Deciding on Tanks, 1925

"Minutes of a meeting with the Chief of the Mobilization Planning Directorate of the RKKA
October 24th, 1925

Present:

1. Directorate chief, comrade Volpe
2. Special Artillery Department chief, comrade Tonilov
3. Artillery committee member, comrade Rozhkov
4. GUVP Tank Bureau chief, comrade Shukalov

Chair: comrade Volpe.

Secretary: comrade Pleshkov.

Topic: on supplying the Red Army with tanks. Presenter: Volpe.

It is necessary to define measures and deadlines to equip the Red Army with tanks. Suggestions:

1. Rely on domestic production, using imports as auxiliaries.
2. Investigate the following parts of the issue separately:
1. Importing tanks: capabilities, types, amount.
2. Existing domestic tanks and domestic tank building.
3. Design and the future of tank building.

On the issue of importing tanks, comrades Shukalov and Tonilov:

Last year (1924) we received an offer from Italy to buy no less than 10 Fiat-3000 tanks. Regarding France and England, the issue of buying tanks cannot be resolved due to political reasons.

As a result of preliminary preparations by the GUVP Tank Bureau and Artillery Committee with the Artillery Inspectorate, consider the following models compatible with technical requirements of the Red Army:

• Support tank, Fiat-3000, Italy
• Support tank: Meniliet, France
• Maneuver tank: V-9, England.

Consider it necessary to purchase one or two of each tank from abroad as experimental machines for study by GUVP engineers. In case of a denial, buy only minimal amounts of Fiat-3000 and V-9 tanks, in the amount of an RKKA tank unit, with an additional tank for use by GUVP.

Ask the Revolutionary Military Council to give orders to the People's Commissariat of External Trade to determine the ability to purchase these tanks, the minimal amount, cost, and time of fulfilling that order.

Buy two Card motors (America) as samples for installing in a maneuver tank and for design work to produce a domestic tank engine.

On domestic tanks and tank designs, comrade Shukalov:

A support tank has been designed (air cooled, 37 mm gun), and is currently being examined by the Artillery Committee. Blueprints and descriptions have been given to the Obukhov factory, with the aim of producing an experimental prototype by August 1925. The issue of mass production of these tanks can be resolved by Spring of 1927.

Decision: GUVP ensures that the work at the Bolshevik factory on a support tank is completed in time. The Artillery Committee finishes the examination of blueprints and descriptions, and sends the results promptly to the GUVP Tank Bureau.

On domestic design work, comrade Shukalov:

Work is being done to equip the support tank with a water cooled engine.

A maneuver tank with a 45 mm gun is being designed.

The design of a positional tank is postponed due to a lot of work at the Tank Bureau.

Decision: Taking into account difficulty with supplies and variety of armament, the GUVP Tank Bureau and Artillery Committee should build a support tank that uses a regimental gun (three units). 

Continue work on a maneuver tank, and finish it by June of 1926. 

Aim for unification of armament. Define a positional tank in general terms only. Determine the most suitable tank we can produce.

Signed: Chair, A Volpe

Secretary Pleshkov"

V. Lehn Collection

As usual, the indices are a little obscure, so let's go through them. The V-9 (9-ton Vickers) is a Vickers Medium Tank Mk. I. No idea what a Meniliet is (maybe they meant Chenillette), but the "support tank" is quite obviously an MS-1, leading me to believe that the "support tank with a regimental cannon" is a SU-18. The "maneuver tank" is a T-12, which was eventually finished and went through trials in December of 1929 (unsatisfactorily). A "positional tank" is a heavy tank. One was indeed designed at the Bolshevik factory in the coming years (T-30), but was considered too complicated to build.

Another interesting part of the document is the reference to the Bolshevik factory by its old name: "Obukhov factory". The name changed in 1922, but it looks like some people were still slipping up and using the old name.

World of Tank History Section: Taking Iwo Jima, Hell on Earth

The air over Iwo Jima smells of sulphur. It was mined here since before WWII. The name of the island itself means roughly "sulphur island" in Japanese.

When war erupted in the Pacific, Iwo Jima became the home of a radar station and a Japanese garrison. General Tadamichi Kuribayashi was appointed as the commander on June 30th, 1944. Under his command, the island turned into a stronghold with underground tunnels, pillboxes, and caponiers. Additional forces were moved to the island, including the 26th Tank Regiment commanded by Colonel Takeichi Nishi with 22 Chi-Ha and Ha-Go tanks.

When Nishi arrived at Iwo Jima, he could see that the island was far too small for any maneuvers. Japanese tanks were largely used as immobile guns. The Japanese also built stone replicas of tanks to scare the Americans. The deception could only be discovered close up. The island was ready for a defense.

Key to Japanese Skies

The reinforcements were not for nothing. The island had great strategic value. After the Americans knocked Japan out of the Mariana Islands, Japan was within range of B-29 Superfortress bombers. The radar at Iwo Jima gave an early warning when Japan was about to be bombed and helped Japanese fighters intercept American bombers not only on the way to the target, but on the way back. Additionally, when refueling at Iwo Jima, Japanese bombers could reach the Mariana Islands and pay the Americans a visit.

Capturing Iwo Jima would not only punch a hole in Japanese air defences, but obtain a base for American escort fighters and damaged Superfortresses. Losing a B-29 was undesirable, as it cost half a million dollars and 11 trained airmen.

Lieutenant-General Holland Smith's corps was chosen to attack the island. The American landings began on the morning of February 19th, 1945. The first wave of attackers would be supported by LVT(A)-4 amphibious tanks, a modification of the LVT with a 75 mm howitzer in an open turret. However, the offensive started slipping from the very start. Vehicles sank in the soft volcanic terrain before even reaching shore. The Japanese did not impede the landings on the beach. They were waiting until the attackers went deep into the island, onto the minefields and ranged in positions.

After a few minutes, the Americans found themselves under machinegun, mortar, and howitzer fire from hidden fortifications, with no opportunity to entrench. Walls of foxholes dug in the soft terrain would immediately cave in. Even if an American managed to dig a big enough hole or hide in a crater, he would have to deal with sulphuric gas seeping from the ground.

The second wave contained real tanks, M4A3 Shermans. The beaches were filled with vehicles, as the terrain was too soft for even tank tracks.

A bulldozer from A company tried to clear the way, but hit a mine, then was hit three times with large caliber mortars. The bulldozer was completely destroyed. Other Shermans tried to move in as a column, but made it only 90 meters before being immobilized by a minefield. 7 hours after the landing, A company was missing 12 tanks out of 17: 7 were stuck and 5 were knocked out. Other companies also took heavy losses.

By that evening, losses surpassed all estimates, consisting of over 2000 men, dead and wounded. A more sensitive army may have stopped the operation there, but Americans back then were made from tougher stuff. By the evening they numbered 30,000, surpassing the Japanese garrison.

Fire and Armour

Shermans, especially the flamethrower versions, were invaluable when chewing through Japanese lines. Tanks suppressed machineguns with their fire, then closed in and covered pillboxes and tunnels in napalm. That is, if they could close in. The Japanese used not only anti-tank mines, but IEDs made from powerful bombs or torpedoes. Minefields were covered by machineguns and anti-tank guns. A Japanese 47 mm gun was quite obsolete by 1945, but it could still penetrate the side of an American tank at close range. Infantry also hunted tanks, both with explosives on poles and suicide bombers.

American tankers tried to improve their protection with anything they could find: steel plates, sandbags, even boards. Photos from Iwo Jima show tanks that look more like sheds with guns. In reports, tankers demanded Pershing tanks, reasoning that it is not vulnerable to 47 mm guns, pole mines, and other weapons, and the Sherman's 75 mm gun could not destroy reinforced concrete pillboxes. That came later.

Five days after the beginning of the attack, soldiers of the 5th Marine Division raised an American flag over the dead Suribachi volcano. Two hours later, it was replaced with a bigger one, but this flag was the one immortalized in Joe Rosenthal's famous photograph. The flag did not mean that the island was taken. The defending soldiers had to be cleared out meter by meter from the north part, where the main target lay: the airport capable of accepting B-29 bombers. It was only taken by February 26th. On March 4th, the first Superfortress made a successful landing on the hastily repaired landing strip.

Fighting for the island continued for another month. Even when the Americans controlled the surface, the Japanese attacked from hidden tunnels. The last attack, personally headed by General Kuribayashi, took place on the night of March 26th. Individual Japanese soldiers continued hiding in numerous caves even after Japan's surrender.

Article authors: Andrei Ulanov and Aleksandr Tomzov

Sources:

• Jig Report 4th Marine Division Iwo Jima.
• King Report 4th Marine Division IwoJima.
• Operations Report 4th Marine Division Iwo Jima
• Harper, David E. Tank Warfare on Iwo Jima.

Original article available here. 

SU-5 Munitions Carrier

"Experimental munitions carrier project for the SU-5

1. Purpose:
   The SU-5 SPG (small triplex) passed trials and show promising results. This SPG can be used in a mechanized unit as well as regular artillery battery in a motorized infantry or cavalry unit. However, the SU-5-1 (76 mm mod. 1902/30 gun) carries only 8 shells on board. Other variants carry no ammunition. It is necessary to develop an ammunition carrier that has a sufficient amount of shells that follows the SPG. This carrier must have identical or greater technical and battlefield qualities compared to the SU-5. The SPG and carrier will form one fighting unit.
2. Requirements:
1. The carrier will be developed on the chassis of a Komintern tractor, with minimal alterations.
2. The tactical and technical characteristics of the carrier, such as speed, clearance, maximum grade, tilt, etc. must be no lower than those of the SU-5 SPG.
3. It should take no longer than the SU-5 to move from travel position to combat position (30 seconds).
4. The crew will consist of 3, including a driver. If it is not possible to widen the cabin to fit 3 men, 2 is sufficient.
5. The engine, cabin, and fuel tank must be armoured.
6. Armour protection is equivalent to the SU-5.
7. Considering that the Komintern can carry a 2 ton weight, the following amounts of ammunition can be carried:
1. 76 mm: 120 rounds
2. 122 mm: 50 rounds
3. 152 mm: 30 rounds
   The mass for each ammunition supply ranges from 1200-1500 kg, so 500-800 kg can be used for armour.
8. Rounds must be placed in existing containers, and containers placed in slots in ammunition racks.
9. The vehicle must have a roof to prevent moisture from getting to the shells and ammunition racks.
10. It must be possible to continuously pass off shells to the SPG so that the transfer of shells does not limit the rate of fire. Containers should be easy to remove from their slots.
11. The carrier should be easily convertible between shell types (76 mm, 122 mm, 152 mm) simply by swapping slots.
12. The carrier should have tow hooks in the front and back to tow a similar carrier or a SU-5.
13. A DT machinegun should be installed, and 1000-1500 rounds carried for protection."

V. Lehn Collection

Tiger II Trials: Gunnery

The previous article covered the mobility aspect of the Soviet Tiger II trials, this one will cover how its gun and turret performed.

"Maneuverability of fire

Aiming the cannon and coaxial machinegun is done with the turning mechanism, elevation mechanism, and hydraulic turning mechanism which works only when the engine is running. The hydraulic mechanism has two gears and is controlled by a foot pedal.

The horizontal aiming speed of the gun depends on the rate at which the engine is running. Data on the aiming mechanisms is given in the following table.

Mechanism	Range (degrees)	Number of turns in range	Angle for one turn
Turning mechanism (manual)	360	673	30 minutes
Elevation mechanism	22	36	36 minutes

The hand crank and hydraulic rotation mechanism are independent. The effectiveness of the hydraulic turning mechanism is given as follows:

Gear	Engine RPM	Turret traverse	Time
1	500	360	1 min. 20 sec.
2	500	360	1 min. 15 sec.
1	1000	360	1 min. 26 sec.
2	1000	360	43 sec.
1	1500	360	54 sec.
2	1500	360	27 sec.
1	2000	360	40 sec.
2	2000	360	20 sec.

The effort required to elevate the gun when the tank is horizontal is as follows.

Gun position	Effort in kilograms
	Elevation	Depression
-5 degrees	6	1.5
0 degrees	7	1.2
+5 degrees	9	2
+10 degrees	8	1
+15 degrees	10	2

The effort needed to turn the turret with the tank flat on the ground is 2-3 kg.

Turret and gun looseness:

The looseness of the gun is 3 thousandths vertically. The looseness of the turret is 4 thousandths horizontally.

Gunnery trials

Muzzle velocity and maximum pressure:

The stock round from the 88 mm KwK 43 tank gun was used. The results attained were averages from armour piercing and high explosive rounds, six of each.

Type of shell	Number of shots	Muzzle velocity	Maximum pressure
Armour piercing	6	1018	3006
High explosive	6	759	-

Examination of precision and accuracy of the 88 mm KwK 43 gun in place:

To determine the accuracy and precision of the gun with armour piercing tracer shells, the gun was fired at vertical targets from a range of 1000-2000 meters. Aiming was done with the telescopic monocular sight with variable magnification. The visibility was good. The angle of the tank was 0 degrees. Time to fire was unlimited. Correction to aim was made after every shot.

Conditions	Range	# of shots	# of hits	100% radius	50% radius
1st group, 4x4 meter target	1000	10	10	48 cm	36 cm
2nd group, 4x4 meter target	1000	10	10	67 cm	43 cm
3rd group, 6x6 meter target	2000	10	10	93 cm	62 cm

Precision and accuracy of the 88 mm tank gun KwK 43 at ranges of 1000 and 2000 meters are good.

Determining rate of fire and accuracy when shooting in place:

The rate of fire of the gun was checked against one, two, three, and four targets with HE shells, in groups of 5 shots, with the following conditions:

• The shells are in the ready rack.
• The time is counted from the "load" command to the last shot.
• Change of range is performed when shifting fire.
• Correction of fire is performed after every shot.

The results were as follows:

Conditions and targets	Range to target	# of shots	# of hits	# of close misses (within 30 meters)	Time to fire (seconds)	Rate of fire (RPM)
Manual turning mechanism
PzIII	800	5	3	2	54	5.6
PzII	800	2	2	-	58	5.2
PzIII 15 degrees away	900	3	3	-
PzII	800	2	2	-	57	5.2
PzIII 15 degrees away	900	3	3	-
PzII	900	1	1	-	70	4.3
PzIII	800	2	2	-
T-40 35 degrees away	1400	2	2	-
Hydraulic turning mechanism
PzIII	800	5	4	1	53	5.6
PzII	800	2	2	-	52	5.7
PzIII 15 degrees away	900	2	2	-
PzII	500	1	1	-	59	5.4
PzIII	800	2	2	-
T-40 35 degrees away	1400	2	1	1
PzII	500	1	1	-	58	5.2
PzIV	650	1	1	-
PzIII	800	1	1	-
T-40 35 degrees away	1400	2	1	1

The maximum aimed rate of fire when firing in place at one target with the manual traverse is identical to the rate of fire when using the hydraulic traverse, 5.6 RPM. When firing at multiple targets in a 35 degree range, the rate of fire is 5 RPM with the manual traverse and 5.4 RPM with the hydraulic traverse. The accuracy of the gun when shooting in place is good.

Effectiveness of firing from the move

An AP-tracer shell was fired at a 4x6 meter target at a range of 900-1100 meters under off-road conditions while moving at 10-12 kph. There were three attempts at 4 shots each. The tank was aiming at 0 degrees, aiming was done through the optical sight at the 2.5x setting while using the hydraulic turning mechanism.

Results: 12 shots were made, one of which was to range in and 11 were counted. 8 shots hit, or 72%. Effectiveness of firing on the move was as follows, from the center of the target:

1. x: -185 y: -80
2. x: -170 y: -55
3. x: -150 y: -20
4. x: -145 y: -15
5. x: +125 y: -10
6. x: +150 y: +150
7. x: +155 y: +185
8. x: +205 y: +305

Horizontal aiming with the hydraulic traverse allows precise aiming at the target, and the semiautomatic braking elevation mechanism allows precise aiming vertically. These two factors increase effectiveness when firing on the move.

As the tank broke down, it was not possible to fully examine the semiautomatic braking elevation mechanism over a large amount of shots fired on the move.

...

Reliability of the gun and its mechanisms

During trials, 152 shots were fired, of which 60 were AP-T and 92 were HE-fragmentation grenades. The recoil length was normal and fell within the range of 510-525 mm.

After 58 shots, the semiautomatic guide failed. (See photo #11)

Photo #11. Destroyed semiautomatic guide.

After 90 shots, the roller arm failed. (See photo #12)

Photo #12. Destroyed roller arm.

After a new roller was installed, 62 shots were made, and the gun functioned normally."

CAMD RF 38-11355-2860