Monday, 23 March 2015

M2A2 Tanks in the Antarctic

"Excerpts from the assistant USSR military attache in the USA, Major Barayev.

Performance of American M2A2 light tanks in the southern polar territories (Antarctica) according to the American Antarctic expedition.

1. Reduction of tank weight.

Before tanks were sent to the polar expedition, it was decided that they should be lightened. All armament and a part of the armour was removed. When tanks arrived to the polar stations, it was determined that they were still too heavy to work in the icy conditions of the Antarctic. Turrets were removed in order to increase power per ton and improve stability.

The tank ground pressure was reduced to 5 or 6 psi. This was still not ideal, as previous experience in soft snow showed that the ideal value is 4 psi.

2. Power.

In order to increase the tank's power when moving on soft snow and reduce instances of falling through, additional plates made from 1/4 inch thick armour taken from the turret were welded to the tracks. The width of the plates was 8 inches, and they increased the width of the track by 7 inches, to a total width of 11 inches. These plates were welded on the inside of the tracks. This improvement increased the tank's power and protected it from falling through the snow.

3. Controlling the tank.

When the tank moved across loose snow, the snow was thrown up and blocked the driver's viewport. This was resolved by installing a protective plate, a regular automotive fender. It is necessary to install a special de-icing attachment to the glass window on the driver's viewport. The Antarctic service could investigate this issue, but it is preferable if the Army took it upon itself to solve it.

4. Carburettor.

The carburettors didn't have any problems in the cold. They worked normally, but it was assumed that all gasoline had to be filtered through suede to prevent water from getting into the carburettor.

The fuel line to the carburettor runs next to the engine, so the gasoline that goes through it is heated up by the engine's heat.

It is recommended that the fuel tank should be insulated, preventing excessive freezing.

5. Air filter.

Difficulties were encountered with the air filter when it was frozen. Freezing stopped the air from being sucked in and destroyed the pipe to the carburettor. In order to prevent this rubber pipe from rupturing, it is recommended to use a metal pipe. In the end, the air filter was thrown out entirely, as there is no need for it in the polar atmosphere with no mud or dust.

The pipe was replaced with one leading to the engine compartment near the batteries, where air was gathered without any filter.

6. Batteries.

The batteries worked well in cold conditions and no difficulties were encountered. Nevertheless, it is recommended to add a special insulation layer around the battery crates, considering that drafts are formed in this compartment once the air intake pipe is routed here.

7. Oil filter.

Like the air filter, the oil filter is completely unnecessary in polar conditions. In practice, the oil froze in it and caused it to rupture. The expedition removed all oil filters after a series of such cases.

8. Heating the engine.

The last two American expeditions to the Antarctic used Van Pregg heaters to heat up engines. They worked well for heating aircraft engines, but the best heater for tank engines turned out to be the Primus heater. This heater is made in Sweden in two sizes: 3 gallons and 5 gallons. It can keep the temperature of the engine compartment, and thus the motor, to 50 degrees Fahrenheit. Heated air is channeled into the engine compartment through a hose into an area with no electric wiring or fuel lines.

Oil is heated to a temperature of 120 degrees in special tanks with the same heaters. After being heated, the oil is poured into the crankcase and the engine starts. The engine can start at a temperature of 50 degrees, but before moving the tank, the engine temperature is increased to 100 degrees.

During Antarctic expeditions, it was determined that it takes about one hour to heat up the engine to 50 degrees using Primus heaters.

Primus heaters also work well to heat groups of people working outdoors. They do have a drawback, the corrugated pipes, despite being coated in fibers, crack in the cold and break. This can be fixed by adding an elastic metal insert inside the pipe.

9. Lubrication of the tank.

SAE 40 oil was used to lubricate the tank, but experience showed that SAE 50 oil was the superior lubricant for tanks working in winter conditions. Even with an outside temperature of -60 Fahrenheit, the engine worked well and maintained a temperature of 100 Fahrenheit.

Lubricating the wheels, crankshafts, etc. was not problematic and caused no faults. There was also no need to add additional lubrication to these components.

10. Generator.

The generator insulation ended up covered in lubrication oil, but the cause was not discovered at the time.

11. Rubber tracks.

Tracks work well, even in very low temperatures. They do not crack, bulge, or wear prematurely.

12. Speedometer.

The temperature of the fighting compartment dropped so much that the oil in the speedometer became viscous and the speedometer stopped working. In order for this mechanism to work properly, it is necessary to develop and apply some kind of heating device.

13. Clutch.

When the fighting compartment was exposed to an outside temperature of less than -60 degrees, the cold air entered the tank and froze the clutch to the point that it ceased to work normally, as the disks slipped. Experience showed that when the tank stops with an exterior temperature of -50 to -60 degrees, the clutch has to be heated, otherwise the aforementioned problems are unavoidable.

At 0 Fahrenheit, the clutch worked normally,

14. Marches.

At the Western base (Little America), one tank made a 30 mile march at a temperature of -60 Fahrenheit. The tank moved in second gear, dragging a sled with a 2 ton weight. The tank could not move at a higher gear, as it was impossible to control the sled at higher speeds. The tank worked flawlessly at higher speeds without a sled, except for the driver's window being covered with snow.

The following lubricants and fuel were used for aircraft, which the expedition also had:
  • Gasoline: 87 SGR (Army, about 92)
  • Lubricating oil: Navy 1080, winter. Same as Veedal Aero-Special Heavy. "77" under Army specifications.
  • Kerosene: regular commercial.
  • Grease: Royal Special AAA for temperatures of -50 F.
Experience gathered by the Americans in their Antarctic expeditions is of some interest to us, and can be used when using American or Canadian tanks (Canadian MIIIA, American M3) in our harsh winter conditions. 

It is especially important to consider the practice of carefully pouring gasoline into M3 tanks to avoid problems with the carburettor.

It is possible that we will see the same problems with oil and air filters when using these tanks. In order to avoid breakdowns, disconnect them from the engine during the winter campaign."

No comments:

Post a comment