your design indicates how it would get that against kinetic penetrarors.

[Rupert]

Originally Posted by Polydamas

Not being a tank gunner, I'm not sure if there were practical issues with having rounds with wildly different muzzle velocities (eg. setting up the sights or getting good accuracy from the longer barrel).

Nothing that having a different range scale in the sights (which they had to have anyway) wouldn't deal with. Nor should the barrel length, etc. matter if the round is designed for that gun.

[Polydamas]

Originally Posted by weby

An autocannon does make some sense, but historically it has been seen better to put the autocannon in a separate vehicle(the IFV) as giving more roles to an MBT is normally not a good idea as they are heavy enough already and busy enough for the crew.

Its plausible that in the mid 21st century, an autocannon or HMG remote weapons system on a tank would be useful for defense against drones. Lightly armoured vehicles may not be able to get close to the front and drones can try to avoid AA vehicles in the rear by flying low. That is a different task than the autocannon on an IFV which is meant to support the infantry and kill light ground vehicles.

NATO militaries have secret discussions about the relative merits of electronic warfare (details carefully not specified in public) and MGs or autocannons for drone defense, but it seems plausible enough for gaming purposes that EW has not defeated small drones as a threat as of the mid 21st century. Another thing we are seeing in contemporary wars is that combined-arms mechanized warfare is hard and many professional militaries struggle with keeping all the different systems working together. So there is some argument for putting the air defense (and maybe general point-defense system?) on the tank. Two autocannons and a HMG (coaxial with the main gun?) might be pushing it.

[Rupert]

Originally Posted by Polydamas

Its plausible that in the mid 21st century, an autocannon or HMG remote weapons system on a tank would be useful for defense against drones. Lightly armoured vehicles may not be able to get close to the front and drones can try to avoid AA vehicles in the rear by flying low. That is a different task than the autocannon on an IFV which is meant to support the infantry and kill light ground vehicles.

There doesn't seem to be any real need for more than a GPMG as the coaxial. Heavier guns have been used from time to time, but everyone seems to revert back to a basic GPMG.

The 'commander's' MG, on the other hand, is usually an HMG and historically was intended for AA use as much as anti-personnel use, at least originally. Replacing that with an automated anti-drone (and possibly active anti-missile) system using an HMG or cannon would be a simple evolution. It would presumably have over-rides so the commander could use it to shoot up annoying infantry and the like as well.

[mlangsdorf]

One of the possible lessons of the current Russo-Ukranian war is that a cheap drone can act as a scout for tank killing systems or sometimes be a tank killer itself, and therefore tanks (and other elements like IFVs and SPGs) need a cheap system for killing cheap drones. No nation can really afford to spend $150K+ on the SAMs that kill the $5K drone.

Because of that, and the threat of guided missiles, I expect that a TL9 tank is going to have some point defense weapons. Whether those are multiple rifle caliber machine guns with smart targeting systems, some low powered directed energy weapons, or something else, I'm not sure, but I'd expect to see at least two other weapon mounts for anti-drone and point defense.

The TL9 tank might be armed with something like a 130mm high velocity main gun that can fire anti-tank guided missiles, a 25mm autocannon on top of the turret for discouraging large drones and taking out unarmored vehicles, a co-axial light machine gun for shooting infantry, and a anti-drone/point defense laser on each corner of the hull.

[Anthony]

Originally Posted by mlangsdorf

One of the possible lessons of the current Russo-Ukranian war is that a cheap drone can act as a scout for tank killing systems or sometimes be a tank killer itself, and therefore tanks (and other elements like IFVs and SPGs) need a cheap system for killing cheap drones. No nation can really afford to spend $150K+ on the SAMs that kill the $5K drone.

The cheap drone can be a problem for lots of other things besides tanks, it's just that dropping grenades on tanks makes for more dramatic footage than other options. The cheap option appears to be shooting it with an assault rifle, but they've actually sent some Bofors L70s to Ukraine.

[Polydamas]

Originally Posted by mlangsdorf

The TL9 tank might be armed with something like a 130mm high velocity main gun that can fire anti-tank guided missiles, a 25mm autocannon on top of the turret for discouraging large drones and taking out unarmored vehicles, a co-axial light machine gun for shooting infantry, and a anti-drone/point defense laser on each corner of the hull.

Lasers have the advantage that they are cool and science-fictioney so people are likely to give them the benefit of the doubt. Whereas a main gun, two calibres of autocannon, and a MG on a tank raises plausibility concerns for me, because autocannons are old tech and we know what they are good for.

I guess a bit depends on whether you see TL 9 as "the TL 9 in GURPS Ultratech which was rooted in the 1980s and 1990s" or "2050ish technology as seen from 2023." The former has more room for laser weapons than the latter.

[Anthony]

Originally Posted by Polydamas

I guess a bit depends on whether you see TL 9 as "the TL 9 in GURPS Ultratech which was rooted in the 1980s and 1990s" or "2050ish technology as seen from 2023." The former has more room for laser weapons than the latter.

I'm not particularly expecting to see them in Ukraine, but anti-drone laser weapons are in fairly late testing phases.