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Type 89 Knee Mortar

Forgotten Weapons
Published on September 23, 2015
Category: Reviews
Duration: 12:16

The Japanese Type 89 'Knee Mortar' was officially the Type 89 Heavy Grenade Discharger, a rifled bore weapon designed for indirect fire suppression. Despite its name, it was not designed to be fired from the knee due to significant recoil. Its range was adjusted by altering the volume of the combustion chamber, and it could fire both standard grenades and specialized 50mm shells.

Tags

Type 89
Knee Mortar
Grenade Discharger
Japanese Weapon
WWII Weapon
Light Infantry Weapon
Mortar
Grenade Launcher
Indirect Fire
Rifled Barrel
WWII
Imperial Japanese Army
50mm

Quick Summary

The Japanese Type 89 'Knee Mortar,' officially the Type 89 Heavy Grenade Discharger, was a WWII weapon with a rifled bore. Its name is a misnomer; it was braced against the ground, not the knee, to avoid recoil injury. Range was adjusted by altering the combustion chamber volume.

Chapters

  1. 00:00Introduction: Type 89 Knee Mortar
  2. 01:00Classification & Tactical Use
  3. 02:30The 'Knee Mortar' Misconception
  4. 03:55Technical Features & Rifling
  5. 05:50Range Adjustment & Projectiles
  6. 07:20Aiming & Leveling
  7. 08:05Comparison & Projectile Design
  8. 09:50Firing Positions & Direct Fire
  9. 11:35Legal Classification & Auction

Frequently Asked Questions

What was the official name for the Japanese Type 89 'Knee Mortar'?

The official designation for the weapon commonly known as the Type 89 'Knee Mortar' was the Type 89 Heavy Grenade Discharger. This name reflects its intended role as a light indirect-fire explosive weapon.

Why is the Type 89 called a 'Knee Mortar' if it wasn't fired from the knee?

The 'Knee Mortar' name is an American misnomer. While it has a curved baseplate, it was designed to be braced against the ground or a log. Firing it from the knee would cause severe injury due to its substantial recoil.

How did the Type 89 adjust its firing range?

The Type 89's range was adjusted by altering the volume of its internal combustion chamber. This was achieved by moving the firing pin assembly, which changed the expansion volume and thus the propellant pressure and projectile range.

What made the Type 89 unique compared to other mortars?

A key distinction of the Type 89 was its rifled bore, which helped stabilize projectiles. It also featured a unique range adjustment mechanism based on combustion chamber volume, unlike the angle-based adjustments of typical mortars.

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