In late 1939 or early 1940, Japan formally requested the German RLM (Reich Air Ministry) to provide a Junkers Ju 87 for technical and operational testing. The official reasoning was a need for a carrier-based dive bomber for the Imperial Japanese Navy Air Service (IJNAF). The Germans, wary from previous similar requests, suspected (correctly) that Japan was more interested in analyzing the aircraft’s design than purchasing it or acquiring a license for production. Nevertheless, they saw no reason to deny their ally’s request. However, they didn’t provide the latest version of the Stuka but instead sent the first production variant—the Ju 87A-1.
Contrary to many popular accounts that suggest Japan received only one Stuka, there were actually two Ju 87A-1 aircraft delivered: W.Nr 870119 and 870120. These were sent to the research and development center in Tokorozawa. One aircraft underwent a series of flight tests, while the other was disassembled for technical analysis. This distinction partly explains why some sources claim that Japan had only a single operational Stuka.
Interestingly, while the Navy initiated the request, the tests were conducted at a facility more closely associated with the Imperial Japanese Army Air Force (IJAAF). This apparent contradiction stems from the unique dual-purpose nature of Tokorozawa, which supported both IJAAF and IJNAF research—a phenomenon previously discussed regarding the development of early A6M Zero prototypes.
Technical Context
Was the IJNAF genuinely interested in the Stuka, or was this a mere smokescreen to justify the request? The answer is clear: the Navy was indeed interested in the Ju 87, specifically its technical features. The reason lay in the troubled development of the Aichi D3A Val dive bomber. By that time, the Val’s development program had been ongoing for over three years, with little progress.
The Navy urgently needed a stable dive bomber with excellent performance in steep dives—qualities the Val prototypes severely lacked. Early Val prototypes suffered from directional instability (causing “wandering” during flight), a tendency to lose control during sharp horizontal maneuvers, and severe vibrations of the dive brakes at speeds of 360–370 km/h, threatening the airframe’s structural integrity. The IJNAF required a stable dive at minimum speeds of 430–440 km/h. In short, the Val program was at a standstill.
The directional instability issue was later resolved by adding a distinctive dorsal fin ahead of the vertical stabilizer, but the dive-related problems persisted. The solution came directly from the German Ju 87: its dive brakes were copied, and the Val finally shed its flaws.
It’s worth noting that the Val’s design carried significant German influence. Its airframe layout and structural design were derived from studies of the Heinkel He 70, obtained years earlier. While the Val was smaller, powered by a radial engine (unlike the inline engine of the He 70), and intended for different roles, its wings and tail surfaces were almost exact, scaled-down copies of the German aircraft.
Camouflage Mystery
One particularly intriguing aspect of the Japanese Ju 87 concerns its camouflage. Contemporary color profiles and illustrations often conflict with photographic evidence. The aircraft reportedly featured light gray paint with large brown and green patches, similar to early Stuka camouflages used by the Condor Legion in Spain. However, Luftwaffe schemes at the time typically featured geometric patterns with sharp edges, so why would the Germans repaint these aircraft for Japan in a scheme with curved edges?
Some sources suggest that the aircraft were entirely repainted in Japan, at least the one used for flight testing. However, this raises questions, as the Navy at the time did not use patchy camouflage patterns on its aircraft. Even later, such schemes were only applied in the field, mainly in New Guinea, the Solomons, and other front-line areas. These field-applied patterns were neither factory-standard nor regulation-compliant.
If the repainting occurred at Tokorozawa, it might be attributed to the facility’s association with IJAAF camouflage practices, which included similar schemes on aircraft deployed in China. However, test aircraft used for technical and operational trials were almost never repainted, as seen with other German aircraft like the Bf 109E, Fw 190A, and Me 210. Typically, only Hinomaru (Japanese roundels) and minor markings, such as serial numbers or test unit insignias, were applied.
The only plausible reason for repainting the Stuka might have been an intention to deploy it to a combat unit in China. However, there is no evidence that such a scenario—a “real-world battlefield test”—was ever considered. The primary purpose of obtaining the Ju 87 was simply to study its technical features. The camouflage of the Japanese Ju 87A-1 remains a mystery, and frankly… I have no idea what the reasoning was behind it.
Epilogue
The disassembled Ju 87 was never reassembled. The operational Stuka underwent a series of flight tests, though little is known about the results. Once the necessary information had been gathered, the aircraft was displayed in a public exhibition at a large park near the base, widely known as the Tokorozawa Museum. Over time, the exhibit expanded to include other research subjects, captured equipment, and eventually notable Japanese aircraft, such as those that survived ramming attacks against B-29 bombers.
In the spring of 1945, the Japanese Stuka was destroyed during one of the American carpet-bombing raids on Tokyo.
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