Thursday, 28 August 2014

Chrysler Visit and Sherman Inspection

"Report on the visit to the Chrysler factory in Detroit

From September 3rd to September 5th, Lieutenant-Colonel Demyanenko, Engineer Sorvin, and Engineer Prishipenko visited the Chrysler tank factory. The goal of the visit were:

  1. Familiarization with the design of the Chrysler gasoline tank engine and collection of data on its performance, especially in winter.
  2. Familiarization with the Chrysler tank factory for evaluation of its production capacity.
  3. Personal driving of the M4A4 medium tanks on a proving grounds to obtain necessary data for comparison with M3 and M4A2 medium tanks.
We left Washington on September 2nd, at night, and arrived in Detroit on the morning of September 3rd. We were accompanied by Lieutenant Gerber from the War Department, an aide-de-camp of General Christmass, the chief of tank design and production at the War Department. General Christmass is the chief tank designer in the USA.

When we arrived in Detroit, we were presented to the a Colonel, the chief of the Detroit division of the War Department. The Colonel was very interested in our opinion of American tanks. In particular, he wanted to know about our opinion of the M4A4 tank with a Chrysler engine. This tank has been finalized, and production increases with every month. He also told us that production of M4A2 tanks with General Motors diesel engines and Canadian Valentine VII tanks, which also only use the General Motors diesel, will be complicated in the future. This is caused by a shortage of diesel engines, which are in demand by the American Navy for speedboats. The amount requested by the Maritime Department is very high, and will only increase. 

Note: these engines are built by America's only diesel factory owned by the General Motors company near Detroit. In July of this year, Engineer Sorvin visited this factory. By talking to employees and observation, he was able to establish that the factory produces about 5000 double and single tank diesels (model 6046-Series 71 and model 6004) per month with three shifts working around the clock.. The factory was being expanded to increase production. New mechanical and assembly plants were being built.

The discussion with the Colonel indicated that the above reasons will result in a reduction, or even complete cancellation, of the M4A2 medium tank. At the same time, he highlighted the advantages of the Chrysler engines, built based on automotive engines that the factory has built millions of. He mentioned that there will be no problems with supplies, and like car engines, they will be familiar and easy to service for any driver.

Chrysler's deputy chief engineer of engine production joined us during the trip to the engine factory, located close to Detroit. He stayed with us for the duration of the visit. At the factory, we met with the engine production chief, Mr. O'Malley. With him, and a group of managing engineers, we took a tour of the factory. 

Note: before we left the factory, Mr. O'Malley gave us some documents regarding the quality of parts finish at the factory. These documents are included with the report.

In many offices an laboratories, a cooler is present, capable of generating temperatures of -30 degrees Celsius. During our visit, experiments to examine the starting of a Chrysler tank engine were being carried out in one of these coolers. Additionally, two engines were being tested for wear, actual power, oil and fuel expenditure, etc. During our visit, one of these engines has been working for 400 hours, another for 300 hours. The engines were artificially loaded with Froude hydraulic brakes and an electric balancer machine.

Data gathered during these trials is not yet available, but will be available in the near future.

The next day, we went to the Chrysler Tank Arsenal factory. At the factory, we were accompanied by factory director, Mr. Richay, and the chief engineer of the factory.

The Chrysler tank factory was building M4A4 medium tanks. This factory is famous not only in America, but throughout the whole world. A lot has been written about the construction of this factory in American media, especially in 1940.

In 1941, for the opening date of the factory, the July issue of the Army Ordnance magazine had photographs of the factory, and data on the production capacity and amount of workers. The entire factory, excluding the power plant and warehouses, takes up an area of 1400 by 900 feet. Up to 70% of the ceilings and walls are made of glass. 

Until recently, aside from engines and armament, the factory built everything. Currently, due to increased demand, some components are produced at other Chrysler factories (suspensions, front hulls with gearboxes, final drives). According to the factory director, the September production plan is 600 tanks, and in December, the factory should produce 1000 tanks. 

The tank assembly area takes up the left third of the factory building, lengthwise (see map). The area has 5 assembly lines, which allow for work on 500 tanks simultaneously. 

We attempted to calculate the production capacity of the factory:
  1. The amount of turret base production machinery was counted.
  2. The amount of turret ring teeth cutting machines was counted.
    Based on our estimates, this is the bottleneck in the production.
    Note: turrets arrive at the factory already cast, in need of mechanical finishing.
  3. By asking the factory direction (a real enthusiast of his craft), an chief engineer, we learned the time it takes to finish the bottom of the turret and the turret ring teeth. 
12 carousel machines are used for cutting down the bottom of the turret. It takes 7 hours to process one turret base, so in a day, about 4 turrets can be made. The factory director told us that to increase production to 1000 tanks, three more such machines are needed. We witnessed foundations for these machines being built. The need for more equipment is explained by the fact that an amount of machines is always undergoing preventative maintenance, but the production must always continue. 5 large tooth-cutting machines are used for cutting teeth for the turret ring. It takes 3 hours to process a turret ring. In one day, 40 turret rings can be made.

As such, the production of 1000 tanks per month is possible even now. Finished tanks are fuelled and oiled right at the end of the factory, and drive straight to the proving grounds for testing. The proving grounds are positioned close to the factory building, and consist of a 2-3 km long looped road. The road has varied terrain (concrete, dirt road, sand, elevations and descents). Quality assurance takes 50 miles. After driving for 50 miles, tanks with defects are sent to a refurbishment section for defect correction, after which they are subjected to another 10 miles of track trials. If there are no defects, the tanks are shipped by rail to a tank depot, where radios are installed. Here, instruments and ammunition are loaded into the tank. From here, finished tanks go to army units or to export. 

Due to increasing production, every department is working on installing additional equipment.

Proving grounds and tank driving

After breakfast, we drove to the proving grounds, 12-15 miles from the tank factory. The proving grounds used to be a Cadillac car proving grounds. Next to the good road for testing cars, there is a 2-3 km long tank track, which consists of a dirt road with grades. There is a section of the track that crosses a stream 0.5-0.75 meters deep, but with a hard bottom. The exit from the stream is on a 40 degree grade, which continues for 25-30 meters. There are no muddy, destroyed sections of the road. There are no swamps or trenches. There are no vertical obstacles. When we noted that the proving grounds were insufficient, the factory representatives told us that the tanks were tested at the Aberdeen Proving Grounds (Maryland), where there are allegedly all sorts of obstacles. 

Note: Engineer Sorvin went to the Aberdeen grounds in early August to observe trials of an M4A2 medium tank, and concluded that their proving grounds have nearly identical obstacles as this these proving grounds. 

When we arrived at the proving grounds, we started with a loop around the track in a 2.5 ton Dodge truck (a company owned by Chrysler). All three axles of the truck are powered. The vehicle passed the entire tank route well, including the stream and a small section of bushes, covered in deep gouges.

After breakfast, we personally drove tanks through this route.

There were two tanks there, an M3 medium tank with a Wright engine and an M4A4 medium tank produced by the Chrysler factory with their tank engine. Engineer Sorvin and Lieutenant-Colonel Demyanenko drove these tanks. The impressions are as follows:
  1. The M4A4 is undoubtedly superior to the M3, and has superior mobility and acceleration.
  2. The 40 degree grade coming out of the stream can be traversed by the M4A4 tank in second gear, while the M3 tank can only traverse it in first gear.
  3. The M4A4 tank has a more comfortable driver's compartment than the M3.
  4. Both tanks are definitely worse compared to our T-34, and possibly even the KV.
  1. The Chrysler tank factory is the one of the newest and largest tank factories not only in the US, but in the world. All factory equipment (machines, devices, cutting and measuring tools, valves, and internal transportation) is new, mostly produced in 1939-1942.
  2. The factory is currently capable of releasing 1000 tanks monthly. This capacity is guaranteed by the company engine plant, which produces 35 tank engines daily.
  3. The factory produces the M4A4 medium tank with a gasoline engine. This tank is used by the American army and is mass produced at all American tank factories capable of producing medium tanks.
    Note: the M4 medium tank is available in four modifications:
    1. M4A1 with a Wright air-cooled gasoline engine.
    2. M4A2 with two General Motors water-cooled diesel engines.
    3. M4A3 with a special 6-cylinder Ford water-cooled gasoline engine.
    4. M4A4 with a 30-cylinder Chrysler water-cooled engine. 
  4. The M4A4 tank is identical to the M4A2 (as well as other M4 modifications) in hull design, suspension, armament, observation devices, and communications devices.
    The M4A2 is well known in the Soviet Union from previously sent documents, and all of its drawbacks are repeated on the M4A4 (high ground pressure, height, insufficient amount of vision devices, difficulty in installation and removal of components, difficulty in service, etc)
    The tank's mobility (speed, maneuverability), ability to cross obstacles, and hp/ton is nearly identical to the M4A2 tank with the General Motors engine.
    The M4A4 is superior to the M3, both in the engine, which works on much lower octane gas (65-70) and is water-cooled, and the mobility.
  5. Overall, thanks to a lack of experienced tank designers, the Chrysler factory is building tanks whose design and combat performance does not measure up to the potential of such a first-class tank building giant.
Engineer Sorvin.
September 7th, 1942

CAMD RF 38-11355-760

An M4A4 tank was sent to the Soviet Union anyway, where trials showed that it was not good enough to order instead of the M4A2.

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