MANUFACTURER(S): State Factories - Imperial Japan
OPERATORS: Imperial Japan
ACTION: Manual; Firing Pin at Base
SIGHTS: Adjustable Elevation Mechanism
Detailing the development and operational history of the Type 97 81mm Infantry Mortar.
Entry last updated on 2/17/2017.
Authored by Staff Writer. Content ©www.MilitaryFactory.com.
The Imperial Japanese Army made use of various lobbed ordnance weapon systems throughout World War 2 in their conquest of the Pacific. Chief among these became the unique grenade dischargers that were more akin to miniature personal mortar systems firing a lesser projectile. However, like all modern armies of the time, the IJA also placed value on more conventional mortar designs and these appeared in two popular calibers - 81mm and 90mm.
The Type 97 (or Model 97) was an 81mm mortar was not unlike the American M1 system in design, scope and operation. It consisted of three major components to include the firing tube, base plate and an adjustable bipod assembly. A crank handle at the neck of the bipod allowed for elevation changes by the crew. The base plate was heavy and rectangular in shape and the 81mm projectile rounds were small enough to cup in two hands when handling. The crew adjusted all facets of the projectile's launch based on terrain and windage. Operation was via dropping the active 81mm shell down the firing tube to which the shell struck a waiting firing pin and ignited the projectile's propellant charge. This forced the projectile out of the firing tube and towards the calculated arc destination.
The Type 97 81mm mortar held an effective range out to 3,062 yards, firing at a muzzle velocity equal to 643 feet per second. The crew could elevate the firing tube from +45 to +85 degrees for attacking targets closer to the firing point. The system, as a whole, weighed in at 148lbs and required multiple crew for transport, this breaking down into several pieces. The primary 81mm projectile in use with the Type 97 was the Model 100 High-Explosive (HE) shell weighing just over 7lbs.
The Type 97 81mm mortar entered service with the IJA in 1937 and was kept operational through to the end of the war in August of 1945. The weapon saw considerable actions across the Pacific and Southeast Asia, wherever the IJA was active.