Country of origin:

Japan

Description:

Long-range maritime reconnaissance bomber flying boat

Power Plant:

Four 970 kw (1,300 hp) Mitsubishi Kinsei 53 fourteen-cylinder two-row air-cooled radial engines

Specifications:

History:

In 1934 the Imperial Japanese Navy issued specifications for a long-range flying boat, and Kawanishi appointed a design team headed by Shizuo Kikuttara. The prototype, the Kawanishi Type 97, powered by Nakajima Kikari 2 nine-cylinder radial engines, commenced flight testing on 14 July 1936. Some problems were experienced with hydrodynamics. The forward planing bottom step was extended and some changes were made to the tails. Two further prototypes were built with Mitsubishi Kinsei 43 engines. The type became known as the Navy Type 97 Flying Boat Model 1, or H6K1, and production commenced.

At the beginning of World War II 66 examples had been provided to the Japanese Navy and a number were sent to the south Pacific for tropical training. These aircraft regularly alighted and took-off from the open sea, refuelling from surface ships (tankers). Nocturnal operations were made around a number of the island groups. Photo reconnaissance missions were also conducted.

The type was also supplied to Dai-Nippon Airways to operate regular services in the south Pacific, a total of 18 being supplied. These were built as commercial aircraft with civil registrations, the cabin being fitted out to carry mail and freight, with a section to seat 18, toilet facilities and a galley, being known as the H6K2-L.

A total of 217 Type 97 flying-boats of all variants was built. One of these (J-BFOY – named ‘Sazabami’) was photographed by an officer of the Department of Civil Aviation (DCA) in Dili, East Timor on 19 January 1941, DCA at that time being involved in helping to establish an Aeradio Station to support Qantas operations in that area. The civil aircraft at the time was noted to be fitted with an armed tail turret.

First large scale production model was the H6K4, which had a fuel capacity of 13,409 litres (2,950 Imp gals), providing a range of 6,084 km (3,781 miles) and an endurance of almost 27 hours. The military version of the aircraft then became known to the Allies as the Mavis and the civil variant the Tillie.

On 11 December 1941 a flight of H6Ks attacked Wake Island. The Yokohama Kokutai (squadron) later that month moved to Rabaul, New Britain, after the Japanese occupation. On 3 February 1942 raids were mounted on Port Moresby, PNG.

In 1941 the H6K4 was replaced on the production line by the H6K5 with 970 kw (1,300 hp) Kinsei 51 engines. The H6Ks were then deployed to the Solomon Islands where, on 7 August, they were attacked by United States Navy shipboard aircraft, nearly all aircraft being sunk at their moorings.

In 1943, despite their age, a number of H6Ks were fitted with radar. However, attrition meant a lot of aircraft were withdrawn from service for use as transports and eventually the type was replaced by the Kawanishi H8K Emily.

Construction was of all-metal with fabric covered control surfaces. Normal crew was nine, but in the transport role this was reduced to eight, when it could carry passengers, or freight. Units to which the type was attached were the 8th, 14th and 801st Toko and Yokohama Kokutais. A total of 215 H6Ks was built by Kawanishi Kokuki KK at its Naruo facility.

The Mavis flying boat was extensively used by the Japanese forces in the south-west Pacific region during World War II, both in the reconnaissance bomber and transport role. At one stage an attempt was made in 1942 by units equipped with the H6K4 to bomb Hawaii, the aircraft, because of the range, being required to land at French Frigate Shoals to refuel.

Aircraft of this type were operated from New Guinea and the Netherlands East Indies. On 4 January 1942, at approximately 7 pm, eleven Kawanishi H6K4s bombed the airfield at Vunakanau at Rabaul, and two days later a further nine bombed the same target. Attempts were made to intercept them with Australian-built CAC Wirraways but without success.

On 9 January 1942 a No 6 Squadron Lockheed Hudson on a reconnaissance mission noted eight Kawanishi H6K4 flying boats in the harbour at Truk in the Caroline Islands. On 11 June a No 32 Squadron Lockheed Hudson (A16-157) based at Horn Island, flown by F/O L Halliday, shot down a Mavis south of New Britain.

A bombing mission was made on 25/26 June at 11.35 pm against Townsville, QLD by three Mavis flying boats but the city sustained little damage, the aircraft dropping six bombs in the harbour, all falling into the sea some distance from the wharf area. Searchlights located the aircraft but there was no fighter interception.

On 26 June at 2.25 am a Mavis dropped eight bombs in the foothills of the Many Peaks Range, north Queensland, drawing fire from anti-aircraft guns. Six Bell P-39 Aircobras attempted an interception. On 29 June at 2.27 am a Mavis dropped seven bombs, six into the harbour and the seventh on the racecourse, causing some broken windows. Again four P-39s attempted an interception and one got close enough to fire its guns but the flying boat escaped. On 31 June Mossman on the tablelands west of Cairns, QLD was attacked by a Mavis, on this occasion a single bomb being dropped, injuring a child, this being the first civilian air-raid casualty on Australia’s east coast in World War II.

On 15 February 1942 a Mavis was shot down by Lt Robert Buel of the United States Army Air Force (USAAF) whilst it was shadowing a convoy which included the United States Navy (USN) Cruiser ‘USS Houston’. The crew of five was later captured by Tiwi Islanders when they got to Melville Island in the aircraft dinghy but Buel was also shot down by the Mavis.

There are no complete survivors of the type but the wrecks of three lie in the Fiji islands in a channel off Korovou, north of Magusai, and are regularly inspected by divers, these aircraft remaining where they were sunk. Another was sunk in shallow water near Rabaul on the New Britain north coast.