History Podcasts

Kawanishi H8K from the side

Kawanishi H8K from the side

Kawanishi H8K from the side

Here we see a side view of the Kawanishi H8K 'Emily', showing the boat shape of the hull and the tall tail.

Kawaniši H8K [Emily]

Japanese name (combat): ? / transport version – "Seikū"

Allied reporting name: "Emily"

Label the Design of the aeroplane - a description
Kawanishi H8K1 11 1 prototype 2 pre-series aircraft and 14 serial, gradual changes led to the improvement of the properties, engines MK4A Kasei 11 later MK4B Kasei 12
Kawanishi H8K1-L the first prototype was modified into the form of a transport aircraft
Kawanishi H8K2 12 112 serially-produced aircraft, engines MK4Q Kasei 22, self-sealing tanks, armour, gradually introduced changes, the SOP, the shape of the bow and the side střelišť,
later produced machines are equipped as a standard radar detector
Kawanishi H8K2-L 32 36 – 42 transport aircraft, reduced weight and armament
Kawanishi H8K3 22 2 serial aircraft H8K2 were modified into the form of a new version, the retractable buffer of floats, a retractable top turret, and change the side střelišť.
Kawanishi H8K4 23 both aircraft H8K3 got výškovější motors MK4T-B Kasei 25b, so created this version, the planned production
H8K4-L 33 only the project, transport aircraft resulting from the version H8K4

Produced a total of 167 aircraft of this type.
Production took place in factories:
川西航空機株式会社 - Kawanishi Kōkūki Kabushiki Kaisha, Nauro
川西航空機株式会社 - Kawanishi Kōkūki Kabushiki Kaisha, Konan

Used springs: M. C. Richards, Kawanishi 4-Motor Flying-Boats (H6K 'Mavis' and H8K 'Emily'), Aircraft in Profile Volume 11. Windsor, Berkshire, UK, Profile Publications Ltd., 1972. Famous Airplanes of The World, Kawanishi Type 2 Flying boat, Well. 68. 12/1975, Bunrin-Do, No ISBN. Tadeusz Januszewski and Kryzysztof Zalewski, Japońskie samoloty marynarski 1912-1945, tiel 2, Lampart, 2000, ISBN 83-86776-00-05 Leszek And. Wieliczko, Kawanishi H8K, Nowa Technika Wojskowa – Nr. 6/2014, 2014, Warszawa, Magnum X. ISSN 2080-9743. https://www.combinedfleet.com/ijna/h8k.htm

Kawanishi H8K - 川西 H8K

Allied reporting name: "Emily"

History of
Command of the japanese navy air force (海軍航空本部 - Kaigun Kōkū Hombu) in 1938, began taking first pieces of brand new "Large flying boat type 97 model 1" (九七式大型飛行艇 - Kjunana shiki daikei hikótei), the us better known under the shortened designation of Kawanishi H6K1. These flying boats were, in their time, and in its category among the world leaders, have long range, decent feats and also excellent nautical characteristics of the ship hull. Kaigun Kōkū Hombu are pinned back then the commonly established procedure and no longer 18. April of this year drew up the specifications of the development plan marked as 13-Shi, in which zformulovalo your technical requirements for a new flying boat. Thanks to this procedure input to the development of new machines, the imperial naval air force to ensure the supply of increasingly modern aircraft. In this case, everything worked out according to the assumptions and the just adopted flying boat, had already in the production of prepared of his successor, which it replaced in time when this began their performances lag behind and began to manifest itself even design flaws, such as non-existent passive protection.

The specifications of the 13-Shi Kaigun Kōkū Hombu did not require only a new flying boat, although there was no specification of its scope too significant, but it is to see that the imperial naval air force was becoming increasingly more significant force. Required were the following aircraft categories:
• on-board fast reconnaissance aircraft - C4A1
• on-board bomber - D4Y
• twin-engine heavy fighter - J1M1 and J1N
• heavy attack aircraft for land base - G5N
• large reconnaissance flying boat - H8K
• small amphibious transport aircraft (amfibie) - L7P1
• training flying boat - H9A1

For the purposes of this contribution we consider only the parts in which they were the requirements for a large reconnaissance flying boat. Kaigun Kōkū Hombu needed for your needs really powerful aircraft, which was supposed to have a range of up to 7 400 km during the survey years, for years ago, in which he was carrying bombs, or torpedoes, were required in a range of 6 500 km. The maximum speed should be at least at the level of 444 km/h (240 knots) and the cruising speed should be at a very decent level and the boat had long-term fly at a speed of around 300 km/h. In addition to these performances was also claimed relatively solid defensive armament and effective protection of the fuel tanks. The aircraft should be capable of carrying 2 000 kg of bombs or depth charges about the same weight, or two great čtyřistapadesátimilimetrová torpedoes of the type 91, each about the weight of 806 and later in another version of the 848 kg. The development of the new flying boat was no competition entered directly to the company 川西航空機株式会社 – Kawanishi Kōkūki Kabushiki Kaisha based in Nauro (further in the text only Kawanishi). This company had with the construction of the flying boats the most experience.

The project work had already started in the month of August of the year 1938, the factory design team lead engineer Shizuo Kikuhara, and he collaborated with dr. Jishio Hashiguchim. He suggested a completely different aircraft than was its predecessor, Kawanishi H6K, he had a relatively slim fuselage and the wing was mounted by struts above the fuselage, the new flying boat was designed as a compact high-wing is considerably robust hull. Great care has been given to the člunovému the shape of the hull, it was made a few lot of completely wooden mock-ups in scale 1 : 5, these mock-ups were both ofukovány in the wind tunnel and also have been carefully researched nautical qualities of the hull in a large pool, on the basis of these tests, the shape of the hull, refined by. From the very beginning it was planned that the aircraft will operate exclusively from water level, it was not in any way about amfibii (the amphibian), the wheeled chassis used to fit just in case, when was this flying boat was pulled ashore, his wheels were duplicated and it was not a tire – wheel was full of (rubber). Sturdy hull, the designers have used, have installed six large self-sealing fuel tanks, including fire-fighting equipment with carbon dioxide, an interesting feature was the possibility of siphoning fuel from the bottom of the ship hull, the fuel here should be captured after it is shot through some of the fuselage tanks and, subsequently, filled into the tanks intact. The fuselage tanks were supplemented by a further eight smaller tanks in the wing, these tanks were not self-locking. The total inventory carried by the fuel was 17 040 liters. The wings were equipped with special flaps, which were across the trailing edge of the wing, it was a combination of fowler's and split flaps, the combination of deploying and using the company Kawanishi. At the ends of the wings were balancing floats, originally should be retractable to the ends of the wings, but in the end it was from the retraction of these floats dispensed with, thereby simplifying their construction and passed out one of the sources of the problems. The defensive armament was impressive, was made up of five dvacetimilimetrovými cannons and three machine guns of rifle caliber. The drive consisted of four čtrnáctiválcových engines Mitsubishi MK4A Kasei 11 (Ha-32-11), each take-off power of 1 125 kW (1 530 hp), these engines geared up čtyřlisté propeller Sumimoto with a diameter of 3 900 millimeters, it was a propeller with a constant speed. The first prototype was in this form completed on 31. December 1940.

Prototype H8K1 13-Shi.
The first takeoff was made sometime in the first half of the month of January of the following year (some japanese sources indicate that has been completed 29. December and the following day had to be zalétání), however, it is clear that the plane took off from sea-level not far from Osaka, behind the wheel sat a navy pilot Shosha Hiromitsu, and that he had besides some longitudinal instability in flight very poor nautical characteristics at higher speeds from the bow the ship hull picked up a lot of the spray and the subsequently watered the pilot cabin, when he was denied the view. The aircraft was in addition, during take-off and přistáni unstable, and a wrong to operate. The hull was designed so poorly, that another great shower spray was coming up through the wing, were cast into the inner engines. It is surprising that this prototype had such problems, taking into account the number of tests and subsequent adjustments were carried out just on the boat section of the fuselage, on the basis of tests of the mockups on the water surface. The prototype is then quickly returned to the production hall, where the designers have made a few adjustments, the easiest adjustment was the elimination of the longitudinal instability in flight, the designers of the rather substantially modified the vertical tail surface area, and stability has improved. Much more challenging were the modifications on the boat part of the fuselage, was reduced keel, and he changed the whole shape, the bottom along the front of the fuselage were installed two strips, ending approximately below the end of the pilot cabin, these rails prevent the undesired splashing of water. The following tests have confirmed a certain improvement of the sea characteristics and so although it was Kaigun Kōkū Hombu still reservations to the characteristics of this flying boat, was accepted into the armament under the designation "Navy flying boat Type 2 Model 11 H8K1 (here I will remind, that the designation of the flying boat is for our needs, the Japanese they had no idea between the float plane and flying boat and it would be more appropriate to use the word seaplane).

H8K1 Model 11
At the time when the decision was made on the adoption of the flying boat to the armament of naval aviation in Kawanishi already worked on two pre-series machines, the cannon is so completely according to the requirements of Kaigun Kōkū Hombu. These machines are from the first prototype is already noticeable in some parts. Mainly was extended bow in front of the cab and was amended and its shape, a completely new shape also had a vertical tail, another visible change was the installation of a smaller propeller, newly applied the propeller had a diameter of 3 to 400 mm, due to this increased distance from the water surface, but also is negatively reflected their less efficiency and the maximum speed has decreased to a value of 404 km/h at an altitude of 4 000 meters. Visible changes have affected the equipment, pre-series machines carried "only" two cannons Typ 99 Model 1 caliber 20 mm (one in a dorsal gun turret and the other was in the tail střelišti), the cannons were supplemented by four machine guns, Type 92 caliber 7.7 mm (two in the bow and one in the side stations in the shape of large drops. Another change, this time the invisible was the installation of self-sealing fuel tanks and into the wings. These adjustments increased the combat value of the two pre-series machines, both have been operationally used, one aircraft was lost during combat action. In the meantime, began to the units of the coming of mass-produced flying boats, there were produced a total of fourteen, the last few produced aircraft should be amended by the bow, she had a wedge shape, and he already then had all the other planes and at the same time they were in the past produced machines mounted engines Mitsubishi MK4B Kasei 12 (Ha-32-12), which had slightly higher performance at altitude.

The first prototype was in 1943, rebuilt again, this time quite radically, into the form of a transport/ cargo flying boat. This presentation was commissioned by the Kaigun Kōkū Hombu in the fall of 1942. The project received the factory designation of the K-30, and the design team set to work, the modification consisted in the removal of most of the barrel armament was removed, top turret, side kapkovitá guns, remained so only the rear turret and front guns, the question is whether in this particular aircraft, remained in the front střelišti cannon Type 99 Model 1, or whether I was installed the machine gun. Further, the disassembly of the fuselage tank and into the vacated space have been built in two floors, the bottom floor was from the bow to the indentation on the boat floor and the upper started for centroplánem. The fuselage was in two ranks installed a small oblong of the window to make space for passengers prosvětlen, the aircraft could carry 41 passengers and because it was a modified first prototype, it remained in a single copy.

the H8K2 Model 12
The first prototype was meanwhile tested the installation of the engines Mitsubishi MK4Q Kasei 22 (Ha-32-22), these engines achieve a performance of 1 361 kW (1 850 k), and were equipped with a device for direct injection of water into the engine cylinders, it was possible to short term performance increase. These propulsion units are completely proved and the maximum speed rose to 454 km/h, therefore there was launched production of a new version of the marked H8K2 Model 12. In addition to the new engines, increased fuel supply, the newly it was possible to carry up to 18 880 gallons of gasoline, was further amended SOP, this time to the already definitive form. The martial value of this version has increased significantly also thanks to the strengthening of the defensive armament, the aircraft was carrying a total of five cannons Type 99 Model 1, these guns had a supply of ammunition in the drum bins around the 45 grenades, cannons were installed in the front (225), dorsal (450), rear (450) and in the bulging of the side stations (360). The numbers in parentheses we indicate carried a supply of ammunition for each cannon. In addition to the cannon armament was to each aircraft installed and machine-gun armament, it was formed by machine guns Type 92, their number and placement are very often different, but can generally say, that was installed three to six machine guns and, for each was carried by the ammunition supply in the range of 970 – 1 064 rounds in the 10 – 12 drum trays. Each tray could theoretically contain 100 rounds, but in practice it was charging "only" 97 the hub (with a hundred with a machine gun was sticking). This version was also installed solid and the japanese ratios unprecedented armor protection in the form of šestimilimetrových steel plates, these plates protect the pilots ' seat and the gunner in the dorsal and tail gun turret. In the course of production was removed convex kapkovitá side shooting range, is replaced with was the sliding windows. In the case that was carried by a bomb, or torpedo armament had to be reduced supply of fuel to a maximum of 5 670 liters. Machines the later of the date of production were already equipped with first three of these ASV Model 1, the presence of which tells us the antenna type Yagi mounted on the sides of the fuselage before the cockpit. Two flying boats have been modified into the form of a more sophisticated H8K3, among other adjustments herein it was investigated the removal of bulging of the side střelišť and replacing them with straight posunovatelnými windows, this modification was introduced into production H8K2. This version was the most numerous and were built in total of 112 aircraft and their production has also engaged the factory in the town of Konan, Tokyo.

the H8K2-L Model 32
The production of this transport/ cargo version of the build on the redevelopment, which in 1943 passed the first prototype, přeznačený on the H8K1-L, and this prototype more or less match. In the hull of the remaining four fuel tanks of the original six, the total fuel supply could be up to 13 414 litres in the front střelišti was carried by the powerful machine gun Type 2 the caliber of 13.0 mm, the empty weight of the airplane after the repairs were 15 107 kg, take-off weight was 26 683 kg. His own crew consisted of nine men, carrying capacity then amounted to 29 VIP or 64 soldiers, including armament. Japan in the second phase of the war in the Pacific needed more and more often transported by air troops, the wounded and material, because shipping was becoming dangerous mainly due to the american submarines, therefore it is not surprising that Kaigun Kōkū Hombu requested transport aircraft of this size, put them into your loadout under the designation "Maritime transport flying boat Type 2 Model 32" fighting name of this version sounded poetically - "Seikū" (Clear sky). The model designation tells us that this was the third adjustment to the airframe, and a second adjustment motors. Most of these aircraft were manufactured as new, only a few of them was established by a rebuilding of the older H8K1 or newer H8K2, and these rearrangements are to blame, that do not know the exact number of aircraft Seikū likely to have been built and reconstructed into a 36, but it often appears the figure 42. Most of them were made in konanské factory and production ended in 1945, this year has been completed already just a single aircraft.

H8K3 Model 22
As I mentioned, the two flying boats H8K2 Model 12 was redesigned into the form of a more sophisticated H8K3. The new version of this flying had some interesting modifications that they considered the task to increase the performance. The designers have once again returned to the idea of the retractable floats, with this system met already in the late thirties, when they were the airline Dai Nippon purchased two aircraft Douglas DF, which were later forwarded to the company's Kawanishi. Fixed buffer floats on the two struts and their anchorage system using the lan have been removed, more to the ends of the wings were installed two more robust floats, which can be folded towards the ends of the wings, the floats should offsets, which exactly match the end arcs of the wings, and after pushing up so the floats have become a part of the wings and do not impose almost no aerodynamic resistance. A further modification concerned the top of the turret, after the adjustment it was possible to retract into the fuselage and this was also completely eliminated its aerodynamic resistance. Another source of resistance was the side guns, it was quite large and because of that could the shooter to comfortably monitor the space around your half of the airplane, unfortunately, just the tonnage of these střelišť, however, that even brought a considerable air resistance. The designers therefore, this kapkovitá shooting range, located behind the trailing edge of the wings, removed and replaced them with flat, already nevystupujícími windows, whose central part can be pushed, this window was placed slightly below than the range of the original. This adjustment was introduced in the later produced seaplanes H8K2 12. This version is already in production didn't get, and it remained so only for these two specimens.

H8K4 Model 23
This version was created by a development of the engines Mitsubishi MK4T-B Kasei 25b (Ha-32-25) in both aircraft the previous version. New engines have better high-rise properties and only slightly lower power take-off. The test went well and was planned their mass production, but that did not happen, the end of the war these preparations interrupted. There was also a project in which it was calculated, that this version becomes the basis for the version of the transport indicated H8K4-L, however, there remained only in project.

Kawanishi H8K from the side - History

A Type 2 Flying Boat or Kawanishi H8K "Emily" is featured in this NARA photo. According to the caption dated 2, July 1944:
"Japanese "Emily" shot down by a PB4Y piloted by Lt. Stoughton Atwood of VB-115 somewhere in the Central Pacific."
It is a late Model 12 equipped with Type 3 Ku Mk.6 ASV radar as can be attested by the antennae on the nose. The radar was the first IJNAF type for large aircraft and could detect a ship from a height of 4,000m at a distance of 280km. Note that the fuselage side blister has been replaced by a window.

The particular flying boat belonged to the 851 Kokutai. Originally called "Toko Kokutai" from the Japanese reading of the Chinese name of it's base, Donggang in Taiwan, the unit changed it's designation to 851Ku on November 1, 1942 and was equipped with 16 Type 97 Flying Boats or Kawanishi H6K "Mavis". Initially deployed in Rabaul from where they night bombed the US base in the Espiritu Santo Island, the unit moved to the Shortland_Islands in the beginning of 1943. Returned to its home base in Taiwan to recuperate and then deployed to Surabaya in Jawa in April 1943 and stayed in the area until February 1944. During that time the unit performed patrol missions in the Indian Ocean and bombed targets in West Australia. By March 1943 the unit had changed all its flying boats to Kawanishi H8K "Emily".
On March 31, 1944 the most famous tragic event involving flying boats of the unit took place. Two "Emilies" were to transport Admiral Koga Mineichi who had succeeded Yamamoto Isoroku as Commander in Chief of the Combined Fleet, from Palau to Davao but they encountered a typhoon and the admiral's "Emily" was lost.
The unit eventually moved the Davao and on July 1944 to Singapore where it was dissolved with members and material distributed to the 801Ku and other units.
851Ku had the letter O for its marking from November 1942

1943 and then the numbers 51 or 851 from end of 1943


A favorite aircraft of mine and one of the best flying boats of WW2. And one might say that it's the grandfather of the Shinmeiwa US-1 and US-2. Interesting bit of history as well. (I wouldn't mind seeing more!)
Has anyone built the (very old) Hasegawa kit?

Thanks for showing this Emily!
I've seen this photo before but not in this excellent
quality. It's a beautiful plane.

One of the crews in my father's squadron, VPB-118, also managed to overtake and shoot down an Emily.
This occurred several months later than the encounter depicted.

Kawanishi H8K

The Kawanishi H8K was conceived as a replacement for the Japanese Navy venerable and obsolete H6K maritime reconnaissance and bombing platform. The H6K was the only standardized flying boat in operations when Japan attacked Pearl Harbor in December 1941. But it would be only a matter of time before a new, more powerful replacement took its place.

Just over a year after the 6K achieved operational status, the Japanese Navy began planning for its replacement. The requirements were simple enough. An increase of 50% in its original operational range coupled with a 30% increase in speed, would give the new aircraft a performance profile similar to that of the British Short Sunderland. It is remarkable that after only a ten month design and developmental stage, Japanese engineers were able to produce one of the finest military aircraft ever constructed.

Armed with up to five 0.78in cannons, four machine guns and well armed crew cabinets, the 8K was indeed a remarkable flying machine. The 8K first took to the air in the winter of 1940 and after several modifications made to the hull structure (initially the airplane?s narrow hull caused uncontrollable proposing in the water when lifting nose in the water?s surface) the aircraft went into production mode in the summer of 1941. A total of 175 8Ks were produce in three different variants. They were the original 8K1, the advance 8K2 with heavier armament and a new radar system, and the 3H8K2-L, which was a strictly transport version with two passenger decks.

The 8K made its combat debut on the night of March 4th 1942 when a formation of them attempted to bomb the island of Oahu, Hawaii. Bad weather over the target area disturbed the raid. Nevertheless, the complete voyaged proved the aircraft?s worth to the Navy.

Power Plant
Four Mitsubishi 1850hp Kasei radial engines

Wingspan 124 ft.
Length 92 ft.
Height 30 ft.
Total Wing Area 1722 sq ft.
Weight 40454 lb (empty)
71530 lb (fully loaded)
Operational Ceiling 28 740 ft.
Range 4460 miles
Climb Rate 1575 ft. per minute
Top Speed 290 mph

0.78in bow, dorsal and tail cannons fitted in powered turrets. Four 0.303in heavy machine guns located in cockpit, side and ventral hatches.

Kawanishi H8K Type 2 “Emily”

A H8K Emily of 851 Kokutai, moments before it was shot down by a US Navy PB4Y.

As soon as the Kawanishi H6K entered service, the Imperial Japanese Navy began the search for an improved flying boat to eventually supplant the Type 96. The 13-Shi specifications called for a new flying boat design with superior performance to the British Short Sunderland, which was then beginning to enter service with the RAF. The specifications included a desired range of 4,500 miles, with a maximum speed of 276mph. Firepower was also to be greatly improved over the H6K, with up to five 20mm cannon available for defence against enemy fighters.

The H8K featured a high, cantilevered wing as opposed to the H6K’s gondola arrangement. Four powerful Mitsubishi Kinsei engines could drive the big bomber along at over 275mph, much faster than the older aircraft. The H8K could carry two torpedoes or up to 1.000kg of bombs. The initial prototypes struggled with poor on-water characteristics, with spray being thrown up into the engines. Changes to the design of the hull, which was deepened and given ‘steps’, soon rectified this problem. Unlike most Japanese aircraft, the H8K had self-sealing fuel tanks and it also had a recovery system that pumped fuel leaking from damaged tanks out of the bilges and into undamaged fuel tanks. Production models also reduced the number of 20mm cannon from five to two, with additional 7.7mm machine guns substituted in their place.

The Type 2 entered service in spectacular fashion. The first combat operation for the big flying boat was ‘Operation K’, an attempt to bomb the repair works at the Pearl Harbor dockyards in March 1942. Two H8Ks set out from the Marshall Islands, refuelled from a submarine stationed in the French Frigate Shoals, and then headed for Oahu to drop their load of bombs. Bad weather meant that bombing results were very poor, but both planes made it safely back to base. The mission had covered 4,700 miles, an incredible feat regardless of the results.

Thereafter H8Ks were assigned to flying boat units to serve alongside the older H6Ks, which remained in service until the end of the war. They carried out long-range maritime patrol missions, and were occasionally used for bombing missions against distant targets – several were used to bomb towns in Western Australia during 1943 and 1944. Aerial encounters between H8Ks and long range American aircraft like the PBM and PB4Y were common, with many examples of air combat ensuing. With it’s rugged construction and heavy defensive armament, the H8K was considered one of the most formidable Japanese aircraft to meet in combat. Later models were fitted with air-to-surface radar for anti-submarine patrol, and claimed responsibility for sinking several U.S. submarines.

Kawanishi also developed a transport model, the H8K2-L, with extra seating internally – up to 64 troops could be carried. It was a H8K2-L that was carrying the commander of the Combined Fleet, Admiral Mineichi Koga, when it disappeared in March 1944. The aircraft had flown into a typhoon on a flight from the Palau Islands to Davao in the Philippines.

In 1942 the H8K was assigned the reporting name ‘Emily’ by Allied intelligence.

H8K2 "Emily"

In July 1938, Kawanishi Kokuki KK was awarded a contract to build a four-engine naval flying boat to replace the H6K in the Imperial Japanese Navy. The 13-C specifications attached to the order required higher data than those of the British Short Sunderland or the American Sikorsky HRV5-1: the maximum speed was set at 440 km / h, the cruising speed was 330 km / h, and the flight range was up to 8200 km.

Design work under the leadership of Shizuo Kikahara began in August 1938. As a result of blowing the models in a wind tunnel and towing in the experimental pool, a high-wing plane of pure forms appeared. To achieve a given flight range, the designers of Kawanishi installed eight relatively small wing unprotected tanks and six large tanks in the hull on the aircraft. The fuselage tanks were equipped with a neutral gas pressurization system and were partially sealed. Moreover, in the event of damage to the tank, the fuel leaking into the fuselage could be pumped into an undamaged tank. The total capacity of the fuel system reached 17,040 liters, fuel accounted for 29% of takeoff weight.

The crew had good armor protection. The defensive armament was to consist of three 20 mm Type 99 Model 1 cannons in the bow, upper and rear turrets, 7, 7 mm Type 92 machine guns in two side blisters, two side windows and in the lower installation.

The engines were chosen 1530-horsepower Mitsubishi MK4A Kasei 11 14-cylinder air-cooled stars. The first prototype H8K1 was ready on December 31, 1940. The first flight took place in January of the following year. During high-speed taxiing and on takeoff, the plane showed itself extremely unstable, and soon after raising the nose, fountains of spray began to pour in the propellers and rose above the wing. The experienced H8K1 was immediately returned to the factory. There, the contours of the lower fuselage were changed and another cheekbone was added, after which the aircraft was immediately returned for testing. Although handling on water was still worse than that of the H6K, overall it improved markedly, and other characteristics were much higher. At the end of 1941, after military trials, the fleet authorized the start of serial production of the aircraft under the designation Marine Type 2 Flying Boat, Model 11 H8K1.

By this time, two more pre-production boats with modified hulls were built and flown the second of them had an increased keel, which became a model for production vehicles. H8K1 Model 11 production aircraft were equipped with Mitsubishi MK4A Kasei 11 or MK4V Kasei 12 engines. The armament consisted of two 20 mm Type 99 Model 1 cannons, one each in the nose and tail turrets and four 7, 7 mm Type 92 machine guns. The aircraft could carry two 800 kg torpedoes or eight 250 kg bombs, as well as depth charges. The first combat sortie of the H8K1 took place on the night of March 5, 1942, when two aircraft from Kokutai Yokohama, having risen from Vautier Atoll (Marshall Islands), refueled from submarines and bombed Pearl Harbor. Since the weather was bad over Honolulu, the results were nil. Soon such raids had to be stopped due to the fact that the American fleet occupied the Frigate Shoals Islands, which were refueling from submarines. However, as an oceanic reconnaissance H8K1, the good protection of the crew, tanks and powerful weapons, combined with high speed, turned out to be very successful, allowing it to stand up for itself in battle with fighters.

The sufficiently high performance of the Model 11 was improved when the 1850-horsepower Mitsubishi MK4Q Kasei 22 engines equipped with a water injection system were installed on the H8K2 Model 12. The installation of Kasey 22 engines in modified nacelles was tested on an experimental H8K1. Improvement of flight characteristics made it possible to launch a model with Kasei 22 engines from the 17th aircraft. The keel was changed again. In all other respects, the aircraft did not differ from the H8K1. The high power of the engines made it possible to increase the takeoff weight from 31 to 32.5 tons, and the capacity of the fuel tanks to 18 880 liters. The armament was modeled on the first prototype aircraft, in addition, the 7, 7 m machine gun could be used through the side windows in the cockpit. Due to such powerful weapons and the highest speed among flying boats, this plane, in the opinion of allied pilots who collided with it, was the most difficult of all to shoot down. Gradually, the Type 2 Type 12 Flying Boat replaced the older Type 97, becoming the main long-range reconnaissance fleet. Some of the aircraft of the latest series received locators. The flying boat was used until the surrender of Japan.

'Emily' Specification
H6K5 H8K2
Crew 9 9
Wing span, m 40.00 38.00
Wing area, m² 170.00 160.00
Length, m 25.625 28.13
Height, m 6.27 9.15
4×PE (Mitsubishi Kinsey -51 or -52)/(Mitsubishi МК40 Kasey-22), hp 4 × 1300 4 × 1850
Weight, kg:
Empty weight 12380 18380
Loaded weight 17500 24500
Maximum takeoff weight 23000 32500
Maximum Speed, km/h 380 460
Cruise Speed , km/h 255 290
Maximum Rate of Climm, m/min 375 490
Service ceiling, m 9560 8850
Service range, km 4870 7050

Armament: three 20-mm type 99 model 1 cannons in the nose, upper and tail turrets (in the nose and tail turrets), 7.7-mm type 92 machine guns in the lower installation, in the side hatches and in the cockpit (in side blisters, lower and upper units) 2x 800 kg torpedoes or up to 2000 kg bombs

The first prototype aircraft, after using it as a prototype H8K2 with Kasey 22 engines, was converted into a transport version of the boat. The high fuselage made it possible to install two decks inside it. The lower deck ran from the bow to the rear step, and the upper deck ran from the wing to the tail. Accommodation was provided for 29 passengers or 64 soldiers. The armament was reduced to one 13 mm Type 2 machine gun in the forward turret and one 20 mm Type 99 Model 1 cannon in the stern. Installation of the lower deck required a re-arrangement of the fuel system: the fuel supply was reduced to 13,414 liters. After successful tests, the vehicle was transferred to the operational headquarters of the fleet in Yokosuka, where it was used as a liaison. The aircraft was put into production under the designation Marine Type 2 Seiku (Clear Sky) Transport Flying Boat or H8K2-B. A total of 36 H8K2-B were produced from 1943 to 1945, which were used in the transport units of the fleet.

Even at the beginning of work on the boat, it was planned to install removable stabilizing floats, but then this was abandoned to save weight. However, in 1943, an idea appeared to increase the speed of the H8K. Two experimental boats with Kasey 22 engines were equipped with retractable floats in 1944. They were actively tested. The armament of the new H8K3 was similar to that of the H8K2, but the side blisters were replaced by hatches later, a similar revision was made to the serial H8K2, and the upper turret became removable. In 1945, these two boats were re-equipped with engines of Mitsubishi MK4T-V Kassey 25b with a capacity of 1825 hp. The aircraft were renamed H8K4 Model 23. But neither this model nor its transport version H8K4-b Model 33 were launched into production: the fleet needed fighters and he instructed Kawanishi to focus on the production of N1K2-J Syden.

A total of 167 H8Ks were produced, much less than the English Sunderlands or the American Catalin, but the Japanese boat proved to be one of the most outstanding naval aircraft in the world throughout the war.

H8K1 : designation of three prototypes and 14 first production aircraft with MK4A engines.

H8K1-L : designation of the sample after converting it into a transport aircraft with an MK4Q engine.

H8K2 : variant with MK4Q engine, enhanced weaponry and surface target detection radar 112 vehicles were built under the designation Navy Type 2 Flying-Boat Model 12.

H8K2-L : a transport aircraft based on the H8K1-L model could accommodate from 29 to 64 passengers had less powerful weapons launched into production under the designation Navy Type 2 Transport Flying-Boat Seiku Model 32 (Seiku - clear sky) built 36 cars.

H8K3 : Designation of two prototypes with retractable stabilizing floats at the wing tips. The dorsal rifle tower acquired a cylindrical shape and became removable. This option did not go into production.

H8K4 : new designation of the prototype H8K3 after the installation of Mitsubishi MK4T-B Kasei 25b engines (Mitsubishi MK4T-B Kasei 25b) with a capacity of 1361 kW (1825 hp) was not put into production.

Kawanishi H8K (Emily)

The Empire of Japan wanted a flying boat superior than the United Kingdom’s sterling Short Sunderland and the American PBY. Their own contributions resulted in the form of the Kawanishi “H6K Mavis” and “H8K Emily” flying boats. Therefore, in 1938, a four engine powered reconnaissance design came into picture in the form of Kawanishi-H8K. Allied forces had nicknamed it “Emily”. The H8K1 prototype was first flown in January 1941, but the initial design proved to possess very poor water handling qualities.

After making a number of amendments and several service trials, the aircraft finally entered into production. The H8K had a stout fuselage and single vertical tail fin. The cockpit was located just forward of the shoulder-mounted wing assembly which housed 4 x Mitsubishi brand engines of 1,850 horsepower (H8K2). The original design had retractable floats and a dorsal turret. It was made in such a way that a single mission could last up to 24 hours. Appropriate armor provided shelter to the crew. The wings had a metal frame covering. The design had a slight dihedral for better stability. The fuel tanks were located in the hull and were self sealing with carbon dioxide fire suppression, a feature which earlier Japanese designs lacked.

Initial armament included 4 x 7.7mm machine guns and 2 x 20mm cannons. Later, H8K got equipped with 4 x 7.7mm and 5 x 20mm cannons. Adding to this, the improved armor protection, impressive speed and range and the ability to deliver torpedoes or bombs made H8K arguably the best flying boat of the Second World War. Its effectiveness in the anti-submarine role, finding and sinking several American submarines proved its point.

The H8K entered service in early 1942. The very first mission the Kawanishi H8K was used on was a bombing mission that started at Wake Island and bombed Pearl Harbor in 1942 which changed the course of the World War 2.

Kawanishi H8K2

Post by drmessimer » 24 Sep 2009, 17:31

Re: Kawanishi H8K2

Post by Takao » 24 Sep 2009, 19:27

Re: Kawanishi H8K2

Post by drmessimer » 24 Sep 2009, 20:12

Re: Kawanishi H8K2

Post by cstunts » 24 Sep 2009, 21:47

EMILY: Bigger, stronger, faster, it is said. The "other" Pearl Harbor attack is covered in the following book:
http://www.amazon.com/Second-Attack-Pea . 1591143888

Here's a good page with basic EMILY stuff: http://www.vectorsite.net/avemily.html

However, I would not hesitate to ask the fellows over at Combined Fleet's j-aircraft.com -- Many of whom are really the experts in such questions. They could also lead you to primary source docs in JACAR that I suspect would be of interest.

Re: Kawanishi H8K2

Post by drmessimer » 25 Sep 2009, 02:51

Re: Kawanishi H8K2

Post by Sewer King » 27 Sep 2009, 06:50

This too is in Francillon. EMILYs out of the Marshalls made the attempt on Oahu in March 1942 after refueling at French Frigate Shoals, but were foiled by cloud cover (I think they simply dumped their bombs and caused a nuisance at most). A second raid was meant to coincide with the Midway operation as a reconnaissance-in-force, but this time was foiled by the presence of a US seaplane tender at French Frigate Shoals.

Had one or both raids succeeded, they might well have raised the naval air history attention paid to the H8K and better confirmed the regard for it (even more). But their lack of success there had nothing to do with either the plane's capability or its operational use. For a flying boat it would have played a large enough part in a major battle like Midway, in an offensive role for which they had been purposely designed to meet.

    One might be that of the PBYs also at Midway, using torpedoes to which their crews were not accustomed. They holed a single Japanese oiler (Akebono Maru), but this was an improvisation that does not compare to the intended long-range attack role of a heavily-armed seaplane.

This is so, but seaplanes are slightly different in that they did not fight each other as did tanks or fighter planes. They did not play a great offensive role throughout the war on either side. It is largely that the H8K was the best designed for the attack role, even if it had few chances to actually demonstrate it and no real success.

The PBY had anti-submarine capability but not a particularly great record for it, yet still has its high regard too. Its recce contribution to victory at Midway, and its damage to a Zero in the Aleutians that allowed the US to recover it, were high points over the H8K in operational accomplishment. But these can't be attributed to the PBY's design.

  • Survivability is not simply the ability to beat off determined attackers. To a palpable extent It includes the ability to keep flying and return even after serious damage, as was legendary for the B-17 Flying Fortress. Just here we have neither the EMILY 's record for this, nor the opinion of US airmen who fought this type. Here too, there were a great many B-17s to replace the incredibly damaged ones that made it back to base. Not so for the H8Ks.
  • "Have 6 flyable transport versions of "Emily" available. If required, suggest either sending crews from United States of grant authority for use of Japanese crews to fly these aircraft across the Pacific." (!)

This last sums up the high technical regard for the EMILY besides that of its performance, outside of its operational record, and regardless of how many might have been lost in action.

It might be noteworthy that postwar Japan remained one of the last major operators of large flying boats such as her Shin Meiwa design. The other was the Soviet Union with her Berievs. Japan's maritime patrol needs continued well after her loss of a blue-water navy, indeed, maybe proportionally more so with her white-water defense force. The attention given this type by an aggressive naval power would not be lost upon the small defensive force that would succeed it.

Furthermore, flying boats have largely passed from the American public mind since World War II. If something of the H8K survived in postwar US Navy designs, that says enough for it by that much, even if the US no longer flies these types. Another analogy might be the German MG42 general-purpose machine gun, which survives in parts of the American M60 and NATO MAG machine guns as well as continued copy and adaptation of the MG42 itself. Most can easily appreciate the high regard for that weapon, without superlatives, or with small qualification.

I might not convince you of the H8K's "best" rating, but maybe some more of the reasons why others think so.

Re: Kawanishi H8K2

Post by Peter H » 27 Sep 2009, 09:12

36 Model 12s were built as troop transports in 1943.Could hold 64 troops,plus crew of 9.

Re: Kawanishi H8K2

Post by Peter H » 27 Sep 2009, 09:16

Re: Kawanishi H8K2

Post by Sewer King » 27 Sep 2009, 17:17

Thanks Peter, I haven't seen photos of the H8K's interior before although there well should be some around. Considering her long range and large capacity, I suspect this flying boat of having at least a simple sort of galley as well.

What was done with the last surviving H8K that was returned to Japan in 1979? Mikesh showed it in the mothballed condition in which it had been stored, but never taken up by American air museums. I imagine there is some small wealth of modern-day Japanese information and maybe photos of whatever has been done with the last EMILY .

Despite this extreme close-up I think it's a Kokusai Ki-59 light transport ( THERESA ). There were few other high-wing Army transport planes, and none other with what looks like the square-section nose shown here. The Army designated it the Type 1, but only 59 were built before it was replaced with the Tachikawa Ki-54c transport ( HICKORY ), also designated Type 1 but Model C. (Francillon, pages 145-147) Since the Ki-59 entered service in 1941, that dates the illustration from around then.

The escorts are Nakajima Ki-43 Hayabusa ( OSCAR ) of course, which as Army fighters would seem unlikely to escort a Navy flying boat. Not sure, but I think the H8Ks usually flew without escort.

One other mention about the survivability of the EMILY from Francillon, page 310:

Could it also be that the sheer volume of the plane made it hard to bring down, aside from its speed, defensive armament, and fuel protection? There is also the relative performance of the fighters attacking it at altitudes where the H8K could best defend itself with guns and speed.

Re: Kawanishi H8K2

Post by drmessimer » 27 Sep 2009, 17:27

Re: Kawanishi H8K2

Post by drmessimer » 27 Sep 2009, 17:28

Re: Kawanishi H8K2

Post by Mostlyharmless » 28 Sep 2009, 00:37

Re: Kawanishi H8K2

Post by Peter H » 28 Sep 2009, 09:39

Re: Kawanishi H8K2

Post by Peter H » 28 Sep 2009, 09:41

One's that didn't make. going down.

Re: Kawanishi H8K2

Post by Peter H » 28 Sep 2009, 09:55

Admiral Yamagata Seigo died in one in 1945.

The truth is, all officers on board managed to escape right before the explosion except one: Yamagata Seigo (山縣正), the Admiral of the Fourth Southern Expeditionary Fleet of the Japanese Imperial Navy, who was the last Japanese military officer who died in battle in China before the war ended.

On March 14, Admiral Yamagata had taken off aboard the Kawanishi H8K in Ambon, Indonesia, in the final days of the Pacific War. The Japanese position continued to deteriorate. The Fourth Southern Expeditionary Fleet, led by Admiral Yamagata and deployed in Indonesia, was forced to withdraw. Yamagata's plane flew through Singapore, Hong Kong, and Hainan Island of China. On March 17, it landed in Guangzhou, where Yamagata attended a military conference presided over by Tanaka Hisaichi (田中久一) , then commander-in-chief of Southern Expeditionary Army. The conference was viewed as the final death struggle of the empire.

Due to bad weather, the plane made an unsuccessful landing previously in Hainan Island that damaged the fuselage bottom. After taking off in Guangzhou before midday of March 17, it headed Taiwan for repair.

Officers on board were soon informed of the bombing in Taiwan by Allied Forces. The Kawanishi H8K then turned toward mainland China, hoping to land in Japanese-occupied territory, but soon ran into a series of troubles. The U.S. maritime patrol bomber PB4Y-1 detected the flying Kawanishi H8K, and targeted it. One naval officer in the plane was shot dead.

The Kawanishi H8K finally approached the coast of mainland China, but could only fly five minutes more on its remaining fuel. Yamagata ordered the plane landed in Zhenhai, a occupied harbor near Hangzhou Bay. It was this decision that make it the final flight of Yamagata. At around 4 p.m. local time, the plane landed mistakenly in Haimen, hundreds miles south of Zhenhai.

Geographically Haimen and Zhenhai are extremely alike. The two towns lie on the estuary of major rivers and an ancient tower stands on a hill of the north bank of the river in both place. It’s hard to distinguish the two cities by sight.

Yamagata committed suicide in the plane, using an extreme way of "stomach-cutting," known as "harakiri." This was according to archives released by Japanese authorities. Who knows the truth all Yamagata's secrets of have sunken with the flying boat.

To this day, the wreck of Kawanishi H8K, and the remains of Yamagata Seigo, along with the mystery of "the last admiral," have been buried under the silt for over six decades.


The H8K was developed in 1938/1939 and had its first flight in 1941. The prototype had several problems when landing on water, particularly stability and so it was modified until it finally was ready for service in 1942. Δ] The H8Ks first mission was carried out in 1942 and it was known as Operation K. Two H8Ks were to bomb Oahu, Hawaii, but due to bad weather, all the bombs missed their targets, only four actually hitting the island.

However, the attack did renew American fears of Japanese raids. During the war, H8Ks also served in the anti-submarine role and in fact sunk several US submarines. Ε] The H8K also engaged in reconnaissance missions and due to heavy armament, long range, and radar, the H8K is considered by many, the best flying boat of WWII.

Watch the video: Kawanishi H8K IJN Flying Boat upgrade Roblox Plane Crazy (December 2021).