The was a rocket used by the Imperial Japanese Army in the final stages of World War II.
Development and design The Type 4 40cm rocket was developed in the final stages of World War II by the Imperial Japanese Army Technical Bureau, as a relatively low-cost, easy to produce weapon, which had an advantage of greater accuracy over conventional mortars in that it fired a spin-stabilized projectile. Due to its ease of construction, it was produced in limited numbers and distributed to hidden arsenals for use as last-ditch weapons during the projected Allied invasion of the Japanese home islands. Unlike the Japanese Type 4 20cm rocket mortar, the Type 4 40cm rocket did not see action and stocks were confined to the mainland.Ness, Leland. Rikugun: Volume 2 - Weapons of the Imperial Japanese Army & Navy Ground Forces (p. 135). Helion and Company.
The Type 4 40cm rocket was restricted to launch via standardized fixed wooden troughs which were largely constructed by Japanese Army garrison troops, and not steel tubes like the Type 4 20cm rocket mortar. During 1945 construction of the fixed wooden launchers outpaced actual production of the Type 4 40cm rocket. Range of the Type 4 40cm rocket was controlled via variable bleeding of the propellant gases.Ness, Leland. Rikugun: Volume 2 - Weapons of the Imperial Japanese Army & Navy Ground Forces (p. 135). Helion and Company. Taki's Imperial Japanese Army home page Taki's Imperial Japanese Army home page
Notes
References Bishop, Chris (eds) The Encyclopedia of Weapons of World War II. Barnes & Nobel. 1998. Chamberlain, Peter and Gander, Terry. Heavy Field Artillery. Macdonald and Jane's (1975). McLean, Donald B. Japanese Artillery; Weapons and Tactics. Wickenburg, Ariz.: Normount Technical Publications 1973. . US Department of War, TM 30-480, Handbook on Japanese Military Forces, Louisiana State University Press, 1994.
External links Type 4 on Taki's Imperial Japanese Army page