View source for Kawanishi H8K

{{Short description|Imperial Japanese Navy flying boat}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. -->
{{Infobox aircraft
| name                 = H8K
| image                = Kawanishi H8K2 (Emily) flying boat.jpg
| image_border         = 
| caption              = Kawanishi H8K2 at Kanoya Museum, Japan
| type                 = [[Maritime patrol aircraft|Maritime patrol]] [[flying boat]]
| national_origin      = Japan
| manufacturer         = [[Kawanishi Aircraft Company|Kawanishi]]
| designer             = Shizuo Kikuhara
| first_flight         = January 1941
| introduction           = February 1942
| retired              = 1945
| status               = Retired
| primary_user         = [[Imperial Japanese Navy Air Service]]
| more_users           = 
| produced             = 1941–1945
| number_built         = 167
| unit cost            = 
| developed_from       = [[Kawanishi H6K]]
| variants = H8K2-L ''Seikū''
| developed_into       = 
}}
The '''Kawanishi H8K''' was a [[flying boat]] used by the [[Imperial Japanese Navy Air Service]] during [[World War II]] for [[Maritime patrol aircraft|maritime patrol]] duties. The Navy full name was {{nihongo|"'''Type 2 Flying Boat'''"|二式飛行艇|Nishiki Hikōtei}},  and was also called {{nihongo|"Type 2 Large-sized Flying Boat"|二式大型飛行艇|Nishiki-ō-gata hikō-tei}}, or just {{nihongo|"H2K flying boat"|二式大艇|Nishiki Taitei}}. The [[World War II Allied names for Japanese aircraft|Allied reporting name]] for the type was "''Emily''".

The Kawanishi H8K was a large, four-[[Radial engine|engine]] aircraft designed for long [[Range (aeronautics)|range]] and extended endurance on patrols or bombing missions typically flown alone over the [[ocean]]. The [[prototype]] first flew in January 1941, and H8K1s made their first combat [[sortie]] in March 1942. The robust H8K2 flying boat was also fitted with powerful defensive armament, for which [[Allies of World War II|Allied]] pilots had substantial respect wherever this aircraft was encountered in the [[Pacific Ocean theater of World War II|Pacific theater]]. Aircraft historian René Francillon called the H8K "the most outstanding water-based combat aircraft of the Second World War."<ref name="Francillon 1979 312">{{Harvnb|Francillon|1979|p=312.}}</ref>

==Design and development==
[[File:Kawanishi H8K2 -tail gunner.jpg|right|thumb|Tail gunner position (without gun)]]

At the same time the type's predecessor, the [[Kawanishi H6K]], was entering service in 1938 the [[Imperial Japanese Navy|Navy]] ordered the development of a larger, longer-ranged patrol aircraft under the designation Navy Experimental 13-''Shi'' Large-size Flying Boat.<ref>{{harvnb|Francillon|1979|pp=307, 547.}}</ref><ref>{{Harvnb|Richards|1972|p=242.}}</ref> The result was a large, shoulder-winged design that is widely regarded as the best flying boat of the war.<ref>{{Harvnb|Green|1962|p=131.}}</ref><ref>{{Harvnb|Van der Klaauw|1977|p=86}}</ref><ref name="Francillon 1979 312"/> Despite this, initial development was troublesome, with the prototype displaying terrible handling on the water. Deepening of the [[hull (watercraft)|hull]], redesigning of the planing bottom and the addition of spray strips under the nose rectified the water handling problems.<ref>{{Harvnb|Richards|1972|p=244.}}</ref> Two further [[prototype]]s — actually pre-production aircraft — joined the development program in December 1941.

The [[Imperial Japanese Navy Air Service|IJNAS]] 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 [[Allies of World War II|Allied]] [[Aircrew#Military|aircrew]]s.<ref>{{Harvnb|Francillon|1979|p=310.}}</ref> 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 {{nihongo|''Seikū''|晴空|Clear Sky}}''', were also built, capable of carrying 62 troops. The side defensive blisters, ventral defensive hatch, and dorsal [[Gun turret#Aircraft|turret]] were discarded. To increase the available space within the aircraft its hull tanks were removed, thus reducing its [[Range (aeronautics)|range]].

==Operational history==
[[File:Kawanishi H8K Emily take off.png|left|thumb|H8K1 supplementary prototype number 2 taking off in February 1942.]]

The H8K entered production in 1941 and first saw operational use on the night of 4 March 1942 in a [[Operation K|second raid on Pearl Harbor]]. Since the target lay out of [[Range (aeronautics)|range]] for the flying boats, this audacious plan involved a refuelling by [[submarine]] at [[French Frigate Shoals]], some {{convert|900|km|-1|abbr=on}} north-west of [[Hawaii]], ''en route''. Two planes from the [[Yokohama Air Group|Yokohama Kōkūtai]] (Naval Air Corps)<ref>{{Harvnb|Richards|1972|pp=250–251.}}</ref> attempted to bomb Pearl Harbor but, due to poor visibility, did not accomplish any significant damage.<ref>{{Harvnb|Raymer|1996|pp=96–98.}}</ref> Six days after the second Pearl Harbor raid, one of the H8K was sent on a daylight photo-reconnaissance mission of [[Midway Atoll]]. It was intercepted by radar-directed [[Brewster F2A Buffalo]] fighters of Marine Fighting Squadron 221 ([[VMF-221]]) and shot down. All aboard were killed, including Lt. Hashizume Hisao, the lead pilot of the second Pearl Harbor raid.{{citation needed|date=November 2012}}

H8K2s were used on a wide range of [[Maritime patrol aircraft|patrol]], [[Aerial reconnaissance|reconnaissance]], [[Bomber|bombing]], and [[Military transport aircraft|transport]] missions throughout the [[Pacific War]].
{{-}}

==Variants==
[[File:Kawanishi H8K Flying Boat Emily h8k-1.jpg|thumb|right|A Kawanishi H8K2 Type 2 Flying Boat ashore.]]
[[File:Kawanishi H8K in flight July 1944.jpeg|thumb|An H8K2 ''51-085'' of the 851st Kōkutai in flight, immediately before being shot down by the [[United States Navy|U.S. Navy]] [[Consolidated B-24 Liberator#PB4Y-1|PB4Y-1]] from which the photograph was taken, 2 July 1944.]]
<ref name="FAW_P1922">Famous Airplanes of the World (1994), pp. 19–22.</ref><ref name="TMM_P71">The Maru Mechanic (1979), pp. 71–73.</ref><ref name="MA_P61">Model Art (1999), pp. 61–69.</ref><ref>{{Cite web | title=The Kawanishi H6K & H8K Flying Boats | url=https://www.airvectors.net/avh6kh8k.html | archive-url=https://web.archive.org/web/20130207122150/http://www.airvectors.net:80/avh6kh8k.html | access-date=2025-11-16 | archive-date=2013-02-07}}</ref>
;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 [[Radar in World War II#Air-Surface Vessel|Air-Surface Vessel (ASV)]] search radar, and removed side gun blisters. 112 produced.<ref name="Richards1972p262">{{Harvnb|Richards|1972|p=262.}}</ref>
;;H8K2-L ''Seikū, 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&nbsp;mm cannon and 1 × rearward-firing 13&nbsp;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 (nautical)|float]]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&nbsp;hp MK4T [[Mitsubishi Kasei]] 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. Abandoned due to priority being given to fighters for home island defense, so no more H8Ks were being produced.

There was also was a proposed land-based attack bomber variant (project only), often called "'''G9K ''Gunzan'''''" as a post-was extrapolated name following the Navy naming system.
{{-}}

==Operators==
;{{flagicon|Empire of Japan}} [[Empire of Japan|Japan]]<ref name="TMM_P71" /><ref name="FAW_P1">Famous Airplanes of the World (1994), each pages.</ref>
*[[Imperial Japanese Navy Air Service]]
**[[Saeki Naval Air Group IJNAS|Saeki ''Kōkutai'']]
**[[Sasebo Naval Air Group IJNAS|Sasebo ''Kōkutai'']]
**[[Takuma Naval Air Group IJNAS|Takuma ''Kōkutai'']]
**[[Yokohama Air Group|Yokohama ''Kōkutai'']]
**[[Yokosuka Naval Air Group IJNAS|Yokosuka ''Kōkutai'']]
**[[14th Naval Air Group IJNAS|14th ''Kōkutai'']]
**[[801st Naval Air Group IJNAS|801st ''Kōkutai'']]
**[[802nd Naval Air Group IJNAS|802nd ''Kōkutai'']]
**[[851st Naval Air Group IJNAS|851st ''Kōkutai'']]
**[[901st Naval Air Group IJNAS|901st ''Kōkutai'']]
**[[902nd Naval Air Group IJNAS|902nd ''Kōkutai'']]
**[[951st Naval Air Group IJNAS|951st ''Kōkutai'']]
**[[1001st Naval Air Group IJNAS|1001st ''Kōkutai'']]
**[[1021st Naval Air Group IJNAS|1021st ''Kōkutai'']]
**[[1081st Naval Air Group IJNAS|1081st ''Kōkutai'']]
*Miscellaneous
**[[Yokosuka Naval District]]
**[[Hiro Naval Arsenal|11th Naval Air Arsenal]]
**[[List of Air Fleets of the Imperial Japanese Navy#11th Air Fleet|11th Air Fleet]]
*[[Kamikaze]]
**Azusa group (picked from 801st ''Kōkutai'', guidance only)

==Surviving aircraft==
[[File:H8K take off NAN8-47.jpg|thumb|right|300px|A captured Japanese Kawanishi H8K Emily taking off at the [[Naval Air Station Patuxent River|U.S. Navy Naval Air Test Center at Patuxent River]], [[Maryland]], [[United States]] in 1946–47.]]
Four aircraft survived until the end of the war. One of these, an H8K2 (work number 426), was captured by [[United States|U.S.]] forces at the end of the war and was evaluated before being eventually returned to Japan in 1979. It was on display at [[Tokyo]]'s [[Museum of Maritime Science]] until 2004, when it was moved to [[Kanoya Air Base Museum]] at [[Kanoya Air Field]] in [[Kagoshima]].

The submerged remains of an H8K can be found off the west coast of [[Saipan]], where it is a popular [[scuba diving]] attraction known erroneously as the "B-29", or the "Emily". Another wrecked H8K lies in Chuuk Lagoon, [[Chuuk State|Chuuk]], in Micronesia. This aircraft is located off the south-western end of Dublon Island.
{{-}}

==Specifications (Kawanishi H8K2)==
[[File:Kawanishi H8K3.svg|thumb|300px|Kawanishi H8K3]]
{{Aircraft specs
|ref=Japanese Aircraft of the Pacific War<ref name=Francillon>{{cite book |last=Francillon |first=René J. |title=Japanese Aircraft of the Pacific War |year=1979 |publisher=Putnam & Company Limited |location=London |isbn=0-370-30251-6 |pages=307–313}}</ref>
|prime units?=met
<!--
        General characteristics
-->
|crew= 10
|length m=28.13
|length note=
|span m=38
|span note=
|height m=9.15
|height note=
|wing area sqm=160
|wing area note=
|aspect ratio=<!-- sailplanes -->
|airfoil=
|empty weight kg=18380
|empty weight note=
|gross weight kg=24500
|gross weight note=
|max takeoff weight kg=32500
|max takeoff weight note=
|fuel capacity={{cvt|18880|L|impgal gal}}
|more general=
<!--
        Powerplant
-->
|eng1 number=4
|eng1 name=[[Mitsubishi MK4Q Kasei 22]]
|eng1 type=14-cylinder air-cooled radial piston engines:
|eng1 kw=<!-- prop engines -->
|eng1 hp=
|eng1 shp=<!-- prop engines -->
|eng1 kn=<!-- jet/rocket engines -->
|eng1 lbf=<!-- jet/rocket engines -->
|eng1 note={{ubl|{{cvt|1850|hp|0|order=flip}} for take-off
|{{cvt|1680|hp|0|order=flip}} at {{cvt|2100|m}}
|{{cvt|1540|hp|0|order=flip}} at {{cvt|5500|m}}}}

|prop blade number=4
|prop name=constant-speed propellers
|prop dia m=<!-- propeller aircraft -->
|prop dia note=
<!--
        Performance
-->
|max speed kmh=467
|max speed note=at {{cvt|5000|m}}
|cruise speed kmh=296
|cruise speed note=at {{cvt|4000|m}}
|stall speed kmh=
|stall speed note=
|never exceed speed kmh=
|never exceed speed note=
|minimum control speed kmh=
|minimum control speed note=
|range km=7152
|range note=
|combat range km=
|combat range note=
|ferry range km=
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling m=8850
|ceiling note=
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|climb rate ms=
|climb rate note=
|time to altitude={{cvt|5000|m}} in 10 minutes 12 seconds
|wing loading kg/m2=153.1
|wing loading note=
|fuel consumption kg/km=
|power/mass={{cvt|0.137|hp/lb|order=flip}}
|more performance=
<!--
        Armament
-->
|guns=<br>
** 5× {{cvt|20|mm|3}} [[Type 99 Mark 1 machine gun]] (one each in bow, dorsal, and tail turrets, plus one each in two waist blisters)
** 5× {{cvt|7.7|mm|3}} [[Type 92 machine gun]]s in fuselage hatches
|bombs= 2× {{cvt|800|kg}} [[torpedo]]es ''or'' {{cvt|2000|kg}} of [[Aerial bomb|bomb]]s or [[depth charge]]s
|avionics=
* [[List of Japanese World War II radars#Navy Radar|Mark VI]] Model 1 [[Radar in World War II#Air-Surface Vessel|ASV radar]]
}}

==See also==
{{aircontent
|similar aircraft=
* [[Blohm & Voss BV 222]]
* [[Boeing 314 Clipper]]
* [[Consolidated PB2Y Coronado]]
* [[Martin PBM Mariner]]
* [[Short Sunderland]]
* [[Short Seaford]]
|lists=
* [[List of aircraft of World War II]]
* [[List of military aircraft of Japan]]
* [[List of flying boats and floatplanes]]
}}

==References==
{{Commons category|Kawanishi H8K}}

===Notes===
{{notelist}}
{{Reflist|2}}

===Bibliography===
* Francillon, René J. ''Japanese Aircraft of the Pacific War''. London: Putnam & Company, 1970 (2nd edition 1979). {{ISBN|978-0-370-30251-5}}.
* {{Cite book|last=Green|first=William|title=Warplanes of the Second World War: Volume Five, Flying Boats|date=1962|publisher=Macdonald|isbn=0-356-01449-5|oclc=655865554}}
*{{cite journal |last1=Millot|first1=Bernard|title=Kawanishi H8K "Emily", avec toilettes modernes local de repos et cuisine, le meilleur hydravion de la seconde guerre mondiale était japonais...|journal=Le Fana de l'Aviation |date=May 1976 |issue=78 |pages=14–19 |issn=0757-4169 |language=fr|trans-title=The Kawanishi H8K Emily: With modern restroom and kitchen, the best seaplane of WWII was Japanese }}
*{{cite journal |last1=Millot|first1=Bernard|title=Kawanishi H8K "Emily", en vols solitaire de plus de 24 heures, ils patrouillaient le vaste Pacifique... (2)|journal=Le Fana de l'Aviation |date=June 1976 |issue=79 |pages=14–19 |issn=0757-4169 |language=fr|trans-title=The Kawanishi H8K Emily: The Only Aircraft Capable of Flying for More than 24 Hours, Patrolling the Vast Pacific, Part 2}}
*{{cite journal |last1=Millot|first1=Bernard|title=Kawanishi H8K "Emily", le seul bombardier stratégique capable d'aller jusqu'à Pearl Harbor (3)|journal=Le Fana de l'Aviation |date=July 1976 |issue=80 |pages=16–19 |issn=0757-4169 |language=fr|trans-title=The Kawanishi H8K Emily: The Only Strategic Bomber Capable of Reaching Pearl Harbor, Part 3}}
* {{Cite book|last=Raymer|first=Edward C.|title=Descent into darkness : Pearl Harbor, 1941: a Navy diver's memoir|date=1996|publisher=Presidio|isbn=0-89141-589-0|location=Novato, CA|oclc=34244509}}
* {{Cite book|last=Richards|first=M. C.|url=https://books.google.com/books?id=ZMDktgAACAAJ|title=Kawanishi 4-motor Flying-boats (H6K 'Mavis" and H8K 'Emily')|date=1972|publisher=Profile Publications|language=en}}
* {{Cite book|last=Van der Klaauw|first=B.|title=Water- en transportvliegtuigen wereldoorlog II|date=1977|publisher=De Alk|isbn=90-6013-677-2|location=Alkmaar|oclc=63363268}}
*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.

{{Kawanishi aircraft}}
{{Japanese Navy short aircraft designations}}
{{Imperial Japanese Navy official aircraft names}}
{{Allied reporting names}}

{{DEFAULTSORT:Kawanishi H8k}}
[[Category:Kawanishi aircraft|H8K]]
[[Category:1940s Japanese patrol aircraft|H8K, Kawanishi]]
[[Category:Flying boats]]
[[Category:Four-engined tractor aircraft]]
[[Category:Shoulder-wing aircraft]]
[[Category:Aircraft first flown in 1941]]
[[Category:Four-engined piston aircraft]]