The Aichi F1A (designated AB-13 by its designers and manufacturers at Aichi) was a prototype Japanese floatplane of the 1930s.
A single-engine biplane, the F1A was intended as a short-range observation aircraft suitable for operation off the Imperial Japanese navy’s warships, but only two were built, the Mitsubishi F1M being selected instead.
The F1A was designed by Aichi in response to a 1935 specification, issued to Aichi, Kawanishi and Mitsubishi for a replacement for the Imperial Japanese Navy’s Nakajima E8N floatplanes, which were used for short-ranged reconnaissance and observation missions from the Navy’s warships.
Aichi at first considered a low-winged monoplane design, the AM-10, to meet this requirement, but this was rejected in favour of a more conventional biplane design, the AB-13.
The AB-13 was a small single-bay biplane of mixed construction.
It had wooden stressed-skin wings with plywood skinning that folded to allow easy storage aboard ship, while combat flaps were fitted as the aircraft was required to have sufficient maneuverability for air combat as well as its normal observation missions.
The fuselage was of metal construction, with the pilot sitting in an open cockpit, but the observer’s position being enclosed.
Both float and wheeled undercarriages were designed, with the seaplane having a single main float, while the landplane version had a fixed tail wheel undercarriage.
Power was provided by a single Nakajima Hikari radial engine.