The Soviet Tank Thread: Transversely Mounted 1000hp Engines

[EnsignExpendable]

Time travelling IS-2s!

 

[xthetenth]

That would be awkward for the Germans, then awkward for the Soviets once they realized they were years away from spare parts.

[T___A]

Color photo of the Object 770:

[Sturgeon]

goddammit, now I have to go clean up my pants

[LoooSeR]

Is that Object 279 on the left? Side armor suggest that it is indeed UFO tank.

[LoooSeR]

 

Soviet T-80Us. 

 

A-220U unmanned turret with 57 mm autocannon.

[EnsignExpendable]

Best tank

 

[LoooSeR]

 

 

 

[LoooSeR]

 

New Arena.

[LoooSeR]

"Uran" [uranus] robot testing.

http://www.youtube.com/watch?v=VbzS256FHWU

[T___A]

wrong thread.

[LoooSeR]

Why? It is Soviet teletank, but with new level of tech inside! 

[T___A]

Comparing the M-50T and the AVSI-1790-6

M-50T

water cooled

horsepower: 1050 at 1850rpm

length: 2005mm
width: 1056mm
height: 1089mm
displacement: 3344 cubic inches
vs

AVSI-1790-6

air cooled

horsepower: 765 at 2800rpm

length: 1849mm
width: 1441mm
height: 1160mm
displacement: 1791 cubic inches

[Xlucine]

Is that including ancillaries like the radiators? Water cooled engines ought to have a better engine block volume : displacement ratio, since you can pack the cylinders closer together.

[T___A]

Is that including ancillaries like the radiators? Water cooled engines ought to have a better engine block volume : displacement ratio, since you can pack the cylinders closer together.

 

No it's just the engine itself.

[Meplat]

Is that including ancillaries like the radiators? Water cooled engines ought to have a better engine block volume : displacement ratio, since you can pack the cylinders closer together.

Kind of-

It depends on how the liquid cooled mill is designed and what it's intended fuel is. Dry sleeved Diesel engines for example can be surprisingly bulky for their displacement.

 

Also- Continental had pretty much figured out how to make an air cooled mill very compact, by the time that engine was made.

[Walter_Sobchak]

Comparing the M-50T and the AVSI-1790-6

M-50T

water cooled

horsepower: 1050 at 1850rpm

length: 2005mm

width: 1056mm

height: 1089mm

displacement: 3344 cubic inches

vs

AVSI-1790-6

air cooled

horsepower: 765 at 2800rpm

length: 1849mm

width: 1441mm

height: 1160mm

displacement: 1791 cubic inches

The HP rating you list for the AVSI-1790-6 is the net HP, not gross HP (Gross HP is usually what gets listed as "horsepower" in most books.)  

[T___A]

The HP rating you list for the AVSI-1790-6 is the net HP, not gross HP (Gross HP is usually what gets listed as "horsepower" in most books.)  

 

That's what you get for using Wikipedia.

[Walter_Sobchak]

The net horsepower figure is actually a more useful figure, but everyone likes to use gross horsepower since it makes for a bigger number, better for marketing purposes.  The really useful stat that is always really hard to find is "Power at the sprocket."

[Collimatrix]

The net horsepower figure is actually a more useful figure, but everyone likes to use gross horsepower since it makes for a bigger number, better for marketing purposes.  The really useful stat that is always really hard to find is "Power at the sprocket."

 

 

This nails it.

 

For those who haven't been keeping score:

 

-Gross horsepower is the horsepower the engine can put out on a test stand in a lab.  This is the biggest number, so it gets into glossy marketing brochures.  Diesels are losers here; they don't put out much horsepower relative to weight and bulk.  Gasoline engines usually beat out diesels here, as they usually squeeze out more horsepower for a given displacement.  Turbines beat both.

 

-Net horsepower is the horsepower after you account for losses from the cooling system.  Diesels are winners here; they typically use 8-17% of the engine horsepower to run the cooling system.  Gasoline engines are losers here; they can use upwards of 20% of their gross horsepower to cool the engine.  Turbines are huge winners here; basically none of their gross output is consumed by auxiliary cooling systems.  Adiabatic diesels would equal turbines in this parameter (and would clobber turbines, or anything else for that matter, in fuel economy), but sadly these exist only in Toyota laboratories covered in a thick layer of dust.

 

-Horsepower at the sprocket is the power available to actually move the tank after the losses of the transmission and final drives.  For the very best transmission designs at peak operating efficiency, this is about 74% of gross horsepower.  

 

Purely mechanical transmissions with layshaft gearboxes (e.g. T-55) are winners here, but these are more demanding for the driver (especially since the T-55 lacks hydraulically boosted tillers or a synchromesh).  Transmissions with torque converters are less efficient, but torque converters reduce wear on the engine and transmission, and give smoother power when the tank is moving over uneven terrain.  The majority of post-war tank designs feature torque converters save the ubiquitous T-54/55/62 family (and the Soviets were quite aware of, and enthusiastic about the potential benefits).  

 

Planetary transmissions (whether automatic as in American designs or with manual gear selectors as in chieftain) are less efficient, but are easier for the driver to use, and have the advantage that gear changes are basically instantaneous, without any pause where there is no power being delivered to the sprockets during gear shifts.  This is a significant advantage during, say, hill climbing.  

 

Electrical and hydrostatic transmissions are even less efficient than automatic transmissions with torque converters, but they have the advantage that they are continuously variable, lacking discrete gear ratios, so they can optimize torque and RPM for given conditions.  They also allow some flexibility in tank design, since power does not have to be provided to the transmission by a rotating power shaft.  You could put the drive sprockets in the front and have their transmission and final drives powered by electrical cables or hydraulic lines that could snake gracefully around the turret basket and not significantly increase the hull height.  I can't imagine why you would ever want to do this, but you could.

[Sturgeon]

Collimatrix, Baron of Driveshaft.

[Khand-e]

Collimatrix, Baron of Driveshaft.

 

Duke of Fly-By-Wire.

[LoooSeR]

Many people know this photo:

 

 

26-27 October 1961, part of the so-called "Berlin crisis".

 

Here is same event from other side, a series of photographs taken in the location of the 3rd Tank Battalion of the 68th Guards tank regiment of the Soviet Army:

 

 

 

 

 

http://477768.livejournal.com/1709628.html

[Collimatrix]

Revisting the Object 277 turret:

 

 

Is the little white bar crossing above the KPV-T a stereo rangefinder?  I think it may be.

[LoooSeR]

Yeah, it looks like rangefiner connected to gunner sight. Layout of that thing reminds me first models of T-64 turrets.