Thursday, 19 April 2018

Composite Hull

"[cut off] September 1942
To GABTU BTU, Engineer-Colonel comrade Alymov
To the head of the 3rd Directorate of the NKTP, A.A. Habahklashev

RE: manufacturing item #70-145304-A2 from two parts

Due to a lack of 35 mm thick plate 1232 mm in width, we are forced to produce item #70-145304-A2 from two parts with a perpendicular joint.

We have the agreement of military representative at factory #180, Engineer-Colonel M.S. Bazumov, to produce 40 units.

We ask for your permission to continue producing this item from two parts.

Attachment: blueprints (1 copy)

Acting factory director Orlov"

Wednesday, 18 April 2018

Clear the Air

"January 27th, 1941
Order of the People's Commissar of Medium Machinebuilding and People's Commissar of Heavy Machinebuilding
#63s/43s
Moscow

Stationary trials performed at factory #75 of air filters for V-2 tank engines produced at factories ##75, 174, and 183 showed that the air filters do not satisfy the requirements for air filters established by Committee of Defense decree #428ss issued on November 19th, 1940.

Considering the exceptional importance of equipping V-2 tank diesels with functional air filters, I decree that:

Tuesday, 17 April 2018

Far East Conversions

"To the Chief of the Tank Directorate of the GBTU, Major-General of the Tank Engineering Service, comrade Afonin

RE: your letter #822338 written on May 23rd, 1944

I report that:
  1. As of June 1st, 1944, the Armoured and Motorized Forces of the Far East Front have applied applique armour to 128 BT-7 tanks, 113 of which were converted in 1942-43 and 13 in 1944.
    Since no proper quality armour was available, applique armour is only installed at factories during refurbishing. Armour of written-off tanks was used. Contoured armour for turrets is not available.
  2. As of June 1st, 1944, 130 T-37/T-38 tanks have been converted to ShVAK guns. Further work to re-arm T-37 and T-38 tanks ceased due to an absence of ShVAK guns.
  3. Repair factories #405 and #77 are converting two-turreted T-26 tanks into single turreted. As of June 1st, 1944, 35 tanks have been converted.
  4. The following is necessary to continue work on rearming and adding applique armour:
    1. Contoured armour for BT-7 turrets.
    2. ShVAK guns.
    3. TMFP-1 sights.
    4. Equipment to convert two-turreted T-26es to single turreted (turrets, turret platforms, turret rings, etc).
  5. Rearmament and installation of applique armour is not being planned due to a lack of aforementioned armament and parts.
    All BT-7s refurbished by the repair factories are being equipped with applique armour.
Acting Assistant to the Chief of the Armoured and Motorized Forces of the Far East Front, Engineer-Major Ryabov
Acting Chief of the UK ORT of the Armoured and Motorized Forces of the Far East Front, Engineer-Major Sviridov"

Monday, 16 April 2018

Peak vs Mean

Previously, I discussed in detail what Soviet rate of fire tests actually measured. Long story short, the difference between the peak rate of fire (loading from the ready racks) and the average rate of fire (loading from all racks) was quite pronounced. Soviet figures reflected the latter scenario, which is why their rates of fire seem significantly slower when ROF figures are compared as is.

Let's take a look at another example: the Firefly, specifically the Sherman Ic. I've seen all sorts of figures on its rate of fire, from ten to twenty (!) rounds per minute. British tests, on the other hand, tell a different story.

Sunday, 15 April 2018

The Winding Road to Nowhere

The French were the first to master the production of SPGs. These vehicles missed WWI by only a few months. Enthusiasm for SPGs died down after the war ended, and France only returned to this topic in the 1930s. This article tells the story of French SPGs built on medium tank chassis, specifically the SOMUA SAu 40, which nearly made it into production.

Thursday, 12 April 2018

Kalashnikov Acceptance

"Order of the Red Banner Scientific Research Small Arms and Mortar Proving Grounds of the Main Artillery Directorate of the Armed Forces (NIPSMVO GAU VS)

January 15th, 1948
Shurovo, Moscow oblast

Report #374
On the issue of: trials of 7.62 mm assault rifles using the mod. 1943 cartridge designed by: Kalashnikov, Bulkin (TsKB-14) and KB-2-MV.

Annotations: The 7.62 mm assault rifles designed by Kalashnikov, Bulkin, and KB-2 (Dementyev) to use the mod. 1943 round were built according to specifications #3131 issued in 1945 and were presented for proving grounds trials a second time, after improvements recommended by the GAU NIPSMVO and GAU USV, based on the results of the first trials (see NIPSMVO report #232-1947).

The overall view of the assault rifles can be seen in the photos.

Wednesday, 11 April 2018

PzIV Ausf. H Intel

"Report on new types of tanks and SPGs according to reports by prisoners of war and armoured staff reports as of July 20th [1943]
...
  1. The suspension, engine, and transmission of the modernized T-4 tank are the same as the regular tank of this type.
  2. The hull has the following changes:
    1. The front of the tank has the following applique armour:
      1. The lower front plate and sloped front plate are protected by track links, held onto the armour by clamps or bolts. The upper front plate of the tank is protected by a 20 mm thick armoured plate, positioned about 200 mm in front of the main armour, and attached by welding.
        As such, the T-4 tank uses spaced armour.
      2. The sides of the tank are protected by 4-4.2 mm thick plates, four plates per side. Each plate hangs on three carriers, bolted to the side of the tank and the fenders. The bent ends of the carriers fit into slots of the 8 plates, and are additionally attached by one bolt that is screwed into a bracket welded to the upper carrier.
        The side plates are made up of very soft armour or iron. The edges are cleanly finished. The plates hang outside of the suspension, about 500 mm away from the sides.
      3. The tank turret is protected in a similar way (aside from the gun mantlet) with 8 mm thick armoured plates, affixed to carriers, which are welded to the turret. The spacing between the plates and the main turret armour is 380-480 mm. The rear of the turret (and the stowage box) is protected by 4-4.2 mm thick plates, similarly affixed to the turret armour with the same spacing.
        Like the side armour, the material is either very soft armour plate or iron. The edges are also cleanly finished.
      4. The rear of the hull has no applique armour."

Tuesday, 10 April 2018

T-60's Future

"Minutes of a technical meeting discussing factory #37's proposal to equip the T-60 tank with a new turret with a 45 mm tank gun and thicker front armour

Present: regimental commissar comrade Vorovbyev, Engineer-Colonels comrades Alymov and Pavlov, Engineer-Lieutenant-Colonels comrades Rogachev, Kovalev, Nenarokov, and Solonin

Presenting: telephone message from Engineer-Colonel comrade Afonin containing factory #37's proposal.

Complaints: comrade Pavlov claims that the increase in the tank's mass will reduce the performance of the already strained transmission of the tank. The torque will be insufficient and the off-road performance will be insufficient.

Monday, 9 April 2018

PzIII Battle Damage

"SECRET
Appendix "A" to AFV Technical Report No.11 
Dated December '42
The following abbreviations have been used in the section dealing with Pz.Kw.III:
  • sa: Spaced armour
  • dfp: Driver's front plate
  • man: mantlet
  • nf: prepared but not fitted
Thus sa(nf)man means that the mantlet was prepared for spaced armour, but it was not actually fitted.
...

Saturday, 7 April 2018

Heavy Tank from Pennsylvania

The American army had the largest fleet of heavy tanks in the world at the start of the 1930s. Unfortunately, these were obsolete Mark VIII tanks, also known as "Liberty". They were built to British specifications using experience learned from the First World War, but these tanks came too late to fight. No heavy tanks were built in the US after the war was over. Work on this topic only resumed after the start of WWII. The result was the Heavy Tank M6, the first truly domestic heavy tank design.

Thursday, 5 April 2018

Theory and Practice

I covered the precision of the ML-20S gun-howitzer before, but numbers on a table are not quite as fun to look at as the trials themselves. Here are the results from the same gun mounted in a SU-152.


"Results of precision trials, February 2nd 1943
Left group: firing from 1000 meters
Right group: firing from 500 meters."

Via Yuri Pasholok.

Mosin vs PPSh

"Jume 16th, 1943
To the Chief of Staff of the 28th Army

1. Totalling up the reports of unit commanders from the division regarding whether or not infantry squads should have rifles or the PPSh, I report that:
  1. The PPSh is the most effective weapon of the infantry squad.
  2. Saturation with the PPSh should be no more than 50%. Leave rifles in the hands of excellent marksmen and snipers (preferably sniper rifles with optical scopes to shoot at a range of over 400 meters). 
Division Commander, Guards Colonel Dobrovolskiy
Chief of Staff, Major Panin"

Tuesday, 3 April 2018

Manufacturing Limbo

"On the T-80 tank: 8 T-80 tanks were built in March and 9 tanks were started, which already have suspensions, engines, and transmissions. Final assembly is stalled due to a lack of armour, elevation, and turning mechanisms. Out of the 17 started vehicles, only 7 have fully turbocharged engines, the other 10 have half-turbocharged engines: with old compression ratios and a cast iron cylinder head. The first 8 vehicles have been broken in, are fully equipped, and are only conditionally accepted while work on the additional return mechanism for AA firing is performed.

It must be said that the factory is dedicating very little attention to the topic of organizing T-80 production due to a lack of production plans.

Senior Military Representative of the GBTU at the Molotov GAZ factory, Engineer-Lieutenant-Colonel Okunev."

Monday, 2 April 2018

OBM-43

"To the Chairman of the NKV Technical Council, comrade Satel
To the Chairman of the GAU Artillery Committee, Lieutenant-General comrade Hohlov
To the Head of the NKVD 4th Special Department, Commissar of State Security comrade Kravchenko

October 2nd, 1943

NKV special telegram #5014 sent on September 24th of this year tasked NKV OKB-172 and Molotov factory #172, as instructed by the People's Commissar of Armament and GAU Chief, to produce an SPG with a 122 mm gun that fired a 25 kg shell at 1000 m/s.

SU-12: The Ill-Fated SPG

Sverdlovsk (modern day Yekaterinburg) was the cradle of Soviet wartime SPG building. The concept of light and heavy assault guns (SPGs) was developed here. However, neither the light nor the heavy SPGs developed here were put into production. One of the reasons for this paradox was the publication of GKO decree #2120 "On the organization of T-34 production at the Uralmash factory and factory #37". According to this document, Sverdlovsk was to produce T-34 tanks instead of the T-70 tank, on which all of their light SPG designs were based. The SU-31 and SU-32 SPGs were left without a production base. All work on SPGs was transferred to factory #38 in Kirov. This was the start of the tragic history of the SU-12, the first SPG to be known under the more famous index SU-76.

Friday, 30 March 2018

PIAT: An Odd Fellow

The British PIAT grenade launcher, a combination of a medieval crossbow and a modern HEAT grenade, became one of the more unusual examples in its class. Heavy and uncomfortable to use, the PIAT went through many fronts of the Second World War in the hands of Allied soldiers. However, its subsequent career was not long. The weapon did not survive competition from the simpler and more reliable RPG.

Thursday, 29 March 2018

M1 Carbine vs Mkb.42(H)


The precision of the MKb 42(H) at ranges of 100, 300, and 500 meters is 1.5 times worse than that of the American M1 carbine.

In automatic fire, the precision of the MKb 42 (H) is unsatisfactory (a burst doesn't fall inside a 1.5 x 1.5 meter target at 100 meters).

The reliability of the automatic mechanism has not been determined.

The design of the sample is complex, but the widespread use of stamped parts deserves attention.

Via kris_reid.