Yokosuka (Yokosho) Navy Ro-go Ko-gata

Navy Yokosho Ro-go Ko-gata Reconnaissance Seaplane with Hispano-Suiza E engine.

 Navy Yokosho Ro-go Ko-gata Reconnaissance Seaplane with Salmson engine.

During the First World War a number of Yokosho seaplane designs were created by Lieut. Chikuhei Nakajima with the assistance of Lieut. Kishichi Umakoshi, and there was much test flying associated with the improvements of these designs. Using foreign techniques, Umakoshi designed a reconnaissance seaplane with the emphasis on stability and control. The first prototype was completed in the autumn of 1917 and flight tests began in early 1918. Better performance was achieved with this aircraft than with any previous Japanese Navy aircraft.

Production began immediately at the Yokosuka Naval Arsenal and four aircraft were built in 1918. Confirming acceptance as a Navy type, they were officially designated Ro-go Ko-gata. Originally powered by a 140 hp Salmson engine, the engine was soon changed to the 200 hp Salmson, followed by the 200 hp Mitsubishi-built Type Hi (Hispano-Suiza) engines which were used in production aircraft. The Ro-go Ko-gata was the first of the Japanese Navy's aircraft to be put into production. The Ro-go Ko-gata was a single-engined twin-float biplane of wooden construction, the crew of two being in open cockpits.

In April 1919 three of these aircraft were converted from two-seaters to single-seaters to increase their fuel capacity. In this configuration they made a record-breaking long-distance flight from Oppama, to Kure near Hiroshima, Chinhae (35.4 km/22 miles west of Pusan in Korea), Sasebo in western kyushu, and return to Oppama. On this flight Sub-Lieut Kanjo Akashiba set a record by flying from Sasebo to Oppama on 20 April, 1919, an indirect distance of 1,300 km (808 miles in 11 hr 35 min at an average speed of 61 kt (70.1 mph).

The manufacture of these aircraft continued at Yokosuka Naval Arsenal until 1921. In 1920 production was begun by Aichi and Nakajima, making this the first naval aircraft built by Nakajima. In November 1923, to conform with a new Navy designation system for aircraft, the official Navy designation for these aircraft was changed to Yokosho-Type Reconnaissance Seaplane.

This first mass-produced aircraft for the Navy was widely used together with the Hansa Reconnaissance Seaplane over the period 1921 to 1926.

In appreciation of his success, which began with the prototype design, Lieut. Kishichi Umakoshi was given special recognition by the Minister of the Navy, the first for an aircraft designer.

The entry into service of the Yokosho Ro-go Ko-gata, with its increased speed and maneuverability, made the Farman pusher seaplanes then in service obsolete, and they were taken out of service. In time, a number of these aircraft were released for civil use on such duties as mail carriers. Some were in service as late as 1928.

Technical Data
Manufacturer: Yokosuka Kaigun Ko-sho (Yokosuka Naval Arsenal).
Type: Single-engined reconnaissance Seaplane.
Crew (2): Pilot and observer/gunner in open cockpits.
Powerplant: (prototype) One 130-140 hp Mitsubishi-built Type Sa (Salmson M-9 ) nine-cylinder water-cooled radial engine, driving a two-balde wooden propeller, (pre-production) one 200 hp Mitsubishi-built Type Sa (Salmson M-7) nine-cylinder water-cooled radial engine, driving a two-blade wooden propeller, (production) one 200-220 hp Mitsubish-built Type Hi (Hispano-Suiza E) eight-cylinder vee water-cooled engine, driving a two-blade wooden propeller.
Armament: One rear-firing flexibly-mounted 7.7 mm (0.303 in) machine-gun in dorsal cockpit.
Dimensions: Span (prototype) 15.53 m (50 ft 11 1/2 in), (Production) 15.692 m (51 ft 6 in); length (prototype) 10.172 m (33 ft 4 1/2 in), (production) 33 ft 4 in); height (prototype) 3.68m (12 ft 1 in), (production) 3.666 m (12 ft); wing area 48.22 sq m (519.052 sq ft).
Weights: Empty (prototype) 1,211 kg (2,669 lb), (production) 1,070 kg (2,358 lb); loaded (prototype) 1,676 kg (3,694 lb), (production) 1,628 kg (3,589 lb); wing loading (prototype) 34.75 kg/sq m (7.1 lb/sq ft), (production) 33.76 kg/sq m (6.9 lb?sq ft); power loading (prototype) 12.9 kg/hp (28.4 lb/hp), (production) 8.1 kg.hp (17.8 lb/hp).
Performance: Maximum speed (prototype) 75 kt (86.3 mph), (production) 84 kt (96.72 mph); climb to 500 m (1,640 ft) (prototype) in 4 min 12 sec, (production) 4 min; range (production) 420 nm (483 st miles); endurance (production) 5 hr.
Production: A total of 218 Ro-go Ko-gata were built as follows:

Yokosuka Kaigun Ko-sho [Yokosho] (Yokosuka Naval Arsenal:

32 - production aircraft between 1917-1921 (Type Sa and Type Hi engines).

Aichi Tokei Denki Kabushiki Kaisha:

80 - between 1920-1924 (Type Hi engine).

Nakajima Hikoki KK:

106 - between 1920-1924 (Type Hi engine).