N-L-M

4 minutes ago, Sturgeon said:

Reminds me of the T-44, which coming from me is quite a compliment.

Can you export your springs as sldprt files? I, uh, may want to poach them.

A quick googling says that Solidworks can import ProEngineer/Creo files, so how do you want it sent?

Springs and sprocket are now a thing:

The springs were mostly eyeballed, and they just barely clear the hull and wheels. This is why the Merkava has such narrow wheels, otherwise the tank gets really wide really fast. Width over the sprockets is barely under the limit.
The intended wheel vertical movement is +300/-100 mm. Ground clearance is 500mm with tracks (to be installed). return rollers also to be installed.

I haven't modeled the sideskirts yet, but my design rather heavily relies on those effects.

22 minutes ago, Toxn said:

With the skirts that's very respectable indeed. You could cut those down to 15mm and still be okay.

 

Just to demonstrate: a 50mm side angled at 30' from the vertical, plus a 25mm skirt angled at 0', gets you ~115mm LOS thickness at the end of your 45' arc. At 30' that soars to ~165mm. This means that your tank's side armour is essentially immune to present-gen guns in the 30' arc, and is well-protected against the most common next-gen threat in the 45' arc.

It's even better than that- at 30', you have, for 600mm wide tracks, 1200mm of air between your first layer and the hull. The first layer sets off fuzes and damages projectiles, they then have 1.2m to destabilize and break up before hitting the main armor, making your main armor more effective.

1 minute ago, Toxn said:

42 tonnes unstowed.

 

I can see why that would be a problem, yes.

3 minutes ago, Toxn said:

On a side note: I seriously cosidered a quasi all-or-nothing armour scheme where the front and side crew compartment is 25mm, but the turret has over 100mm LOS all around (going up to 150mm on the front) and the turret basket is made from a 75mm casting. Everywhere else gets 10mm.

I too had considered that, the problem is the sheer proliferation of fiddycals and HE frag means that on the whole you're increasing your vulnerability by focusing too much on the high-end threat.

I now have a basic suspension, Merkava-3 style (the springs aren't modeled yet). If anyone has a quick easy way to make a drive sprocket I'd love to hear it.
Also the surfaces left in the rough from casting now look the part.

The gun clears the sponson corners:

If anyone's wondering, those are M60 wheels cut down in width by about an inch.

The tank boasts a low-profile silhouette in hull-down positions:
 

2 minutes ago, LoooSeR said:

Agree, this look to be good running contest.

 

I expected to see more modern-tech-like take on designs, as according to contest althistory crap in OP designers know about it, just can't make/produce it.

I've got quite a few plans, part of which is already reflected in the current design as seen and part of which isn't yet. For example, I chose the 105mm as I know ammo developments will keep it capable until at least late T-72 equivalent armor shows up; the internal layout of the hull is a bit more advanced than it looks, and the armor scheme isn't yet fully modeled.

There are more details, which I will point out in my final post, but rest assured that future tech is being considered.

The driver's access is extremely limited when the gun is overhead. At those angles however, the escape to the turret through the gunner's position is available.
There will probably also be a floor escape hatch.

And now that I can no longer reasonably postpone it, I must go and crudely model a suspension.

Alrighty. My turret has no room for such a device, and will have to find the range using other methods.
The commander's toys are barely safe from the gun at full depression:

Just one quick question before you stop- it looks like the rangefinder would obstruct access to the loader's hatch, is this the case?

.60cal M240s are the future, you know. Though I suspect that if your tank is as squished as you say, perhaps it's the BMG that isn't to scale.

Turret details on the way. Commander's cupola requires a fairly large hole, which makes the loader's hatch look a mite small. GPS well is designed for upgradability, being quite a bit larger than it needs to be.

Gun at -10 elevation fits snugly in the shortened turret even at full recoil.

And at full elevation of +20 deg:

Only minor clipping of the frontal armor thanks to low-detail modeling. With minor changes the elevation could be +25.
If anyone's wondering, that's a 105mm L/50 gun, with a concentric recoil mechanism (basically, an M68 to within reasonable error)
The assumed recoil length is 350mm, a bit generous, if I make a light tank variant it'll have a longer recoil mechanism to reduce peak forces.
Also note that the holes for the coax and GSS clear metal in both maximum elevation and depression, so that works.

@Toxn, how on earth do you pump out so much so fast? 

Just to make sure I follow- the mistake is to design a competitor/replacement to [a system currently in service] based on tech which competed with [the design in service] back when they were both concepts, so the (flawed) competitor has no actual advantage over the [design in service] yes? 

Well, the question is what point in the design process are you simulating? An improved M1 achieving IOC in 1944 isn't bad, but starting development at that point is very much behind the times. The competition captures a single moment in time, whereas a development process is drawn out. Is what we wresent supposed to be the end result of handwaved development, or the PDR to a theoretical development process which hasn't even begun?

2 hours ago, Collimatrix said:

There was a nasty rumor that a lot of government tanks in the Ukranian Civil War were going into combat with just the containers installed, but no actual ERA inside those containers.  The explosive inserts had long since been misplaced, and the boxes were just for show at that point.

 

I've heard this rumor before, is there any proof of it being true?

Looks more like a muzzle velocity radar to me, most muzzle programming devices are coils to maximise the magnetic field they produce, the brake would cause problems with that in this offset block.

Also, do they even have 57mm rounds which would benefit from such a system?

And now, the gun installed in the cradle, in the turret. Progress! The turret roof may get dropped later, if it's as over-sized as I suspect.

Got around 1000kg of gun here, perhaps a bit optimistic.

Clearly, a "paratrooper" variant of the taller infantrymen is needed, so they can be folded for stowage.

Right, I think I have a pretty good idea of what the basic turret will look like. The front and cheek armor and ring are cast, the flanks, rear, roof, and under bustle are rolled.

Structure estimated at 5.7 tons, not bad for an initial design. Combined with the hull being slimmed down to 13.3 tons, I get 19 tons so far. Assuming a ~50% armor weight fraction, that leads me towards 40 tons, which is a good place to be.
I should probably stop for the day.

EDIT: ballistic fixes bring me to 5.8 on the turret.
To prevent multiposting:
It seems I got my sizes a bit off, the turret is a bit too small for the hull.

That's significantly higher ammo capacity then what I'm currently expecting, very nice indeed.
@LostCosmonaut, are there any ammo capacity requirements? Or requirements for performance vs. soft targets?

55 minutes ago, Sturgeon said:

73 rounds fit in the turret bustle behind a firewall:

 

That doesn't look particularly accessible, what racking provisions are there?

In other news, for those who don't model cartridges every day, I now have a dummy shape of my intended cartridge:

Finally, I too can post some progress!
Using Creo 3 (I need to learn it anyway), I have finally been able to assemble the barest form of hull. The extensions for the turret ring took forever and a half.

The hull is mostly welded rolled plates, with a few cast details. Currently the only cast detail is the "ears", but when I can the suspension mountings and some of the sponson auxiliaries will be cast.
The current form is extremely rough and will be refined, but at least it's *something*.
Current mass for just the hull is 15 tons, have to cut that way down later.