12 cm (4.7") AA Rocket
Updated 27 May 2012
The Imperial Japanese Navy developed a number of spin-stabilized rockets during World War II, but only this one ever saw service use.  These went to sea in launchers containg 28 rockets with six launchers on most carriers.  The rocket had an incendiary shrapnel warhead, somewhat similar in design to the "Sankaidan" Type 3 projectile used for guns, and had a time fuze set to explode the warhead at either 1,000 or 1,500 meters (1,100 or 1,640 yards).  They were electrically fired in pairs or automatically in 14-rocket sets, the latter action taking 10 seconds to fire all rockets.

12 cm Incendiary Rocket
Sketch from US Naval Technical Mission to Japan report O-19:  Japanese Projectiles General Types

Rocket Characteristics
Designation 12 cm (4.7") AA Rocket
Ship Class Used On Carriers
Date Of Design 1944
Date In Service 1944
Firing Rails 42.65 in (1.083 m)
Warhead Weight N/A
Maximum Velocity 656 fps (200 mps)
Rate Of Fire 14 rockets in 10 seconds
Note:  Reloading was by hand.
Range with time fuzes 1,100 or 1,640 yards (1,000 or 1,500 m)
Maximum Range
5,250 yards (4,800 m)
Maximium Height at 80 degrees about 7,545 feet (2,300 m)
Note:  Time fuzes were set to either 5.5 seconds or 8.5 seconds.  Propellant burnt for 1.6 seconds.
Mount / Turret Data
Designation 28-rocket launchers

Most Carriers (6) and Shinano (12):  Type 5 (1945)

Weight  3,521 lbs. (1,597 kg)
Elevation +5 / +80 degrees
Elevation Rate 18 degees per second
Train N/A
Train Rate 22 degrees per second

1) These mountings were adapted from the 25 mm AA triple gun mounting and could be controlled by Ward-Leonard RPC or by two men in protected cabs.  The launcher resembled a large box which consisted of four rows of seven rockets each.

2) This rocket or a similar one with an HE warhead was also carried by some explosive motor boats fitted with a simple launching trough.

3) These launchers were not installed on Shinano before her loss.

Data from
"Naval Weapons of World War Two" by John Campbell
"The 12 cm Multiple Rocket Launcher of the Imperial Japanese Navy" article by Hans Lengerer and Tomoko Rehm-Takahara in "Warship Volume IX"
US Naval Technical Mission to Japan report O-19:  Japanese Projectiles General Types
Page History

04 July 2006 - Benchmark
27 May 2012 - Updated to latest template