Hiro H4H

H4H
Role	Patrol flying boat
National origin	Japan
Manufacturer	Hiro Naval Arsenal
First flight	1931
Introduction	1933
Primary user	IJN Air Service
Number built	47

The Hiro H4H (or Hiro Navy Type 91 Flying Boat) was a 1930s Japanese bomber or reconnaissance monoplane flying boat designed and built by the Hiro Naval Arsenal for the Imperial Japanese Navy.

Contents 1 Design and development 2 Variants 3 Operators 4 Specifications (H4H2) 5 See also 6 References 6.1 Notes 6.2 Bibliography

Design and development

First appearing in 1931 the H4H1 was a twin-engined high-wing monoplane flying-boat. Powered by two 500hp (597kW) Hiro 91-1 engines strut-mounted above the wing it was produced by the Kawanishi company and entered service in 1933.^[1]

An improved version of the design, the H4H2, followed into production two years later. The H4H2 has re-designed twin fins and rudders and was powered by two 800hp (597kW) Myojo radial engine. A total of 47 of both versions was produced.^[1]

Both the H4H1 and H4H2 remained in front-line naval service through the 1930s.

Variants

H4H1 (Hiro Navy Type 91 Model 1 Flying Boat)

Variant powered by two 500hp (597kW) Hiro 91-1 engines.

H4H2 (Hiro Navy Type 91 Model 2 Flying Boat)

Variant powered by two 800hp (597kW) Myojo radial engines.

Operators

 Japan

• Imperial Japanese Navy Air Service

Specifications (H4H2)

Data from ^[1]

General characteristics

• Length: 54 ft 4¼ in (16.57 m)
• Wingspan: 76 ft 11½ in (23.46 m)
• Height: 20 ft 5 in (6.22 m)
• Wing area: 890.20 ft² (82.70 m²)
• Empty weight: 10280 lb (4663 kg)
• Gross weight: 16534 lb (7500 kg)
• Powerplant: 2 × Myojo radial piston engine, 800 hp (597 kW) each

Performance

• Maximum speed: 145 mph (233 km/h)
• Range: 793 miles (1260 km)
• Service ceiling: 11880 ft (3620 m)

Armament

• 1 × 7.7mm (0.303in) Machine Gun (mounted over bow cockpit)
• 2 × 7.7mm (0.303in) Machine Guns (mounted over midship cockpit)
• 2 × 250kg (551lb) bombs

See also

Related lists

• List of military aircraft of Japan
• List of seaplanes and flying boats
  

References

Notes

Bibliography

Hiro Naval Arsenal Aircraft designed and produced by Hiro H1H · H2H · H4H · G2H Prototypes and experimental aircraft R-3 · H3H · H10H Aircraft designed by others produced at Hiro Yokosuka B3Y · Nakajima B5N "Kate" · Aichi E13A "Jake" · Yokosuka D4Y "Judy" Engines designed and produced by Hiro Type 14 · Type 61 · Type 91 · Type 94

Japanese Navy Flying Boats designation series H1H  • H2H  • H3H/H3K  • H4H  • H5Y  • H6K  • H7Y  • H8K  • H9A HXC • HXD • HXP

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