Type 2 Ho-I

The Type 2 Gun tank Ho-I (二式砲戦車 ホイ Ni-shiki hōsensha Ho-I?) Support Tank was a derivative of the Type 97 Chi-Ha medium tanks of the Imperial Japanese Army in World War II. Similar in concept to early variant of the German Panzer IV, it was designed as a self-propelled howitzer to provide the close-in fire support for standard Japanese medium tanks with additional firepower against enemy anti-tank fortifications.

Design work on the Type 2 Ho-I began in 1937, after experience in Manchukuo taught Japanese war planners that an armored vehicle with a larger weapon would be useful against fortified enemy positions such as pillboxes, against which the standard low-velocity 57mm and high-velocity 47mm tank guns were ineffective. Since this vehicle was to be able to keep up with the rest of an armored formation, the Japanese began work on mounting a Type 41 75 mm Mountain Gun onto the chassis of the Chi-Ha medium tank. 
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Type 2 Ho-I
Specifications
Weight: 16.1 tons
Length: 5.73 m 
Width :2.33 m 
Height: 2.58 m 
Crew: 5
Armor: 12-50 mm
Armament: 75 mm Type 99 Gun and 1 x 7.7 mm Type 97 machine gun
Engine: Mitsubishi Type 100 air cooled V-12 diesel, 240 hp / 179 kW
Suspension: Bell crank
Range: 100 kilometers

Speed: 45 km/h

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The adapted mountain gun, known as the Type 99 7.5 cm Tank Gun, was completed in 1940. By 1942, with the start of World War II, the Japanese army began to encounter the Allied M4 Sherman and M3 Stuart tanks, which they could barely cope with. The design parameters on the Type 2 were then changed to include a tank destroyer role, with its 75 mm gun equipped with armor-piercing shells.

The main armaments of the Type 2 Ho-I was a Type 99 75 mm tank gun, and secondary armament was a single 7.7 mm Type 97 Light Machine Gun in the hull. The short barreled 75 mm Type 99 Gun was mounted in a fully rotating two-man gun turret.

The Type 2 Ho-I utilized the chassis of the Type 1 Chi-He, which was itself a modified Type 97 Chi-Ha.

Production was hampered by material shortages, and by the bombing of Japan in World War II. All thirty existing Type 2 Ho-Is were conversions from existing Type 1 Chi He medium tanks. The Tokyo factory of Mitsubishi Heavy Industries was unable to retool for mass production by the end of 1944, when the program was cancelled. These units were allocated to the Japanese home islands to defend against the projected Allied Invasion. As the cessation occurred before that invasion, the Type 2 Ho-I never saw combat.