Monday, 18 November 2019

Experimental Work at Factory #183 March 1941

"To the Chief of the 3rd Department of the BTU, Military Engineer 1st Class comrade Afonin

Summary report of experimental work performed at factory #183 in March 1941
  1. Trials of cooling fans: three types of cooling fans entered trials.
    1. 1st variant: instead of blade supports special ribs were used. A vehicle with this fan travelled for 800 km. Trials will continue in April.
    2. 2nd variant differs from the production type only in the riveted rim that is the same as the BT-7M type. A vehicle with this fan travelled for 400 km. rials will continue in April.
    3. 3rd variant: production fan attached to the flywheel with a friction clutch to slip in cases of rapid changes of RPM in the driveshaft. A vehicle with this fan travelled for 80 km. Trials will continue in April.
  2. Trials of the constant mesh gearbox were completed. This gearbox shows no advantages over the production type, and the top speed in 4th gear dropped by 5 kph, which is not desirable. There were also a number of defects found in several parts. It is pointless to implement this design into production.
  3. New types of cast driver's hatches with different types of thermal treatment were tested by fire. One type showed good results in terms of ballistic resistance. The decision to put it into production is being made by the BTU.
  4. Trials of a new type of turret ring with a different bearing runner to tighten tolerances. Trials showed that tolerances are tighter, but the turret can jam. Work on other variants is being performed.
  5. 8 types of air cleaners were produced. One of the types showed the best results (95% clearance) and was sent to Leningrad for government trials.
  6. Reinforced Hadfield steel tracks were produced and tested. The assembled tracks made it to 2500 km after which the pin eyes were severely worn and the tracks began to break, the same thing as with production tracks.
  7. Major modernization of the T-34: the model is complete. The design bureau is producing blueprints for the experimental design.
Military Representative of the GABTU, Military Engineer 3rd Class, Alekseev"

Saturday, 16 November 2019

A Barrel Too Long

Rapid growth in power of tank and SPG guns continued throughout WWII. Designers of some nations achieved the increase in firepower through a harmonious increase of gun caliber and barrel length. Other schools of design preferred to keep the caliber, but significantly lengthen the gun. The second approach was very common for German armoured vehicles. This decision had both positives and negatives. It turned out to be not so simple to install long guns on medium tanks. The Panzer IV/70 is a good example of this. An attempt to create a more powerful variant of the Jagdpanzer IV gave the tank destroyer both new abilities and serious problems.

Thursday, 14 November 2019

Pistol Power

Conservative elements within the tank corps favoured the Nagant M1895 revolver. It was relatively simple and could be fired out of a smaller pistol port than the TT. However, the Nagant took much longer to reload and could not use submachinegun ammunition in a pinch.

"For ISU-122 crews it is desirable to have a TT pistol, since the long loading time for Nagant revolvers puts the crew into a critical position. The limited amount of ammunition in a revolver causes frequent reloads. There is also much more ammunition for a pistol available inside the vehicle."

Via Andrei Ulanov.

Wednesday, 13 November 2019

Small Arms

"August 8th, 1942

To the artillery quartermasters of the 124th and 125th Tank Battalions

I report to you the supply of 7.62 mm rifle cartridges and F-1 grenades carried in KV, T-34, T-60, and T-40 tanks for precise inventory.

Total MG ammunition
Ammunition by type
F-1 grenades
Light bullet
AP-I bullet
At the same time, I instruct you that AP-I ammunition should be loaded in magazines separately, not mixed with ammunition that has light bullets. Magazines with AP-I ammunition must be specially marked. Check how magazines were loaded in your units and load AP-I ammunition separately.

Report on execution of this order to the artillery supply department of the brigade by 16:00 on August 9th, 1942

Artillery quartermaster of the 112th Tank Brigade, Intendant 3rd Class, Tomilin"

Tuesday, 12 November 2019

On to Tallinn

"Award order
  1. Name: Gorban, Vasiliy Moiseyevich
  2. Rank: Major
  3. Position and unit: commander of the 2nd tank battalion, 152nd Leningrad Independent Tank Brigade.
  4. Year of birth: 1916
  5. Nationality: Ukrainian
  6. Party affiliation: VKP(b) member
  7. Participation in the Civil War and subsequent action in defense of the USSR or in the Patriotic War: in the Patriotic War since June 22nd 1941, Leningrad Front
  8. Wounds and contusions in the Patriotic War: wounded twice lightly in 1941, once heavily and once lightly in 1942
  9. In the Red Army since: 1937
  10. Recruited by: career officer
  11. Prior awards: Order of the Red Banner, Order of Aleksandr Nevskiy, Order of the Red Star, Defense of Leningrad medal.

Monday, 11 November 2019

7.5 cm KwK 42 Penetration Table

I've posted a number of these diagrams before, for instance here is one for the Pak 40. The set of images for the more powerful KwK 42 is unfortunately incomplete and only available in low resolution, but I am including it for completeness sake.

The Valentine is not surprising at all. The armour piercing ammunition can penetrate any surface from up to 2000 meters. HE can knock off the tracks.

Saturday, 9 November 2019

First Try at a Medium Tank

To a casual observer, German tank industry was like a jack in a box. 15 years after the end of WWI it suddenly sprang to life and began to crank out world class designs. However, there is no such thing as miracles. In addition to German specialists like Joseph Vollmer and Otto Merker who worked abroad, Germany had its domestic tank program. It was conducted in secret and birthed some very unconventional designs. One of them was the Grosstraktor, a medium tank that became the culmination of German tank building of the 1920s. It was the first step on the way to the PzIV, the most numerous German tank of WWII.

Thursday, 7 November 2019

Small Arms Feedback

"HQ of the 27th Rifle Division
Dept 1
November 14th, 1945

To the commander of the 132nd Rifle Corps

I present my notes and conclusions on infantry weapons, ammunition, and preparation of infantry based on experience in the Patriotic War of 1941-45.
  1. Notes on design.
    1. TT model 1930 pistol: has design defects. The center of mass is bad (almost in the center of the pistol), it must be closer to the handle, like the Borchardt-Luger pistol. It is desirable to reduce the mass to 800-850 grams, change the shape of the pistol grip to make shooting more comfortable, and increase the angle between the barrel and handle.

Wednesday, 6 November 2019

Finnish Zimmerit

"Copy from a copy
For service use only
Translated from Finnish

Methods of combat against anti-tank magnetic charges

The British, Americans, and also the Russians use magnetic charges, especially against tanks and cars. They are supposed to stick to metal including painted metal or armour.

Report: this is likely a device of British origin, shaped like a half-cylinder 14 cm in length made of artificial materials and filled with explosives. The flat half has 4 magnetic poles. The curved half has an 8 cm deep slot for the fuse and detonator. The fuse is held in place with a cap that screws in.

The knife-shaped delayed fuse is 11 cm long and 1 cm in diameter. Two captured delayed fuses show that they cam go off in an hour or in 3 days. It is possible that other time settings exist.

Tuesday, 5 November 2019

Lessons Learned

To Comrade Beria
January 27, 1944

Based on the recommendations given by the commander of the 3rd Ukrainian Front, Army General comrade Malinovskiy, we report that:
  1. Item 1 in comrade Malinovsky's letter proposed installation of spaced armour 30-50 mm thick on the SU-85 and SU-122 SPGs.
    We consider that it would be unacceptable to install 30-50 mm thick spaced armour on the SU-85 and SU-122 SPGs on the T-34 chassis due to excess weight and overloading of the front suspension, which would radically reduce the lifespan of the transmission and running gear.
    An experimental SPG with a 100 mm gun is being built which will have 75 mm of front armour. Trials will show how feasible this undertaking is.