Aviation of World War II
On Aichi, Tetsuo Miki, the most experienced engineer of the company, in fact, a student of E. Heinkel and a permanent representative of the company at Heinkel's company in Germany, was appointed the chief designer of the near-ship reconnaissance ship.
Miki immediately dismissed the idea of a monoplane design, and began work on two parallel versions of the machine - an aerodynamically very clean AB-13 biplane - in a float version and in a version with a fixed wheeled landing gear.
The version with float landing gear (one central float and two supporting ones) was ready in June 1936. In September, the "land" version was ready.
Design. To ensure the required dynamic parameters of the new machine, Tetsuo Miki designed a biplane box with critical profile wings. This wing design, developed at Tokyo Imperial University, was designated "Koken No. 1". The wings had a very complex internal frame structure to provide the necessary rigidity while maintaining a minimum mass. They were sheathed on the outside with special plywood, the leading edge of the wing was made of plexiglass. Such a skin was working, taking part of the load. Outside, the casing was impregnated with a special waterproof varnish, waterproof paint, and then sanded to give the perfect shape. Also in the AB-13, combat flaps, which were quite rare in those days, were used.
No less attention was paid to the design of the fuselage, the all-metal frame of which also had a very complex structure, which provided additional structural strength. The fuselage was covered with large-area duralumin sheets to minimize the number of seams and joints that spoil aerodynamics. The design of the floats was seriously worked out; in the wheeled version, the chassis were hidden in fairings and attached to the fuselage on single racks. In the AB-13 project, Tetsuo Miki painstakingly worked out every detail of the aircraft in an effort to reduce the drag of the aircraft while ensuring maximum structural strength.
The power plant is a 9-cylinder air-cooled Nakajima "Hikari 1" with a take-off power of 730 hp, hidden in a streamlined hood, with a pair of synchronized machine guns placed between the cylinders on top. Screw metal two-bladed variable pitch.
In September 1936, the AB-13 aircraft was handed over to naval pilots for testing. Then he received the designation F1A1. Test flights were conducted by shosa (lieutenant commanders) Minematsu and Honjuki. In total, 61 flights were carried out from the Kagamigahara airbase, totaling 38 hours 47 minutes spent in the air.
Tests of the land version of the F1A1 are somewhat behind the times. The wheeled F1A was flown by the chief pilot of the company Tamizo Amagai, who spent a total of 19 hours and 21 minutes in the air. These tests also required some modifications to the fin and landing gear.
At the end of 1937, both F1A1 prototypes were armed and took part in comparative tests with the brainchild of Mitsubishi F1M1, which unexpectedly became the winner, showing the best data in terms of handling and stability in flight. By the end of 1939, the Mitsubishi aircraft was declared the winner and accepted into service as the Type 0 Observation Seaplane of the Fleet, taking its place aboard warships for a long time.
The fate of the Aichi aircraft remains unknown. Their trace is lost in 1939.
Armament. Two 7.7 mm Type 97 synchronous machine guns; one 7.7 mm Type 92 movable machine gun in the rear cockpit. Two 60 kg bombs on external nodes.