This WWII paper model is a Kaiten Suicide Torpedo, were manned torpedoes and suicide craft, used used by the Imperial Japanese Navy in the final stages of World War II. The paper model was created by RocketmanTan, and the scale of the papercraft model is in 1:33.
In recognition of the unfavorable progress of the war, towards the end of 1943 the Japanese high command considered suggestions for various suicide craft. These were initially rejected, but later deemed necessary. Various suicide mission vehicles were developed in the Japanese Special Attack Units.
For the Navy this meant Kamikaze planes, Shinyo suicide boats, Kaiten submarines and Fukuryu suicide divers or human mines. The Kamikazes were somewhat successful, and the second most successful were the Kaitens.
Research on the first Kaiten began in February 1944, followed on July 25 of the same year by the first prototype. By August 1, an order for 100 units had been placed. The very first Kaiten was nothing much more than a Type 93 torpedo engine compartment attached to a cylinder that would become the pilot’s compartment with trimming ballast in place of the warhead and other electronics and hydraulics. The torpedo’s pneumatic gyroscope was replaced by an electric model and controls were linked up to give the pilot full control of the weapon.
The original designers and testers of this new weapon were Lieutenant Hiroshi Kuroki and Lieutenant Sekio Nishina. They were both to die at the controls of Kaitens, Lieutenant Kuroki in a very early training prototype.
In total six models of Kaiten were designed, Types 1, 2, 4, 5 and 6 being based on the Type 93 torpedo. The Type 10 was the only model based on the Type 92 torpedo. Types 2, 4, 5, 6 and 10 were only manufactured as prototypes and never used in combat.
Early designs allowed the pilot to escape after the final acceleration toward the target. There is no record of any pilot attempting to escape or intending to do so, and this provision was dropped from later Kaitens, so that, once inside, the pilot could not unlock the hatches. The Kaiten was fitted with a self-destruct control, intended for use if an attack failed or the impact fuse failed.
The island of Otsushima in the Inland Sea was used as a training site. It was equipped with cranes, torpedo testing pits and launch ramps, and had a large shallow bay for test running and firing. The Kaiten Memorial Museum is now situated there.
Initial training consisted of sailing fast surface boats by periscope and instrument readings alone. When a pilot had advanced past this basic training, he would begin training on Kaitens. Training craft were fitted with a dummy warhead that contained telemetry equipment and an emergency blowing tank that could return the craft to the surface should the trainee dive to a dangerous depth. Kaiten training started with basic circular runs to and from a fixed landmark at a reduced speed; the training advanced to faster and more hazardous runs around rocks and through channels in deeper waters. The more difficult runs required the pilot to surface and check the periscope repeatedly and also required conscientious adjusting of trim tank levels because of the reducing weight as oxygen was used up. When the instructors were confident of the pilot’s abilities, he would be advanced to training in open waters against target ships. Training at this level was often done at full attack speed and at night or in twilight. The final phase of training would be a submarine launch and more open water attack runs on target ships.
Training was dangerous, and 15 men died in accidents, the most common being from collision with the target vessel. Although the warheads were only dummies, the impact at ramming speed was enough to not only cripple the Kaiten but also severely injure the pilot.
In action, the Kaiten was always operated by one man, but the larger training models (Types 2, 4 and 5) could carry two or even four. Kaiten pilots who were leaving for their final missions would leave testaments and messages behind for their loved ones.
You can download the paper model template here: WWII IJN Kaiten Suicide Torpedo Free Paper Model Download