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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.

Renault FT 17 75BS tank prototype - case report

Brave Poilus!!

    Mes amies...Today we are going to know a little about what can be considered one of the cars that originated the concept of "aggressive" self-propelled artillery, such as the Soviets' Su and the Germans' Stugs... Let's go back in time, in the muddy and cruel WWI and we meet with the french prototype Renault FT 17 75BS tank.

Colorized picture of Renault FT 17 75BS, prototype of the "artillery tank"
 with the 75mm BS gun in the front hull

History:

    The artillery is known as "The King of the Battlefield". And never has this been so exemplified as in the bloody fields of Europe in the WWI... The amount of projectiles that were fired by the countless cannons, mortars and howitzers of all the powers involved in the conflict is unimaginable. And all this artillery barrage convulsed the terrain of the battlefield, And all this artillery barrage convulsed the terrain of the battlefield, transforming the soil of the battlefield into a real challenge to be traversed by men, animals, machines and equipment.
Passchendaele battlefield and craters in which man often drown.
Third Battle of Ypres , July to November 1917, Belgium
    At the beginning of the WWI, France (like all other countries) used teams of horses to pull artillery pieces, but with the increase in the calibers (and weight...) of the guns and materials involved, as well as the terrain, which was convulsed by enemy artillery, the animal traction became increasingly complicated, with the animals being easy targets and not supporting the load imposed on them. 
The effort and the silent sacrifice...
The breakthrough west of St. Quentin, Aisne, France.
German Artillery drawn by horses advances through
captured British positions on March 26, 1918...
An estimated 8 million horses died during the four years of the WWI.
National Archive / Official German Photograph of WWI

    With the advent from the first sketches of mechanization at the front, with the presence of trucks and agricultural tractors adapted to be artillery tractors, there was an improvement in the situation, but the logical solution was to provide the artillery with self-propelled capacity. 
    This (logical) concept was fought at first, mainly in the minds of old Generals with mentalities rooted in old principles. The massive advances of infantry units against automatic weapons was bloody proof of the obtuseness of ancient tactics in the face of modern weapons...and exacted a terrible price.
    Something had to be done...Wheeled vehicles faced great problems in difficult terrain...the few and primitive agricultural tractors with tracks used as artillery tractors proved to be much more useful for the task, being seen as a path to be followed by the military.
    In France, the Ministry of Munitions and the French Army High Command have researched almost every possible option for moving artillery using tracked vehicles. The conclusion was that there were only two chassis suitable for the task: the Renault FB Artillery Portee and Schneider CD tractor. The Char Saint-Chamond had an off-road speed of only 2.5 km/h, so it was considered unsuitable for a quick response to the fluidity of the artillery's tactical situation.
A French Renault FB Artillery Portee
carrying a heavy cannon on the Western front.
Schneider CD tractor in trials
front view
The slow and clumsy char Saint-Chamond tank
    With the satisfactory use of the tank, someone soon imagined equipping these vehicles with more powerful weapons. And so, the concept of self-propelled artillery was born.

Renault FT 17 75BS tank prototype:
    The Renault FT light  gun tank appeared on the battlefields late in 1917, and in significant numbers in 1918,  featuring in a 360° rotating turret a machine gun or a low-velocity 37mm cannon. With combat use, it became evident that although the 37mm gun was quite competent to deal with light fortifications, a weapon that delivered greater explosive weight was needed to attack more elaborate fortified positions.
Takom (#TAK1003) kit box art
    In July 1917, General Estienne, known as "Father of the French Tank Corps", specified that a vehicle should be developed using the chassis of the new Renault FT-17 light tank, carrying a 75mm Blockhaus Schneider (BS) gun. The 75mm BS gun was originally a short-range demolition gun, which was mounted on the side of the Schneider CA1 tank
Schneider CA1 at the head of the ranks of French troops.
Notice the 75 mm Blockhaus Schneider (BS) gun in the front right side of the vehicle
   Although the 75 mm BS gun had a short effective range with low projectile velocity, its small dimensions, combined with light weight and high rate of fire made it attractive as the main weapon of an FT fire support tank.
75 mm Blockhaus Schneider (BS) gun
3/4 front view
Musée de l'Armée aux Invalides - Paris, France.

75 mm Blockhaus Schneider (BS) gun
3/4 rear view
Musée de l'Armée aux Invalides - Paris, France.

75 mm Blockhaus Schneider (BS) gun
3/4 front view
Musée des Blindes - Saumur, France.

75mm Blockhaus Schneider (BS) gun

caliber

75mm

barrel length (caliber)

L/9.5 (rifled)

effective elevation

-10° to +30°

traverse

40° (20°+20°)

projectile weight

5.55 Kg

muzzle velocity

200 m/sec

maximum range

2.100m

effective range

600m

weight of gun (firing position)

210 Kg

rate of fire

4-6 rounds/min


    In response to the War Ministry's request, Renault itself built a single prototype, based on the chassis and suspension of the light tank FT-17, but with a strange and improvised look box-shaped upper hull. An interesting detail was the presence of the main armament installed in a low position, in the forward portion of the hull, with limited drift. 
Renault FT 17 BS 75 tank prototype
 Notice the armament in the tank's nose...
Trials in France, 1919.
3/4 front right view.

Renault FT 17 BS 75 tank prototype
right side view.
The only two known (this and above) pics (so far) of this model...
Trials in France, 1919.
   This design, without a doubt, can be considered the conceptual predecessor of what would be the powerful Russian and German tank destroyers of  WW II, like the Su-85 and Stugs III and IV.
    During the trials with the prototype, the vehicle proved to be unstable and clumsy to drive, thanks to its high profile, which greatly raised center of gravity. The Commander/driver, moved up and to the middle of the vehicle, had a 360° view, but it was very limited by the small size of the vision slits of the stocky fixed quadrangular cupola. 
Renault FT 17 75BS Commander/driver cupola
Notice the small sizes of vision slits
    Worse was the position of the two gunners of the 75mm BS gun, which were squeezed into a narrow and awkward battle stations in the front hull. In general, the behavior in field of the prototype did not meet expectations...
    The Char de Combat C-2 was a design developed by Peugeot in 1918, to compete again with Renault's FT17 75BS, using the same main gun, the BS 75mm.
Peugeot Char de Combat C-2
Notice the gun, the same BS 75mm.
3/4 front view

Peugeot Char de Combat C-2
3/4 rear view
    Although the concept of using a 75mm cannon was well accepted, but both the Renault FT 17 75BS and the Peugeot C-2 were not accepted for production, the version that was produced (1918) being a much more simplified version FT 75 BS, as it kept the same hull as the FT17 light tank, with the replacement of the 360° rotating turret for a fixed octogonal turret, carrying the approved 75mm BS gun. But this is another history...
Renault FT 75 BS in trials

Renault FT 75 BS in trials

Line of  brand new Renaults FT 75 BS ,
waiting delivery to combat units.
    It is not known the fate of the only prototype built, after its rejection.

Specs:
Renault FT 17 75BS tank prototype
Typeself-propelled artillery
Place of origin France
Service history
In servicesingle prototype
Used byFrance
Designed
  • 1918 (late)
Specifications
Mass6.7 tonnes
Length5.003 mm with tail
4.114 mm without tail
Width1.714 mm
Height2.730 mm
Crew3 (Commander/driver
+ 2 gunners)

Armor8 to 16 mm
Main armament
75mm Blockhaus
Schneider (BS) gun
EngineRenault 4-cyl, 4.5 litre,  Gasoline (petrol);
Zenith carburettor,
Magneto ignition
39 hp @ 1500rpm
Power/weight5 hp/t (3.7 kW/t)
TransmissionSliding gear;
4 forward x 1 reverse.
Main clutch plus two subsidiary clutches
(tracks) for steering 
Suspensionvertical springs
Fuel capacity84 litres (about 8 hs)
Operational.range
35 km
Maximum speed                                  7,5 km/h road
3,5 Km/h off road

The kit:
    To do this commission work, I received this 3d printed kit from my client, for the construction: Renault FT-17 75BS prototype tank (R3D-220), from Vargas Scale Models.
Vargas Scale Models kit (#R3D-220) box illustration
        The kit is printed relatively well, with the highlight being the sponsos with the suspensions. The hull has the faint print lines, but still present... I am really concerned about the final appearance of the model after painting...
Kojak with printed parts of Vargas kit...
Notice the kit name plate folded...maybe a greater care
with the pieces after printing would prevent this...

Kit box contents...
    But the big problem was the hull of the vehicle. My piece came from Vargas with great contractions between the side panels, as if a weight had been placed on each surface. This "crush" formed like a "waist" in the tank...And the problem gets worse with the kit having the "bottom" of the hull glued (badly) with superglue, preventing access to the inner walls of the kit...
Right side of the hull, in front view.
Notice the bulging of the vehicle's surface, as if an elephant were on that face...

The worst degree of deformation is in the vehicle midline,
vertically and horizontally...
No good, Vargas!!!

Right side - front portion
As you approach the ends, the deformation becomes smaller...

Right side - mid portion
The greatest degree of deformation...

Right side - rear portion
Deformation is reduced...

Left side - front portion
The deformation is a little smaller, as on the left side...

Left side - mid portion
The deformation is huge!!

Left side - rear portion
Deformation decreases again, as on the other side

In a frontal view, the tank has a waistline that reminds someone...
But in a kit, that's pretty ugly!!
3/4 front right view

Really, the thing is very deformed!!
3/4 rear left view

The rivets lines graphically show the degree of deformity!!

The bottom of the hull is glued at the factory, with superglue.
Excess of material and dripping glue..
A little more care, Vargas, please...

But Kojak is not intimidated by certain problems...

Fractured part in the sid tail (red arrow)

In addition to the Marilyn Monroe-like waist,
the bottom had a downward bulge... Ouch...the thing promises!!
    Let's sand everything on the sanding glass plate, for the flattening of this surface...I tried to detach the piece from the bottom, but the crumbly consistency of the material prevented me from continuing...
Trying to rectify the bottom surface...
The lower portion of the hull does not have any rivet or plate joining details...
   My idea is to open up the bottom of the tank to gain access to the interior and install structural reinforcements to keep the hull in line. I'm going to heat the hull (face by face) with hot water and try to realign the surface of the armor...
First step: open the lower hull to gain acess to te tank's interior...
Using my rotatory tool in my Dremel. A very risc procedure...

Cutting four 2mm thick plasticard parts for the reinforcements...
I repositioned the walls as vertical as possible, compressing the faces into a flat and cold surface...and applied cold water to maintain initial stability...
The hull with walls after use of hot and cold water.
Notice the reinforcements...

The reinforcements installed and "sewn" with superglue,
throughout the contact area... This will keep the walls
aligned and stable...

Reinforcement done..
No more a curvy girl, but a smooth, perpendicular and straight hull.
Like a modern top model: a pool cue!!

Right side... Straight like a board!!!
The bottom was closed with 0,3mm thin plasticard

Left  side... Straight like a board!!!

Testing the flat surface!!
Mid position in the left side...

All ok!!!

Testing the flat surface!!
Mid position in the right side...

After this "frissom", everything seems to be back to normal...
Sponsons in position, in perfect perpendicular position...

3/4 front left view... I think everything is correct now...

Much better!!

Now it's time for the details... The 75mm Schneider Mortar

Let's rectify the hole in the gun...

    With the construction of the kit, I realized that the quality of the kit's printing leaves something to be desired... The presence of the printing lines really bothers me... Their removal would almost be a complete reconstruction of the kit, which is not the case. of this article. 
    But the big flaw would be in the dimensions and shape: the hull rivets are too big and deformed; the seams between the armor plates are wrong in the kit. 
   And the inexplicable thing is that these lines are perfectly visible in the existing photos, as well as the mistakes made by the manufacturer, such the centralized (...and wrong) position of the Commander's cupola, its shape, the rivets, the vision slits... Worse are the hatches in the front upper part of the hull, with wrong dimensions and positioning. 
   I hope Vargas Scale Models can and want to correct these flaws, as the kit is expensive. As the kit is by 3D printing, I think the correction is not that difficult... just look carefully at the photos and the 3-way drawings and re-render the model in 3D... Quite different from modifying an expensive one. machined form of an injected kit. See the picture below:
Some of the kit's most glaring flaws...
See below the correct shape of the vehicle

Ft 17 75 BS blueprint

Another unexplained failure is the absence of the vehicle's manual
engine starting system. But the scratch is easy...

As kit construction evolves, the "paternity" of future WW II destroyers is evident!!
Renault FT 17 75BS tank - left side

Renault FT 17 75BS tank - right side

Renault FT 17 75BS tank - right rear side view
Notice the anti-trench tail installed
Details broken in transport are made with white plasticard

Renault FT 17 75BS tank - left  rear side view
Notice the delicate cranks in the tail...
    The construction is very easy and fast, taking the corrections of the inherent defects of the kit... After the construction is complete, we will apply the primer. The print lines have diminished, but they haven't disappeared... to the point of interfering with my camera's auto-focus... the photos don't focus properly, which is very strange...
Primer Vallejo bronze green, with tones

right view of the vehicle

left rear view

Adding colors to the tracks...

Shades of dark-green

Vehicle muffler, after basic painting. Severe weathering will not be done
on this part, as the vehicle was a prototype of little use...

Painting with the application of Pledge, to facilitate the wash...

The wash in progression...

Wash in old-school way...
I decided to make one more detail to give the kit an "upgrade"...
How about using a Value Gear wooden crate as a tool chest???
Thin plasticard...

The padlock was made with plasticard
and fine copper wires...

The toolbox is in dry-run. The painting will be
performed separately from the kit...

Painting done!
Glued in position!!

Final results...
Notice the chain in the tank's rear...

Right side of the kit...

The lovely french maids (Kojak's assistants) approved and loved the skid tail...

Starting dust and earth shadows with airbrush...
left view

Dust and earth shadows with airbrush...
right view
    And the Renault FT 17 75BS tank prototype was ready...In summary, the kit is quite nice, but a pity that Vargas could have done something much better...
Renault FT 17 BS 75 tank prototype
Trials in France, 1919.

Renault FT 17 BS 75 tank prototype
upper front left view

Renault FT 17 BS 75 tank prototype
left view

Renault FT 17 BS 75 tank prototype
left rear view

Renault FT 17 BS 75 tank prototype
right rear view

Renault FT 17 BS 75 tank prototype
upper right rear view

Renault FT 17 BS 75 tank prototype
right view

Renault FT 17 BS 75 tank prototype
right front view

Renault FT 17 BS 75 tank prototype
with Kojak and Rover, the dog.

Renault FT 17 BS 75 tank prototype
with .Little Willie, in background


Sherman II direct vision with Renault FT17 75BS, side by side.

Renault FT 17 BS 75 tank prototype
Trials in France, 1919.

Thanks for following the article, guys!!!