WesWorld

I have a question about the main armament. If the intended role of the tank is to break through enemy lines wouldn't it be better to go for gun with more HE-power? Maybe something along the soviet D-25T 122mm gun?
Would suck if you encounter enemy heavy tanks but to destroy earth fortifications, machine gun nests and other entrenchements it would be better.

Quoted

Originally posted by Daidalos
I have a question about the main armament. If the intended role of the tank is to break through enemy lines wouldn't it be better to go for gun with more HE-power? Maybe something along the soviet D-25T 122mm gun?
Would suck if you encounter enemy heavy tanks but to destroy earth fortifications, machine gun nests and other entrenchements it would be better.

I have thought about using something in the 120mm range. The historical precedent is there on several tanks at this time, KV-122 IS/IS-2 would be the main ones. Would make a good place for that naval gun to end up...

120mm armed tank. Armor is not as strong as the preceding types. Based on the KV-85, which historically has several hulls equipped with prototype turrets of the IS. These were refered to as the KV-122.

Dimensions
Length: 7.5m without gun.
Width: 3.5m
Height: 3m

Handling
Weight 46 metric tons
Road Speed: 40kph
Off-road speed: 18kph
Range: 250 km
Engine: 600hp Isotta-Fraschini diesel
Power/Weight ratio: 13.04hp/ton
Suspension: Torsion Beam, six road wheels

Armament
Main Gun: 120mm/45
Secondary Guns: Two 8mm MG, one hull mounted, one on top of the turret.

Armor(maximum thickness)
Hull Front: 90mm
Hull Sides: 60mm
Hull Rear: 60mm
Hull Top: 30mm
Hull Bottom: 20mm
Turret Front: 100mm
Mantlet: 100mm
Turret Sides: 90mm
Turret Rear: 90mm
Turret Top: 30mm

*dives into foxhole*

From those four proposals I think proposals B and D are the most reasonable designs and proposal D is best suited for the role you are intending. The armor is sufficient, the main gun would do fine against targets you would likely to encounter at the frontline and the power/weight ratio is acceptable for the period and this kind of vehicle.

Proposal A is just insane. Just think of the terrain you would have to employ this 57ton monstrum. Italy or Jugoslavia maybe, are both hilly and mountainous and have a lot of broken terrain. It wouldn't be any fun to drive a 57ton tank uphill along a serpentine road. Such a tank wouldn't only be unnescessarily expensive, it would suffer from frequent breakdowns too.

Any further comments? Im leaning in the direction of Proposal D at this point.

Proposal D, more fleshed out version.

Dimensions
Length: 7.5m without gun.
Width: 3.5m
Height: 3m

Handling
Weight 46 metric tons
Road Speed: 40kph
Off-road speed: 18kph
Range: 250 km
Engine: 600hp Isotta-Fraschini diesel
Power/Weight ratio: 13.04hp/ton
Suspension: Torsion Beam, six road wheels

Armament
Main Gun: 120mm/45
Secondary Guns: Two 8mm MG, one hull mounted, one on top of the turret.

Armor (degree inclinations are from vertical tilted into the body of the tank)

Front Upper Plate: 90mm @ 30
Front Lower Plate: 80mm @ 20
Side Upper Plate: 60mm @ 30
Side Lower Plate: 40mm @ 15
Rear Upper Plate: 60mm @ 30
Rear Lower Plate: 40mm @ 15
Top: 30mm @ 90
Bottom: 20mm @ 90
Turret Front: 100mm @ 20
Mantlet: 100mm @ Rounded
Turret Sides: 90mm @ 25
Turret Rear: 90mm @ 15
Turret Top: 30mm @ 90

After some more thought, I think this is going to end up as Proposal C. As stated earlier, Proposal C is the intended replacement for the Triarii in the later 1940's. So this tank will not be doing much aside from working its way around testing tracks and firing ranges for the next few years. While proposal D is nice, there is no real justification for a 120mm armed turreted tank at this time.

I kinda agree on dropping the 120mm armed tank. Little need, russian design parameters don't quite fit Italy anyhow - shallow turrets limited elevation choices. Plus, if you wanted an anti-tank type 120mm, you'd need a bigger turret ring than the IS w/122mm, meaning an even bigger tank- and while the bigger dimensions you provided may have served, they would really spiral that weight higher than expected.

Now, for the other discussion :

Semi-Quick Comment on Decapping plates.

The Italian navy specifically called out (so I've read) decapping plates for the Littorio class in real life.
However, with a major shell, the APC cap is something that can be knocked off, and if you have the right thickness of plate....and several feet behind it for the ballistic trajectories to separate, you will have the uncapped shell impact the main belt, and overall penetration will be substantially reduced in comparison to if the armor had been a unified plate.

It's debatable if Tank APRC projectiles work the same way, and with the HVAP rounds they probably don't.

This brings us to the second concept- something I've seen attributed to the Panzer III (as I recall) - which was the front armor was actually 2 separate plates. The first was a extremely hard and thin plate, with a small space before the second plate of more conventional armor. This was meant to shatter the AP nose and allow the fragments to seperate a bit before impacting the second plate. This works up until it doesn't. Vague memory supplies that as face hardening techniques and welding of armor plate became better, this became an unnecessary complication.

Armored Skirts you can see in varying types from WWI when they protected the treads, to WWII where the PzIVH has numerous pics of funny looking skirting meant to gain stand off range as the early RPGs were weak.


Disclosure : Long ago, when I was modifying the data of the Souma S-35 (which provided the picture) concept to be my T-35A, I had the concept of a cast hull with flanges built in. The thinner a casting, the faster & more evenly it cures, so the better the quality and rate of production. This flanges would be "deep" enough that a riviter (later a welder) could attach the main face hardened armor plates to them. The thin casting would then act both as frame and spall lining. A bit complicated, but peacetime the rate of production wouldn't be a huge problem. This became my T-35 write up. Tanksharp came along after, and so I put that into tanksharp and discovered my Dutch tanks are bazooka proof in large areas. So yes, the Dutch have spaced armor, but no, it's not deliberate, but rather a happy accident.