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Kawanishi H6K (Mavis)

Maritime Reconnaissance Flying Boat Aircraft

Kawanishi H6K (Mavis)

Maritime Reconnaissance Flying Boat Aircraft


The Kawanishi H6K series was really the only viable long-range flying boat in service with the Empire of Japan when the nation went to war in 1941.
National Flag Graphic
ORIGIN: Imperial Japan
YEAR: 1938
MANUFACTURER(S): Kawanishi - Imperial Japan
OPERATORS: Imperial Japan; Indonesia

Unless otherwise noted the presented statistics below pertain to the Kawanishi H6K (Mavis) model. Common measurements, and their respective conversions, are shown when possible.
LENGTH: 84.09 feet (25.63 meters)
WIDTH: 131.23 feet (40 meters)
HEIGHT: 20.57 feet (6.27 meters)
WEIGHT (EMPTY): 27,293 pounds (12,380 kilograms)
WEIGHT (MTOW): 50,706 pounds (23,000 kilograms)
ENGINE: 4 x Mitsubishi Kinsei 53 14-cylinder air-cooled radial engines developing 1,300 horsepower each.
SPEED (MAX): 239 miles-per-hour (385 kilometers-per-hour; 208 knots)
RANGE: 4,210 miles (6,775 kilometers; 3,658 nautical miles)
CEILING: 31,496 feet (9,600 meters; 5.97 miles)
RATE-OF-CLIMB: 1,215 feet-per-minute (370 meters-per-minute)


1 x 7.7mm machine gun in bow position
1 x 7.7mm machine gun in dorsal position
1 x 7.7mm machine gun in left fuselage position
1 x 7.7mm machine gun in right fuselage position
1 x 20mm cannon in tail position

Up to 4,409 lb (2,000 kg) of bombs OR 2 x 1,764 lb torpedoes.

Series Model Variants
• Navy Type 97 Flying Boat - Initial Production Designation.
• H6K1 - Initial Production Evaluation Models; four produced; fitted with 4 x Nakajima Hikari 2 type engines.
• H6K1 (Navy Flying Boat Type 97 Model 1) - Follow-up prototype model but fitted with Mitsubishi Kinsei 43 type engines; 3 produced.
• H6K2 Model 11 - Initial Production Model; 10 produced.
• H6K2-L (Navy Transport Flying Boat Type 97) - Based on the H6K2 model but powered with Mitsubishi Kinsei 43 engines; sans armament; 16 produced.
• H6K3 Model 21 - VIP Transport Conversion Model based on the H6K2; only 2 produced.
• H6K4 Model 22 - Full-Scale Production Version; fitted with 4 x Mitsubishi Kinsei 43 radial engines of 930 horsepower; 10 produced; increased fuel capacity; revised defensive armament; capability for torpedo and bomb load out as needed.
• H6K4-L - Dedicated transport model of the H6K2-L; fitted with Mitsubishi Kinsei 46 series engines; 20 produced; seating for 18 troops.
• H6K5 Model 23 - Fitted with Mitsubishi 51 OR 53 series engines of 1,300 horsepower; open dorsal gun position replaced by enclosed turret; 36 produced.


Detailing the development and operational history of the Kawanishi H6K (Mavis) Maritime Reconnaissance Flying Boat Aircraft.  Entry last updated on 5/22/2016. Authored by Staff Writer. Content ©
Though looking very much the part of a German-produced Dornier series flying boat, the Kawanishi brand H6K series (codenamed "Mavis" by the Allies) had more in common with Western flying boat designs if anything. Interestingly enough, when one considers the Empire of Japan as the island nation that it is, it becomes astounding to think that the H6K was really the only viable reconnaissance flying boat in service with any long-range capabilities with the Empire at the time of the attack on Pearl Harbor. In practice, the H6K was a serviceable breed of flying boat with impressive endurance and adequate offensive capabilities but the type shown similar drawbacks of other aircraft models of Japanese design - namely poor armoring and no self-sealing fuel tanks.

Design-wise, the aircraft was of a sleek design. All four engines (of types that varied throughout the course of development and the war itself) were mounted high atop the wing assembly which sat on the fuselage via struts. Pontoons adorned either wing for water-based operations and the boat-like hull could clearly be distinguished. The fuselage was long and slender ending in a twin vertical tail design. Accommodations amounted to 9 personnel and positions included defensive armament consisting of 4 x 7.7mm machines found in the open bow, dorsal and two beam blister positions. A 20mm cannon turret was seated at the extreme rear of the aircraft. Offensive armament could amount to over 4,400 pounds of ordnance or 2 x 1,764 pound torpedoes for anti-shipping duty.

The H6K1 was the initial service model to enter production but this service was limited in 1938. The first major production model series became the H6K2 and that was followed by the solid addition of the H6K4 which sported 4 x Mitsubishi Kinsei 43 radial engines (later production models featured the Kinsei 46) and improved defensive armament. Dedicated transport derivatives were designated by an "L" and were spawned from the H6K2 and the H6K4 models. As these models went to war, it was found that they were highly susceptible to enemy fire and as such the H6K5 series was developed.

The H6K5 featured self-sealing fuel tanks and better armor protection for the crew and systems alike. Additionally, the open bow gun position was altogether removed in favor of a covered dorsal machine gun turret above the cockpit flight deck. Despite these improvements, the H6K was never really up to the demanding and changing tasks of the Pacific War and thusly production of this model was limited.

As the production line evolved and progressed during war time, the H6K "Mavis" also took on the codename of "Tillie" for the Allies to represent the dedicated transport derivatives of the H6K series. Some 215 total H6K's were produced by and for Kawanishi. Japan ceased operation of the type in 1945 whilst Indonesia gave up operations in 1948. The H6K was replaced in production by the more capable Kawanishi brand H8K series of flying boat, detailed elsewhere on this site.


Our Data Modules allow for quick visual reference when comparing a single entry against contemporary designs. Areas covered include general ratings, speed assessments, and relative ranges based on distances between major cities.

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Relative Maximum Speed Rating
Hi: 300mph
Lo: 150mph
    This entry's maximum listed speed (239mph).

    Graph average of 225 miles-per-hour.
City-to-City Ranges
Graph showcases the Kawanishi H6K5 (Mavis)'s operational range (on internal fuel) when compared to distances between major cities.
Aviation Era
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Pie graph section
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Pie graph section
Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units

  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.

Altitude Visualization
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Supported Roles
Ground Attack
Aerial Tanker
A2A=Air-to-Air; UAV=Unmanned; CAS=Close Support; ASW=Anti-Submarine; AEW=Airborne Early Warning; MEDEVAC=Medical Evac; EW=Electronic Warfare; SAR=Search-Rescue