- Yes
- No
caid’s suggestion #162
I will suggest here a most needed ammunition for the French early vehicles, the Brandt 37/25
the Brandt 37/25 was a newly introduced ammunition for the France tank gun and light infantry cannon known as the Puteaux SA18 and TR16. the 37mm gun was a WW1 gun that was still massively used in 1940 by the French army but was in the process of replacement in the tanks division by the 37mm SA38 and in the infantry by the 25mm SA34. In 1935 an APCR round was introduced for the tank regiments to be used in the 37mm SA18 mounted on the Char R.35 and H.35, the gun needed a small modification, the gun sight had to be changed to give the proper accuracy of the projectile over the range (in theory the older SA18 could still fire the APCR) but the battle of France starting in 1939 against the German show the SA18 was too ineffective, even with the new APCR who had nearly twice the penetration of the regular AP rounds. it was clear the 37mm SA18 needed to be replaced and the replacement was ongoing.
with the production of the new gun being unable to catch up with the needs of the army, sometimes unable to produce the gun at the same rate as the tank produced, it was clear that the 37mm SA18 would still be in use for a bit longer and the necessity of the war force them to be used in the frontline. it was why the French army turned to a french industry named Brandt who was developing a new family of anti-tank ammunition for the existing armament.
Brandt had recently designed an innovative type of round which were using a sub-caliber inside a discarding projectile. the aluminum sabot would break when leaving the barrel after being fired, the 3 parts of the sabot would fall in the field and a smaller and lighter core would become the only real projectile, flying at a higher speed and offering a higher anti-tank capacity. the core has been caliber 25 mm, would have gather the whole energy of a 37mm rounds concentrated to give it a higher speed. this would be commonly known later in the tank weaponry as APDS (armor piercing discard sabot)
this APDS was offering an important buff to the 37mm SA18 and TR16 used in the French army. in early 1940 an order of 200,000 rounds was made in emergency by the French army who hoped to give their obsolete armament a bit of effectiveness while waiting for their replacement. of the 200,000 rounds, it is unknown how many were produced. it is assumed that only a small quantity was delivered to the French army and certainly used nearly immediately by the frontal units who were having heavy fighting and were in dear need of something capable of penetrating the German tanks at combat distance using the obsolete guns.
only 2 projectiles is known to have survived and were used as a display. it is assumed it originally had 2 other projectiles in the same display in different forms, in the display we can see the full projectile with the sabot, the projectile with part of the sabot removed showing the 25mm core well and we can see 2 other cavities for the 25mm projectile and the hardened core the 25mm carry. the information we can find on the projectile in the archive so far offers 2 details, the velocity, and a brief description of the projectile saying it was a 25mm projectile with a hardened core. we still need to find essential information which is the weight of the projectile and the dimension and weight of the core. this is where the display come handy as we can easily calculate the approximate size and weight who are missing.
Calculation
he average weight of Steel: 7.80 g/ cm3
the average weight of tungsten: 19.25 g/cm3
knowing the basic weight of the composite, the only thing I need to do is to evaluate the volume of the projectile
I happened to have found a photo of the rounds who give away a lot of information about his proportion. stating with the fact that the round is a sub-caliber round of 25mm, we can start with the 25mm for referential data of the total weight.
from what I do understand about this picture, it was a display of the rounds and his various compositions. you might notice the right part has 2 empty holes, that were probably meant to have the whole projectile without Sabot and the Tungsten core next to it.
so we will just evaluate the size of those part to get a approximate weight. that is not verified weight but just an estimation. That might be different in real but it would at least allow Gaijin to have a bit of referenced guesswork rather than randomly assume his weight by using other rounds (like the Swedish APDS) i will give you the measurement picture. I simply count the pixels to evaluate the dimension.
reference measurement
Red A : 70 pixels = 25mm (about 2.8 pixels by mm)
Red B : 105 pixels = 37mm (about 2.83 pixels by mm)
that seems close enough to estimate the size as there is the similar result on both using a rule of 2.81 pixels by mm.
here is the measurement of the cylindrical part of the projectile in blue (will be calculated as a cylinder)
Blue A : 70 pixels = 25mm
Blue B : 111 pixels = 43mm
giving a 21.108 cm3
here is the measurement of the pointy end of the projectile in green (will be calculated as a cone) the angle is not perfect so the calculation is adjusted to 1mm = 2.64 pixels
Green A : 66 pixel = 25mm
Green B : 154 pixel = 58mm
giving a 9.49 cm3
the estimated total volume of the projectile should be around 30.6 cm3
but it seemed there was also a tungsten core inside. that is likely to be the small empty hole at the far right. I would just calculate this core and calculate both parts with different weight references, so we should get the proximate weight of the real projectile
reference measurement
Red A : 70 pixels = 25mm (about 2.8 pixels by mm)
Red B : 105 pixels = 37mm (about 2.83 pixels by mm)
I will just measure the core as a cone from the start. but I will do it in two parts. since the tips are a lot less sharp than the rest.
Yellow A : 54 pixels = 19.3 mm
Yellow B : 147 pixels = 52.5 mm
giving 4.962 cm3
with those two parts estimated, we can calculate the total volume of the rounds, but we need to be careful, as the core would be inside the projectile so we have to remove the core volume from the total projectile volume to calculate his weight separately.
30.6 - 4.96 = 25.64
the projectile vole would be around 26.25 cm3 without the core. that would be the volume of the steel part of the rounds.
25.64 x 7.8 = 199.992
199.99 is the estimated weight in grams of the round without a core. let’s just say 200g
now the core. it is to assume it was made of pure tungsten or almost pure one.
4.96 x 19.25 = 95.48
Let’s simplify it to 95…5 winches would be the weight of the core in grams.
so according to this calculation, the weight would be more or less 305 g which is similar to the 25mm rounds found in other guns. the velocity is known to be 825 m/sec at the muzzle. this gives us all the data we need to figure out the performance of the projectile against a tank at 90°
- Weight : 305 g (average estimation)
- Velocity : 825 m/sec
I - 54mm at 0 meter, angle 0°
- 51mm at 100 meters, angle 0°
- 45mm at 500 meters, angle 0°
- 38mm at 1000 meters, angle 0°
- 30mm at 1500 meters, angle 0°
if we consider the 37mm SA18 in game has a penetration of 34mm at point-blank, we can safely say this round offers a neat improvement. it is even better at distance the than the 37mm SA38. but there is a catch. the SA18 is a very short gun with a short barrel that gives little accuracy and the APDS is a round that offers a lower accuracy than the conventional round. while capable of penetrating most targets at 1000m, it would have difficulty landing a hit on a target at 500m.
the round would not be accurate, which is not a real problem. the 37mm SA18 is a quick reload gun and the tanks that have it are well protected, they are ideal for close combat.
adding this round would make the French H.35 and FCM 36 playable even with the new player. it would also make it possible to add other French tanks that have the same armament such as the R.35, AMD 165, or P.26
Sources
evenement survenue en france 1933 - 1940 (those are investigation record to find out why France had lost the war) page 2159. the engineer Martignon confirmed the rounds was ordered for the army. see the fallowing spoiler
France 1940 : l'armememnt terrest, by Stephane Ferrard, page 93/94, it show the schematic of the rounds, indicate the velocity and give a few details about it. page in the fallowing spoiler
