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ATENÇÃO:
A publicação de qualquer imagem ou informação referentes ao nazismo, fascismo ou quaisquer outros regimes totalitários deve ser entendida como reprodução do rigor histórico e não como apologia a estes regimes, líderes ou símbolos.

Sturmgeschütz IV (StuG IV) - Sd.Kfz. 167 - assault gun and dozer version - case report

Soldaten und Kanoniere !!
Today we will get to know in more detail one of the most efficient weapons developed by the Germans, in WWII. Let's talk about Sturmgeschütz IV , the StuG IV assault gun and a variation made to clean cities after bombing: Stug IV dozer version.

A StuG IV assault gun destroyed in an ambush position
France - Summer - 1944.
Sturmgeschütz IV (early) equipped with a dozer blade - Magdeburg, Germany - 1944.

History:
      The Sturmgeschütz IV (StuG IV) (Sd.Kfz. 167), was a German assault gun variant of the Panzer IV used in the latter part of the Second World War.
StuG IV early - Ron Volstad - Dragon box art

Panzer IV Ausf G 2 - Ron Volstad - Dragon box art
      It was identical in role and concept to the highly successful StuG III assault gun variant of the Panzer III.
StuG III Ausf G - Ron Volstad - Dragon box art
Panzer III Ausf F - Ron Volstad - Dragon box art
     Both StuG models were given an exclusively tank destroyer role in German formations and tactical planning in the last two years of the war, greatly augmenting the capability of the dwindling tank force available to the German army on the Eastern and Western fronts.

Development:
      The Sturmgeschütz IV resulted from Krupp's effort to supply an assault gun. As Krupp did not build Panzerkampfwagen IIIs, they used the Panzerkampfwagen IV chassis in combination with a slightly modified Sturmgeschütz III superstructure.
     The first known proposal for a Sturmgeschütz on the Panzer IV chassis is in Krupp drawing number W1468 dated February 1943. This initial drawing unitized the outdated Sturmgeschütz Ausf. F superstructure on a Panzer IV chassis.

     This proposal had a sloped front superstructure with a combat weight of 28.26 tons. Krupp abandoned it in February 1943 because it was too heavy. Plans for the StuG IV were halted.
      During the Führer Conference of 19 to 22 August 1943, after the Battle of Kursk, Hitler had seen reports of the StuG III outperforming the Panzer IV when used in an infantry support role and tactical defence. Convinced that a tank-hunter version would be superior to the tank version, Hitler planned to switch Panzer IV production to "Panzerjäger IV" production as soon as possible. It was to mount the same 7.5cm L/70 used for the Panther.
Panther Ausf  D  - Ron Volstad - Dragon box art
      Another manufacturer, Vomag built a prototype Panzerjäger IV with 7.5 cm L/48 gun and demonstrated it on 20 October 1943. It was later re-designated as Jagdpanzer IV Ausf. F.
Jagdpanzer IV L/48 - Ron Volstad - Dragon box art
     As the Jagdpanzer IV was already being produced by Vomag, the StuG IV may not have materialized, had it not been for the major disruption of StuG III production, and the scarce supply of the 7.5cm L/70 gun designated for the Jagdpanzer IV.
Jagdpanzer IV L/70 - Ron Volstad - Dragon box art
      In November 1943, Alkett, the manufacturer of the StuG III, suffered damage due to an Allied bombing raid. They produced 255 StuG III in October 1943, but in December production fell to just 24 vehicles. A conference held from 6 to 7 December 1943, addressed possible solutions to this problem. Hitler welcomed the suggestion of taking the StuG III superstructure and mounting it on a Panzer IV chassis.


      The combat weight was 23000 kg, lighter than the 23900 kg for the StuG III Ausf. G. Between 16 and 17 December 1943, Hitler was shown the StuG IV and approved it. To make up for the large deficit in StuG III production StuG IV production was now given full support.
    The StuG IV could be more quickly manufactured than the Jagdpanzer IV at the time. This restarted the Sturmgeschütz IV project. This time, the superstructure of the StuG III Ausf. G was mounted on a Panzer IV chassis 7.
Stug IV late, with Zimmerit and ostketten tracks...
Notice the wild boar painted in the gun's mantlet.
Russian front - 1944
       The major change, resulting from different frame-chassis lengths in PzKpfw III and PzKpfw IV tanks, consisted in enlarging and extension of top front plate of frame-chassis and placing the driver's station in a special, small protruding superstructure (more plainly referred to as a "cage" in a British wartime technical description of that vehicle), fitted with a two part hatch on the top of superstructure. This solution concerning the location of driver's station was caused by the fact that his "workplace" was located more in the front than the remaining part of superstructure (fighting compartment). Although it was possible to shift the location of driver station, this would imply major changes to the drive system and transmission gear, for which there was simply no time. The driver could use two periscopes. StuG III G and StuG IV assault guns are often mistaken for each other.

StuG IV driver's station: Notice the periscopes and the layer of concrete as
extra armour in front of the station (red arrow).

Compare with the photo below...
A Stug IV with complete set of armour screens (Schürzen)
Notice the prominent driver's "cage" (red arrow) with two periscopes (green arrows).
This vehicle don't use concrete...
     The easiest criterion that allows us to assess which vehicle we are dealing with is checking whether the vehicle has the above-mentioned "cage" (i.e. driver's station), as well as identifying the type of drive sprockets, which were different in PzKpfw III and PzKpfw IV. StuG IV guns were fitted with drive sprockets from PzKpfw IV tank. However, they were not fitted with a two-stroke DKW engine moving the turret, which was standard equipment of PzKpfw IV tanks.
Armor thickness of the Stug IV

     In June 1944, the production of tank chassis PzKpfw IV Sd Kfz 161/2 Ausf. J with 6 (instead of 8) return rollers was launched; this chassis type was not used for production of StuG IV assault guns until December 1944.
     
   Krupp Works in Magdeburg launched production of StuG IV after having completed the manufacture of PzKpfw IV tanks. In total, more than 1100 vehicles of that type were produced and converted. It was quite a large number in comparison to e.g. production of Tiger family heavy tanks. The number of Tiger I  Sd Kfz 181 was slightly bigger, and the production of Tiger II Sd Kfz 182 was half that number.   
    Manufacture of StuG IV assault guns was to be continued until May 1945. The production plan of November 3, 1944 provided for manufacture of 100 assault guns in that very month. From December 1944 to March 1945 the monthly production was to be at the level of 130 items, in April 100 vehicles and in May 1945 - 50 assault guns. 
       The first 30 Sturmgeschutz IV Sd Kfz 167 vehicles were manufactured in Nibelungenweike on the basis of series chassis of PzKpfw IV tanks. Some of these vehicles had guns fitted with standard box-type gun mantlet from StuG III Ausf G assault guns; later, Saukopf type gun mantlet were applied.

Modifications:
      During Stug IV production, numerous modifications of vehicle construction were introduced. Although as early as on 24 January 1944, the General Artillery Inspector stated that additional concrete armour did not significantly improve the armour resistance, combat units still tended to apply concrete. It is interesting to mention that the allies also came to the same conclusions, with studies indicating that concrete reinforcements were not effective, but the crews insisted on applying these layers. The psychological effect of that was the most important factor ...
Stu.G. IV leading a Stu.G. 40 from Stu.Gesch.-Abt.177
probably during the defensive fights of early 1944 on Eastern front.
Notice the rough concrete armour in the front glacis and upper hull
giving a characteristic rounded shape to the vehicle's casemate.
The Stug III in background shows the same characteristic
A Sturmgeschütz III that was captured during January-February 1945
in the Battle of the Bulge by the U.S. Army's 104th Infantry Division,
here seen in service with the 104th Division.
Notice the "rounded" aspect of the Stug's upper hull and the
"absence" of zimmerit (the concrete was applied over the paste).
The americans loved concrete armour...
Concrete armor being installed on an M4 105 tank
      A "remnant" of PzKpfw IV chassis tank was an emergency hatch placed in the vehicle floor under wireless operator's station. The above-mentioned station was removed (the radio station was operated by the gunner), and therefore, on 27 March, Krupp Company suggested that the hatch should be welded.
A disabled Sturmgeschütz IV from Heeresgruppe Nord
 Army Group North- winter 1944.
Notice the track links welded in the vehicle, as add-armor...
Really, it wasn't just the Allies who did this ...
     Order No. 256, dated I May 1944, required the use of wider tracks (the so-called Ostkette) in the winter season. At the end of May 1944 Krupp suggested the use of side armoured screens on the sides of the vehicle, the so-called Schürzen.
A Stug IV with schürzen and ostketten roaring in a dusty road,
somewhere in a Russian front 
     After the mass production of Panzer IV chassis had been launched, suppliers were not informed in due time whether the chassis would be used for a tank or for an assault gun. Therefore, it was not always possible to carry out the above-mentioned vehicle chassis modifications. Thus, Krupp designed a new type of ammunition container for 8 shells, which could be fitted both in tanks and in assault guns. The minutes of a meeting held in Magdeburg on 20 March 1944 enable us to identify the scope of other changes and modifications: 
  • ammunition container was to be additionally protected with a metal sheet insulating it from the exhaust system
  • simplified gun mount type SKB 6124
  • adjustable driver's seat
  • improved driver's periscopes, better mounts of prismatic elements in the periscopes
  • machine gun for combating enemy infantry mounted on top of superstructure
  • additional transport lock for fixed a gun. 
   In early June 1944, the applied tow hooks (so-called type "C") were replaced with type "S". 
"S" hooks

"S" and "C" hooks

A Stug IV with "S" hook in his front glacis...

Two "C" hooks in this Stug III captured.
     In mid-June the vehicles started to be fitted with special hooks, the so-called Pilzen, mounted on top of the superstructure. They were intended for mounting an additional fold-up crane with maximum lifting capacity of 2.000kg. To facilitate dismantling of the gun. top part of the superstructure was fixed with screws. In this way, top armour of the superstructure could be easily dismantled and the gun could be removed.
A Stug IV early under gun maintenance.
Due to the lack of specialized crane trucks, a 2-ton capacity Behelfskran (auxiliary crane)
was designed. The simple device could be used to replace the engine or gun.
    Also in June the armour of driver's station was reinforced. In the front, an additional plate (30mm thick) was mounted with six screws. Later, the front armour of the superstructure to the left of the gun (driver's station) and to the right (ammunition container) was reinforced with additional concrete reinforcement. Moreover, an additional armour was used, made of steel plates inclined at the angle of 40-50°, and fixed to the superstructure and front armour of the frame-chassis. On June 24,1944 Krupp submitted a proposal of mounting additional armour.
The crew of this StuG IV has attempted to improve the armour protection on their vehicle.
A short length of Ostketten  has been welded to the front of the driver’s position
and covered with a thick metal plate (red arrow). Parts of he superstructure
has been rounded off with a smooth coating of concrete (green arrow).

A Sturmgeschütz IV from a Luftwaffe infantry unit has had the
80mm frontal armour and driver station 
reinforced by welded-on thick armour plates (red arrows).
Notice the concrete rounded layers in the front hull (green arrows)
     The driver's station was fitted with an adjustable seat regulated with a bolt. Moreover, the location of prism in right driver's periscope was changed, to limit the so-called "blind zone" to only 5-6 metres in front of the vehicle.
    Additional railing was fitted on the rear armour to facilitate transportation of infantry or extra equipment on top of engine compartment. Since August 1944 some of the vehicles were fitted with rotary commander's cupola.
StuG IV cutaway view - crew stations
     Originally, StuG IV assault guns had standard armour screens (Schürzen), made of 5-8 mm thick steel plate; later screens made of metal mesh were applied, the so-called Thoma Schürzen.
   Vehicles manufactured until the end of September 1944 had armours coated with Zimmerit. Usually whole vehicle was covered with Zimmerit, only with horizontal and vertical ripples.
A Sturmgeschütz IV with a Zimmerit coating identifies it as being from a mid-1944 production batch.
Notice the Schürzen screens and the cammo

Rear view of the same vehicle above.
She's fitted with Rundumfeuer-Maschinengewehr (allround fire machine gun).
Two Flammenvernichter (flame suppressor) pipes have been fitted
in place of the standard exhaust.
Color profile of the StuG IV above.
Notice the beautiful cammo pattern
    Gun loader's hatch was changed from two-piece to a single-piece one. Later versions of the vehicles were fitted with vertical exhaust pipes, typical of PzKpfw IV Ausf J tanks. The base of commander's cupola was also modified. Originally it was angular and welded; later a cast element was used, welded to the superstructure and commander's cupola.
    In November 1944 an additional lock was added on the front body armour to stabilise the gun during troop movements. Barrel was mounted on the prop at 6° angle of elevation. At the same time rain shields started to be fitted over the prisms of driver's periscope. When it rained or snowed the prisms were not clear. which limited the driver's vision. 
    Outer fuel line, mounted to tank No. 3, was fitted with addi-tional sheet screen, for protection against mechanical damage.
     Also the construction of sideshafts for lateral transmission was reinforced to eliminate the risk of transmission teeth breaking. 
    Additional guard rails were fitted to avoid the hatch slamming shut when driving. Moreover, an additional hot air nozzle was introduced, leading from the engine to the batteries. The batteries were given additional wooden shields for thermal insulation.
     In the same period tow hooks were modified to enable the use of towing shaft 
     From December 1943 to May 1945, Krupp built 1,108 StuG IVs and converted an additional 31 from battle-damaged Panzer IV hulls. While the number is smaller than the 10,000+ StuG III, the StuG IV supplemented and fought along with StuG III during 1944–45, when they were most needed.

Dozer version:
     Were found interesting pictures showing this unique and unarmed Sturmgeschütz equipped with a dozer blade used to clear debris in Magdeburg, after the Allied bombings the Krupp-Gruson Werke A.G. tank plant. 
One of the first StuG IV at the Krupp-Gruson Werk AG assembly plant in Magdeburg, December 1943
A mass of 40 cm tank tracks in an assembly shop of the Krupp Grusonwerk A.G. 
works in Magdeburg, Germany. Note the StuG IV assault gun in the background.
      In the picture below, the vehicle seems to have been painted only in the base color (at that time, dark yellow) and the dozer blade appears to be a little darker, perhaps even with an antioxidant background only ....We could imagine the use of a factory test vehicle or even a production specimen, awaiting the arrival of its armament. The correct assumption is that a vehicle as deadly as this one would not be used in a second-line activity unless it was a "dispensable" vehicle due to a defect in armor or even just a concept viability test.
 Sturmgeschütz IV  equipped with  dozer blade

Same vehicle, showing the dozer blade.
At this angle we can see that the blade is fixed, with no lifting mechanism.
Notice that pic it seems to be prior to the photo above, with the dozer blade design still evolving,
without details like the curved baffles at the top of the blade

The StuG IV dozer in action, with the "early" dozer bade design.
Notice the dozer blade is not really movable.
It appears to be bolted to the vehicle's front hull.

The device seems to be very effective ...
      In this film below, you can see Magdeburg destroyed by the allied bombers, and the ruins of the Krupp plant. At 33 seconds of film, notice the amount of StuGs IV on the Krupp's production lines. 
      Maybe those responsible for the factory used a StuG IV chassis without combat conditions (vehicle sent to the factory for repairs or even a vehicle with the armor damaged by fire during bombings) as a civilian support vehicle,  like MAN do with his Panther Ausf D Dozer.




      Not much else is known about this strange vehicle, only the date in the photo places the "definitive" version on March 30, 1944. And that is more than enough for us to try to reproduce it here ...

Specs:


Sturmgeschütz IV - SdKfz 167 assault gun
TypeAssault gun
Place of origin                                        Nazi Germany
Service history
In service1943–1945
Used byNazi Germany
WarsWorld War II
Production history
ManufacturerFried. Krupp Grusonwerk AG, Magdeburg-Buckau
ProducedLate 1943–1945
No. built1,108 +31 conversions
Specifications
Mass23 tonnes 
Length6.7 m
Width2.95 m
Height2.20 m 
Crew4 (Commander, Gunner, Loader, Driver)

Armor10–80 mm (.39–3.14 in)
Main armament
1 × 7.5 cm StuK 40 L/48
63 rounds
Sec. armament
1 × 7.92 mm
Maschinengewehr 34
600 rounds
EngineMaybach HL120 TRM V-12-cylinder gasoline
300 PS (296 hp, 220.6 kW)
Power/weight13 PS (9.6 kW) / tonne
TransmissionZF SSG 76 Aphon,
6 forward gears, 1 reverse
SuspensionLeaf spring
Ground clearance40 cm 
Fuel capacity430 liter
Operational range
210 km
Speed40 km/h

The kits:
      For this double project, I will use the Italeri kits Sturmgeschütz IV (# 6223) and a set of metal tracks from Friulmodel ATL-83: PanzerIII / IV Ostketten for the assault gun version. The dozer one used the normal tracks, provide by the kit.
Italeri's box art 
Friulmodel box art (#ATL-83)
      An interesting thing about this kit is that it is a very old kit (1976) with several reboxes and injections, under different brands. But the kit is very well made and injected. Of course, it will present a greater workload, but that is also part of the pleasure of turning this old lady into a contemporary girl !!! 
      Another interesting detail: In the model world, this vehicle came with the name StuG VI - Sd.Kfz 163. But over time, the name 163 was first erased from the box covers and later changed to the correct StuG IV - Sd.Kfz 167. My kit is from the "middle" period, with no Sd.Kfz number in the box, but still with the wrong one in the instruction booklet.
"Early" Italeri's StuG IV model (#223): notice the Sd.Kfz 163
(below Roman numeral)

"Mid" Italeri's StuG IV model (#6223): notice the absence of Sd.Kfz number
(this is my girl!!)

But the first page of the brochure still has the number Sd.Kfz 163...
Notice the stock number 6223
"Late" Italeri's StuG IV model (#6491): notice the number  Sd.Kfz 167
      But let's get to work .... The first steps are simple and smooth ... in the old Italeri style !!
Chassis and suspensions... The drive-sprockets are in dry-run
These are the wrong model, without reinforcements.
They will be replaced by the correct ones ...

Smooth and easy!!
      Parallel work saves a lot of time ...
Wheels..lots of wheels to clean-up!!

I love my Dremel...
Cleaning the return rollers...

The return rollers after and before my
magical Dremel!!

The main wheels...64 parts needing cleaning...
Dremel, scalp and sandpaper ...
After and before!!!

The wheels in dry-run... Notice the reinforced drive sprocket
in position and the age of the kit manifesting itself here ...
Shame on you, Mrs. Italeri !!!
But putty is a magical thing...
A dry-run with the wheels...
     But, continuing with the building of the double project: An interesting thing is to notice some peculiar details, in the vehicle with the dozer blade ... let's list them, to start the differentiation changes between the girls ...
  1. Presence of additional armor plate bolted to the right portion of the front hull.
  2. Absence of the main gun and possibly obliterated cavity (no ingestion of debris and dust)
  3. Armor of the gunner's MG34 machine gun positioned in the horizontal position.
  4. Absence of the commander's cupola. I speculate that the hatch persists, with a new hinge...
  5. Absence of tools, fire extinguisher and extra wheels
  6. Idler wheel type straight spoke.
  7. Early suspension bumpers
  8. Periscopes primitive type, without covers.
  9. and finally, the dozer and accessories, itself.
Closing the large "mouth" of the 75mm gun and its huge mantlet with 1mm plasticard.
Imagine if that open, the amount of things that could be "ingested"...
 The photos of the vehicle do not show this clearly, but if
I were building this vehicle at Magdeburg in 1944, without a doubt, I would do it ...

The big spece closed!!!

Closing the upper huls; the assault gun one by the booklet... and the
dozer version by the logic!!
     A small detail that does not appear in the big photo above with the differences of the dozer version: the front flap of the fenders flexed backwards, on their hinges ...
Front fenders flaps flexed backwards...
Space for dozer...

      Surgery time: cutting the flaps with care and scalpel. The important is not damage the hinges and flap details ... Notice the suspension bumpers, under "plastic surgery"...

The right fender flap under surgery (red arrows) and the new
suspension bumpers, made with Plastruct (green arrows)

The end of surgical time:  two fender flaps ready and the new "early" bumpers...

The girls, side by side...

Notice the flaps from the dozer version...

Cutting the periscopes protections, for dozer girl...
Virgin, in red arrow...and after cut, in green arrow...
They will be glue in the yellow positions...

Some details marked as ready (in clokwise):
The "Big Hole" closed; MG shield in flat position; commander hatch without cupola
idler wheel type straight spoke from Tamiya (yellow one); the new bumpers;
the new periscopes guards and the fender flaps flexed backwards...

Upper vision: notice the new commander hatch hinge
and corrected pin marks in the MG shield  from our old friend Italeri...

The assault gun version...

The gals is in rest, now!!!
      It's time to making the additional armor bolted to the right front hull of the two StuGs ... These kit from Meng of Nuts and Bolts are simply useful!!!
Making two add armors with 1mm thick plasticard and
Nuts and Bolts large set from MENG (#SPS-004)

The SuG girls with add-on armor

Starting the dozer: making two blades with very-thin plasticard, as template
Measures in milimeters...

Gluing the two blades together ...

And testing in front of vehicle...
So far...so good...

Side view...
      The frame on the front deck seems to me to be rigid (green arrows), with two screws acting as a jack-type to press and lock the frame on the Stug's snout (blue arrows below).
Dozer's frame details...
      The vehicle has only two hooks on the front glacis and I think that the engineers must have made a system that could be assembled and disassembled using the normal vehicle mountings, in order to be interchangeable with other vehicles of the same standard (see red arrows below):
The StuG's front hull tow hooks. I cut the locking pins
to start the dozer blade frame construction process ...
      I am trying to design a structure that could be "fitted" to the front of the vehicle, attached to the two front tow hooks and locked with the two jacks. There could be a pivoting system, suggested by the rounded cuts of the two forks of the frame and a possible access to this adjustment through the rounded cut at the top of the junction between the two "leaves" of the "V" blade dozer (see the red arrows in the picture of real vehicle above). A blade movement would be highly desirable, to relieve the structural pressures of a totally rigid system, for example ... The Panther blade system seems to be quite different, but perhaps following the same principles. I will try to reproduce what is visible and extrapolate what is hidden ... 
Panther Ausf D Dozer.
      Damn it, Jim ... I am a Dentist, not an Engineer!!
Sorry, Guys!!!
       The first attempts to build the frame, with Plastruct stuff; If everything goes correctly, I will publish a photo with the final measures ...
The frame: top view

The frame: front view

The frame: 3/4 front view

And in place: the frame will be
locked in the front hooks (red arrows) and
with the jacks (vertical red arrows)...
Stay sharp!!!