Kawasaki Ki-28

The , World War II Allied reporting name "Bob", was an experimental fighter aircraft designed for the Imperial Japanese Army and meant as a replacement for the Kawasaki Ki-10. It flew in 1936, but was never produced for actual use as the Army chose the Nakajima Ki-27.
Design & Development.
The Ki-28 was initially produced by Kawasaki Kōkūki Kōgyō K.K. in response to Japanese army specifications for a fighter to replace the existing Kawasaki Ki-10. In mid-1935, Kawasaki, Mitsubishi and Nakajima were instructed to build competitive prototypes. The Kawasaki design was based on its earlier, but unsuccessful Ki-5. It was a low-wing cantilever monoplane of all-metal construction, except for fabric-covered control surfaces, with a conventional tail unit, fixed tailskid landing gear and powered by a Kawasaki Ha 9-II-Ko liquid-cooled inline V12 engine.
Service trials proved that the Kawasaki Ki-28 was the fastest of the three contenders, but the Nakajima Ki-27 was by far the most maneuverable and had the lowest wing-loading, and on this basis was selected by the Imperial Japanese Army Air Force. Despite losing to the Ki-27, the Ki-28 provided Kawasaki with valuable experience which would later help with development of the Kawasaki Ki-60 and Kawasaki Ki-61 fighters.
Mistakenly believing the Ki-28 to have entered production in Japan as the Army Type 97 Fighter, the Allies assigned it the reporting name "Bob" during World War II.