The Heinkel HD 25 was a two-seat shipboard biplane reconnaissance floatplane developed in Germany during the 1920s for production in Japan.
It was intended to provide a spotter aircraft for warships, to take off from a short ramp since shipboard catapults had not yet been developed by the Japanese. The HD 25 was a conventional biplane with staggered wings and twin pontoon undercarriage. The pilot and observer sat in tandem, open cockpits. A single example of a modified demilitarised version was built by Aichi as the AB-1, and three surplus Type 2 Two-seat Reconnaissance Seaplanes were converted with two seat cabins aft of the open rear cockpit, to seat three passengers, for use by the Kouchi Shimbun newspaper.
Two prototypes were built by Heinkel in Germany, with the first flying in 1926. Following trials, the Navy officially accepted the type in March 1928 and gave it the designation Type 2 Two-seat Reconnaissance Seaplane. 16 were built by Aichi and saw brief service aboard the cruisers of the Imperial Japanese Navy.
Type 2-seat reconnaissance floatplane (Aichi Type 2)
Engine 1 Napier Lion
Dimensions Length 9,60 m, height 4,27 m, wingspan upper 14,85 m, lower 14,15 m, wing area 55,8 m2
Weights Empty 1550 kg, flying weight 2500 kg, fuel 900 l in a tank above fuselage in mid section of wing
Performance Max. speed 190 km/h, range 920 km, climb to 1000 m 3,0 min., to 2000 m 6,2 min., endurance 4,5 h, service ceiling  (full load) 5800 m, landing speed 77 km/h
Armament 1 flexible rearward-firing 7,7 mm machine gun , 4 30 kg bombs
Type Werk.Nr Registration History
222 First flight in 1925, trials with starts from a 20 m long start ramp. In August 1925 to Japan , trials on land and from battleship Nagato. Crashed during land trials
223 Successful trials led to licence production by Aichi