Type 4 70 mm AT Rocket Launcher

Infobox Weapon|is_ranged=yes|
name=Type 4 70 mm AT Rocket Launcher
type=Rocket Launcher
origin=flagcountry|Empire of Japan
era=WW2
design_date=1944
prod_design_date=-
serv_design_date=-
used_by=Imperial Japanese Army
wars=World War II
spec_type=-
caliber=74mm
part_length=-
cartridge=-
feed=-
action=-
rate=-
velocity=???
weight=8 kg
length=1.5 m
variants=None
number=3,500

The Type 4 70 mm AT Rocket Launcher was a Japanese rocket launcher used during the last period of World War II. They were used in the Japanese mainland in case of an invasion by the allies.

Japan developed this weapon compared to the german panzerschreck and the american bazooka.

History

By 1944 the Japanese forces had been exposed to the US 2.36” anti tank rocket launcher commonly called the Bazooka. Apparently they saw a need for a similar weapon. In 1944 they adopted a 70mm rocket launcher as the Type 4. Unlike the US rocket that used fins to stabilize it in flight, the Japanese rocket had angled ventures in the base to spin the rocket for stabilization. The 20cm (8”) HE rocket used by the Japanese was also spin stabilized so they were familiar with the production of this type of rocket.

Development

The launcher was made in two parts that were joined in the middle similar to the US 3.5” Rocket Launcher. From the pictures in a Japanese book on artillery, it was made to be fired from the prone position. The front half of the launcher had a bipod that looks like one from a Type 99 LMG attached to it. The gunner lay with his body at approximately a 45 degree angle to the bore on the left side while the loader was positioned similarly on the other side. The firing mechanism appears to be crude but effective. The pistol grip & trigger mechanism are attached to the rear half of the launcher. A cable runs from the trigger to the rear of the launcher where the hammer is located. The hammer with firing pin is mounted on an arm that looks like a mouse trap mechanism. The arm is above the bore and out of the way of loading the rocket when it is in the cocked position. Pulling the trigger pulls the pin holding the arm in position & the arm swings around under spring pressure striking the primer & igniting the rocket.

The 70mm rocket, like the 20cm one, used a mortar fuze. There would be no set back when the rocket was fired to arm an artillery fuze. The Japanese mortar fuze for the 81mm & 90mm use a simple shear wire to make it bore safe. The wire goes through the brass body & aluminum firing pin plunger. Upon impact the plunger is forced back shearing the wire and freeing the plunger to strike the firing pin to detonate the round. This system would work well with a rocket & was an already available item in the Japanese supply system

References

* [http://www3.plala.or.jp/takihome/AT.htm#ex]