kleinerPanzer

SU-76: Faulty First Steps

Would you like to see the SU-76 in-game?  

15 members have voted

  1. 1. Would you like to see the SU-76 in-game?

    • Yes, in the tech tree
      14
    • Yes, as a premium (please explain)
      0
    • Yes, as a gift/rare (please explain)
      0
    • No (please explain)
      1


The SU-76 was a Soviet self-propelled gun from WWII which was an earlier (and inferior) version of the SU-76M. The primary differences are a different layout for the drivetrain and a thin armored cover for the fighting compartment.

 

Su76 nn.jpg

A late-production SU-76M in Nizhny Novgorod. There do not appear to be any surviving SU-76 in the world, however, the late-production SU-76M resembles the SU-76 with the full-walled fighting compartment.

 

OVERVIEW

 

The SU-76 is very similar to the SU-76M currently in-game. In terms of firepower, they are identical. As for mobility, the struggles of the different transmission and drivetrain would not reflect any changes in the game. The only functional difference would be the addition of improved armor for the crew compartment, which is fully enclosed from the sides.

 

In-game, it would function as a slightly better armored version of the SU-76M by being protected from all sides (except the roof) from light machine gun fire. It is not particularly unique and is not needed to fill any gaps as many of my other suggestions are. Any demand for this vehicle would simply be for "completionism" and having a full roster of historically-used vehicles available in-game.

 

Images

Spoiler

Image result for SU-76

 

SU_76_5.jpg

 

SU_76_3.jpg

SU_76_4.jpg

 

SU_76_2.jpg

It is a bit more difficult to tell in the above photograph, but the the engine vents on the tank's left are present.

 

SU_76_1.jpg

This is either a later SU-12 prototype or early production SU-76. The strange cover above the fighting compartment was atypical and not found on other examples. 

su76_march1943_volkhov_1.jpg

Another late SU-12 prototype or early SU-76.

sau_n37.jpg

An early SU-12 prototype, built on a special chassis of mixed T-60 and T-70 components.

 

 

Image result for su-76

Late production SU-76M, retaining the enclosed fighting compartment.

Image result for su-76

More late-production SU-76M. Again, they bear extreme resemblance to the SU-76, with the differentiating feature being the lack of any exhaust/ventilation systems for the engine on the tank's left. 

 

HISTORY

 

The SU-76, also referred to by its pre-production name SU-12, was the first serious (and somewhat successful) attempt by the Soviet Union to produce a proper self-propelled gun. 

 

In November 1941, the plan was drafted to mount the 76 mm Divisional Gun Model 1939 (USV) or 76 mm Divisional Gun Model 1942 (ZiS-3) onto the chassis of a T-60 light tank to be used as an SPG. This failed as the T-60 was simply too weak. The new T-70 light tank, however, was more capable of taking the heavy load. By late Autumn or early Winter of 1942, Factory No. 38 had produced an SPG known as SU-12. The SU-12 was built on a specially designed chassis with components from both the T-60 and T-70. The chassis was lengthened from the T-70's standard 5 road wheels up to 6 road wheels to accommodate the gun and provide additional stability. By the time the later-model SU-12 prototypes and SU-76 entered production, the T-70 had switched to T-70B production, with, among other changes, a revised driver's hatch.

 

One interesting quirk of the SU-12 was its setup for the drivetrain. The SU-12 used two 4-cylinder GAZ-202 petrol engines. They each independently drove one track. However, the lack of synchronization between the two engines (and therefore tracks) led to a number of issues with mobility and reliability. This design was never introduced to the T-70, despite many sources citing so. The choice for this design was likely to keep the gun centered on the chassis to facilitate equal traverse to the sides.

 

Despite the major aforementioned flaw, the SU-12 was allowed to enter production as the SU-76. Production likely started in Winter or early Spring of 1943, as state tests only started in December of the previous year. Initial complaints led to a very slight amount of revision and modification to the design in April 1943, but it was overall negligible and did nothing to prolong the lifespan of the SU-76 in the field.

 

The faulty design of the drivetrain would quickly come back to bite the SU-76. In June 1943, only a few months after being greenlit, the order was made to cease production of the SU-76. 

 

To add insult to injury, the problems didn't stop with the desynchronized tracks. The observation devices and general visibility received complaints, as did the ammunition storage. The maneuverability of the vehicle was deemed lackluster. The transmission was extremely unreliable, frequently tearing itself apart during harsher maneuvers. The tracks themselves also jammed frequently and the suspension was prone to breaking down. Inspections of the drivetrain had to be conducted very frequently to prevent a disastrous breakdown.

 

With only 560 vehicles produced*, the SPG's designer was barred from any future work on vehicle design. Prior to the halt in production, Factory No. 38 had already begun working to resolve the failings of the SU-76. Two vehicles were developed to replace the failing SU-76: the SU-15 and SU-16. The SU-15 featured the two engines driving a single drive shaft, powering both tracks, as opposed to the complex system the original SU-76 had, as well as a few other minute changes. The SU-16, on the other hand, was a much different vehicle, built on an standard T-70B and with the fighting compartment resting across the bulk of the vehicle's length.

 

Although both the SU-15 and SU-16 suffered reliability issues, the former was chosen for production as the SU-76M. It was more stable with its longer chassis, had a larger fighting compartment, and was still more reliable than both the original SU-76 and the competing SU-16. With SU-76M production, the rear wall of the crew compartment was cut down to improve accessibility to the gun for servicing, albeit later models re-introduced the full rear armor wall. The fate of the peculiar design of the SU-76 was finally put to rest. 

 

* Some sources claim as low as 360 to as high as 800. The number 560 is mentioned in source 5.

 

STATISTICS

Crew

4 (Driver, Gunner, Loader, Commander)

Length

4.88 m

Width

2.73 m

Height

2.17 m

Ground Clearance

0.30 m

Weight

10.7 t (other sources cite 10.8 t)

Ground Pressure

0.55 kg/cm2

Track-Ground Contact

3.3 m long, 0.3 m wide

Engine

2× GAZ-202 petrol (other sources cite GAZ-203)
2x 85 hp at 3000 rpm (other sources cite 70 hp)

Power-to-Weight Ratio

13.0-16.0 hp/t (depending on numbers used)

Transmission

4 forward, 1 reverse

Speed

45 km/h (road), 32 km/h (cross-country)

Fuel

440 L (other sources cite 420 L)

Range

300 km (road), (unknown) km (cross-country) (numbers vary wildly and are not consistent)

Vertical Obstacle

0.7 m

Trench-Crossing

2 m

Max Gradient

46% (25°)

Max Fording Depth

0.9 m

Armor

Hull:

 25-30 mm front (sources vary. Gaijin's setup has it 25 mm upper glacis and 30 mm lower glacis)

 15 mm sides

 15 mm rear

 10 mm roof

  7 mm floor

Superstructure:

 25 mm front

 10 mm sides

 10 mm rear

 (Optional) Canvas roof

Smoke

None

Armament

1x ZiS-3 (some sources call it ZiS-3Sh)

Primary

76,2 mm ZiS-3 (60 Rounds)

Elevation: Manual, -3 to +15°

Traverse: Manual, ±15°, 2.8°/s

Secondary

No Secondary Armament*

 

* The crew would often have their own sidearms, including PPSh submachine guns. Allegedly, some vehicles could mount a DT machine gun somewhere on the edge of the fighting compartment. 

 

SOURCES

1 - https://en.wikipedia.org/wiki/SU-76

2 - https://tanks-encyclopedia.com/ww2/soviet/soviet_SU-76.php

3 - http://tankarchives.blogspot.com/2014/05/su-76-review.html - CAMD RF 38-11355-1553

4 - http://tankarchives.blogspot.com/2013/12/end-of-su-76.html - RGASPI 644-2-178

5 - http://tankarchives.blogspot.com/2013/11/soviet-light-tank-destoyers.html - CAMD RF 38-11369-1

6 - http://catainium.blogspot.com/2016/09/su-76-self-propelled-artillery.html

7 - http://catainium.blogspot.com/2016/09/su-12-self-propelled-artillery.html

8 - http://catainium.blogspot.com/2016/09/su-15-self-propelled-artillery.html

9 - https://en.wikipedia.org/wiki/T-70

10 - http://www.wardrawings.be/WW2/Files/1-Vehicles/Allies/2-USSR/05-TankDestroyers/SU-76/Data/SU-76.htm

11 - GOKO decree #3530

Edited by HugoTroop
corrected a historical error involving the T-70 and transmission design.
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