T-34 Prototype Mobility Trials

"4. Off-road Performance

General off-road performance characteristics of the T-34 tank:

• Combat mass: 25.6 tons
• Ground pressure: 0.60 kg/cm²
• Contact surface length: 5219.3 mm
• Grouser height: 650 mm
• Effective power: 19.5 hp/ton

Natural obstacles.

1. Maximum grade and tilt traversable by the tank at low gears in winter or spring conditions:
   

   Obstacle	Ground	Angle	Limit
   Grade	Snow, 1.5 m deep, tank submerged to 400 mm	15-16°	At higher grades, the hull sits on the snow and the tracks slip.
   Grade	Mud with dirt cover, moist, tank submerged to 220 mm	15-16°	Tracks slip
   Tilt	Snow cover up to 1.6 m deep	15°	Slipping in the direction of tilt
   Tilt	Mud with dirt cover, moist after snow melted	15°	Slipping in the direction of tilt

   Brief (2-3 meters) grades up to 20° can be navigated by the T-34 in second gear. Traversing grades and tilts in winter and summer conditions is limited by the traction of tracks on terrain, which is insufficient for winter-spring conditions. It is necessary to quickly develop a device to increase traction of tracks and terrain: spurs or winter tracks.
   No cases of slipping or jamming tracks were observed during trials. Consider the track fixation mechanism reliable.
2. Traverse of difficult terrain:
   

   Terrain	Cover depth	Tank submerged	Note
   Deep snow	Up to 1800 mm	420 mm	In first gear
   Swamped valley after melted snow	Up to 430 mm	360 mm	In first and second gear

   The mobility of the T-34 on snow is significantly higher than that of the BT-7M tank and can be considered good.
   The mobility of the T-34 on terrain that is swamped after snow melts is satisfactory.
3. Breaking of trees and movement in the forest:
1. Individual trees:

   Type of tree	Diameter (mm)	Conditions		Result
   		Gear	Attempts
   Pine	457	1	3	The tank could not knock over the tree, tracks slipped.
   Pine	457	2	1	Knocked over.
   Pine	605	2	2	Knocked over.
   Pine	879	3	1	Tree broke, the falling tree broke the headlight and floodlight, damaged elevation mechanism gear teeth, bent fenders and mudguards.

   When breaking individual trees, the tank continues moving forward, driving over the roots, trunk, and branches of the tree.
   The maximum thickness of a pine tree that can be knocked over by the tank in second gear is 600-700 mm. In third gear (with a running start) the T-34 can break pine trees up to 900 mm in thickness.
2. Groups of trees:

   Type	Number	Diameters	Conditions		Results
   			Gear	Attempts
   Pine	5	255-416	2	4	The tank knocked over the group of trees and drove over the felled trees.
   Pine	7	309-446	2	5	The tank knocked over the group of trees and drove over the felled trees.

   The T-34 tank can cross tightly growing groups of pine trees with the diameter of 250-450 mm after 4-5 attempts and drives forward over the felled trees.
3. Movement in the forest:
   The T-34 can drive in first and second gear in areas of medium density with the majority of trees being 200-300 mm thick.
   The T-34 tank has good mobility in the forest, in groups of trees, and against individual trees, greatly surpassing the BT-7M.
   The robustness of the tank is overall sufficient. The weakest parts of the tank, which must be reinforced, are:
1. Observation devices.
2. Air intake shield actuator.
3. L-11 gun elevation mechanism.
   In addition to this, the crew must be protected from trauma when the tank hits a tree by means of removing sharp angles or protruding objects, introduction of soft padding (mostly around the head), and handles for bracing with hands.

Artificial obstacles

MZP (hard to notice obstacle): the tank crosses a 40 meter long MZP at 3rd gear, with the wire wrapping itself around the suspension. The tank retains mobility and, while moving, partially frees itself of the wire.

Denting of rear mudguards is characteristic."

The tank crosses a 1.5 meter deep snow bank.

The tank is driving through a valley made swampy by melting snow.

The tank broke a pine tree 879 mm in diameter at third gear.

The tank is driving over felled trees.

The tank is traversing a group of pine trees 255-416 mm in diameter.

The tank is driving through an oak forest with 200-300 mm diameter trunks.

A hard-to-notice obstacle wrapped itself around the tank's tracks. The tank retains mobility.

RGVA 31811-2-1181

"History of the T-34 tank" Memorial Museum Complex, Documentary Historical Collection #4