Nakajima Kotobuki

In 1917, Chikuhei Nakajima set up the "Airplane Institute" at Ojima Town in Gunma Prefecture.

[1] In 1920 the company sent Kimihei Nakajima to France to study European advances, and in 1922 started their own engine factory in Tokyo.

He observed the English Gloster Gamecock fighter with its Bristol Jupiter engine, which was an advanced design for the era with an automatic adjustment device for tappet clearance, spiral piping for even intake distribution, and a four-valve intake and exhaust system.

[1] In June 1930 the first prototype of was completed and it passed the durability test for the type approval in the summer.

In December 1931, this engine was approved and adopted by the Navy as the Ha-1 Ko for the Type 97 carrier fighter.