The Kawanishi H8K was a

flying boat A flying boat is a type of fixed-winged seaplane with a hull, allowing it to land on water. It differs from a floatplane in that a flying boat's fuselage is purpose-designed for floatation and contains a hull, while floatplanes rely on fusela ...

used by the

Imperial Japanese Navy Air Service The was the Naval aviation, air arm of the Imperial Japanese Navy (IJN). The organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War. The Japanese military acquired their first air ...

during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

for

maritime patrol {{Unreferenced, date=March 2008 Maritime patrol is the task of monitoring areas of water. Generally conducted by military and law enforcement agencies, maritime patrol is usually aimed at identifying human activities. Maritime patrol refers to ac ...

duties. The Allied reporting name for the type was "Emily". The Kawanishi H8K was a large, four-

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...

aircraft designed for long

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

and extended endurance on patrols or bombing missions typically flown alone over the

ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...

. The

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...

first flew in January 1941, and H8K1s made their first combat

sortie A sortie (from the French word meaning ''exit'' or from Latin root ''surgere'' meaning to "rise up") is a deployment or dispatch of one military unit, be it an aircraft, ship, or troops, from a strongpoint. The term originated in siege warfare. ...

in March 1942. The robust H8K2 "Emily" flying boat was also fitted with powerful defensive armament, for which

Allied An alliance is a relationship among people, groups, or states that have joined together for mutual benefit or to achieve some common purpose, whether or not explicit agreement has been worked out among them. Members of an alliance are called ...

pilots had substantial respect wherever this aircraft was encountered in the

Pacific theater The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

. Aircraft historian René Francillon called the H8K "the most outstanding water-based combat aircraft of the Second World War."

Design and development

At the same time the type's predecessor, the

Kawanishi H6K The Kawanishi H6K was an Imperial Japanese Navy flying boat produced by the Kawanishi Aircraft Company and used during World War II for maritime patrol duties. The Allied reporting name for the type was Mavis; the Navy designation was . Design ...

, was entering service in 1938 the

Navy A navy, naval force, or maritime force is the branch of a nation's armed forces principally designated for naval warfare, naval and amphibious warfare; namely, lake-borne, riverine, littoral zone, littoral, or ocean-borne combat operations and ...

ordered the development of a larger, longer-ranged patrol aircraft under the designation Navy Experimental 13-''Shi'' Large-size Flying Boat. The result was a large, shoulder-winged design that is widely regarded as the best flying boat of the war. Despite this, initial development was troublesome, with the prototype displaying terrible handling on the water. Deepening of the hull, redesigning of the planing bottom and the addition of spray strips under the nose rectified the water handling problems. Two further

s — actually pre-production aircraft — joined the development program in December 1941. The

IJNAS The was the air arm of the Imperial Japanese Navy (IJN). The organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War. The Japanese military acquired their first aircraft in 1910 a ...

accepted the first production version as the H8K1, Navy Type 2 Flying Boat, Model 11, of which 14 would be built. The improved H8K2 variant soon appeared, and its extremely heavy defensive armament earned it deep respect among

aircrew Aircrew, also called flight crew, are personnel who operate an aircraft while in flight. The composition of a flight's crew depends on the type of aircraft, plus the flight's duration and purpose. Commercial aviation Flight deck positions ...

s. The H8K2 was an upgrade over the H8K1 with more powerful engines, slightly revised armament, and an increase in fuel capacity. This was to be the definitive variant, with 112 produced. 36 examples of a dedicated transport version, the H8K2-L, were also built, capable of carrying 62 troops. This aircraft was also known as ''Seikū'' (晴空, "Clear Sky"). The side defensive blisters, ventral defensive hatch, and dorsal

turret Turret may refer to: * Turret (architecture), a small tower that projects above the wall of a building * Gun turret, a mechanism of a projectile-firing weapon * Objective turret, an indexable holder of multiple lenses in an optical microscope * Mi ...

were discarded. To increase the available space within the aircraft its hull tanks were removed, thus reducing its

Operational history

The H8K entered production in 1941 and first saw operational use on the night of 4 March 1942 in a second raid on Pearl Harbor. Since the target lay out of

for the flying boats, this audacious plan involved a refuelling by

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

French Frigate Shoals The French Frigate Shoals ( Hawaiian: Kānemilohai) is the largest atoll in the Northwestern Hawaiian Islands. Its name commemorates French explorer Jean-François de La Pérouse, who nearly lost two frigates when attempting to navigate the ...

, some north-west of

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

, ''en route''. Two planes from the Yokohama Kōkūtai (Naval Air Corps) attempted to bomb Pearl Harbor but, due to poor visibility, did not accomplish any significant damage. Six days after the second Pearl Harbor raid, one of the Emilys was sent on a daylight photo-reconnaissance mission of

Midway Atoll Midway Atoll (colloquial: Midway Islands; haw, Kauihelani, translation=the backbone of heaven; haw, Pihemanu, translation=the loud din of birds, label=none) is a atoll in the North Pacific Ocean. Midway Atoll is an insular area of the Unit ...

. It was intercepted by radar-directed

Brewster F2A Buffalo The Brewster F2A Buffalo is an American fighter aircraft which saw service early in World War II. Designed and built by the Brewster Aeronautical Corporation, it was one of the first U.S. monoplanes with an arrestor hook and other modifications ...

fighters of Marine Fighting Squadron 221 (

VMF-221 Marine Fighting Squadron 221 (VMF-221) was a reserve fighter squadron of the United States Marine Corps. Originally commissioned during the World War II, it flew the Brewster F2A-3, and after reconstitution in 1943, the F4U Corsair. The squadron ...

) and shot down. All aboard were killed, including Lt. Hashizume Hisao, the lead pilot of the second Pearl Harbor raid. H8K2s were used on a wide range of

patrol A patrol is commonly a group of personnel, such as Law enforcement officer, law enforcement officers, military personnel, or Security guard, security personnel, that are assigned to monitor or secure a specific geographic area. Etymology Fro ...

reconnaissance In military operations, reconnaissance or scouting is the exploration of an area by military forces to obtain information about enemy forces, terrain, and other activities. Examples of reconnaissance include patrolling by troops (skirmisher ...

bombing A bomb is an explosive weapon that uses the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy. Detonations inflict damage principally through ground- and atmosphere-transmitted mechanica ...

, and

transport Transport (in British English), or transportation (in American English), is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land (rail and road), water, cable, pipeline, an ...

missions throughout the

Pacific War The Pacific War, sometimes called the Asia–Pacific War, was the theater of World War II that was fought in Asia, the Pacific Ocean, the Indian Ocean, and Oceania. It was geographically the largest theater of the war, including the vast ...

. The H8K2 was given the Allied code name "Emily".

Variants

Famous Airplanes of the World (1994), pp. 19–22.The Maru Mechanic (1979), pp. 71–73.Model Art (1999), pp. 61–69. ;H8K1 ''Experimental Type 13 Large-sized Flying boat'' (13試大型飛行艇 ''13-Shi Ōgata Hikōtei'') : One prototype and four supplementary prototypes. Prototype was mounted Mitsubishi Mk4A Kasei 11 engines, supplementary prototype was mounted Mitsubishi MK4B Kasei 12 engines. Supplementary prototypes were renamed ''Type 2 Flying Boat Model 11'' on 5 February 1942. Prototype was rebuilt to H8K1-L in November 1943. ;H8K1 ''Type 2 Flying boat, Model 11'' (二式飛行艇11型 ''Nishiki Hikōtei 11-gata'') :Developed on 5 February 1942. First operative model of series, 12 produced. Mounted Mitsubishi MK4B Kasei 12 engines. ;;H8K1-L ''Type 2 Transport Flying Boat'' (二式輸送艇 ''Nishiki Yusōtei'') :Rebuilt from H8K1 prototype. Fitted augment exhausts. Up to 41 passengers. ;H8K2 ''Type 2 Flying boat, Model 12'' (二式飛行艇12型 ''Nishiki Hikōtei 12-gata'') :Developed on 26 June 1943. Mounted Mitsubishi MK4Q Kasei 22 engines and improved tail gun turret. Latter batch was equipped with Air-Surface Vessel (ASV) search radar, and removed side gun blisters. 112 produced. ;;H8K2-L ''Seikū'' ("Clear Sky")'', Model 32'' (晴空32型 ''Seikū 32-gata'') :Transport version of H8K2. Initial named ''Type 2 Transport Flying Boat, Model 32''. Armaments were 1 × forward-firing 20 mm cannon and 1 × rearward-firing 13 mm machine gun. Up to 64 passengers. ;H8K3 ''Provisional name Type 2 Flying Boat, Model 22'' (仮称二式飛行艇22型 ''Kashō Nishiki Hikōtei 22-gata'') :Experimental version, H8K2 modified. Equipped with retractable

float Float may refer to: Arts and entertainment Music Albums * ''Float'' (Aesop Rock album), 2000 * ''Float'' (Flogging Molly album), 2008 * ''Float'' (Styles P album), 2013 Songs * "Float" (Tim and the Glory Boys song), 2022 * "Float", by Bush ...

s in wingtips, Fowler flaps, sliding hatch side gun locations in place of the blisters and a retractable dorsal turret, all in an effort to increase speed; two prototypes only (work number 596 and 597). ;H8K4 ''Provisional name Type 2 Flying Boat, Model 23'' (仮称二式飛行艇23型 ''Kashō Nishiki Hikōtei 23-gata'') :H8K3 re-engined with 1,825 hp MK4T

Mitsubishi Kasei The was a two-row, 14-cylinder air-cooled radial engine built by Mitsubishi Heavy Industries and used in a variety of World War II Japanese aircraft, such as Mitsubishi J2M and Mitsubishi G4M.Gunston 1989, p.104. The Mitsubishi model designa ...

25b engines, two converted from H8K3. ;;H8K4-L ''Provisional name Seikū, Model 33'' (仮称晴空33型 ''Kashō Seikū 33-gata'') :Transport version of H8K4. Only a project, because all H8K4s were lost in March 1945. ;G9K :Proposed land-based attack bomber variant, only a project.

Operators

;

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

Famous Airplanes of the World (1994), each pages. *

** Saeki ''Kōkutai'' ** Sasebo ''Kōkutai'' ** Takuma ''Kōkutai'' ** Yokohama ''Kōkutai'' ** Yokosuka ''Kōkutai'' ** 14th ''Kōkutai'' ** 801st ''Kōkutai'' ** 802nd ''Kōkutai'' ** 851st ''Kōkutai'' ** 901st ''Kōkutai'' ** 902nd ''Kōkutai'' ** 951st ''Kōkutai'' ** 1001st ''Kōkutai'' ** 1021st ''Kōkutai'' ** 1081st ''Kōkutai'' *Miscellaneous **

Yokosuka Naval District was the first of four main administrative districts of the pre-war Imperial Japanese Navy. Its territory included Tokyo Bay and the Pacific coasts of central and northern Honshū from the Kii Peninsula to Shimokita Peninsula. Its headquarters, a ...

** 11th Naval Air Arsenal **

11th Air Fleet The was a grouping of naval aviation and surface units. Assignments and Components Commanders Chiefs of Staff Notes References * {{Use dmy dates, date=June 2017 Fleets of the Imperial Japanese Navy Units of the Imperial Japanese N ...

Kamikaze , officially , were a part of the Japanese Special Attack Units of military aviators who flew suicide attacks for the Empire of Japan against Allied naval vessels in the closing stages of the Pacific campaign of World War II, intending to d ...

**Azusa group (picked from 801st ''Kōkutai'', guidance only)

Surviving aircraft

Four aircraft survived until the end of the war. One of these, an H8K2 (work number 426), was captured by

U.S. The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

forces at the end of the war and was evaluated before being eventually returned to Japan in 1979. It was on display at

Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...

Museum of Maritime Science The Museum of Maritime Science (船の科学館, ''Fune-no-kagakukan'') is a marine science museum located in Higashiyashio, Shinagawa, Tokyo on Odaiba island, Japan. Exhibits include Japanese boats, items related to the navy, shipping industry, f ...

until 2004, when it was moved to

Kanoya Air Base Museum is an aerospace museum of the Japan Air Self-Defense Force in the city of Kanoya, Kagoshima Prefecture, Japan. The museum is located adjacent to Kanoya Air Field. History The museum opened in December 1973 (Showa 48) and reopened in July 1993 as ...

Kanoya Air Field is a military aerodrome of the Japan Maritime Self-Defense Force . It is located southwest of the city of Kanoya in Kagoshima Prefecture, Japan. Runway 08R/26L is equipped with ILS. On April 6, 2016 a U-125 airplane operated by the Flight Ch ...

Kagoshima , abbreviated to , is the capital city of Kagoshima Prefecture, Japan. Located at the southwestern tip of the island of Kyushu, Kagoshima is the largest city in the prefecture by some margin. It has been nicknamed the "Naples of the Eastern wor ...

. The submerged remains of an H8K can be found off the west coast of

Saipan Saipan ( ch, Sa’ipan, cal, Seipél, formerly in es, Saipán, and in ja, 彩帆島, Saipan-tō) is the largest island of the Northern Mariana Islands, a Commonwealth (U.S. insular area), commonwealth of the United States in the western Pa ...

, where it is a popular

scuba diving Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply. The name "scuba", an acronym for "Self-Contained Underwater Breathing Apparatus", was coined by Chris ...

attraction known erroneously as the "B-29", or the "Emily". Another wrecked H8K lies in Chuuk Lagoon, Chuuk, in Micronesia. This aircraft is located off the south-western end of Dublon Island.

Specifications (Kawanishi H8K2)

References

Notes

Bibliography

* Francillon, René J. ''Japanese Aircraft of the Pacific War''. London: Putnam & Company, 1970 (2nd edition 1979). . * * * * * * * *Famous Airplanes of the World, No. 49 ''Type 2 Flying Boat'', Bunrindō (Japan), November 1994. *The Maru Mechanic, No. 19 ''Feature, Type 2 Flying Boat'', Ushio Shobō (Japan), November 1979. * Model Art No. 541, Special issue ''Type 2 Flying Boat and Imperial Japanese Navy Flying Boats'', Model Art Co. Ltd., July 1999. {{DEFAULTSORT:Kawanishi H8k H8K H8K, Kawanishi Flying boats Four-engined tractor aircraft Shoulder-wing aircraft World War II Japanese patrol aircraft Aircraft first flown in 1941 Four-engined piston aircraft