Saturday, 14 June 2014

Mobility Trials Part 2

We've already seen some on and off-road trials, but those were for foreign tanks only. This time around, there are a few domestically produced participants, as well as tanks we've already seen. 


"Results of Trials

1. Trials of mobility on a swampy field

Characteristics: swampy field with silty bottom. Silt is 500-600 mm deep, in some places up to 1000 mm deep. There is sand and clay under the silt. The field is covered in water, 40-370 mm deep. The trial distance was 400 meters. A probe could be inserted 450-700 mm with the force of one hand.

Fig. 1. M3 medium tank crossing the field in second gear. The tracks submerge to 160-450 mm, 600 mm in some places. 


Fig. 2. M3 light tank crossing the field in second gear. The tracks submerge 240-300 mm. 

Fig. 3. T-60 tank crossing the field in first gear. The tracks submerge to 90-240 mm."

It appears that the original photo was misplaced here. Two things give it away. One is that the tank pictured is a T-60 and the other is that the next photo (which is supposed to feature a T-70) is the same.


"Fig. 4. T-70 tank crossing the field in first gear. The tracks submerge to 130-270 mm.

Fig. 4. The 38-T Praga crossing the field in second gear. The tracks submerge to 120-260 mm. 


2. Trials on a swampy field with thick silt surface.

Characteristics: the swampy field is covered in silt, 500-800 mm deep. There is clay underneath the silt. Water on the surface is only present in some places, 40-100 mm deep. A probe could be inserted 550-920 mm with the force of one hand.

Fig. 6. The M3 medium tank was moving in second gear and got stuck. The tracks submerge to 280-570 mm. The tank was towed out of the swamp.


Photo #7. M3 light tank crossing the swamped field with thick silt in second gear. The tracks submerge to a depth of 160-360 mm. The M3 light tank passed the location where the M3 medium tank was stuck.

Photo #8. T-60 tank crossing the swamped field with thick silt in first gear. The tracks submerge to a depth of 100-300 mm. The T-60 passed the location where the M3 medium tank was stuck.

T-70: The T-70 was driving next to the T-60 tracks in first gear when it got stuck. The tank was towed out of the swamp. The tracks submerged to 130-340 mm.

Praga 38-T: The tank can cross the swamped field with thick silt in second gear. The tracks submerged to 150-260 mm.

3. Trials in a peat bog

Characteristics: peat bog with thick base, 60-100 mm of water covers the ground. A probe can be inserted with the strength of one hand to a depth of 1000 mm and deeper.

M3 light: travelled 30 meters in second gear. The tracks submerged to 400-560 mm. After driving 30 meters, further movement forwards or backwards was no longer possible.

T-60 tank: travelled 25 meters in second gear and got stuck. The tracks submerged 280-350 mm. The tank was towed out of the swamp. 

Conclusions:

As a result of comparative trials of off-road performance of domestic and American tanks, it was established that:
  1. The American M3 light tank has good mobility in a swamp. The tank can freely pass over a section of swamp with up to 600 mm of silt or 800 mm of peat. The M3 light tank is superior in off-road performance to the M3 medium, T-60, and T-70.
  2. The American M3 medium tank has poorer mobility than the M3 light, T-60, and T-70 tanks. The M3 medium can cross sections of swamp with up to 400 mm of silt. If the silt is deeper than 400 mm, especially if it is thick, the tank can only travel 15-20 meters.
  3. The performance of T-60 and T-70 tanks on swamp covered in grass is limited due to the wheels getting gummed up with grass. After the wheels are gummed up, the tank stops, and sinks.
  4. When moving through a swamp, stopping, turning, or changing gears is not recommended.
  5. If a tank must stop in the swamp, do not let the tracks slip. A tank that is stuck in a swamp should be evacuated by towing or with handy materials (boards, logs, etc)."


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