Warplanes of Japan: Kawanishi HK6

Kawanishi HK6

(IJNAF Photo)

Kawanishi H6K Type 97 seaplane.

The Kawanishi H6K was an Imperial JapaneseNavy flying boat produced by the Kawanishi Aircraft Company and used duringSecond World War for maritime patrol duties. The Allied reporting name for thetype was Mavis; the Navy designation was "Type 97 Large Flying Boat"(九七式大型飛行艇). Developed in the 1930s, it was used for reconnaissance,transport, bombing, naval warfare, and executive transport by the ImperialJapanese Navy. The national airline also used it as commercial airliner. TheBritish mistakenly identified this aircraft as the Kawanishi Navy 97 Mavis.

The aircraft was designed in response to a Navy requirement of 1934 for along-range flying boat and incorporated knowledge gleaned by a Kawanishi teamthat visited the Short Brothers factory in the UK, at that time one of theworld's leading producers of flying boats, and from building the Kawanishi H3K,a license-built, enlarged version of the Short Rangoon. The "Type S",as Kawanishi called it, was a large, four-engined monoplane with twin tails,and a hull suspended beneath the parasol wing by a network of struts. Threeprototypes were constructed, each one making gradual refinements to themachine's handling both in the water and in the air, and finally fitting morepowerful engines. The first of these flew on 14 July 1936 and was originallydesignated "Navy Type 97 Flying Boat", later H6K. Eventually, 217were built.

Four prototypes were produced leading to the production version, with ten H6K2built, then 124 H6K4 were produced which had better fuel capacity. All H6K werepowered by 4 radial piston engines of different types. Some aircraft wereupgraded with the 1000 hp Kinsei 46, and the H6K5 had the 1300 hp Kinsei 51/53.

The H6K prototype was powered by four 9-cylinder Nakajima Hikari 2 with 840 hp.

Additionally production:

Sixteen H6K2-L unarmed transports
Two (2) H6K4-L VIP transports
Twenty (20) H6K4-L unarmed transports with the Kinsei 46 engines
Thirty-six H6K5s with Kinsei 51/53
Sixteen (16) aircraft were civilian air transports operated by Dai-NipponAirways (the Imperial Japanese National airline), with on board toilet, galley,and room for 18 passengers. They had civil registration and were used for mailand passenger service to the Pacific.

Combat H6K were armed with various combinations of Type 92 machine guns, and itcould also carry two torpedoes or 1000kg of bombs.

H6Ks were deployed from 1938 onwards, first seeing service in the Sino-JapaneseWar and were in widespread use when the Pacific War began in December 1941. Atthe start of the war, four Kōkūtai (naval air groups) operated a total of 66H6K4s. Also, 16 were used by the Imperial Japanese airline for mail andpassenger service to the Pacific.

On 12 December 1941, during the Battle of Wake Island, an H6K bombed Wakeisland, but was shot down by an F4F Wildcat.

On 15 February 1942, a P-40 Warhawk intercepted an H6K about 190 km west ofDarwin, Australia, which had attacked Allied shipping; both the P-40 and H6Kwere shot down.

The type had some success over southeast Asia and the southwest Pacific. H6Kshad excellent endurance, flying up to 24-hour patrols, and were often used forlong-range reconnaissance and bombing missions. From bases in the Dutch EastIndies, they could fly over a large portion of Australia.

However, the H6K became vulnerable to a newer generation of more heavily armedand faster fighter aircraft. In front-line service, it was replaced by theKawanishi H8K. It continued in service throughout the war, but in areas wherethe risk of interception was low.

Variants

An H6K2-L Navy transport flying boat Type 97
H6K-3
H6K1
Evaluation prototypes with four Nakajima Hikari 2 engines, four built.
H6K1 (navy flying boat Type 97 Model 1)
Prototypes with 746 kW (1,000 hp) Mitsubishi Kinsei 43 engines, three convertedfrom the original H6K1 prototypes
H6K2 Model 11
First production model. Includes two H6K2-L officer transport modification, 10built.
H6K2-L (navy transport flying boat Type 97)
Unarmed transport version of H6K2 powered by Mitsubishi Kinsei 43 engines, 16built
H6K3 Model 21
Modified transport version of H6K2 for VIPs and high-ranking officers, 2 built
H6K4 Model 22
Major production version, modified H6K2 with revised weapons, some with 694 kW(930 hp) Mitsubishi Kinsei 46 engines. Fuel capacity increased from 7,764 L(1,708 Imp gal) to 13,410 L (2,950 Imp gal). Includes two H6K4-L transportversions, 100 to 127 (if other numbers are all correct) built.
H6K4-L
Transport version of H6K4, similar to H6K2-L, but with Mitsubishi Kinsei 46engines, 20 built and another two converted from the H6K4
H6K5 Model 23
Fitted with 969 kW (1,300 hp) Mitsubishi Kinsei 51 or 53 engines and new upperturret replacing the open position, 36 built. (Wikipedia)

(USAAF Photo)

Kawanishi H6K Type 97 seaplane, code-named Mavis wearing green cross surrender markings.

(SDASM Archives Photo)

Kawanishi H6K on fire as it is being shot down.

(RAF Photo)

Mechanics of 3219 Servicing Commando, Royal Air Force, check the engines of a Japanese Kawanishi H6K 'Mavis' flying boat at Sourabaya (Soerabaja), Java, in preparation for an air test flight. Of interest are the markings added by Indonesian nationalists and the fact that an additional band of blue has been added to the fuselage marking by the Dutch.