japanese anti-aircraft grenade launchers

[tom!]

Hi.

Another piece of very less known japanese equipment:

Japanese barrage mortars:



This was a simple infantry air-defence weapon agains low-flying aircraft. A smooth-bore barrel was mounted on a wooden block with a long nail.

The mortar was pressed into soft ground with the nail giving the necessary stability. A pipe-type container with a simple propellant charge was put inside the barrel. It was fired when the stationary firing pin inside the barrel hit the primer below the grenade.

After a defined period of time (no further infos, sorry) the cap of the grenade was removed by opening a parachute releasing 7 shrapnel-clusterbombs with delayed friction fuzes. These bombs were placed in seperate pipes equipped with a parachute which started the friction igniters of the delay train when released. The shrapnel charges of the clusterbombs also had parachutes to slow-down the fall.



The exploding shrapnel charges should damage the aircraft.

As there was no chance for aiming only barrage fire was possible.



The US-Forces found versions with 70 mm and 80 mm barrels.

No additional infos avaliable.

Yours

tom!

[spidge]

Interesting weapon. Did it work?

[Adrian Roberts]

Did it work?

I doubt it. Firing parachute devices into the air never did. The Royal Navy had a far more sophisticated version, the UP system ("Unrotating Projectile" Rocket launcher), and that didn't work either. The account below is from the website of the HMS Hood Association

Hood was outfitted with 5 UP mounts which were added in 1940. One was atop "B" turret, and the remaining four on the Shelter Deck. In general, the UP (AKA "rocket-on-a-string") was a largely unsuccessful attempt at a low altitude anti-aircraft defence system. The basic concept was to create an aerial minefield: When hostile aircraft were detected, the UP "layer" (operator) would manually launch a salvo/spread of 10 rockets.

Upon reaching @1000ft, the rockets would detonate and expel mines attached to three parachutes by @400ft of cable. Aircraft flying through the aerial minefield would snag the cables and pull the mines into themselves. In reality, the system was slow & cumbersome. The aerial minefields were clearly visible & easily avoidable. This, coupled with other factors such as the volatile nature of the cordite/rockets & the risk of mines floating back onto the launching ship, doomed this weapon to mothballs. There are no records of UPs bringing down any aircraft. It's entirely possible that this system injured or killed more Britons than enemies due to accidents, fires, etc.

Tom - thanks for the information though: this shows how desperate the Japanese were by the end.

[tom!]

Hi.

Originally Posted by Adrian Roberts

....

Tom - thanks for the information though: this shows how desperate the Japanese were by the end.

This was not a last-ditch weapon system. AFAIK IJA developed it during the early stages of the 2. Sino-Japanese War 1938.

Regarding efficiency I´d agree that it needed a "lucky shot" to take down an aircraft. But a psychological effect flying into such a barrage can´t be denied. And main purpose of air defence at this time was to disturb the enemy while aiming to lower accuracy.

Yours

tom