Hiro H4H

Having failed with his H3H flying boat in a competition with Kawanishi , in which he defeated the Kawanishi H3K , the 11th Hiro Fleet Arsenal took into account the mistakes made in his new project. The new aircraft, which was a continuation of the H3H project, but much smaller, was developed by a team of designers led by Jun Okamuri.

The first prototype was built in 1931. It received the name "Type 91 Model 1 Marine Flying Boat" ( or H4H1 ). According to the test results, 2 more aircraft were built, which they began to operate in 1933. On these aircraft tested various engines, types of plumage and propellers.

The first aircraft were equipped with Hiro 91-1 engines with a capacity of 500 liters. with. each. After testing, they were replaced by 800 L Myojo radial engines. with. each. This option is called “Type 91 Model 2 Flying Sailing Boat ” ( or H4H2 ). In addition to engines, in this embodiment, the vertical tail was changed.

The H4H1 was an all - metal monoplane , with a metal wing sheathed in duralumin . Advanced automation was used on the plane, in particular, Junkers double flaps. However, the seaworthiness of the aircraft was unsatisfactory. Even a small disturbance at sea created great difficulties, and takeoff and landing on the open sea, outside the protected bays, posed a mortal danger. However, the fleet, having no alternative (the Hiro H1H , Hiro H2H and Kawanishi H3K biplanes could no longer be considered modern, and the development of the new Kawanishi H6K boat was slow ), ordered the production of H4H . A total of 47 aircraft of both modifications were produced.

Specifications

• Crew : 6-8 people
• Length : 16.57 m
• Height: 6.22 m
• Wingspan : 23.46 m
• Wing Area: 82.70 m²
• Empty weight: 4,663 kg
• Curb weight: 7 500 kg
• Engines: 2 x Myojo
• Power : 2 x 800 liters. with.

Flight performance

• Maximum speed : 233 km / h
• Cruising speed : 158 km / h
• Practical ceiling : 3,620 m

Armament

• Machine gun: 3 × 7.7 mm machine gun
• Bomb load: 2x250 kg bombs

• H4H1 ( Flying boat Type 91 Model 1 ) - version with Hiro 91-1 engines (500 hp)
• H4H2 ( Flying boat Type 91 Model 2 ) - version with Myojo engines (800 hp)

H4H aircraft began to serve in 1933. They took an active part in the Sino-Japanese war , patrolling the Chinese coast, and were used as long-range transport aircraft, repeatedly crossing the East China Sea . There were no skirmishes with Chinese planes and combat losses, however formally the H4H were the first flying boats that participated in the hostilities.

Before the start of World War II, the H4H were withdrawn from combat units. Despite the short service life, these aircraft played a large role in the development of Japanese hydro-aviation.

• Putnam. Robert C. Mikesh, Shorzoe Abe. Japanese Aircraft 1910-1941
• Tadeusz Januszewski, Krzysztof Zalewski. Japońskie samoloty marynarki 1912-1945 ISBN 83-86776-50-1