Staff Writer (Updated: 6/3/2016):
By the middle of 1945, Adolf Hitler had committed suicide, Germany had capitulated to the might of the Allied war machine and the Axis was no more - the war in the Europe was officially over and symbolized by "VE" day. The war in the Pacific was an ongoing affair and progress was steadily made on the part of the Allies though with much blood to show for it. However, the war had ultimately closed in the shores of the Empire of Japan with all its major cities within reach of Allied fighters and bombers thanks to the capture of Iwo Jima (February) and Okinawa (April). Like Germany in the closing months of the European Campaign, it was a time of desperate measures for the island nation and the full-scale Allied invasion of the mainland was an all-too certain reality. The invasion had already garnered a codename under "Operation Downfall" and plans were being drawn up.
The amphibious invasion of the Japanese mainland would involve a massive outpouring of man and machine coming from a sea armada to be divided into two invasion forces - a southern island invasion fleet and a main island invasion fleet. Air cover was critical but so to was the logistical side of such an endeavor. The operation would need heavy support in all forms, not the least of these being the powerful Allied shipping arm that indirectly forced subsequent Japanese retreats throughout the Pacific campaign up to this point in the war. It was one thing to gain ground from the enemy with guns, tanks and planes but it was another to hold that ground indefinitely with bullets, fuel and bombs - logistics would play a key role in the intended invasion plans.
Japanese High Command looked to developing a low-cost, easy-to-use and quick-to-field suicide fighter plane to be used in the "kamikaze" role against key Allied shipping. Kamikaze's proved of some value to this point in the war for Japan but mostly as psychological terror weapons. While Allied sailors became painfully introduced to these suicidal attacks, the attacks did little to disrupt the actions of the United States Navy and British Royal Navy throughout the latter half of the war. If anything, they cost the Empire dearly in both man and material. However, it was envisioned that a great air fleet of these suicide aircraft could turn the tide of the mainland invasion in favor of the defenders, perhaps securing a favorable surrender. This sort of strategy was not lost on Hitler and his Germany - pouring funding, materials and manpower into "dead-end" projects by war's end - though only one of these designs proving suicidal in nature. For the Empire of Japan - where death for the Emperor was an honorable death - one of these last-ditch results became the Nakajima Ki-115 suicide fighter.
A "throw-away" design such as the Ki-115 attempted to make light use of material- and time-saving measures wherever possible. The fuselage was made into a cylindrical form - easier to produce than the elliptical types of more modern fighter types. Steel and wood featured heavily throughout its construction as these were deemed less strategic to the Japanese war effort. Additionally, the fuselage was designed from the outset to take on a wide variety of pre-existing engine types to help speed production along. These engines would come from the stockpile of old surplus powerplants as available. The only known powerplant to have been fitted to the Ki-115, however, became the Nakajima Ha-35 Type 23 series radial piston engine of 1,150 horsepower. All these factors lent themselves well to the speedy production effort needed to get the Ki-115 into available hands in quantity. Like German High Command in the desperate, closing months of the European Campaign, Japanese authorities were equally optimistic and projected a monthly output of 8,000 such aircraft with hundreds of factories committed to the effort.