Japan's Kawanishi H8K; Type 2 Flying Boat Model 11
Allied code name: Emily

Photos

Kawanishi H8K, "Emily" flying boat:	Kawanishi H8K, "Emily" flying boat:	Kawanishi H8K, "Emily" flying boat:	Kawanishi H8K, "Emily" flying boat:
Kawanishi H8K, "Emily" flying boat:	Kawanishi H8K, "Emily" flying boat: Mark Holloway
Kawanishi H8K, "Emily" flying boat:

Design

In 1938 a requirement was given for a four engine reconnaissance flying boat superior than the United Kingdom's Short Sunderland.^1,2 To many, the H8K was the best flying boat used in World War II.³

Specifications for the H8K called for an aircraft that could fly 5,000 miles at 210 mph and have a maximum speed of 280 mph.³

The original design had retractable floats and a dorsal turret.¹

A mission for the H8K could last up to 24 hours.²

Crew

The crew was protected by armor.¹

Wing

The wings were made from a metal frame and covering.¹ There was a slight dihedral for better stability on long flights.¹

There were eight small fuel tanks located in the wings.³

Fuel Tanks

There were six fuel tanks that were located in the hull and were self sealing with carbon dioxide fire supression.^1,2,3 The fuel was about 1/3 the total weight at takeoff.³

Prototype

In January 1941 the prototype first flew.^1,3
On December 31, 1940 the prototype first flew.²

The prototype had problems with handling on the water.^2,3 To correct these issues a second step in the hull was added and changes to the flaps were made.^2,3

Production

The first production H8K1 flew in August 1941.²

• Kawanishi H8K1: 14³, 17²
• Kawanishi H8K2: 112³, 120²
• Kawanishi H8K2-L: 36^2,3
• Kawanishi H8K3: 2²
• Total: 167^1,3, 175²
  • Manufacturer: Kawanishi Kokuki K.K.³
  • Production: 1941 - 1945³

Variants

• Kawanishi H8K ??: VIP transport version.¹ Could carry 29 passengers.¹
• Kawanishi H8K2-L Seika (Clear Sky): Transport version that could carry 64 passengers.^1,2,3 Had Mitsubishi MK4Q engines and not as many weapons.¹ The engines drove Hamilton propellars.¹
• Kawanishi H8K1: First production version.²
• Kawanishi H8K2: Used more powerful engines.² The armament was increased.² Starting in 1943 a few had ASV (air surface vessel) radar installed.²
• Kawanishi H8K3: Had additional armor protection.² The wing tip floats were retractable.²
• Kawanishi H8K4: Was the H8K3 modified by fitting Kasei 25b engines.²

Usage

The H8K entered service in early 1942.² The first mission was to have two H8K1s fly from the Marshall Islands and bomb Oahu on the night of March 4 to 5, 1942.³ Cloud cover prevented any good results but it did show the aircraft's potential.³

Allied fighter pilots proceeded with caution when attacking a H8K due to it's heavy armament.² As a result it was nicknamed the "flying porcupine."³

Pearl Harbor Bombed

The first mission the Kawanishi H8K was used on was a bombing mission that started at Wake Island and bombed Pearl Harbor in 1942 (March 4-5, 1942²).¹ The H8Ks had to refuel by rendezvousing with a submarine.²

Anit-Submarine

North of the Philippines, in 1945 three American submarines were sunk by radar equipped Kawanishi H8Ks.¹

Specifications

	Kawanishi H8K2	Kawanishi H8K12	Kawanishi H8K21,2,3	Kawanishi H8K2-L2
Type	Reconnaissance flying boat2		Flying boat1, Reconnaissance1,3
Crew	102		101,3
Engine (Type)		4: Mitsubishi MK4B Kasei 122	4: Mitsubishi Kasei 22 piston1 4: Mitsubishi MK4Q Kasei 222,3
Cylinders		Radial 142	Radial 141,3
Cooling			Air3
Net HP			1,850 each1,3
Propeller blades		4 each2	4 each1,2
Fuel capacity	4,250 gallons3
Dimensions
Span			124' 8"1,2,3 38 m1,2
Length			92' 3"1, 92' 4"2,3 28.13 m1, 28.14 m2
Height			30'1,2,3 9.14 m2, 9.15 m1
Wing area			1,141 ft2 1 106 m2 1
Weight
Empty		34,000 lb2 15,422 kg2	40,520 lb1, 40,521 lb2 18,360 kg1,2
Loaded		68,343 lb2 31,000 kg2	54,013 lb3, 71,650 lb1,2 32,500 kg1,2
Performance
Speed			290 mph1 467 kph1
Speed @ 16,400' / 5,000 m			290 mph2 467 kph2
Speed @ 16,405'			290 mph3
Cruising speed			185 mph2 298 kph2
Climb			1,575'/minute2 480 m/minute2
Climb to 13,120' / 4,000 m			8 minutes2
Service ceiling			28,740'1,2, 29,035'3 8,760 m1,2
Range			3,000 miles2, 4,445 miles3 4,828 km2
Maximum range			4,460 miles2, 4,461 miles1 7,777 km2, 7,180 km1
Armament			5: 20 mm3 5: MG3	1: 20 mm2 1: 12.7 mm MG2
Bow turret	1: 20 mm2		1: 20 mm1
Dorsal turret	1: 20 mm2		1: 20 mm1
Tail turret	1: 20 mm2		1: 20 mm1
Beams	2: 20 mm2		2: 20 mm1
Cockpit	1: 7.7 mm MG2
Beam hatches	2: 7.7 mm MG2		4: 7.7 mm MG1
Bombs	4,408 lb2 2,000 kg2		4,400 lb1,3 2,000 kg1
OR
Torpedoes	2: 1,764 lb2 2: 800 kg2		2: 1,760 lb1 2: 800 kg1