55th Army's Offensive Operation

I obtained a report on an offensive by the 55th Army, from March 19th, 1943 to March 27th, 1943 (CAMD RF 411-10189-436). It's quite lengthy, and not as suitable for episodic as Guardsmen in the Fall was, and hardly at all about tanks, but there are a few relevant parts. One is quite interesting.

"Senior Sergeant Matveev from this same unit [690th IPTAP], on March 19th, set fire to an "Elephant" tank from 300 meters with his 76 mm gun, thus dispelling the opinion that this tank is immune to AT artillery."

A Ferdinand, an upgraded one even, at Leningrad? Of course not. This is one of the first encounters with a Tiger tank. Due to an elephant figure seen on the first knocked out tanks (the insignia of the 502nd s.Pz.Abt), the tank was called Elephant. It is only when some German literature was captured that referred to the tank did the Red Army find out its proper name.

As always, let's confirm this event. Schneider's Tigers in Combat I indeed mentions that a Soviet offensive took place on March 19th at Krasniy Bor and Sablino. Only 4 Tiger tanks remain operational in 1/s.Pz.Abt 502. Sadly, as always, the diaries are not exactly forthcoming on the details.

That's really the only tank-related thing in the artillery section. The infantry section only mentions presence of tanks here and there, and doesn't really reveal anything interesting for analysis. Now for the good part: Tanks!

"Tanks

1. The terrain made using tanks difficult. Tank-accessible regions were only available between the flanks of the 123rd and 291st Infantry Divisions, which covered a large amount of forested areas, limiting the coverage and maneuverability of tanks on the front echelons and first lines of defense.
2. Organization of tank cooperation with infantry and aircraft:
1. After a decision by the Military Council of the 55th Army on the combat use of tank units, which was communicated to the commanders of the 222nd Independent Tank Brigade, 220th Independent Tank Brigade, 152nd Independent Tank Brigade and 31st Guards Heavy Tank Breakthrough Regiment, the units began reconnaissance of rendezvous points, starting positions, and movement routes. The starting positions were determined as follows: 31st Guards at the north outskirts of Krasniy Bor, 220th at the south outskirts of Kolpino, 222nd on the western outskirts of Kolpino, 152nd on the western outskirts of Kolpino, after the 222nd vacates the area.
2. On March 10th, 1943, tank commanders received excerpts from the 55nd Army HQ order, which determined the objectives of the tank units in the upcoming offensive. Based on the order, tank commanders began joint reconnaissance with commander of infantry divisions acting in the offensive sector, and developed cooperation plans.
3. From March 11th to March 14th, the units continued reconnaissance, a task which consumed all personnel, including the drivers.
4. From March 14th to March 17th, tank units performed exercises in the region, practising their cooperation with 123rd and 291st infantry divisions, in places where the mobile groups had to enter the breakthrough and cooperate with aviation.
5. After all questions have been resolved, mobile group HQs received representatives from artillery and aviation. From artillery: one fire correction team per battalion, which practised correcting fire using the tank's radio. From aviation: radio teams with powerful radios that could call in and direct aircraft. All cooperation between infantry, artillery, sappers, and aviation was recorded in the battle plan, as well as the main predetermined signals.
3. Battle dynamics
1. On March 19th, 1943, at 9:05, the breakthrough group, consisting of the 222nd ITB and 31st GTBR, attacked the enemy's front lines along with elements of the 123rd and 291th infantry divisions. By 20:00, the 222nd reached: the cemetery (1867) and Lesn. (1868-v) with one battalion, and Krasniy Bor at the north-eastern clearing (1867-a) with another. The brigade had no further successes in battle, taking losses in personnel and materiel. Overnight, the brigade continued on to their nighttime objectives.
   By 20:00 on March 19th, the 31st GTBR reached (1870-n), (1870-v), (1870-v). When the regiment reached this line, the tanks remained with their infantry. In order to keep the position that the infantry captured, they were reinforced with ammunition without leaving the defensive line.
2. The 71st Independent Armoured Train Division, in cooperation with elements of the 72nd infantry division, opened fire on the Voyskorovo, Kattelovo, Petrovshina, Samsokovka regions from the Kolpitsino railroad station. At 10:00, the division concentrated at the Rybatskaya and Obuhovo stations, entering the reserve of the 55th Army commander.
3. From March 20th to March 24th, the 222 ITB and 31 GTBR supported 123rd, 291st, 268th, and 189th infantry divisions, and continued the offensive with the objective of destroying the enemy's reinforcements and capturing the line: Bezymyannaya height (1172), mark 43.8 (1273), mark 43.6 (1274), mark 36.3 (1375), Gertovo, widening and supporting the breakthrough at Kordelevo, Chernaya Rechka, Polisarka river, bridge (1467), mark 41.1 (1568), and to the left of the line: Vorobyevy Dachi, foothold (2172), Mishkino.
   The 222nd ITB, remaining in the reserve of the army commander, was ready to deflect an attack from the previous directions. On March 20th, one tank company, received orders from the HQ chief of the 55th Army, Major-General Tsvetkov to, at 19:10, acting as an infantry support group alongside 1/56 Independent Infantry Brigade re-group with cut off elements of the 123rd infantry division, clear the clearing at Smol., clear the clearing along Kordelovskiy stream, and fortify for a defense, arranging an ambush of four tanks in the Poperechnaya clearing (1767-b), and three tanks north of the Smol. clearing (1866-1867), where, alongside elements of the 123rd, they will deflect enemy attacks. The company completed their objectives. The 152nd ITB, 31st Guards Light Tank Brigade, 49th Guards Heavy Breakthrough Regiment, and 3rd Independent Armoured Car Brigade remained in the reserves of the 55th Army commander. 
4. Between March 25th and March 27th, the 152nd ITB and 220th ITB conducted preparations for an offensive. The 220th ITB and 291st ID were tasked with striking with their left flank between the Kordelovskiy stream and Poperechnaya clearing, form up at the Kamenistaya clearing, capture the forest north-east of Chernaya Rechka, and capture the line: Vinokur river, Polisarka river, until the Konnaya Pustosh swamps.
   152nd ITB, with one battalion and elements of the 13th ID strikes with their left flank, with the objective to capture the Pesochnaya clearing (1568), destroying the enemy's hardpoints along the highway. Further, guarding its right, it was to capture the Vuinaya clearing (1269-1279), marker 47.0, and ready to deliver a strike at Sablino.
   One tank battalion, with elements of the 189th ID, captured the line: mark 42.7 (on the highway), Vazhnaya clearing (1770-1771), destroying the enemy hardpoints along the railroad, exiting the forests west of Ulyanovka.
5. On March 24th, the 222nd ITB and 31st GTBR were removed from the advancing army. 222nd ITB was transferred to the Front reserves at Rybatskoye, which it reached by 12:00 on March 25th. The 31st was transferred to the army reserves at Ust-Izhora, which it reached by 24:00 on March 25th. Units in reserve performed maintenance and were resupplied with personnel and materiel.
   The 30th Guards Light Tank Brigade was transferred to the Front reserve by the commander of the Armoured Forces of the Leningrad Front, due to its inability to be used in the offensive sector due to spring mud and limited off-road performance of the Brigade's tanks.
   48th Battalion of the 152nd Independent Tank Brigade reached the ravine (1770-b), but could not advance further due to poor terrain. Infantry moving behind the tanks could not advance due to heavy enemy resistance. Tanks attempting to cross (1770-b) were stuck, and left without infantry cover. Later, on March 28th-31st, the tanks remained with infantry, repelling enemy attacks in parallel with working on evacuation and repair of damaged materiel. The 152nd ITB commander deployed a motorized infantry brigade as support.
4. Conclusions
1. Due to the heavily swamped forests, spring mud, insufficient communication between tank, infantry, and artillery, tank units could not notably impact the course of the battle, and took heavy losses.
2. Tank units and crews were not ready to fight in forests and maneuver in difficult terrain. The reconnaissance performed during battle was unsatisfactory, resulting in many losses due to stuck and sunken tanks.
3. Poor terrain and concentrations of artillery would not let tank units maneuver, which cased losses and did not allow concentrated use of tanks in any direction.
4. Cooperation between tanks with artillery and infantry was lacking. Artillery spotters communicated the most dangerous targets slowly, artillery poorly supported tanks, infantry could not keep up with tanks, leaving them without much needed infantry cover. The enemy swiftly transported 88 mm guns in the most likely directions where tanks would be used, causing damage to our tanks. Most likely, tanks that were stuck would be hit by these guns."

 Tanks come up once more in the conclusions.

"Tanks took heavy losses when fighting in forests. This was due to the fact that they had no infantry or artillery cover, and were left on their own. Tanks must advance behind infantry, not in front of it, and as fire support in already scouted directions."

Regrettably, I do not have the appendix with the loss numbers in it. It would have been interesting to compare against the German claims in Tigers in Combat. However, some crude comparisons can still be made: the 502nd claims to have knocked out 10 tanks on March 19th, 12 tanks on March 20th, and 18 tanks on March 21st, for a total of 40 tanks. Next, nothing happens until March 31st. 

An Independent Heavy Tank Breakthrough Regiment would contain 21 tanks, and an Independent Tank Brigade two 24-tank platoons, for a total of 48 tanks. Therefore, at their full strength, the 31st GTBR and 222nd ITB could have brought 69 tanks to the fight. It's hard to believe that, having knocked out more than half of the enemy tanks, the 502nd Battalion would immediately withdraw, and the Soviet tank units would continue fighting for three more days before being transferred to reserves, not to mention that the Soviets documented heavy beatings specifically at the hands of towed anti-tank guns.

The 502nd Heavy Tank Battalion and 31st Guards Heavy Tank Breakthrough Regiment met again, under much better documented terms.

World of Tanks History Section: Sharing Parts

Two articles on similar themes were posted, and both were pretty short, so I am going to merge them into one. The theme is components that belonged in both a tank and an airplane, in this case, engines and guns.

A Tank's Winged Heart

The tank is a mobile battle unit. Therefore, its engine is no less important than the gun or armour. Every country building a tank encountered the problem of an engine that combined two important factors:. First of all, a tank engine needs to be powerful enough to move a multi-ton vehicle. Second, the engine needs to work in conditions far from ideal, it needs to be reliable and forgiving.

The optimal solution would be a special tank engine, but it was not always possible to develop one. Tanks used engines from tractors, cars, airplanes. 

The talented American engineer J. Christie used airplane engines for his vehicles. The experimental M1928 used a V-shaped Liberty L-12 engine. The tank reached a speed of 120 kph in trials on wheels, and 65 kph on tracks. This engine was used on aircraft until 1927.

Liberty engines were used on British cruiser tanks, including the Crusader tank, widely used in the first parts of WWII. The later Cromwell tank used an engine derived from an aviational design, the 12-cylinder Rolls-Royce Merlin III. Famous airplanes such as the Spitfire, Hawker Hurricane and Mustang X used this engine.

The Continental W6709A engine was used on the American M5 Stuart tank, one of the country's most massively produced tanks. The M2 Medium tank, another tank from the early days of WWII, used the 9-cylinder Continental R975EC2. 

The USSR developed the M-5 engine based on the Liberty L-12, which was used on BT series tanks. Later, the USSR developed another engine that was installed on planes, as well as tanks. The M-17 engine was based on the German BMW-VI. M-17 engines were installed in heavy TB-3 bombers, I-3 fighters, MDR-2 flying boats, and other vehicles. Modified M-17 engines were used on BT-7, T-35, and T-28 tanks.

It's hard to find a person that has not heard of the German super-heavy Maus tank. Many don't know that one of the potential engines that could have powered it was the Daimler-Benz DB.603 airplane engine, manufactured since 1942. This engine was used in He-219A-7 long range bombers, Me-410B heavy fighters, and other aircraft.

The eventual decline of aircraft engines used in tanks was due to the fact that airplane engines are more suited for working in the air. They were unreliable on tanks and needed high quality fuel, which was expensive to produce. Finally, airplane engine factories simply could not provide enough engines for all customers. Nevertheless, over the course of many years, tanks from many countries rode into battle with "winged hearts".

Original article available here.

Weapons of Two Worlds

Development and improvements in airplane design led to aircraft that were difficult to shoot down. This was especially true for bombers, whose toughness grew with size. Typical armament of a 1930s fighter consisted only of rifle caliber machine guns, making shooting down a bomber very difficult.

Adding more machine guns did not solve the problem. 

Earlier, we spoke of airplane motors used in armoured vehicles. The same thing happened with guns. Some of them descended from the skies, others did the opposite, flying upward after being developed for land combat.

Airplane guns usually had a small caliber, 20-37 mm, but they were automatic, which meant they could fire in bursts. Cannons drastically increased the firepower of aircraft.

The small T-60 tank was developed and produced in 1941 to replace the losses of Soviet tank units during the first stages of the Great Patriotic War. The first T-60s were armed with the tank version of the 20 mm automatic ShVAK cannon, based on the ShVAK-20 aircraft cannon. The use of the ShVAK did not start with the T-60, it was used on earlier T-40 and T-30 tanks. The gun proved itself picky: it was not used to a dirty tank, and the automatic mechanisms would jam. The gun was modified, and the result was called TNSh-20 (Tank, Nudelman-Shpitalniy). The VJa (Volkov-Jartsev) cannon was also explored, but was never implemented in metal.

There were also large caliber plane guns. For example, G and H modifications of the Mitchell B25 bomber had 75 mm cannons. This gun was later used on the M24 Chaffee tank. It was planned with an M3 gun, like the Sherman, but it turned out that the mass and recoil were too much for a light tank. Engineers decided to equip the Chaffee with the bomber's gun.

An example of a gun that migrated from tanks to planes would be the 50 mm KwK 39 German gun, used in the PzIII tank. The BK-5 aircraft cannon was inspired by its design, and was used on the Me.410, Junkers Ju88P4, and jet fighter Me.262.

Original article available here. 

German Analysis of the T-34 and KV

The Red Army didn't just perform their own tests, they let the enemy do it for them. This is one such case, where an enemy AT guide is used to suggest improvements to their own tanks.

"To the chief of GABTU's 3rd Department, Military Engineer 1st grade, comrade Afonin
October 10th, 1941

As a result of examination of a document published by the German commanders titled "Memo on fighting Russian tanks", it was established that:

1. Live fire tests of the T-34 and KV from the front and rear, as well as the turret from all sides, reveals that:
1. The T-34 is superior to the KV in this regard. The T-34 resists all artillery from 28 mm to 75 mm inclusive. 
1. The KV can be penetrated under the following conditions:
1. With the 47 mm gun from 50 meters.
2. With the 50 mm gun from 50 meters.
3. With the 50 mm model 1938 gun from 250 meters.
2. The tanks can be penetrated with larger calibers: the 88 mm AA gun and 105 mm gun:
1. KV from a distance of 1000-1500 meters.
2. T-34 from a distance of 100-800 meters.
2. Firing on the sides of the tanks shows inverse results. Namely:
1. The T-34's lower side, behind the suspension, is weak. It can be penetrated by 28 mm guns at 400 meters.
2. The sloped plate of the turret platform is inferior to the KV in resisting two types of shells, specifically:
1. Model 1938 50 mm AT gun, armour piercing grenade:
1. KV can be penetrated at 400 meters.
2. T-34 can be penetrated at 700 meters.
2. 105 mm gun, armour piercing grenade:
1. KV can be penetrated at 300 meters.
2. T-34 can be penetrated at 700 meters.
   In all other cases, the armour of the T-34 and KV is equivalent.
3. Firing on the suspension reveals that the T-34, due to its high density of road wheels and thin track pins is vulnerable to HE shells from the 75 mm gun.

Based on this data, if the German conclusions are correct, then we deem it necessary to direct your attention to improving the T-34 in the following ways:

1. Add armour screens to the turret platform sides, increasing them to 60 mm.
2. Protect the turret ring from the front and side to prevent it from jamming.
3. Add 25 mm skirt armour to increase the thickness of the vertical side armour.
4. Develop smaller road wheels with internal cushioning and a smaller diameter for the same axles.

GABTU NIP chief, Colonel Romanov

GABTU NIP Regimental Commissar, Dolgov

Scientific-Technical NIP Advisor, Military Engineer 1st grade, Gluhov

Chief of the 1st Department of GABTU NIP, Military Engineer 2nd grade, Sych"

CAMD RF 38-11355-158

This report appears to be consistent with the other German AT tactics manuals, as well as the Tigerfibel, which also instructs that the gunner should hold fire at a T-34 until it reaches 800 meters. The 100 meter figure is not a mistake in the Russian translation, the original document did indeed state that the T-34's upper glacis is only penetrable by the 88 mm FlaK gun at 100 meters.

It is interesting that the KV-1 is not mentioned in the areas for improvement. Looks like it was already deemed a developmental dead end by some, even in the fall of 1941, although it continued fighting successfully for years.

Birth of the KV

"History of the development of the KV tank

The KV tank began development according to the decisions of the Main Military Council on December 9th, 1938. Tactical-technical requirements were set by RKKA ABTU and confirmed by the People's Commissar of Defense on February 19th, 1939. The final revision of the requirements and permission to build the tank was given on February 27th, 1939, by the decision of the Commissar of Defense in the Council of People's Commissars #45ss and #118ss from May 15th, 1939.

The factory began working on the design on February 1st, 1939. The chief engineer of the project was Nikolai Leonidovich Dukhov. The technical project and a model were provided for inspection on April 7th, 1939. The model commission, chaired by deputy ABTU chief, military engineer 1st grade comrade Korobkov, with the following suggestions:

1. Hull and turret:
1. Increase the thickness of the rear plates to 75 mm and the front sloped plate to 60 mm.
2. Test the hull, turret, and hatches by firing at them.
3. Install a guard against hand grenades outside the turret and under the turret bay.
4. Move the turning mechanism of the turret forward to make it more convenient. 
2. Armament:
1. Place machinegun ammunition in the turret first, and then use the remaining space for shells.
2. Simplify the gun mantlet.
3. Follow the Commissar of Defense's order and install a removable AA machinegun in addition to the forward facing machinegun. 
4. Provide a means for every crew member to open fire from personal weapons.
3. Engine:
1. Lower the engine by 50 mm.
4. Transmission:
1. Robustness calculations should use a 660 hp M-17F engine with M=330 kg-m. Dynamic calculations should use the 580 hp V-2F engine with [missing handwritten figures make the rest of the paragraph meaningless]
2. From the gearboxes provided, #3 (planetary gearbox with a reductor) should be the main variant. In parallel, develop a simple gearbox. The gearboxes should be able to replace each other. Lower the engine axis by 50 mm. The side friction clutch should be the same type as on the SMK, with a diameter of 500 mm.
3. The final drive should be of the same type as on the SMK. Change the design of attaching the inner gears to make it easier to produce. 
5. Suspension:
1. Increase the length of the foundation to 4600 mm, with the width of 700 mm and ground pressure of 0.6 kg/cm^2.
2. Use an SMK-style track (stamped). The space between the wing and track must be no less than 20 mm.The track spur should be at least 70 mm away from the hull.
3. Develop two kinds of idlers and drive wheels: one with rolling bearing, one with a sliding bearing.
4. Use SMK-style road wheels and idlers, with armoured bearings, according to the technical requirements. Place the torsion bars in armoured covers.
6. Observation devices and equipment:
1. Give the driver mirrored devices for looking left and right, as well as a periscope in a hatch as a backup.
   The radio operator should have a mirrored observation device for looking left.
   The turret needs devices to look forward, back, left, and right, as well as a backup periscope.
2. Place the radio left of the driver, as stated in the technical requirements.
3. Provide a spare parts and instruments container for the tank.
4. Add small hatches for throwing hand grenades from the tank.
5. Develop a project for servo-controls, and present it to ABTU for approval.

Working blueprints were delivered to the Izhor factory on May 20th, 1939. The approximate processing time was one week. On May 28th, 1939, the following list of changes was provided to ABTU.

1. The tank hull is 50 mm lower.
2. The turret is 60 mm lower.
3. The rear plate was thickened to 75 mm.
4. A planetary gearbox is being developed.
5. The foundation length was increased to 4.4 m.
6. The diameter of the brake drum was decreased to 500 mm.
7. A 700 mm wide track was developed.
8. Mirrored observation devices are being developed.

May 25th: factory #75 receives an order for two V-2 tank engines. The first is due by June 10th, the second by July 1st. 

June 4th: the 75 mm armour plates are tested at the Izhor factory against the 76 mm 40-caliber gun with the muzzle velocity of 650 m/s. The homogeneous armour with hardness of 3.5-3.6 successfully resists these shells at 200 meters. At 50 meters, the armour forms bumps 25-30 mm deep, and occasionally forms cracks.

June 5th: ABTU instructs the factory to:

1.  Use the V-2 engine only, and not use the M-17 engine anymore.
2. Change the air intake and exhaust. Install a coaxial 45 mm gun.

June 10th: the factory begins production of a simple gearbox, final drive, suspension, tracks.

September 1st: the first tank was assembled. After travelling 7 km, due to poor assembly, the clutch between the gearbox and final drive disconnected. This defect was temporarily solved by sleeve welding. A variant with a cam-bearing sleeve is in development.

September 2nd: the tank travelled 45 km at factory trials. The following was discovered.

1. The 4 small oil reservoirs in the tank aid foaming of the oil, as a result of which it escapes the reservoirs. A decision was made to throw these reservoirs away and use the rear left 120 L gas tank as an oil reservoir.
2. Due to the 45 mm and 76 mm L-11 guns installed in the tank, the position of the crew was not finalized.
3. The mechanism for tightening tracks is inconvenient.
4. The mirrored observation devices are not installed.

September 5th: the tank was sent to Moscow to show to the Government."

CAMD RF 38-11355-934

Fedorenko's Tank Guide

We've seen what German guides on tank tactics, now it's time for a Soviet one. There are some interesting points mentioned here that the German documents don't contain.

"On the issue of tank unit combat, to Front and Army tank commanders, and commanders of tank Corps.

Combat experience in 1942 showed that front and army tank commanders did not understand the principles of using large tank units in modern war. For example, the 22nd Tank Corps was split into separate brigades, and assigned to infantry divisions, which sent them into battle piecemeal at the right flank at Kharkov, as a result of which, the Front tank commander could not direct the corps. This led to the 21st and 22nd corps being discovered by the enemy long before entering battle. Directions for either corps from the Front commander were absent.

Until the People's Commissar develops instructions for tank combat, I order that:

1. The Tank Corps is the largest tank unit, and is meant for achieving operational level objectives.
2. The Tank Corps is subordinate to the Front commander, and completes front-wide objectives, acting together with other types of armed forces.
3. Assigning a tank corps to armies and splitting them up as infantry reinforcements is forbidden. The tank corps is to cooperate with infantry, but it can never forget its main objective, the Front.
4. In offensive operations, the tank corps is to deliver a deep assault, divide the enemy's forces, surround them, and destroy them, acting with aviation and other types of forces.
5. In order to maintain the force of the tank corps for combat in operational depth, using the tank corps to break through heavily reinforced positions is forbidden. The tank corps, with the aid of artillery, aviation, infantry, and sappers, can destroy field fortifications.
6. The tank corps is allowed to move 40-50 km into enemy lines, provided it is being followed by a second echelon. Frequently, the situation demands that after penetrating 15-20 km, the enemy's forces must be surrounded and destroyed with aid from other types of forces.
7. The tank corps must be ready for 24 hour per day combat for 3-4 days.
8. The successful completion of objectives depends on the experience of officers, junior command staff, and privates, on internal cohesion of companies, battalions, and brigades, on air support, and on correctly practised cooperation with artillery, assault aircraft, sappers, and other types of forces.
9. When the tank corps reaches operative depth, it must establish communications with airborne troops and partisans.
10. In defense, the tank corps counterattacks enemy forces that penetrated our line, especially tanks and motorized infantry. In this case, the attacks are not delivered head on, but from flanks and the rear.
11. In any case, the tank corps' most decisive ally is the element of surprise.
12. Due to this, any regrouping and movement must be done at night. If it is not possible to avoid maneuvers in daytime, do them with small groups of 3-5 tanks.
13. When selecting the direction of attack, pay attention to the terrain. It must allow for mass use of tanks.
14. If there is a unidirectional railroad, it is forbidden to use it for transfers over a distance of more than 50 km.
15. When planning a tank corps sized operation, especially in operational depth, keep in mind supplies of fuel and oil, ammunition, food, repairs, and evacuations. 
1. The corps should carry the following:
1. Oil and fuel: 3 resupplies
2. Ammunition: 2-3 resupplies
3. Rations: 5 daily portions
2. Tank crews carry with them the following: 2-3 cans of meat or smoked sausage, ham, concentrated pea soup, bread or biscuits, sugar, tea or water in thermoses.
16. The corps commander, Front tank forces commander, and Front military council are responsible for correct use of tank corps in battle and their material and technical well-being."

CAMD RF 500-12462-93

KV and T-100 in Battle

"Work of heavy tanks in the active army from February 22nd to March 13th of this year [1940]

Schedule of active participation in battle of KV #0, KV #1U, KV #2U, KV #3U, and T-100 heavy tanks.

CAMD RF 38-11355-6

Data on damage and technical breakdowns of tanks over the combat period.

T-100

Impacts by 20, 37, and 47 mm guns:

1. Right side: 6
2. 45 mm gun mantlet: 1
3. Large turret bay: 3
4. Left track: 2
5. Left idler: 1

Additionally, shrapnel knocked off the head of the periscope on the small turret and dented the armoured cup over it.

Damage and technical problems:

1. Starter and dynamo gear breakage.
2. Main friction clutch pin breakage (x2).
3. Main friction clutch pin breakage and tearing of the power control cup lug.
4. 7 track links broke on rocks and mines.
5. 5 track pins broke (overhardened).
6. Right exhaust pipe was destroyed.
7. The nut stopper of the right drive wheel broke, as a result the nut was loosened and the wheel fell off.
8. Loosened road wheel retention nuts.

KV #0

Impacts:

1. Front plate joint: 1
2. Upper front plate: 3
3. Lower front plate: 2
4. Rear: 2
5. Right side: 3
6. Left side: 1
7. Right idler hub: 1
8. Upper idler: 1
9. Road wheel hub: 1

Damage and technical problems:

1. Road wheel retention nuts burst: first right wheel and third left wheel.
2. Road wheel hub nuts burst: 3rd right and 2nd left.
3. Road wheels destroyed by mines: 1st right and 1st left.
4. 1st right winch destroyed by mine.
5. 3rd left shock absorber torn off by mine.
6. Right idler hub destroyed by shell.
7. 2nd right shock absorber torn off by mine.
8. 2nd idler on the right destroyed by shell.
9. 8 track links destroyed by mines.
10. Two cases of fuel pump socket breaking.
11. Pipe from the fuel pump to the filter broke.
12. Oil meter broke. 

KV #1U tank

No impacts from AP shells, but there are scratches from a large caliber shell detonation.

Damage and technical problems:

1. Three cases of fuel pump socket breaking.
2. Engine piston rod broke.
3. 11 track links destroyed by mines.
4. 6th torsion bar on the right broke.

KV #2U tank

1 hit from a 37 mm shell in the front plate joint.

Damage and technical problems:

1. 1 left road wheel destroyed by mines.
2. 3 track links destroyed by mines.
3. Left fuel tank is leaking.
4. 5 cases of fuel pump socket breaking.

KV #3U tank

Impacts from shells:

1. Upper front plate: 1
2. Lower front plate: 1
3. Right side: 4
4. Rear: 1
5. Turret: 1
6. Limiter: 1
7. Road wheels: 2
8. Tracks: 1

Damage and technical problems:

1. 4th road wheel on the right destroyed by mine.
2. 4th shock absorber on the right destroyed by mine.
3. Power control disk of the left side friction clutch jammed.
4. Left friction clutch power control cup retention nuts burst.
5. Left friction clutch ball bearing broke.
6. 3 cases of fuel pump socket breaking.
7. As a result of HE shell explosion, the gearbox retention frame was bent.
8. Due to the same explosion, the gearbox case burst.
9. Turret jammed with a shell.
10. A fan loosened due to poor cone calibration. 

All shell impacts made dents 10-40 mm deep. No shell impact affected crew performance in any way.

Composed based on reports from Captain Kolotushkin, commander of the heavy tank group.

Senior engineer of the 8th ABTU department, Military Engineer 3rd Grade, P. Voroshilov

June 28th, 1940"

So what happened to these tanks? You hear people go on about "poor reliability" this and "fifty thousand tanks lost in the first day" that, but the majority of these first batch of vehicles survived, at least until their modernization. CAMD RF 38-11355-321 tracks incoming and outgoing tanks from the Kirov factory as of August 1st , 1941, and contains almost the entire initial batch. KV-2 tanks U-1 and U-2, and KV-1 tanks U-5 through U-18 (missing U-7) all arrived from the Kiev Military District for modernization and were sent off to various destinations after the procedure was performed. KV-1 U-5 was the luckiest, as it mentioned in documents as late as spring of 1944.

World of Tanks History Section: Airborne Tanks

The question of reinforcing airborne infantry with armoured vehicles was explored in all countries that played a major part in WWII. Earlier, we talked of flying tanks, but that went nowhere. For countries with mature aircraft industries, a simpler and more effective method was to transport vehicles using transport planes or cargo gliders.

From the late 1930s, engineers from various countries developed special tanks for airborne forces. These vehicles were lightly armoured, weighed less than 10 tons, and were armed with machine guns or small caliber cannons.

The British light Mk. VII tank was developed by the Vickers-Armstrong company as a reconnaissance vehicle. The main quality of the vehicle was its speed, as its armour was very thin, 4-14 mm. The suspension consisted of four large road wheels on each side, built using the ideas of American engineer Christie. The tank was armed with a 2-pounder gun and a 7.7 mm machine gun.

In 1942, the British decided to use the Mk. VII in an airborne role. This is when the tank received its name: "Tetrarch". The Hamilcar glider was developed to transport the Tetrarch. During transit, the tank was held in a special compartment. The crew remained inside. Tetrarchs were used during landings in Normandy in June of 1944, as well as during crossing of the Rhine in 1945. The Mk. VII did not have a large effect on the flow of battle.

Another vehicle was built on the Tetrarch chassis, the Mk. VIII Harry Hopkins, which had thicker armour than its predecessor (38 mm), as well as a differently shaped hull and turret. 90 of these vehicles were built, but they never saw combat.

In the US, a T9 light tank was developed for airborne units. The vehicle was designed by the Marmon-Harrington company's plans, weighed 7.7 tons, and was armed with a 37 mm gun. In 1942, the tank was modernized, and received an improved turret, increased front armour, and a gyroscopically stabilized gun. The new vehicle received the index T9E1. 1900 tanks of this type were planned, but only 930 were built. In 1944, the tank was renamed to M22, nicknamed "Locust" on the battlefield. The vehicle was used by the British army, using the same Hamilcar gliders meant for the Tetrarch.

Germany's engineers, possessing the heaviest airplane of the war, the Me.323 Gigant, also worked on an airborne tank. The VK 601 project was developed by Krauss-Maffei and Daimler-Benz, from fall of 1939 to the middle of 1942. Formally, the vehicle was a modified PzI, but realistically, it was a radically new vehicle. The tank, indexed Pz.Kpfw. I Ausf. C had a Kniepkamp suspension with a 150 hp engine, allowing it to achieve a speed of 79 kph. The turret housed a semi-automatic 7.92 mm anti-tank rifle and an MG-34 machine gun.

Different sources claim that between 40 and 46 of these tanks were built. Two vehicles were sent for testing to the Eastern Front in 1943, the rest were included in the 58th reserve tank corps and were lost in France after the Allies landed in the summer of 1944.

Original article available here.

World of Tanks History Section: Winged Armour

The first World War gave a push to the development of military technologies. As a result of this global conflict, tanks, SPGs, fighter planes, and many other things hit the battlefield. In those years, not a single one of the deadly novelties had a significant impact. The first World War was won by the ordinary rifleman.

After the end of the war, military theorists seriously investigated the question of how to avoid this trench stalemate. The direction was clear: new war must be a lot more maneuverable. It must maximally use the new technologies that showed themselves in 1914-1918.

One of the most important aspects of a maneuver war is the rapid movement of vehicles and soldiers into battle. Mastery of the air opened up new possibilities. Even the first airplanes surpassed ground units in speed. However, difficulty was caused by the low reliability and cargo capacity of airplanes at the time.

Transport aviation was actively developed. At the same time, engineers of various nations thought of an idea: equip the most promising type of vehicle, the tank, with wings.

One of the first engineers to propose this was J. Walther Christie. In 1932, he tested a prototype of a convertible drive vehicle, weighing less than 5 tons and accelerating to 90 kph on tracks, and up to 190 kph on wheels. Christie proposed equipping it with biplane wings, a propeller, and a tail. Christie did not expect it to cover large distances. The device was meant for crossing water hazards and difficult terrain.

Christie's project was not implemented practically, as the level of technology at the time could not provide a reliable system for switching the tank's motor between its wheels and propeller. The department of armament in the United States had little enthusiasm for Christie's inventions, and would not finance them. The winged M.1932 remained on paper.

The USSR also developed a flying tank. In 1933, engineer A.N. Rafaelantz was designing a motor-less glider, which could carry a BT tank in a special frame. Among Rafaelantz's good ideas was a separate landing gear for the glider, which avoided damage to the tank's suspension during landing. The glider was not developed, as it turned out that it was much easier to deliver a tank by strapping it to a heavy bomber.

O. Antonov's project was much more successful. In fall of 1941, he created a single use towed glider, meant to transport the light T-60. Antonov's glider would detach from the TB-3 bomber towing it 20-30 km from its destination, landed independently, and entered battle. The single flight of the A-40, also known as "Tank Wings", was performed in the fall of 1942. The trials revealed the low weight capacity of the glider, its low flight characteristics, leading to rapid height loss, and many other problems. The weight was the biggest problem of all: even though the T-60 did not have a turret and was maximally lightened, the TB-3 still struggled. The more powerful Pe-8 were in too short a supply to tow tanks.

Japan also developed a glider tank. The Japanese Type 3 Ku-Ro vehicle was meant for support of paratroops. Unlike the USA and USSR, the Japanese developed their tank from scratch. The result of their work was a tank with a narrow hull, there the commander was positioned behind the driver. The tank would be equipped with a 20 mm or 37 mm cannon, or a 7.7 mm machinegun. Work on the Ku-Ro lasted until 1945, but its designers never got past a wooden mockup.

Original article available here.

Tanks in the Air

Some of you may have read about attempts to make a tank fly. Here is a brief summary of Soviet efforts:

"After 1939-1940 tank transport experiments involving TB-3 and TB-4 planes, mass production of mounts for the TB-3 plane started at the end of 1940. As of May 1941, the Army has 130 mounts for the TB-3 plane capable of carrying T-37 and T-38 tanks, up to 3.3 tons in mass. There are no mounts for the T-40 tank, 5.5 tons in mass.
The Committee of Defense order #23ss dated February 28th, 1941 ordered the People's Commissariat of Heavy Machine-building to produce 20 mounts for the TB-3 plane capable of carrying 3.3 tons, and 12 mounts for the TB-7 plane capable of carrying 4.5 tons.
On May 12, 1941, GABTU chief Lieutenant-General of Tank Forces comrade Fedorenko reported to the Head of the General Staff of the Red Army comrade Zhukov, in letter #145965s, that the order was not fulfilled.
According to information from the Aero-paratroop Directorate of the Red Army, the reason for this was that TB-3 and TB-7 planes are discontinued, and are not available in large numbers.
In 1942, attempts to tow a T-60 with wings (in a glider configuration) with two TB-3 planes were conducted, but ceased for the same reason.
The Aero-paratroop Directorate is suggesting that the experiments restart, except with two P-8 planes towing a T-60.
However, based on the above information, I deem that it is currently impossible to use T-60 tanks in paratrooper operations.

Engineer-Captain Bukatin
Assistant of the Chief of the 6th Department of GABTU KA
April 4th, 1944"

-CAMD RF 38-11355-1377

Bukatin was right, efforts to make a tank glide were unsuccessful in WWII. However, there are other ways of getting a tank in the air.

From Tanks Theory, N.I. Gruzdev.

The equations provided describe how to figure out a jump that lands the tank in such a way that it lands flatly, and does not significantly damage the components.

If the jump is performed incorrectly, the tank may be damaged: "The jump was performed off a wooden ramp, half a meter high, and angled 5 degrees, over a 30 meter wide river, off a 7.5 meter tall shore...
...The tank reached a speed of about 65 kph, flew 30 meters through the air, hit the opposite shore with its front. Upon traveling 20 meters on the opposite shore, the driver stopped the tank. After examining the tank, the right front and rear balancers were significantly bent. After examination, the vehicle was capable of independently driving away." - from the Russian State Military Archive

In the 1938 movie "Tankers", a number of tank maneuvers were shown, including a jump into a river. From the memoirs of the director Grebnev: "We only had bad luck once. We needed to film a tank jumping over a river from a tall shore. We found a small river that flows into the Luga. Started filming. The first jump was successful, but we needed a second take, to be sure. Camera, jump, and...the tank got stuck in the middle of the river. The river was sandy, the ground was damaged by the first jump, and didn't hold out for the second. What a catastrophe! With two tanks, we had to drag that one out of the water, where we had to clean it for an entire day. But the commanders did not get angry. They thought of it as gathering experience. If they had to do it in a war, two tanks should not jump in one place."

The BT series could jump well, but what about the T-26? It did not want to get left behind!

"Report on the trials of the TPP-2 vehicle, confirmed by Barykov
1938, Leningrad, Kirov factory #185
January

The TPP-2 tank "Tank Preodoleniya Prepyadstviy" [Obstacle Crossing Tank] is designed to cross obstacles by jumping over them. A jump in this case is defined as the tank breaking contact with the ground and flying through the air freely. Currently, tanks jump in two ways:

1. Using a naturally occurring difference in terrain height.
2. Using a ramp, or an artificially occurring difference in terrain height.

The TPP-2 is designed to use the kinetic energy of a moving tank.

In order to test the principle of jumping using an artificial ramp, a tractor on the T-26 chassis was used. In order to increase speed, the tank's mass was reduced, and the tractor was without:

• The upper armour plate (roof)
• Track covers
• Various equipment, extra braces
• The tank was only loaded with 1/3rd of its fuel capacity

Despite all this, the TPP-2 was not significantly lighter than a regular T-26, which is seen in the component weights:

1. Hull: 4770 kg
2. Suspension: 940 kg
3. Tracks: 748 kg
4. Eccentric gear: 484 kg
5. Automatic gearbox: 334 kg
   Total mass: 7276 kg

The mass of the production machinegun and cannon armed T-26 is 8300 kg, so weight reduction of one ton was achieved.

Order and results of trials

Trials of the tank were as follows, and had the following results:

November 26, 1937

Function of the automatic mechanisms, (priming, launching, eccentric rotation, fixation mechanism) was tested in place, with the tank on a tall jack. The entire system was also checked this day by being launched with two 12 volt batteries. The system was also checked by being launched with the engine. No defects that would prevent testing were observed.

November 27, 1937

The tank was tested on the factory's race track. The tank moved at 23-25 kph. After priming and releasing the automatic mechanism, it triggered without fault, but the eccentrics did not rotate fully, and the tank did not jump, due to the icy ground and a lack of friction. The tank performed a U-turn and lost speed rapidly. 

When the tank was inspected, the following defects were found:

• Four gear teeth were broken (part 91-108)
• Two direction limiters were broken (part 10x20N44)
• The right half-axle was caught in the pipe and was damaged (part 91-108)
• One of the teeth on the quadrant broke, and cut off the rear of the plug (part 91-112)
• The pusher shaft was bent (part 93-3)
• The crankcase lug in the area of the pusher shaft ruptured

December 26, 1937

After correcting the aforementioned defects, a second attempt at a trial was made. In order to increase the tank's speed, a special track was built with packed snow covered in sand. A speed of 25 kph was achieved. In order to improve the friction on the eccentrics, they were equipped with spurs, and turned off automatically when reaching a wooden ramp at the end of the track. The results were as follows:

Trial #1: The mechanism worked flawlessly, the tank jumped in the air, but due to the sharp loss of speed, did not jump very far, and landed on its tracks roughly.

Trial #2: The mechanism worked flawlessly, the tank was launched in the air, but due to the loss of speed, the eccentrics did not have time to rotate fully. The tank landed very roughly.

The poorer performance in the second trial can be explained by the eccentrics' half-axles, attached to pipes on the suspension, steel on steel, were stuck.

After these trials, the following defects were found:

• One gear tooth broke (part 91-108)
• The crankcase developed a crack next to the pin attachment
• The front and rear eccentric half-axles were stuck in the suspension, and show scuffs.

December 31st, 1937

After correcting the aforementioned defects, and due to removing the air filter from the engine, the tank reached 30 kph on an improved track. At this speed, the mechanisms performed flawlessly, the tank was raised by the eccentrics, the eccentrics rotated fully, but the tank lost speed rapidly and barely jumped at all. The tank landed roughly.

Conclusions:

1. It was proven that propelling the tank into the air using its kinetic energy with an artificial ramp (the eccentrics) is possible.
2. The TPP-2 prototype has the following defects preventing it from achieving satisfactory performance:
1. Insufficient speed, and therefore insufficient kinetic energy, of the tank
2. A suspension that is too stiff, resulting in rough landings leading to destruction of the mechanisms
3. Unsatisfactory attachment of the eccentrics to the hull of the tank, preventing them from working properly. 
3. As a result of the above, subsequent trials of the TPP-2 will not be productive, and must cease. Use the TPP-2 as a tractor.
4. Department #8 must continue experimental design work on jumping tanks.
5. The design of the TPP-2, despite trials results, can be evaluated as follows:
1. The mechanism was designed well, and must be used as an example of what can be done with limited dimensions using an existing vehicle. 
2. Individual assemblies are of interest, and are designed boldly and originally.
3. Individual parts of the mechanism are of interest, their design indicates excellent engineering thought, and demands close attention.
4. The driver's seat, with hydraulic shock absorbers and straps, is very successful, and should be standardized used on other tanks.
6. Defects are as follows:
1. Unacceptable use of steel on steel in the eccentric half-axles.
2. Unacceptable location of the eccentrics, reducing the tank's clearance from 380 mm to 260 mm.

Chief of the #2 Bureau of the 8th department engineer Masalkin

Military representative of the RKKA ABTU, military engineer 3rd grade, Poklonov

Trials and assembly managers:

Section chief of the #2 Bureau of the 8th department engineer Fedorov

Engineer-designer of the #1 Bureau of the 8th department, engineer Linder

Chief of the 8th department Gudkov"

World of Tanks: Today in History: Vasiliy Gavrilovich Grabin

One of the best known Soviet artillery engineers was born on January 9th, 1900 (December 18th, 1899 in the old calendar) in the Kuban region. In 1923, he graduated from the Petrograd heavy field artillery command school, and served in Karelia until 1926. In 1926 he became a student at the mechanical engineering faculty of the Technical Military Academy of the Red Army.

In November of 1932, Grabin was appointed the deputy chief of the Main Design Bureau #38, which developed barrelled artillery systems. In 1933, the bureau was disbanded due to Tukhachevskiy's fondness for recoilless guns. Grabin did not want to participate in projects that he thought had no future, so he was reassigned to Gorkiy (Nizhniy Novgorod today) in 1933, to the "Novoye Sormovo" artillery factory #92.

First, factory #92 only built cannons. It was in need of a design bureau. Grabin created such bureau, and became its chief. The design bureau of factory #92 produced many high quality artillery designs.

In 1942, Grabin, already a Lieutenant-General, became the chief of the Main Artillery Design Bureau, in Kaliningrad (Korolev today). He worked here for many years.

The sheer amount of material prevents us from talking about all of Grabin's guns, but we will examine several of them.

The gun of the famous T-34 was born in the design bureau of the Gorkiy factory: the 76 mm F-34. It was accepted in 1941 under the name "76 mm tank gun model 1940". Over 38 000 F-34 guns were produced before 1944.

The ZiS-4 was another one of Grabin's creations that was installed on the T-34. It was based on the 57 mm ZiS-2 gun, and started production in July of 1941, but was only produced in very limited numbers. Tanks armed with this gun fought in defense of Moscow in the 21st Tank Brigade.

In 1941, based on the F-32 and F-34 tank guns, Grabin's bureau designed a gun for heavy tanks, initially indexed F-27. This gun was renamed to ZiS-5, and adopted by the army under the name "76 mm tank gun model 1941". It was installed on KV-1 and KV-1S tanks.

In May of 1941, Grabin, under his own initiative, began development of the 76 mm ZiS-3 divisional gun. It consisted of a 76 mm gun barrel on the ZiS-2 gun mount. In June of 1941, the prototype was ready, entered trials in July, and was demonstrated to Marshal Kulik on July 22nd. Despite the gun's excellent performance, Kulik opposed its adoption. Grabin, due to his stubborn personality, decided to produce the gun anyway. The engineer's work did not go to waste, and the gun was adopted by the Red Army in February of 1942. This gun became not only the most numerous gun in the Red Army, but in the world. Over 100 000 barrels (including the ones installed on the SU-76 SPG) were produced. This gun was the first in the world that was assembled on a conveyor belt. From 1943, this gun became the main gun of divisional artillery, as well as anti-tank regiments.

We will cover one more of Grabin's guns, the 130 mm S-70. This was the first domestic gun with an automatic loading mechanism. The mechanized ammo rack held both shells and propellant. The gun was loaded with mobile carriages and a mechanical rammer. The S-70 reached a rate of fire of 5.5 RPM with the automatic loader and 1.1 RPM without. A small batch of guns was produced in 1948.

Original article available here.