WesWorld

I figured I would compile all of my thoughts on various Esercito Italiano projects for the latter half of the 1940's in one place. Im going to try and keep various ideas contained within there own posts, finalized stats/summaries will be edited in here.

Quoted

M45/XX Praetorian Tank

Dimensions
Length: 7m without gun
Width: 3.25m
Height: 3m

Handling
Weight 45 tons
Road Speed: 45kph
Off-road speed: 32kph
Fuel Capacity: 620L internal, 400L removable external
Range: 206km (internal tanks) 340km (internal and external)
Engine: 810hp Isotta-Fraschini diesel
Power/Weight ratio: 18hp/ton
Suspension: Torsion Beam, six road wheels
Turning Radius: 8 meters

Armament
Main Gun: 90mm/66
Elevation: Front and sides -10 to +24, rear -7 to +24
Secondary Guns: One 14.5mm MG, co-axial. Two 8mm MG, on top of the turret in twin mount.
Other: Smoke grenade launchers.

Armor (degree inclinations are from vertical)
Front Upper Plate: 110mm @ 50
Front Lower Plate: 100mm @ 30
Side Upper Plate: 75mm @ 10
Side Lower Plate: 50mm @ 0
Rear Plates: 50mm @ 10
Top: 40mm @ 90
Bottom: 20mm @ 90
Turret Front: 190mm @ Rounded
Mantlet: 200mm @ Rounded
Turret Sides: 190mm @ Rounded
Turret Rear: 90mm @ Rounded
Turret Top: 40mm @ Rounded

Quoted

Beretta 14.5mm Heavy Machine Gun
Caliber: 14.5x115mm
Weight: 50 kg
Length: 1,985 mm
Barrel length: 1,350 mm
Width: 165mm
Height: 225mm
Action: Gas and spring
Rate of Fire: 590RPM
Muzzle Velocity: 1000m/s
Effective Range: 3000m (2000m air engagement ceiling)
Max Range: 4000m
Feed: 30 round drum magazine OR 50 round belt
Sights: Mounting appropriate

Quoted

Breda-Scotti Mod.46 Semi-Automatic Rifle
Calibre : 7.35x51
Muzzle velocity: 700m/s
Loading technique: gas operated semi-automatic
Total length: 1114mm Barrel length: 610mm
Weight: 3.9kg Unloaded, loaded weights noted next to magazine.
Max Range: 2000m
Effective range: 400m (w/o optics)
Magazine: Detachable 6 round (4.3kg), 15 round (4.6kg) or 25 round (5.00kg)
Rate of fire: 40rpm

Quoted

OTO Melara Mod.45 120mm Mortar
Barrel length : 1.9 m
Total weight : 350 Kg
Elevation : +45° to +85°
Traverse : 6°
Muzzle Velocity : 270 m/s
Range : 6,000m

First, some tanks. Starting us off is the M37.5/45 Princeps (renamed from original designation). Slated to be introduced in early 1945, it will replace those M26/39 equipped units not replaced by the M34/44 Triarii in 1944.

Dimensions
Length: 6.5m without gun
Width: 3m
Height: 2.7m

Handling
Weight 37.5 tons
Road Speed: 50kph
Off-road speed: 32kph
Fuel Capacity: 498L internal, 400L removable external
Range: 166km (Internal only) 300 km (Internal and external tanks)
Engine: 600hp Isotta-Fraschini diesel
Power/Weight ratio: 16hp/ton
Suspension: Torsion Beam, five road wheels
Turning Radius: 8 meters

Armament
Main Gun: 90mm/53
Elevation: Front and sides -8 to +26, rear -3 to +26
Secondary Guns: Two 8mm MG, one hull mounted, one on top of the turret.
Other: Smoke grenade launchers.

Armor (degree inclinations are from vertical)
Front Upper Plate: 85mm @ 30
Front Lower Plate: 75mm @ 20
Side Upper Plate: 75mm @ 10
Side Lower Plate: 50mm @ 0
Rear Plates: 50mm @ 10
Top: 40mm @ 90
Bottom: 20mm @ 90
Turret Front: 90mm @ 30
Mantlet: 100mm @ Rounded
Turret Sides: 90mm @ 25
Turret Rear: 90mm @ 15
Turret Top: 40mm @ 90

Next is the slated successor to the Triarii/Princeps as the main battle tank. Some aspects of this tank have been undergoing testing since 1944. It mounts a new powerful 90mm gun, well sloped front armor and good handling characteristics. Note that this design will be introduced at some point post-1950

M45/XX Legionary

Dimensions
Length: 7m without gun
Width: 3.25m
Height: 3m

Handling
Weight 45 tons
Road Speed: 45kph
Off-road speed: 32kph
Fuel Capacity: 620L internal, 400L removable external
Range: 206km (internal tanks) 340km (internal and external)
Engine: 810hp Isotta-Fraschini diesel
Power/Weight ratio: 18hp/ton
Suspension: Torsion Beam, six road wheels
Turning Radius: 8 meters

Armament
Main Gun: 90mm/66
Elevation: Front and sides -10 to +24, rear -7 to +24
Secondary Guns: One 14.5mm MG, co-axial. Two 8mm MG, on top of the turret in twin mount.
Other: Smoke grenade launchers.

Armor (degree inclinations are from vertical)
Front Upper Plate: 110mm @ 50
Front Lower Plate: 100mm @ 30
Side Upper Plate: 75mm @ 10
Side Lower Plate: 50mm @ 0
Rear Plates: 50mm @ 10
Top: 40mm @ 90
Bottom: 20mm @ 90
Turret Front: 190mm @ Rounded
Mantlet: 200mm @ Rounded
Turret Sides: 190mm @ Rounded
Turret Rear: 90mm @ Rounded
Turret Top: 40mm @ Rounded

And last, a light chassis to serve a multitude of rolls. Detailed here is the light tank vesion, other variants will include Self-propelled gun carriages, utility designs (bridging units, recovery platforms, etc.), anti-aircraft carriages and eventually missile platforms. The chassis is designed to be amphibious, but early models (pre 1950) will not have the final amphibious drive installed and are slower over water.

L14/48 Accensus

Dimensions
Length: 7m without gun
Width: 3m
Height: 2.4m

Handling
Weight 14 tons
Road Speed: 44kph
Off-road speed: 26kph
Swimming speed: 5 kph (pre 1950 models), 10kph (Post 1950 models)
Fuel Capacity: 250L internal [External not detailed at this time]
Range: 400 km land, 50km swim [Note swim range is maximum with full internal fuel load under flat water conditions. Maximum practical range is 5-20km, but most uses are <2km]
Engine: 240hp Isotta-Fraschini diesel
Power/Weight ratio: 17.14hp/ton
Suspension: Torsion Beam, six road wheels
Turning Radius: 7 meters

Armament
Main Gun: 75mm/46
Elevation: Front and sides -4 to +30, rear -5 to +30
Secondary Guns: One 8mm MG co-axial mounted.
Other: Smoke grenade launchers.

Armor (degree inclinations are from vertical)
Front Upper Plate: 15mm @ 80
Front Lower Plate: 20mm @ 10
Side Upper Plate: 10mm @ 0
Side Lower Plate: 10mm @ 0
Rear Plates: 5mm @ 10
Top: 10mm @ 90
Bottom: 10mm @ 90
Turret Front: 20mm @ Rounded
Mantlet: 20mm @ Rounded
Turret Sides: 15mm @ Rounded
Turret Rear: 10mm @ Rounded
Turret Top: 10mm @ 90

A couple of observations on the M45/49 Legionary;

I find it interesting that you have identified the eventual need to upgrade to a 105mm main armament.

I find the the projected range (which I presume is road radius) much too good to be believed. How fuel efficient are these Isotta-Franchini diesels? The first generation of US postwar battletanks were barely good for 120 kilometers, and it was not until the introduction of the M-60 (second generation) that engine efficiencies allowed such an extended range. Or are you implying the use of large external auxiliary fuel tanks?

I am having difficulties envisioning a configuration that would allow a turret depression of -7 degrees when the turret is traversed to rear. Is there something unusual about the hull and turret layout that I would need to know to properly make a judgment?

I find the turret armor a bit on the excessive side - thicker than a Kingtiger. And I am not certain how to interpret the "rounded" notation. Is the turret circular rather than angular? I'd infer that but I am not certain.

The 105mm upgrade is not in the cards at the time of design. I am noting OOC that the design will be gunned at an appropriate date. Think the M46->M48->M60 line of development. Seeing as 105s ideally should not make an appearance until after 1950, I did not detail those variants here.

The Triarii/Princeps have a range of 300km, so coming closer to that is possible.

Does your question arise from the value being to large or small?

The turret is T-54/55 like, both in armor thickness and approximate shape. The turret is meant to be hemispherical to eliminate shot traps caused by overhangs as found in the Triarii/Princeps. The sides should probably be thinned to 160mm, but that would come with a increase to 200mm on the front.

If you are envisioning the Legionary on the model of the T-54/T-55, I will point out that it is a significantly heavier vehicle with a significantly larger engine. The fuel consumption rate of the T-54/55 - 1.9 litres/km - might not hold. I think your stated range is somewhat excessive, unless you posit a very large internal fuel volume, or specify the stated range is with external auxiliary fuel tanks.

Given the amplification of the turret design, I can now envision your intent.

The Legionary is derived from both the T54/55 and the OTL Centurion. The latter is where I got the range numbers from, given its size in comparison to the Legionary. I could bump the range down closer to the 300km of the Triarii/Princeps, would that work better?

Hmm. I've consulted my copy of Jane's Main Battle Tanks and it cites road range for the Centurion Mk.5 as 102 km and the Mk.13 as 190 km. On that basis, the road range on the Legionary would need to be revised downward significantly. Of course, the Centurion was powered by a gasoline vice a diesel engine. The fuel consumption for the Centurion Mk.5 was about 4.4 litres/km and for the Mk.13 about 5.5 litres/km.

Have you estimated the internal fuel capacity of the Legionary's design?

No, but running with the sources I have available (read, Wikipedia) and working with data from the T-54/T-55 [580 l internal, 320 l external (less on early T54), 400 l jettisonable rear drums], M46 [878 liters overall, no data on how it is stored] and Cent [A 450L external tank is noted as being added during Vietnam, no other data] , I would say between 580-620L internal, 200-240L in fixed external. Anything else would come from jetisonable external tanks, call those 400L.

You are postulating as much fuel riding outside the vehicle as you do riding inside the vehicle. I see that as a Molotov cocktail waiting to happen, but it your design and your doctrine.

If it is carrying that much fuel, and the efficiency is as good as a T-55 (which I doubt, the vehicle being heavier and having an engine of higher horsepower) then you postulated range works out. I believe though the fuel consumption would be far higher, closer to the 3 litres/km fuel consumption of the M-48A-3 (750 hp diesel, 47 ton vehicle). On that basis your presumed available fuel (internal and external) would only be good for 400 km.

Ok, thets work with the 3L/km figure and a 620L internal capacity [the 400L externals being optional and removable while elimiating the fixed external tanks] then we have ranges of 206km and 340k, without and with the external tanks. Do those figures seem reasonable?

Quoted from "snip"

Ok, thets work with the 3L/km figure and a 620L internal capacity [the 400L externals being optional and removable while elimiating the fixed external tanks] then we have ranges of 206km and 340k, without and with the external tanks. Do those figures seem reasonable?

With those parameters, yes, the downward-revised figures would be quite reasonable from my perspective.

Interesting discussion, I hadn't really come across fuel consumption figures before. Interesting stuff to know.

Quoted from "Hood"

Interesting discussion, I hadn't really come across fuel consumption figures before. Interesting stuff to know.

Jane's does more than warships.

After some thought, I am going to hold the Legionary design in reserve until after 1950. Stats will say similar.

I think that's a wise choice, unless we suffer another tank arms race, which I wish to avoid.

The only one for right now is the 14.5mm MG from the Legionary design. Ment to fill the gap between the current 8mm MG and the heavier 25mm Madsen in a variety or rolls ranging from towed Anti-Aircraft batteries to secondary armament on tanks to primary armament on light armor. Designed by Beretta.

Caliber: 14.5x115mm
Weight: 50 kg
Length: 1,985 mm
Barrel length: 1,350 mm
Width: 165mm
Height: 225mm
Action: Gas and spring
Rate of Fire: 590RPM
Muzzle Velocity: 1000m/s
Effective Range: 3000m (2000m air engagement ceiling)
Max Range: 4000m
Feed: 30 round drum magazine, 50 round belt
Sights: Mounting appropriate

I'll have to compare the specs against similar weapons later; but at first glance it seems okay.

A few comments I'd make. First, using a 30-round drum magazine on a weapon of this size strikes me as somewhat odd - almost every weapon of my recollection has just belt feed. This may just be poor memory on my part, though... Due to the way belt feed and drum/magazine fed firearms work, it's a potential source of complexity and therefore unreliability. It might be better to have different variants - one belt-fed, one drum-fed, and use the proper variant in the place it will work best.

The second thing is the effective range. The rounds would be effective at that range, but bullet drift from windage, recoil from previous rounds, and aiming inaccuracy from the human operator will make the effective range closer to 600-1,000 meters. This might just be a terminology nitpick on my part.

Otherwise, seems reasonable at first glance...

It looks to be based upon, if not a clone of, the Soviet KPV-14.5 heavy machine gun. On that basis, it would work, though I would agree that belt feed would be better.

Quoted from "BruceDuncan"

It looks to be based upon, if not a clone of, the Soviet KPV-14.5 heavy machine gun. On that basis, it would work, though I would agree that belt feed would be better.

For lack of another weapon of similar caliber (approximately 15mm) that saw widespread service ,to my knowledge, Bruce is correct in that I based the stats of the KPV.

Quoted from "Brockpaine"

It might be better to have different variants - one belt-fed, one drum-fed, and use the proper variant in the place it will work best.

I chose to include a Drum option for uses where such might be preferred over a belt. Whether these are just different feeds or different enough weapons to warrant two versions is something that can be figured out. In the case it is two distinct weapons, the belt fed version would be the primary variant and would have the stats outlined above.

Quoted from "snip"

Quoted from "Brockpaine"

It might be better to have different variants - one belt-fed, one drum-fed, and use the proper variant in the place it will work best.

I chose to include a Drum option for uses where such might be preferred over a belt. Whether these are just different feeds or different enough weapons to warrant two versions is something that can be figured out. In the case it is two distinct weapons, the belt fed version would be the primary variant and would have the stats outlined above.

Ah, I see.

Generally speaking, belt and drum/magazine-fed firearms don't tend to mix well, primarily because the manner of feeding is different. A belt-fed system pulls the belt, and thus the next round, into the loading position. I've generally seen it as a sort of deeply-notched wheel that rotates during the firing cycle, pulling up the belt and the next round and allowing the action to strip the cartridge out of the links. Conversely, a drum or magazine is spring-fed, and thus the cartridge is pushed into position by magazine pressure. There are some firearms that can operate both ways, such as the MG-34 - but in the case of the MG-34 at least, the top cover had to be replaced before switching back and forth. In other words, you couldn't fire a drum magazine and then shift immediately to a belt. I'm presuming the case would be the same with your design here - you can fire one way, or you can fire the other way, and in order to convert you need to change a piece of the firing mechanism.

I suppose you can, in theory, get both systems incorporated at the same time, but that would be a very challenging piece of engineering, and, like I said earlier, probably prone to mechanical breakdown.