From,
http://www.strategyplanet.com/commandos/h8k2.html Official designation: Kawanishi H8K2
Allied code name designation: Emily
Type: long-range maritime reconnaissance flying-boat
Manufacturer: Kawanishi Kokuki K.K.
Production: 167
Engine: four Mitsubishi MK4Q Kasei 22 fourteen-cylinder air-cooled radial engines
Horsepower: 1,850 per engine
Crew: 10
Weight Empty (lbs): 40,521 (18,370 kg) Max Take-off Weight (lbs): 71,650 (32,500 kg)
Length: 92ft 4in (28.15 m) Height: 30ft (9.15 m)
Wingspan: 124ft 8in (38 m)
Fusalage Covering: N/A
Cruising Speed (mph): 184 mph (295 km/h) at 16,405
Maximum Speed (mph): 290 mph (465 km/h) at 16,405
Range (miles): 4,445 (6,440 km) Service Ceiling: 29,035 ft (8,760 m)
Armament: one 20-mm Type 99 Model 1 cannon in bow, dorsal and tail turrets
one 20-mm Type 99 Model 1 cannon in beam hatches
one 7.7-mm Type 92 machine-gun in nose, ventral, port and starboard positions
Racks under inner wings for: two 1,764 lb. (800 kg) or eight 550 lb. (250 kg) bombs
History: World War II was the great age of the military flying boat, producing famous aircraft such as the American PBY and the British Sunderland. The Japanese provided their own major contribution to the art in the form of the Kawanishi H8K Type 2 flying boat. The H8K flying boat was conceived in 1938 as a replacement for the Kawanishi H6K / Type 97 (later known as "Mavis" to the Allies), which represented an earlier generation of flying boat design. The Japanese Navy wanted a flying boat that was 30% faster, had 50% greater range, and better defensive capability. The result was a clean, high-wing monoplane design. It was designed for use as a reconnaisance aircraft, bomber, torpedo plane, or antisubmarine aircraft. The H8K was built by Kawanishi Kokuki Kabushiki Kaisha (The Kawanishi Aircraft Company Limited), 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.
The first prototype H8K1 made its maiden flight in Jan. 1941 and proved to be unstable on the water and prone to "porpoising". Many changes were made to improve its seaworthiness, including an 11% increase in the depth of the hull. The second and third prototypes (which used the same engine configuration) incorporated further hull improvements, and the third prototype was fitted with an enlarged vertical stabilizer. The engineers worked the bugs out, and the type was formally put into production in 1941 under the designation H8K1 Type 2 Model 11. The 18th H8K flying boat was built with uprated Kasei 22 engines, each offering 1,850 horsepower, and was given the new designation H8K2 Type 2 Model 12. The H8K2 added armor protection for fuel tanks as well as crew and a surface search radar system. The Allies gave the H8K the codename "Emily", in accordance with the doctrine that gave Japanese fighters male names and other types female names. However, the H8K's good armor protection and heavy defensive armament made it a nasty customer to tackle, and some Allied pilots called it the "flying porcupine".
Work had also been proceeding on a transport variant of the H8K. The first prototype was modified for this role and was fitted with the Kasei 22 engines, and was given the designation H9K1-L. It was followed by 36 similar H8K2-L transports, built between 1943 and 1945. The transport version was named "Seiku" ("Calm Sky"), and had accommodations for 29 to 64 passengers. Two experimental variants of the H8K were built as well, but not put into production. The H8K3 was a modified late-production H8K2 that featured retractable wingtip floats and a retractable dorsal turret. Two H8K3s were built. They were later reengined with more powerful Kasei 25b engines and redesignated H8K4. Production of the H8K declined in the last year of the war, as the Japanese material situation became increasingly desperate, and priority was given to the production of fighters for the defense of the home islands. The end of the war put a final stop to the manufacture of this impressive aircraft. A total of 167 H8Ks were completed in all.
Features: The Kawanishi H8K1 "Emily" flying boat is universally recognised as the finest flying boat of World War II. It possessed excellent flight performance for its class, and was remarkably seaworthy and was mostly used for bombing and reconnaissance purposes and sometimes transport. It was also well able to take punishment and dish it out in air combat, and as such was treated with respect by Allied fighter pilots. The prototype was originally intended to have retractable floats, but these were abandoned in favor of fixed floats to save weight before the prototype was completed on 31 December, 1940. This initial prototype was designated H8K1. It was powered by four 1,530 HP Mitsubishi MK4A Kasei ("Mars") 11 engines, a 14-cylinder radial design based on Pratt & Whitney technology. The plane was huge with a wingspan of almost 125 feet and a length of over 92 feet. Compare those dimensions and power plants to the British Short Sunderland flying boat and the Boeing B-17E Flying Fortress which had wingspans of almost 115 feet and over 103 feet respectively. Both of these were also powered by four 1,200 hp engines.
The 'Emily' was a high-wing aircraft with a deep, stepped fuselage; four radial engines were fitted in the wings and the aircraft had large, fixed stabilizing floats. The improved H8k2 had upgraded engines, fully protected fuel tanks, armor protection for the crew, and surface search RADAR. The H8K2-L Seiku (Clear Sky) was a transport variant that could be configured to carry up to sixty-four passengers. The experimental H8k3 variant had retractable wing-tip floats and a retractable dorsal gun turret.
Service Record: Given the Allied code name 'Emily', the plane made its first serious combat operational debut in an attack on Oahu, Hawaii, on the night of March 4-5, 1942 - the second attack on Pearl Harbor ( Operation K). The three H8K1s involved were based in the Marshall Islands, which were roughly 3,700 kilometers (2,000 nautical miles) from the island of Oahu. This was beyond the round-trip range even of the H8K1, and so the flying boats were refueled by submarine at a waypoint. However, on arrival at the target, the aircraft found it socked in with heavy clouds, and had to call off the attack.
The Kawanishi H8K1 was also responsible for three attacks on Townsville in Queensland Australia in late July 1942. On the night of 25/26 July two Kawanishis 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 Kawanishi 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 Kawanishis (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 place continued and was attacked by Bell P-38 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 Kawanishi made it safely back to base.
Additional info,
* Production: A total of 167 H8Ks were built by Kawanishi Kokuki K.K. in their Naruo and Konan plants as follows:
o 1 H8K1 prototype (Dec 1940)
o 2 H8K1 pre-production aircraft (1941)
o 14 H8K1 production aircraft (1941-42)
o 112 H8K2 production aircraft (1943-45)
o 2 H8K3 prototypes (1944)
o (2) H8K4 prototypes modified from H8K3 frames (1945)
o 36 H8K2-L production aircraft (1943-45)
