|Role||Patrol Flying boat|
|Manufacturer||Hiro Naval Arsenal|
|Primary user||Imperial Japanese Navy|
|Developed from||Supermarine Southampton|
The Hiro H2H (or Navy Type 89 Flying boat) was a Japanese patrol flying boat of the 1930s. Designed and built by the Hiro Naval Arsenal, it was a twin-engined biplane that was operated by the Imperial Japanese Navy.
Development and design
In 1929, the Imperial Japanese Navy purchased a single example of the metal hulled Supermarine Southampton II metal-hulled flying boat, and after evaluation, it was passed onto the Hiro Naval Arsenal (who designed the wooden Hiro H1H flying boat based on the Felixstowe F.5), to study its advanced metal hull structure. Following this study, Hiro designed a new flying boat, closely resembling the Southampton.
The new aircraft was a twin-engined biplane, with an all-metal hull, and fabric covered metal wing and tail structures. It was powered by two Hiro Type 14 water-cooled W engines. The first prototype was completed in 1930, and following successful testing was ordered into production, with 13 aircraft being built by Hiro and a further four by Aichi. Later aircraft were powered by more powerful (600-750 hp (448-560 kW)) Hiro Type 90 engines.
It entered service in 1932 as the Type 89 Flying boat, with the short designation H2H1. Type 89 Flying Boats entered service in time for the Shanghai Incident, and along with Hiro's earlier H1H, served in front line service until the early years of the Second Sino-Japanese War.
Specifications (Early version)
Data from Japanese Aircraft 1910-1941 
- Crew: 6
- Length: 16.28 m (53 ft 5¼ in)
- Wingspan: 22.14 m (72 ft 7¾ in)
- Height: 6.13 m (20 ft 1¼in)
- Wing area: 120.5 m² (1,297 sq ft)
- Empty weight: 4,368 kg (9,629 lb)
- Loaded weight: 6,500 kg (14,330 lb)
- Powerplant: 2 × Hiro Type 14 12-cylinder water-cooled W engine, 550 hp (410 kW) each
- Maximum speed: 192 km/h (104 knots, 119 mph)
- Cruise speed: 130 km/h (70 knots, 80.5 mph)
- Service ceiling: 4,320 m (9,840 ft)
- Endurance: 14½ hours
- Climb to 3,000 m (14,100 ft): 19 min
- Guns: 4× 7.7 mm machine guns (two in bow, one each in port and starboard mid-ships stations)
- Bombs: Two 250 kg (550 lb) bombs
- Related development
- Aircraft of comparable role, configuration and era
- Related lists
- Andrews and Morgan 1987, p.110.
- Mikesh and Abe 1990, pp. 95-96.
- Mikesh and Abe 1990, pp.96-97.
- Mikesh and Abe 1990, p.97.