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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.

15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I - case report

 Kanoniere !!!

    Our subject today is a peculiar self-propelled artillery vehicle. Built in small numbers at the beginning of WWII, it played a decisive role in supporting fire for infantry in the shocking early days of applying the Blitzkrieg doctrine.
      We are talking about the 15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B, the Bison I, which looks dubious, but has proven great efficiency!

Two 15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B
named DORA and BERTA from 7th Panzer Division
705 sIG Company waiting in Anheé - Belgium
May, 12 - 1940.

History:
    The 15cm sIG 33(Sf) auf Pz.Kpfw.I Ausf B, sometimes referred to (unofficially) as the Sturmpanzer I Bison was a German self-propelled howitzer used during World War II
15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B
proudly bearing the name Cambrai.
Notice the chicken coop screen to facilitate the use of branches as camouflage
2nd Panzer Division - 703 sIG Company
Battery C - Russian front - 1941

    The Invasion of Poland had shown that the towed 15cm sIG 33 guns assigned to the infantry gun companies of the motorized infantry regiments had difficulties keeping up with the tanks during combat. 

A battery of 15cm sIG 33 in action
Liege - Belgium - May, 1940.
    The easiest solution was to modify a spare tank chassis to carry it into battle. A sIG 33 was mounted on the chassis of the Panzer I Ausf. B, complete with carriage and wheels, in place of the turret and superstructure. 


15cm sIG 33 on the Pz.Kpfw.I Ausf. B chassis
First prototype of Bison I
Germany, Spring, 1940.
    Plates with13mm (0.51 in) thick were used to form a tall, open-topped fighting compartment on the forward part of the hull. This protected little more than the gun and the gunner himself from small arms fire and shell fragments, the loaders being completely exposed. The rearmost section of armor was hinged to ease reloading.
The Bison I - superstructure detail
    There was no room to stow any ammunition, so it had to be carried by a separate vehicle. When mounted, the sIG 33 had a total traverse of 25° and could elevate from -4° to +75°. The gun used an Rblf36 sight. The chassis was overloaded and breakdowns were frequent. The vehicle's high profile (and therefore an easy target ...) and lack of on-board ammunition were severe tactical drawbacks. Thirty-eight were converted in February 1940 by Alkett.
   In the video below, see the evolution of the 15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B concept:
    In the video above, the scenes in which the 15 cm sIG 33 (Sf) auf Pz.Kpfw. I Ausf B is shooting are too dark (Game of Thrones - final season effect ...). I dig this movie in  the Internet, remastered and much more visible, showing this part of ht firing action (see video below). Notice how the vehicle "jumps" when its main weapon is fired, as the lightness of the chassis does not allow an adequate dissipation of the energy generated by the shot.

A 15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I
 "roaring" down a road, on a convoy with Peugeot DK 5J 1.4 ton truck
9th Panzer division - 701 sIG Company - Battery D
Operation Barbarossa - 1941

15cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I
10th Panzer Division - 706 sIG Kompanie
Battery E - Russian front - 1941

In Action:
    Thirty-six vehicles were organized into independent schwere Infanteriegeschütz-Kompanie (mot.S.) ("self-propelled heavy infantry gun companies") numbers 701-706, assigned to Panzer divisions in the Battle of France, as follows:
    As part of the 5th Panzer Division, assigned to the German XIVth Motorized Army Corps, the 704th company participated in Operation Marita, the invasion of the Balkans.
    Later in 1941, the same assignment was maintained for Operation Barbarossa, the invasion of the Soviet Union. The 705th and 706th belonging to the 7th and 10th Panzer Divisions respectively, were destroyed at this time. Of the remaining companies, only the 701st participated in the opening stages of the subsequent Case Blue in 1942, although it, and its parent 9th Panzer Division, were transferred to Army Group Center by the end of the summer of 1942.
15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I
DOAUAUMONT - 2nd Panzer Division - 703 sIG Kompanie
Battery D - France - 1940

15cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I
1st Panzer Division - 702 sIG Kompanie
Battery F - France - 1940

15cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I
EDITH - 2nd Panzer Division - 703 sIG Kompanie
Battery E - France -  June, 1940
Notice the cross painted in the left fron gun shield:
a crew member killed in 24, May - 1940.

Same 15cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I above
EDITH - 2nd Panzer Division - 703 sIG Kompanie
Battery E - France - 1940

15cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I
1st Panzer Division - 702 sIG Kompanie
Battery B - France - May, 1940

Drawing of the same vehicle above

15cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I
ALTER FRITZ - 2nd Panzer Division - 703 sIG Kompanie
Battery A - Greece -  April, 1941
Drawing of 15cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I
ALTER FRITZ

The same ALTER FRITZ Bison I above, few months later...
2nd Panzer Division - 703 sIG Kompanie

War butin... a Voroshilovets tractor towing a badly damaged
15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B from
10th Panzer Division - 706 sIG Kompanie
Russian front - Winter, 1942
    The last reference to these vehicles is with the 704th Company of the 5th Panzer Division during the middle of 1943.
The last of the few...
Specs:

15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B - Bison I
TypeSelf-propelled gun
Place of origin                        Nazi Germany
Service history
In service1940 - 1943
Used byNazi Germany
WarsWorld War II
Production history
Designed1939-1940
ManufacturerAlkett
ProducedFebruary 1940
No. built38 converted
Specifications
Mass8.5 tonnes 
Length4.67 m
Width2.06 m
Height2.8 m
CrewFour

Armor13 mm - 5 mm
Main armament
Engine6-cylinder, water-cooled 
Maybach NL38 TR 100 hp
Transmission5 forward +1 reverse 
Operational range
140 km
Maximum speed40 km/h

The kit:
    For this commission project, the kit I'm going to use is a classic (2005) from the scale model world: the Alan (#019) Bison I. 
The veteran from 2005 Alan Bison I (#019) box art
    I think I bought this kit at that time and I haven't had the opportunity to build it yet ... And that opportunity has arrived. Nowadays we have even more modern and detailed options to represent this SPG model, like the excellent Dragon (#6259) 15cm s.IG.33 (Sf) auf Pz.Kpfw.I Ausf.B Smart Kit , but as I have the child Alan in my closet, we will dare to build it !!!
Dragon 15cm s.IG.33 (Sf) auf Pz.Kpfw.I Ausf.B Smart Kit box art 
        Let the battle begin !!!  The Alan Bison I is a very complete kit, with plastic sprue, photoetched fret, decalsheet (waterslide) for 4 versions and tracks link-by-link (which many like, but I hate ...). The details are poor, but I've seen much worse kits ...
Kojak doesn't seem to be very excited ...

Starting from the beginning ...
The bathtub on the chassis came without warps or problems ...
The interior details are very Spartan ...

The holes for the drive sprockets are huge ...
I closed the holes with plasticard and I'm going to
reopen them with drills in the correct diameter ...

New "bushing" for the drive sprockets

Using the old technique of heating a metal to melt the ends
of the axles and keep the sprockets turning ...
    As I always do, I like to study the construction drawings to avoid surprises and headaches ... And here's a big problem: after step 2 of construction, there should be a step on how to glue the front bottom armor to the front portion of the lower hull. This stage simply does not exist ... 
    Well ... let's deduce that the part fits the lower hull front opening and after sliding to the rear bottom armour, it rotates and the transmission shaft cover fits into a recess in inner portion of the bottom armour. See the "original" drawing of the Alan's Bison I instructions booklet, below:
Alan's booklet: steps 1 and 2.
    The big problem is the C3 parts, which support the suspension shock absorber arms. The C3 parts have a small tab (see below - red arrows) that should fit into a slot in the front portion of the armor bottom, but when trying to do this maneuver, the bottom of the driver's station just doesn't fit. The best option I found was to cut this small tab of the C3 pieces (left and right) and glue this fragment into the armor at the bottom of the driver (pink details below). Also cut the two suspension bars that are on the sides of the drive shaft cover (light green arrows). You'll be able to replace them later, much more easily. With that, the armor bottom front rotates normally and everything fits together satisfactorily ...
The "new" step 1+2 in details...
    See the C3 tabs cutted and glued in the bottom armour of driver station (red arrows below):
The C3 tabs glued in the new positions...

The surgery in the suspension bars. These are the
light green arrows in the drawing above...

The driver station already painted, ready to be glued
to the lower hull (which has also been painted ...)

The driver station glued in position.
Notice the suspensions bars glued in place...
A pity that almost no detail is visible

By the booklet, now: PE grill in position in the rear deck
        After that, I used the rest of the paint in my airbrush and sprayed over the kit... I hate waste !!!
The rear deck in position and the little girl
with their paws installed ....
left side

Right side...
    Sometimes, it is very pleasant to make a small up-grade with simple materials, but that represent great details. Here is a good example: The C30 parts (in the red circle, below), which "reproduce" the return springs of the rear fender flaps are simply horrible ... 
      Its replacement is simple and quick: two little parts of Plastruct (0.5mm round rods) supporting the "spring" made with the handle cut from an acupuncture needle. Here is the final result ...
How nice and fun it is to improve a "spartan" kit with simple techniques ...
Here's the detail of the fender flap springs ...

The new spring in the fenders flap...

Another detail to enrich our poor kit: grills in the rear deck (red arrow).
In red, the flaps springs...

Testing the fit of the Bison's front armor. NOT GLUE THIS PART, YET!!!
Man, the thing is too big...
A headwind should be a nightmare for the poor engine ....

The driver's view was tunneled... Poor Kraut!!
I finally found a worse visual field than the Churchills drivers ...
Next step: the Big-badah-boom gun!!!
    Indeed, the big 15cm sIG 33 howitzer is a big weapon. The instructions are perverse... You need to study pics, drawings and other better instructions for other kits (thanks a lot, Scalemates!!) to build this gun in the right way... From what I've built so far, Alan's kit isn't that bad. The worst, in my opinion, are the instructions, which do not clarify the small "big" details. And this defect is evident at this stage of the howitzer's building.
The gun barrel in his cradle. Many important details are omitted in
the damn instruction booklet ... Definitely not a starter kit ...

Rear view of the breech and cradle...

The gun barrel in his cradle, finished...

The gun's front shield. Internal view...

The gun shield and wheels...
Again, the booklet is a true nightmare...
The holes in the shield must be must be closed at this stage ...
 and the retard here forgot this...

The complete trial of the howitzer...
That lever (red arrow) is glued in wrong position...

Adding thin plasticard (0,3mm) to "laminate" the big, very big
"canyon" between the two parts of the gun's trial.
This was the biggest defect in the kit detected so far.
The looks would be just awful without this "lamination",
as the trim would be visible on the finished vehicle ...

The cradle in the trail. The howitzer's elevation and depression
capabilities were maintained... with blood, sweat and tears!!
    The worst part is the installation of the wheels in the trial of the weapon. In this matter, the booklet is practically useless... I recommend anyone who builds this kit to study the Dragon booklet (... of the same vehicle) or the AFV Club booklet, of SIG 33 kit, which allows a "spatial" view that can guide you through this Valley of Shadows and of Death. Be very careful with the perpendicularity of the wheels in relation to the "chassis" (trial) of the howitzer.
    Testing the gun in dry-run on the vehicle is very, very important ... And do not stick the front shield of the vehicle except in the last step ... A great reference is to glue the wheel supports to the hull of the vehicle, with the front shield installed (but not glued ...) in position. The wheel supports have two tie rods that extend from the rear deck to the correct position of the parts. Forget the bottom pins of the brackets: they get in the way that help. I cut them without the slightest remorse. 
    Sorry for the absence of the photos, but this stage is so "manipulated" that it was almost impossible to photograph it. What was left of teaching was what I mentioned: first install the wheel supports!! These parts are your guide on installing the gun on the vehicle ... See the diagram below, modified from (damn) booklet:
The gun assembly sequence: See red circles:
  1. Glue the part B49 in the rear edge of the rear deck. Be very careful with the alignment 
  2. Install (NOT GLUE) the front shield in correct position. You can move it back and forth
  3. Glue (minimum quantity) the rods in the part B49 and part B44 (minimum quantity)
  4. Glue (minimum quantity) the wheel supports. Careful that glue not stick in the front shield
  5. Test the howitzer position in place...
  6. The pin B69 is the final test of the correct position.
    If all ok, you can reinforce the glue, now.
The final picture of the sequence above...
Left side

Right side

The girl almost ready for painting...
I choose to use the spare wheels in the front armour...

Do you remember the little holes??
Closed with 0,3mm plastic discs cutted by my punch-and-die tool...

This girl is sooo cute!!

Indeed, very interesting...

The end is near!!

For those who still doubted that Kojak is "kind of weird"...
Look what he is planning ...
If Alan wasn't enough, how about an old Zvezda to train his skills ???

Indeed, the Bald one is a brave and courageous man !!!
    Now, the best part ... the markings. The decal sheet is very good, but as I chose the spare wheels in the front armour, the decals provided are incompatible with my research, since this positioning of the spare wheels was almost a characteristic of the 701 Company, of the 9th Panzer Division, on the Russian Front in 1942. It was a temptation to use decals with vehicle names, but History is History !!!
       So, let's go to the torrid summer of 1942, meet our little girl:


    First of all, primer. I use the Vallejo one. No, I'm not a sponsored modelist, but I have adapted to this product and use it constantly. Many love him ... many hate him. I just use ... and I like it. 
    My two cents !!
And I also love using light-colored primers.
I didn't adopt the dark primer of "fashion ntendence" (which I really don't like !!!).

Right side

Panzer-gray with many shades...
and Future to prevent silvering...
(again, Johnson & Johnnson don't sponsor me ... but I love Future!!!)

Right side

Rear view

Two Panzer-gray girls, in in the beauty salon, waiting for the makeup ...
But this is another history...

  Stay with us, to see more about this Bison!!!