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Restricted: for Operating Thetan Eyes Only By order of Her Gracious and Serene Majesty Queen Diane Feinstein the VIII The Dianetic People’s Republic of California Anno Domini 2250

Comrades! The time of your waiting is over! I introduce to you the Sierra Nevada VagonZavod AFV-50 Gun Tank   Frontal Dimensions Frontal Armor Turret Cheek Armor Array (n

Report from Lt. Col. [REDACTED] People's Auditory Forces Directorate of Political-Moral Reliability, Auditory and Political Officer for SNVZ and Military-Industry Liaison Officer for RFP "New Battle T

So I have been working on a schematic for my hydrostatic transmission.


In short, its a hydraulic open circuit. A swash plate pump delivers the power to the system.  A over pressure valve makes sure excess pressure and pressure spikes are vented into the reservoir. The power is split by a distributor valve, acting as a sort of differential lock in the case of a track slipping.  The flow is then regulated by a flow valve  that feeds into a direction changer valve. It feeds the hydraulic motor, also a swash plate motor. In parallel, it has a freewheel valve for when you simply want the vehicle to rotate freely. Both feed back into the reservoir.  A accumulator is also hooked into the high pressure side of the system, providing regenerative breaking and smoothing out the power delivered to and from the motors. 


This is just a first draft, I will most likely add more safety features and refine the system. Also it lacks the auxiliary equipment like the suspension.  I am also researching ways of making the pump more efficient past simply running constantly and the excess pressure being vented into the reservoir, wasted. Maybe also making the pump into a starter for the engine.  I also lack the oil cooler. 


I have been pondering on using two engines to power the system, one for each motor, or two pumps. The issue would be that power could not be shared between the motors and same with regenerative breaks. 






I am also working on the hydropneumatic suspension. This is a schematic for the front and rear most road wheels.  Pressure is feed into a 3/4 valve which is used elevate the roadwheel, a over pressure valve is used to regulate the amount it elevates. Outside of that, the pressure is fed though a over pressure valve that regulates the height of the suspension.  Then a accumulator is coupled in parallel to provide the "springyness". Before the hydraulic cylinder is a flow valve, which regulates the amount of flow, that is used to modify the stiffness of the suspension. 


This system is feed by the open circuit shown above in the first picture. 



And yes, everything is written in Norwegian, because diversity, a core principle of the most supreme state. 
And yes, it was all hand written while cutting steel, because I lack proper schematic software. 



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Looks very nice, very competently done.

If you want more efficiency, put a limit switch on the reservoir that declutches the main pump and locks it, while at the same time throttling down the prime mover. Will require a reservoir large enough to provide propulsion effort while the prime mover throttles up and the pump reconnects, but that gives you good idle efficiency.


You seem to have forgotten the out line from the second motor block to the reservoir, but thats just overly pedantic details.

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3 hours ago, N-L-M said:

Looks very nice, very competently done.

If you want more efficiency, put a limit switch on the reservoir that declutches the main pump and locks it, while at the same time throttling down the prime mover. Will require a reservoir large enough to provide propulsion effort while the prime mover throttles up and the pump reconnects, but that gives you good idle efficiency.


You seem to have forgotten the out line from the second motor block to the reservoir, but thats just overly pedantic details.



Taking your idea, I came up with something like this. 



A pressure sensor sits on the accumulator. When the accumulator compresses, it compresses a hydraulic fluid which controls the engine throttle, the more the accumulator is compressed, the less throttle the engine gets. Also, when at the dead bottom, it activates a valve which decouples the prime mover from the pump and locks it hydraulically, while also bypassing it with a check valve. 


I could add a hydraulic/pneumatic PID for more precise control. Also note that the control lines are simplified, and probably will be changed to better reflect their behavior later. 


And thanks, I almost flipped my table when I noticed the missing line. Luckily it is too heavy. 



Updated my schematic with a PID, am wondering if I should use a electric PID instead of a hydraulic. A worry would be lack of pressure could stop the system. 


I think I might need a separate flow chart for the control engineering.  One schematic for the main hydraulics, and one for the control scheme. 



Damn, the spring in the clutch cylinder is on the wrong side. Please ignore. 

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Here's the engine model I'll be going with:



That is 3 V-55AM2s stretched out so that their cylinders each have a 1-cylinder sized gap between them, and then the center engine is mounted upside down, and the outer two are mounted right-side up and interleaved with them

It weighs 3500 kg and produces a net of 2,340 hp.


Current hull cross-section looks like this:




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So this week I did my usual 'run hard with the first idea that pops into your head' approach. This is what I came up with:



This is Brick junior. It fulfils the objective requirements for firepower and armour protection, and the threshold requirements for specific power (I don't know about the rest yet).


The Brick series of vehicles are all built around the idea of the essential crew (see below) being housed in the hull/turret ring under the hull line. The turret superstructure, in turn, is thinly armoured except for the mantlet, although the addition of lightweight armour panels to the turret periphery can readily increase the protection provided to the gun and its associated equipment. As a result, Brick junior weighs 49 tonnes fully loaded and can run on a stretched T-72 derived suspension (Basically one extra road wheel). The engine is an AVDS-series derived unit running to a rear transmission assembly (again, T-72 derived).


The gun is a 150mm L/45 piece designed primarily to sling HEAT-FS and HE-FS. It also has an emergency supercharge APFSDS round which can penetrate a base-model Norman from the front out to 2000m if needed. The range of HEAT-FS ammunition (steel-coned HEDP,  copper-coned and improved copper-coned tandem charge) means that no practical level of up-armouring will save the existing models of Cascadian tanks.


The gun is fed by an autoloader unit running from an ammunition compartment in the left side of the turret. The compartment holds up to 20 charges and 20 shells, and feeds them to a loading rail in the turret rear. The ammunition compartment can be topped up from a secondary 20+20 compartment left of the driver when the turret is locked forwards. Both compartments have blow-off panels on top. 


The M-model Brick would use a more simple autoloader unit, so it would have to level the gun between shots. The more sophisticated version would be able to follow the gun through most of it's elevation and depression range. The gun itself and elevate/depress 30/-10 degrees. The coax is a 12.7mm piece.


The most unusual feature of the Brick is the armoured pulpit mounted to the rear of the turret superstructure. This acts as a counterweight, and also houses the observer-gunner. Xis job is to observe and operate the rangefinder, freeing up some work from the commander and gunner. This crewmember is, however, not necessary to operate the tank and so only enjoys base levels of protection. A 12.7mm pintle-mounted gun may be provided for particularly trusted observer-gunners to operate.


Brick junior identifies as gender-fluid demisexual polyamorous, and xer preferred greeting  is 'please, oh god no'. 

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10 minutes ago, LostCosmonaut said:

@N-L-M What is the average / 95th percentile shoulder width of Californian soldiers?


In other news, I think I've finished my armor array. ~3.1 tons/m2 and ~650 mm thickness.

Is the base armour included?


Edit: hmmm... thats either very light (and a typo) or remarkably heavy.


My calculations have the base armour (4.5cm RHA) as 4.5x7.8x(100×100÷1000)= 351kg/m2. So at 3100kg/m2 your array is about equivalent to 40cm of RHA.

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so my turret spec

1. 155 mm main gun - anti armour (kill Norman)

2. 75 mm coax - general purpose (HE, Frag etc.)

3. 8mm coax - anti-personnel

3. 15 mm remote with 8 mm coax = light vehicles and anti-personnel


Auto loader for 155 operates over plus minus 10 degrees elevation, auto loader for 75 operates over 0 to 30 degrees elevation.


This combo covers all threats at an ideal level.  It packages nicely (in my head) so now to the modeling.

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Mostly it was overloaded and underbuilt.

It was a very small and light engine, running very fast to achieve the rated power. That combined with Kharkovite QC leads to... interesting things.

Being a 5 cylinder engine and therefore unbalanced and suffering from excessive vibration didn't exactly help either.


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8 hours ago, Toxn said:

Is the base armour included?


Edit: hmmm... thats either very light (and a typo) or remarkably heavy.


My calculations have the base armour (4.5cm RHA) as 4.5x7.8x(100×100÷1000)= 351kg/m2. So at 3100kg/m2 your array is about equivalent to 40cm of RHA.



The base armor is included, I'll check my spreadsheet again to make sure I didn't mess up anything but I'm fairly certain it's correct.


This whole exercise has provided a nice illustration of how annoying tandem charges are.


edit: heh, if I put my NERA on the flimsiest brackets allowed it goes under 2.9 tons/m2.

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4 hours ago, N-L-M said:

Mostly it was overloaded and underbuilt.

It was a very small and light engine, running very fast to achieve the rated power. That combined with Kharkovite QC leads to... interesting things.

Being a 5 cylinder engine and therefore unbalanced and suffering from excessive vibration didn't exactly help either.


So simply down rating it would solve that problem? 


Also, how is a opposed piston unbalanced? 

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Dowrating would solve a lot of the issues, yes.

Opposed pistons have one shaft with a 13-17 deg lead angle to allow good axial scavenging, so they aren't perfectly inherently balanced; at the same time, the individual crankshafts cannot be perfectly balanced in a "straight 5" config, so you have both shafts badly vibrating inside the engine.

Upping the 5TD to 6 cylinders would go a long way to solving some of these problems. And in fact, this is what the Kharkovites did. The 6TD is a more reliable beast (if still not reliable in absolute terms). 

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