Thursday, 23 March 2017

SU-122-2 in Combat

The CIA has a tendency of detecting all sorts of armoured vehicles that are as interesting as they are fictional, but this time they might have hit the mark.


Two guns, like a SU-122, but larger. There can be only one answer!

Wednesday, 22 March 2017

SU-76-57

"Mounting of a 57 mm mod. 1943 gun on a SU-76M SPG

This project is being designed according to an order from the Artillery Committee and consists of the installation of a 57 mm mod. 1943 ZIS-2 anti-tank gun barrel on the mount from the 76 mm mod. 1942 ZIS-3 gun on the SU-76M SPG chassis.

The ZIS-2 and ZIS-3 have identical semi-automatic systems and breeches.

The main characteristics of the prototype are shown in the table next to those of the SU-76M:

Tuesday, 21 March 2017

Light Tanks, 1944, Part 2

"To the Chief Engineer of factory #174, comrade Demyanovich
January 26th, 1944

Regarding your inquiry relating to tactical-technical requirements for a light tank, here are the possible changes to requirements:

Monday, 20 March 2017

Light Tanks, 1944, Part 1

"To the Chief of the GBTU Tank Directorate, Major-General comrade Afonin
January 5th, 1944

The preliminary tactical-technical requirements for a light tank that you sent were examined by a small circle of design and technology managers. Having studied your requirements in detail, we came to the following conclusions:
  1. In general, the requirements are realistic and such a tank can be designed and built at our factory.
  2. A number of issues you presented require special investigation and only then can they be implemented in a production vehicle.
Based on the above, we ask you to consider the following wishes of the factory when composing the revised tactical-technical requirements.

Saturday, 18 March 2017

Light Tank M3A1: Basket into Battle

History knows many instances when an attempt to improve a design led to, if not a worse one, then at least an equivalent. The American M3A1 light tank is one such example. Even though its modernization improved some characteristics, the well-intentioned modifications had some unintended consequences. Let us go through them in order.

Friday, 17 March 2017

Sweden's Autoloaders

Sweden's tank industry was in crisis in the second half of the 1940s. On one hand, the middle of this decade was a time when Swedish self propelled artillery thrived. That is when the Swedish army finally received assault guns, tank destroyers, and SPAAGs. However, the tank program lagged behind. Sweden's luck ran out with the Strv m/42. Pricken, LS 46, Leo, all of these projects remained on paper. Attempts to build a new tank weighing between 25 and 30 tons encountered various problems. A way out of this dead end appeared in the early 1950s, which led to two interesting heavy tank projects: the EMIL and the KRV.

Turtle Tank

Continuing the theme of sketchy intel on the Soviets the CIA got from the Germans, a phantom tank appears on the Volkhov Front, completely unknown to the Soviets, but apparently common enough in German eyes to even earn a nickname.

Wednesday, 15 March 2017

S-51

"Installation of a 203 mm mod. 1931 howitzer (B-4) on a KV-1S chassis (factory index S-51)

Produced by NKV TsAKB by order of the GAU Artkom.

The self propelled S-51 howitzer consists of the oscillating part of the 203 mm mod. 1931 howitzer (B-4) installed on a KV-1S. The installation is done in the following way:

The turret and turret ring are removed from the KV-1S. Instead of the turret, a plate is installed above the driver's head and the 203 mm mod. 1931 howitzer (B-4) is installed on it.

The fighting compartment remains free and is used to house the recoiling parts of the howitzer at high gun elevations.

Tuesday, 14 March 2017

Under Pressure, Part 2

In Part 1, we saw what happens to a tank crew when it's hit with a HEAT shell, whether that shell penetrates or not. However, getting hit with a kinetic penetrator has consequences too! Let's take a look.

"To compare, a table of measurements inside armoured compartments on impact from armour piercing and high explosive 76, 85, 100, and 122 mm shells with sensors positioned 200-1000 mm from armour, under the condition that the armour integrity was not compromised."

Monday, 13 March 2017

Under Pressure

HEAT is a much more complicated armour penetration mechanism than traditional kinetic penetrators, and thus leads to more interesting experiments. For example, in this one, the objective of the test was to determine how effective ERA was at disabling the heat blast, but more importantly, what an ERA block detonation would do to the crew.

The trials were performed on a model simulating a tank with ERA. Rabbits inside the model simulated crew.

Fig. 29. Overall view of model #2 with a U-5TS gun barrel installed.

Friday, 10 March 2017

CKD Export Tanks: An Offer You Can't Refuse

Czechoslovakian tank manufacturing caught up to world standards in the mid-1930s. The P-II, CKD's first light tank and the first mass produced domestically designed tank, was close to the world's leading designs. The LT vz. 35 that won the tender for a new cavalry tank caught up with the rest of the world's leaders. It's not surprising that Czechoslovakian tanks were considered for purchase in countries without a domestic tank design program. This caused the design of the CKD TNH and LTP (Tanque 39); excellent tanks that became the backbone of the Iranian and Peruvian tank fleets.

Thursday, 9 March 2017

SU-85 Light

"Installation of an 85 mm D-5 gun in a light SPG

The Gorky Automotive Factory is building an experimental 85 mm SPG using T-70 tank and SU-76M SPG components

Tactical technical characteristics of the prototype:
  1. Mass: 12,000 kg
  2. Full length with the barrel: 5500 mm
  3. Bore axis height: 1670 mm
  4. Maximum speed: 35 kph
  5. Muzzle velocity: 782 m/s
  6. Armour piercing shell mass: 9.2 kg
  7. Vertical range: -5° to +15°
  8. Horizontal range: +/- 12°
  9. Sights:
    1. Mechanical with Hertz panorama: 1
    2. TSh-15 telescopic: 1
  10. Ammunition capacity: 40 shells
  11. GAZ-203F engines: 2
  12. Total engine power: 170 hp"

Wednesday, 8 March 2017

D-10 CIA Intel

The following are penetration and ballistics tables for the D-10 gun mounted in a T-54 tank recovered by the CIA from a Soviet manual. 


Tuesday, 7 March 2017

PzI Trials

"Conclusions

After concluding trials of tank #1, it's possible to make the following conclusions:
  1. The tank has the following mobility characteristics:
    1. Maximum speed on a paved highway in packed snow: 39.96 kph
    2. Average speed:
      1. On paved highway in packed snow: 25 kph
      2. On dirt road covered in loose snow, 200-300 mm deep: 9-10 kph
      3. Off road with snow 300-450 mm deep: 6-7 kph
    3. The dirt road and off-road performance of the tank in 200-450 mm of snow is satisfactory.

Monday, 6 March 2017

American Ergonomics

Ergonomics in tanks is an important factor, one that I touched on previously in some detail. It turns out that despite certain prevalent stereotypes, the ergonomics of various tank schools are more complicated than many people believe. Having already applied Soviet ergonomics standards to a German design, let us hop across the pond and see what the Americans thought about the topic.

Thankfully, this time, the Fort Knox Medical Research Laboratory report "Adequate Head Room in Tanks" provides us proper measurements, which makes my job a lot easier. The adequate head room for a sitting crewman, excluding the upper and lower 5% of men, is stated as 34" to 38.25", or 86-97 cm. The Soviet "dimensions of an average man" define the same measurement to be 90 cm (35.4"), which falls pretty well in the middle of that range. The American tank helmet adds a whole 1.5" to the height of a tanker by his crash helmet, a thickness that is found to be excessive. At the time of the study (November 27th, 1942), a thinner helmet was already being tested.

Let's see how well average people could fit into American tanks.

Sunday, 5 March 2017

Pz.Sfl.IVb: Halfway to the Hummel

German wartime SPGs are well known. However, it took some time to develop the "selbstfahrlafette" concept of a large open casemate, like the one used on the Hummel. Initially, the idea was to built medium SPGs instead of light ones, and their layout differed noticeably from the vehicles that showed up on the battlefield in 1943. Even though German SPGs developed along a different path, the Pz.Sfl.IVb was built and even got to fight.

Saturday, 4 March 2017

02SS Aerosan: A Tank in the Snow

The history of the aerosan in Russia and then the USSR is old and varied. The first mass produced aerosans were built in 1912, were actively used in WWI and then the Russian Civil War. Development of aerosans received great attention due to the geographical features of our country. It was not surprising that the Red Army had the largest aerosan fleet in the world during the Great Patriotic War. Meanwhile, the widely used NKL-26 reconnaissance aerosan was a pale shadow of what was initially planned for production. The wishes of the Soviet military materialized as the 02SS battle aerosan which had no equivalent in any country in the world.

Thursday, 2 March 2017

New KV-2 Turret

On May 6th, 1940, the deputy chief of Kirov factory's SKB-4 design bureau proposed a modernized turret for the KV-2 tank.


This new turret was 2000 kg lighter than the old one due to reducing the height by 370 mm and length by 300 mm. The turret would retain 360 degree rotation with a gun elevation of 15 degrees and gun depression of 7 degrees. However, this turret could not be used until the gun recoil length was decreased from 900 mm to 650-750 mm. This was considered unacceptable and the turret was not produced.

Wednesday, 1 March 2017

Tank Costs, 1943

"To the Deputy Chair of the Council of People's Commissars, comrade Malyshev

I present to you a report on the cost of KV-1S, KV-8S, T-34, and T-70 tanks, their armament and optics.

Type
Cost w/o armament or optics
Cost of armament and optics
Cost of radio
Cost of hull and turret
Cost of engine
Cost of track links
KV-1S
225,000
32,287.95
12,000
65,000
27,000
Link: 105
Pin: 8
KV-8S
234,000
27,033.03
12,000
65,000
27,000
Link: 105
Pin: 8
T-34
135,000 (#183)
162,000 (##112, 174, UZTM, Kirov)
25,589.09 with PT-K
25,614.07 with PT-4-7
3,300
45,000
27,000
With tooth: 51.75
W/out tooth: 36.80
Grousers: 18.60
Pin: 2.40
T-34 (radio)
139,500 (#183)
166,500 (##112, 174, UZTM, Kirov)
25,589.09 with PT-K
25,614.07 with PT-4-7
T-34 (flame-thrower)
139,500 (#183)
166,500 (##112, 174)
31,711.84 with PT-K
31,836.82 with PT-4-7
T-70
61,300
7,702.80
12,500
7,000
Link: 22
Pin: 1
T-70 (radio)
63,800