CHAPTER 9 - WWII JAPANESE TRACTORS AND CONSTRUCTION EQUIPMENT



TABLE OF CONTENTS








4. WWII JAPANESE PRIME MOVERS AND TRACTORS.

a. Japanese WWII Komatsu tractor.
This small, full-tracked vehicle (Figure 316) is designed solely for towing purposes. Steering is of the clutch-brake type, with hand levers opertating the clutches. Two foot brakes are located on the right side, and are so placed that either or both brakes may be operated by the right foot.

The gear box allows 3 forward and 2 reverse speeds. The vehicle is supported by 4 small bogie wheels on each side. Examination of a specimen revealed that a number of bearings were of swedish manufacture. Characteristics are as follows:

1. Weight --------- Estimated 3 tons.
2. Length --------- 8 feet. 2 inches.
3. Width --------- 4 feet. 4 inches.
4. Engine --------- 4 cylinder. gasoline.
5. Cooling --------- Water.
6. Ignition --------- Bosch magneto.
7. Length of track in contact with ground --------- 5 feet 7 inches.
8. Width of track --------- 10 inches.

Figure 316.
Komatsu tractor.



b. WWII Japanese Light prime mover.
The model number and date of manufacture of this vehicle (Figure 317) are not known. In the case of a specimen examined, the word "seventy" was found marked in English on the side of the radiator, probably indicating the engine horsepower. A name plate on the power unit shows it to be a "Kato engine model K 3". Suspension consists of 2 bogies mounted on each side of the vehicle.

Each bogie has 3 small wheels, and the sprocket is at the rear. Details are reported to be as follows:

Approximate characteristics:
1. Weight --------- Estimated 4 tons.
2. Length, width, height --------- No details.
3. Engine --------- 4 cylinder, gasolinge.
4. Cooling --------- Water.
5. Length of track in contact with ground --------- 7 feet 5 inches.
6. Diameter of sprocket --------- 2 feet 2 inches.

Figure 317.
Light prime mover.




c. WWII Japanese Model 92 (1932) 5-ton prime mover.
It is reported that there are 2 variations of this vehicle. Model A is powered by a 6-cylinder in-line "L" head "Sumida" gasoline engine, and model B by a 6-cylinder in-line, air cooled "Isuzu" Diesel. As far as may be ascertained, with exception of a modification in radiator design, the general appearance and suspension of these 2 models are similar. Both vehicles are reported to be identical in the following respects:

Common characteristics:
1. length --------- 11 feet 8 inches.
2. Width --------- 5 feet 11 inches.
3. Height --------- 7 feet 8 inches.
4. Ground clearance --------- 11 3/4 inches.
5. Fording depth --------- 1 foot 7 1/2 inches
6. Grade --------- 30 degrees.
7. Turning radius --------- Can pivot.
8. Winch capacity --------- 2 3/4 tons.


(1) 5- ton prime mover (Model A) (Figure 318)

Characteristics;
1. Weight --------- 5 1/3 tons.
2. Engine --------- 6 cylinder, "Sumida".
3. Cooling --------- Water.
4. Cylinder bore --------- 110-mm (4,3 inch)
5. Piston stroke --------- 135-mm (5.3 inch).
6. Horsepower --------- 64 to 98 (160 theoretically indicated hp at 2,800 RPN - based on reported engine specifications).
7. Ignition --------- Bosch magneto.
8. Generator --------- Bosch, 12 volts
9. Storage batteries --------- 2 - 12 volts, 60 amperes.
10. Fuel tank capacity --------- Main 27.5 gallons, auxiliary 12.1 gallons.

Figure 318. 5 Ton prime mover (Model A)


Note: The Model A is believed to be similar to, if not identical with, a recently examined prime mover. This vehicle was found to be well constructed and capable of operating over most types of terrain. The present gasoline engine is estimated to be of approximately 140 horsepower, considerably more powerful that the standard unit. It is believed that this particular engine is a replacement of the unit originally installed.

(2) 5-ton primer mover (Model B) (Figure 319).

Characteristics:
1. Weight --------- 5.5 tons.
2. Engine --------- 6 cylinder, Diesel.
3. Cooling --------- Air.
4. Cylinder bore --------- 110-mm (4.3 inch).
5. Piston stroke --------- 140-mm (5.3 inch).
6. Horsepower --------- 65 to 90 (135 theoretically indicated hp at 2,000 RPM - based on reported engine specifications).
7. Ignition --------- Compression.
8. Generator --------- 12 volts, 300 watts.
9. Storage batteries --------- 2 - 12 volts, 120 amperes.
10. Fuel tank capacity --------- Main 22 gallons, auxiliary 13.2 gallons.

Figure 319. 5 - Ton prime mover (Model B).




d. WWII Japanese Model 92 (1932) 8-ton prime mover.
It is reported that 2 versions exist of this vehicle; the Model A is powered by a 6-cylinder in-line water cooled gasoline engine, and the Model B by a 6-cylinder in-line water-cooled Diesel. The following data are believed to be common to both models A and B:

Common characteristics:
1. Length --------- 14 feet 1 inch.
2. Width --------- 6 feet 6 inches.
3. Height --------- 8 feet 6 inches.
4. Grade --------- 15 degrees.
5. Winch capacity --------- 5 tons.
6. Cylinder bore --------- 130-mm (5.1 inches).


Characteristics of Model A :
1. Weight --------- 8.45 tons.
2. Ground clearance --------- 11 1/2 inches.
3. Engine --------- 6 cylinder, gasoline.
4. Cooling --------- Water
5. Piston stroke --------- 5.6 inches.
6. Horsepower --------- 80 to 130 (230 theoretically indicated horsepower at 2,800 RPM - based on reported engine specifications).
7. Ignition --------- Bosch magneto.
8. Generator --------- 2 - 12 volts, 100 watts.
9. Storage batteries --------- 12 volts, 100 watts.
10. Fuel tank capacity --------- Main 39 1/2 gallons, auxiliary 9 gallons.
Characteristics of Model B :
1. Weight --------- 9.3 tons.
2. Ground clearance --------- 12 inches.
3. Engine --------- 6 cylinder, Diesel.
4. Cooling --------- Water.
5. Piston stroke --------- 6.4 inches.
6. Horsepower --------- 105 to 120 (215 theoretically indicated hp at 2,000 RPM - Based on reported engine specification).
7. Generator --------- 12 volts, 500 watts.
8. Storage batteries --------- 4 - 12 volts, 140 amperes.
9. Fuel tank capacity --------- Main 39 1/2 gallons, auxiliary 9 gallons.




e. WWII Japanese Model 98 (1938) 4-ton prime mover.
It is believed that this prime mover, powered by an 8-cylinder V type air cooled gasoline engine, is capable of hauling a load at 25 miles per hour, and that it can travel a distance of 125 miles in a period of 10 hours. Steering is of the clutch brake type, with foot and hand operated brakes. A central selector type gear box allows 4 forward speeds and 1 reverse.

Although no 4 - ton model has been encountered as yet (1944), it is believed that the following data apply:

1. Weight --------- 4 tons.
2. Length --------- 12 feet 5 inches.
3. Width --------- 6 feet 1 inch.
4. Height --------- 7 feet 3 inches.
5. Ground clearance --------- 11 1/2 inches.
6. Tread --------- No details.
7. Fording depth --------- 20 inches.
8. Grade --------- 30 degrees.
9. Turning radius --------- Can pivot
10. Winch capacity --------- Over 2 tons.
11. Engine --------- 8 cylinder V-type, gasoline.
12. Cooling --------- Sirocco type fan.
13. Cylinder bore. --------- 90-mm (3.5 inch).
14. Piston stroke --------- 125-mm (4.9 inch).
15. Horsepower --------- 73 to 88 (130 theoretically indicated hp at 2,800 RPM - based on reported engine specifications).
16. Ignition --------- Bosch magneto.
17. Generator --------- Bosch, 75 watts.
18. Storage batteries --------- 12 volts, 80 amperes.
19. Fuel tank capacity --------- Main 22 gallons, auxiliary 13 gallons.




f. WWII Japanese Model 98 (1938) 6-ton prime mover.
Examination of this prime mover (Figure 320) indicates that it is an unarmed artillery tractor, suitable for the additional roles of reconnaissence vehicle and ammunition carrier. Suspension follows the pattern of the Model 2597 medium tank. Since steering is of teh clutch-brake type, the vehicle is capable of turning within its own length. It is reported that this vehicle is used as a prime mover for the 105-mm and 150-mm howitzers and the 105-mm gun.

Details are believed to be as follows:

1. Weight --------- 7.75 tons.
2. Length --------- 14 feet 1 inch.
3. Width --------- 6 feet 9 inches.
4. Height --------- 6 feet 3 inches.
5. Ground clearances --------- 13 1/2 inches.
6. Grade --------- 15 degrees pulling field gun.
7. Turning radius --------- 19 feet.
8. Winch capacity --------- 5.5 tons.
9. Engine --------- 6 cylinder, Diesel.
10. Cooling --------- Water.
11. Cylinder bore --------- 120-mm (4,7 inch).
12. Piston stroke --------- 155-mm (6.1 inch).
13. Horsepower --------- 88 to 110 (175 theoretically indicated hp at 2,000 RPM - based on reported engine specification).
14. Generator --------- 24 volts, 110 watts.
15. Storage batteries --------- 2 - 12 volts, 180 amperes.
16. Fuel tank capacity --------- Main 17.6 gallons, 1st auxiliary 18.7 gallons 2nd auxiliary 6.6 gallons.

Figure 320. Model 98 (1938) 6 Ton prime mover.


g. Japanese Model 95 (1935) 13-ton prime mover.
This heavy prime mover is reported to be produced in two models: the Model A is powered with a 6 cylinder in-line, water-cooled, gasoline engine; the Model B with a 6-cylinder, water cooled Diesel. Both models are believed to be equipped with multiple disc, clutch type steering, with hand and foot operated brakes.

The follwing data is reported to be common to both types:

1. Length --------- 16 feet.
2. Width --------- 7 feet 6 inches.
3. Height --------- 9 feet 3 inches.
4. Ground clearance --------- 12 inches.
5. Grade --------- 13 tons, 15 degrees - 29 tons, 7 1/2 degrees.
6. Turning radius --------- 65 feet.
7. Winch capacity --------- 11 3/4 tons.




Characteristics of Model A
1. Weight --------- 14.3 tons.
2. Engine --------- 6 cylinder, gasoline.
3. Cooling --------- Water.
4. Cylinder bore --------- 5.4 inches.
5. Piston stroke --------- 6 inches.
6. Horsepower --------- 130 to 160 (265 theoretically indicated hp at 2,800 RPM -- based on reported engine specifications).
7. Ignition --------- Magneto
8. Storage batteries --------- 2 - 120 volts, 80 amperes.
9. Piston stroke --------- Main 61.6 gallons, auxiliary 9 1/2 gallons.
Characteristics of Model B
1. Weight --------- 15 tons.
2. Engine --------- 6-cylinder, Diesel.
3. Cooling --------- Water
4. Cyliner bore --------- 5.6 inches.
5. Piston stroke --------- 7.6 inches.
6. Horsepower --------- 145 to 165 (295 theoretically indicated hp at 2,000 RPM -- based on reprted engine specification.
7. Generator --------- 300 watts.
8. Storage batteries --------- 2 - 12 volts, 80 amperes.
9. Fuel tank capacity --------- 60 gallons.