Imperial Japanese Naval Air Service
Yokosuka K5Y
The Yokosuka K5Y, nicknamed “Willow” by Allied forces, was a two‑seat biplane trainer used by the Imperial Japanese Naval Air Service throughout the 1930s and into World War II. First flying in 1934, the K5Y was developed to replace the aging Yokosuka K4Y and quickly entered service as the standard primary trainer for naval pilots. Its airframe was a conventional wood‑and‑fabric biplane with equal‑span wings, fixed tailskid landing gear and a single open cockpit positioned behind the instructor’s seat. Powered by a 260‑horsepower Nakajima Hikari radial engine, the aircraft offered a modest top speed of about 180 km/h (112 mph) and excellent low‑speed handling, making it ideal for teaching basic flight controls, navigation and formation work. More than 3,000 units were built by several manufacturers, including Aichi and Kawanishi, and many were later pressed into secondary combat roles such as light reconnaissance, anti‑submarine patrols and kamikaze missions during the final stages of the war. The K5Y’s long service life and ubiquitous presence in Japanese training schools cemented its reputation as one of the most influential trainer types of the pre‑war era, shaping the skills of a generation of Imperial Navy aviators.
Classification
Production & History
- Units Produced
- 5,768
- First Flight
- 1933