• Military Menu                       

• Introduction
• Systems
• Facilities
• Agencies
• Industry
• Operations
• Countries
• Hot Documents
• News
• Reports
• Policy
• Budget
• Congress
• Links

• WMD
• Intelligence
• Homeland Security
• Space

Type 2 Ho-I (1942) 75-mm self-propelled gun

The Japanese Type-2 75-mm self-propelled gun consists of the tube of the Type 90 (1930) 75-mm field gun mounted on the chassis of the Type 97 (1937) improved medium tank. The chassis remained unchanged, buth the tank turret was replaced by a built-up superstructure which was open at the top and rear. With the exception of the muzzle ring in place of the muzzle brake and a slightly smaller breech ring. The gun tube was identical to that of the wheeled gun. An internal gun mantlet is fitted and the recoil mechanism is propelled at the front by an armored jacket.

Mounted on a pintle, which is bolted to the floor of the fighting compartment, the gun had a total traverse of 20 degrees and elevated from -5 degrees to +25 degrees. Two range drums mounted on the left of the gun are calibrated to range of 13,000 yards and 8,750 yards. The muzzle velocity is estimated as being 2,230 feet per second, and since the weapon fires the same ammunition as the field piece, it is believed that its armor penetration performance is approximately the same, i.e. 3.5 inches at 500 yards.

At the end of the thirties the Japanese imperial army noticed that in its armored weapon there was no real accompanying vehicle, since the standard medium wagon, the Type 97 Chi-Ha, was evolving into a specific medium for countering armored vehicle. The expected weapon would not have been very effective in providing support to the troops with HE ("High Explosive") projectiles. Works on the construction of this tank began in 1937 , after the experience in Manchuria, where the Japanese concluded that an armored vehicle with a strong weapon would be very useful against the established enemy positions - what were the bunkers. The standard tank caliber of 47 and 57 mm cannons proved to be ineffective for this task. As the vehicle had to track the rest of the armored formation, the Japanese began the work by mounting the Hill Type 41 caliber 75 mm on the chassis of the middle tank Chi-Ha. The designers received the specifications for an infantry support vehicle and decided to use the same Type 97 as a platform to extrapolate a vehicle of this kind: a Type 41 mountain cannon was installed on the hull of a modified Type 97from 75 mm, but the evidence showed that this artillery was ill-suited to the self-propelled base. In April 1941 the armament was replaced by a cannon of the same caliber Type 99 and the prototype thus obtained was accepted with the designation "Type 2 Ho-I".

The Type 2 prototype during the tests featured a different conformation of the mantle with respect to the standard model. The Type 2 Ho-I was formed by the hull of the medium Type 1 tank and by a manually rotatable 360° newly designed turret. The self-propelled base had a better designed armor , thicker and mostly obtained by welding than the riveted Type 97: on the front the protections reached 50 mm, the sides measured 25 mm and the back 20 mm; the minimum value of the armor was 12 mm. The motorcycle apparatus placed in the rear compartment, of quite recent conception, was a 12-cylinder Mitsubishi diesel Type 100 V-shaped with a bore of 120 mm and strokeequal to 160 mm; the developed power reached 240 hp at 2,400 rpm and the displacement at 21.7 liters.

The crankshaft connected it to the transmission and front gearbox , with four forward gears and one reverse gear; it was geared to the double-sprocket driven front wheel, always in front. In fact the original mechanics had not undergone changes, since its reliability had already been tested in previous years: there were six double support wheels and the central ones were coupled by two carriages , in the back the double return wheel and the upper rollers were hinged brakets were three (the single central one, the two external ones). The suspensions had longitudinal swinging arms , one for each of the carriages and two independent bearing wheels: the central ones were constrained to the ends of a helical spring mounted in parallel with the ground; the external ones were each equipped with a helical spring resting on the inner arms.

Inside the hull, to the right, was the pilot's position, whose driving took place with the use of two directional levers to be used in concert with the clutch and the brake. On the left sat a machine gunner in charge of a 7.7 mm Type 97 on ball carriage and stocked with over 4,000 cartridges. The hexagonal tower, the seat of the commander, the gunner and the loader, housed the main armament, a cannon Type 99 75 mm long 23 gauge (L / 23) whose muzzle velocity came to 445 m / s : the explosive bullets used weighed 6.6 kilos. Later, the Japanese produced perforating projectiles to use the Type 2 as a tank destroyer, benefiting from this task thanks to the rotatable turret.

It is not known exactly how much the vehicle weighed, since the sources disagree indicating when 15.4 tons, when figures fluctuate between 15.4 and 16.7 tons, or 16.1 tons. Thanks to the tank capable of 235 liters of diesel and the relatively moderate weight, the Type 2 Ho-I could reach 44 km / h on the road and enjoyed an operating range of 210 kilometers; he was also able to overcome ditches up to 2.50 meters wide, he managed to overcome obstacles 0.90 meters high and wade 1 meter of water. A source instead certifies that the maximum operating radius did not exceed 100 kilometers.

Unlike the prototype model, it was planned to manufacture the Type 2 on the hull of the Type 1 Chi-He medium armored vehicle , a project completed towards the end of 1941 and decidedly more advanced than that of the Type 97. The production was delegated at Mitsubishi and at Sagami's arsenal: between 1944 and 1945 only between 30 and 33 were built. One source attests that 30 vehicles were delivered and another, which confirms this data, nevertheless reports that production would begin in 1942.

The production of the tank was hampered by the lack of material, as well as the bombing of Japanese factories. All thirty tanks were produced by conversion of the existing Type 97 Chi-Ha tanks. Beginning in 1943 the army reorganized the structure of its armored wards, inserting in each wagon regiment a fifth company with the nominal strength of 10 Type 2 Ho-I: one was assigned to the company's headquarters (together with two light wagons), the others were divided into three platoons. Due to the paltry number of Type 2s available, almost all the regiments had to replace them with the dated Type 97 Chi-Ha. The totality of the specimens produced was kept in reserve in Japan because the Imperial Grand Quarry was aware that the United States was planning the invasion of the country : however the conflict ended in August 1945, before the great amphibious attack could be implemented, and so none of the thirty Type 2 Ho-I was used in battle.