Kawanishi Kokuki Kabushiki Kaisha (The Kawanishi Aircraft Company Limited) was established in November 1928 with its factory being located at Naruo Mukogun Hyogoken near Kobe. During the war it built four types of sea planes, two very large planes and two small fighters. It also built a land based derivative of one of the fighters.
Before World War II, Kawanishi had an association with Short Brothers of Belfast (builders of magnificient flying boats like the Sunderland/
Sandringham) but their first large flying boat, the
H6K Mavis was based more on the Sikorsky S.42. In 1938 the Imperial Japanese Navy issued specifications for a new flying boat that was 30% faster and with a 50% greater range than the Mavis.
As a result, Kawanishi came up with a proposal for the H8K Emily flying boat. It was reported as being the single biggest leap in flying boat design and other manufacturers did not catch up to the design till after the war was over.
The prototype H8K1 made its maiden flight in January 1941. However, there were some problems with the hull porpoising as it ran over the water (that is, jumping up and down). Modifications were made and after two pre-production craft, the new plane went into production in August 1941. A total of 14 H8K1 were produced during 1941 to 1942. (Note: The Japanese designation H8K1 means H=Flying Boat, 8=8th in the flying boat series, K=Kawanishi and 1=model. The "Emily" name was the English name given to the plane. All Japanese planes were named by the Allies, eg the Zero was actually called Zeke by the Allies but the Japanese name is about the only one used commonly.
he Kawanishi H8K Emily flying boat is now universally recognised as the finest flying boat of World War II. The Japanese designation was Type 2 Flying-boat, Model 12. The plane was huge, with a wingspan of almost 125 feet and a length of over 92 feet. The Emily was an all aluminium high-wing aircraft with a deep fuselage. It had four engines and the plane was stablised on water by two large, fixed stabilising floats.
The production Kawanishi H8K1 was powered by four 1,530 hp Mitsubishi Kasei 12 14 cylinder radial engines driving a four bladed Hamiliton type constant speed prop. Maximum speed was 433 km/h with a cruising speed of 296 km/h. Service ceiling was 8,540 metres (28,000 feet) and it had a range of either 4,800 km, 6,257 km or 7,200 km (I have seen all these figures). It had a maximum take off weight of 30,870 kg (although I have read 24,500 kg). Normal crew was ten. There were 14 or 17 H8K1 built.
The next version was the H8K2 and this was powered by four 1,850 hp Mitsubishi MK4Q Kasei 22 14 cylinder radial engines Maximum speed was 466 km/h with a cruising speed of 296 km/h. There were 114 built from 1943 to 1945. Two H8K3 prototypes were built in 1944 (similar to H8K2) and two H8K4 prototypes modified from H8K3 frames in 1945. There were also 36 H8K2-L transports built from 1943 to 1945. They carried up to 64 passengers. Only a total of 165 or 167 Emilys were built.
The Emily was nicknamed "The Flying Porcupine" due to its heavy armament of five 20 mm guns and four 7.7 mm guns. The H8K2 had a bow turret with a single 20 mm type 99 model 1 cannon, a dorsel turret also with a single 20 mm type 99 model 1 cannon and a tail turret again with a single 20 mm type 99 model 1 cannon. In the cockpit hatch there was a single 7.7 mm machine gun and each side hatch had a single 7.7 mm machine gun. There was another single 7.7 mm machine gun in the ventral hatch. Finally, there were single 20 mm type 99 model 1 cannons in beam blisters. Offensive weapons, carried under the wings, consisted of either two 1,764 lb aerial torpedoes or eight 551 lb bombs or depth charges.
The Emily was mostly used for bombing and reconnaissance purposes and sometimes transport. This plane was much larger and powerful than such famous planes as the British Short Sunderland flying boat (similar to the
Qantas Sandringham in Port Vila Harbour) and the
Boeing B-17E Flying Fortress (north-west of Honiara) which had wingspans of almost 115 feet and over 103 feet respectively and take off weights of 26,332 kg and 27,240 kg. Both were powered by four 1,200 hp engines.
The plane is believed to have had its first combat outing during an attack on Oahu, Hawaii, on the night of March 4-5, 1942. This was the second attack on Pearl Harbor. In late July 1942 Kawanishi H8K1 Emilys were responsible for three attacks on Townsville in Queensland. On the night of 25/26 July two Emilys bombed Townsville port but the bombs fell wide of the mark and landed on mudflats. The planes, W-45 and W-46, were not intercepted and no anti-aircraft guns fired on them. On 27 July one Emily was attacked a it flew over Townsville and it dropped seven of its eight bombs on the Many Peaks Range. This aircraft was W-46.
The third and last raid was on the night of 27-28 July when two Emilys (W-37 and W-47) left their base (I am not sure where this was yet) but W-37 had engine problems and turned around. The remaining plane continued and was attacked by Bell P-39 Aerocobras between Magnetic Island and the mainland. The Japanese plane dropped its bombs and they hit the mud below (one remained in the plane). During the attack by two Aerocobras, the bomb fell out of the bomb bay and hit the ground destroying a palm tree. Cannon fire from the fighters exploded in the rear gunner's compartment. The planes continued their attack until they ran out of ammunition. The Emily made it safely back to base.