The Uprating Capacity of the Ha-45 / Homare Engine
It is well established that the performance of Japanese aircraft engines in WWII was limited by the suboptimal fuels available at the time, among other factors. As a result, in order to achieve boost pressures in the ballpark of high-power Allied engines, it was necessary to rely on water injection…
About the Performance of Type 4 Fighter (Ki-84) ー Pt.2
This is an update to the previous article about the performance of the Type 4 Fighter (Ki-84), addressing some errors and new information that I have found since writing it. It is not so much an article as a set of separate points. The original article is here: Ha-45 Special…
What Was the A6M4?
The A6M4 is an “unknown” variant of the Zero Fighter that has been described as a variety of things over the years. The most common theory in English writing is that A6M4 was a designation for a type of Zero fitted with a turbocharger to its Sakae engine. Another common…
Identifying Japanese Jets Captured by the US in 1945
Following the surrender of Japan in August 1945, the American occupational authorities sought to gather whatever aircraft developments were of potential interest. Naturally, the most cutting edge planes and engines developed in Japan were high on this list. More than a few of these projects had already been destroyed by…
Ōka Trainers: MXY7-K1, MXY7-K2, & Wakazakura
This article is an attempt to clarify the details of the different training aircraft that were developed for the Japanese Navy’s late-war special attacker ‘Ōka’. The designations and purposes of the Ōka trainers are often confused, not only in English but even in Japanese publications. Using a few historical materials,…
About the Performance of Type 4 Fighter (Ki-84)
Update Jun 26 2024: some additional information and corrections to this article in Part 2: The performance of the Type 4 Fighter (project name ‘Ki-84’) is a bit of a can of worms, and a subject of frequent debate. This is due to a significant amount of differing data with…
Ki-109 & the Ki-109-Mounted Cannon: Type 88, Not ‘Ho-501’
As the threat of strategic bombing loomed over Japan from the middle of the Pacific War, the development of effective extreme-caliber aircraft guns was expedited by the Japanese Army. New weapons with calibers ranging from 47 millimeters to as much as 150 millimeters were developed and were planned to be…
R2Y Keiun: Satisfactory… but the Engine Caught on Fire
At the outset of the Second Sino-Japanese War in 1937, the Japanese Navy’s Air Service assumed a leading role in the strategic bombardment of China with their modern force of attack planes. As the battle quickly advanced into the interior of the continent, the Navy developed a new requirement to…
Kōgiken-IST Ne-130: Driven to Destruction After the War
On July 26th, 1944, the Japanese Navy submarine I-29 ‘Matsu’ was sunk by the USS Sawfish near the Philippines while en route to Kure. Onboard ‘Matsu’ were potentially instrumental materials about secret German aircraft technology. Of relevance, there were survey sketches and other data on the Messerschmitt Me 262 and…
Tanegashima’s Group: Birth of the Japanese Jet Engine
By the 1930s, the practical speed limit of piston-engined aircraft was being approached for the first time. Before a propeller-driven airplane can approach the speed of sound, there is a period where the blade tips must reach supersonic speed, resulting in massive turbulence and loss of efficiency. This effect imposes…
Ki-201 ‘Karyū’: The Me 262 Domestic Production Plan
At the dawn of 1944, the German jet fighter Messerschmitt ‘Me 262’ was nearing the beginning of its service life. Due to issues with its power plant and interference from the high command, the aircraft had been in the testing stage since 1941. In the coming months, it would finally…
