(Scanned from "Koku Fan
Magazine" - Drawing by Kazuaki Koizumi)
TECHNICAL DATA
Description: Four-engined long-range maritime
reconnaissance flying-boat (H8K1 to H8K4) or transport
flying-boat (H8K2-L). All-metal construction.
Accommodation: Crew of ten (H8K1 to H8K4).
Crew of nine and 29 passengers or 64 troops (H8K2-L).
Powerplant:
Four Mitsubishi MK4A Kasei 11
fourteen-cylinder air-cooled radials, rated at
1,530 hp for take-off, 1,410 hp at 2,000 m and
1,340 hp at 4,000 m, driving four-blade metal
propellers (13-Shi prototype and early production
H8K1s).
Four Mitsubishi MK4B Kasei 12
fourteen-cylinder air-cooled radials, rated at
1,530 hp for take-off, 1,480 hp at 2,000 m and
1,380 hp at 4,000 m, driving four-blade metal
propellers (late production H8K1s).
Four Mitsubishi MK4Q Kasei 22
fourteen-cylinder air-cooled radials, rated at
1,850 hp for take-off, 1,680 hp at 2,100 m and
1,540 hp at 5,500 m, driving four-blade metal
propellers (H8K2, H8K2-L and H8K3).
Four Mitsubishi MK4T-B Kasei 25b
fourteen-cylinder air-cooled radials, rated at
1,825 hp for take-off, driving four-blade metal
propellers (H8K4).
Armament:
20 mm Type 99 Model 1 cannon in bow, dorsal
and tail turrets and two beam blisters, and 7.7
mm Type 92 machine-guns in ventral, port and
starboard hatches (13-Shi prototype).
20 mm Type 99 Model 1 cannon in dorsal and
tail turrets, and 7.7 mm Type 92 machine-guns in
two beam blisters, ventral and cockpit hatches
and bow turret (production H8K1s).
20 mm Type 99 Model 1 cannon in bow, dorsal
and tail turrets and two beam hatches, and 7.7 mm
Type 92 machine-guns in ventral, port and
starboard fuselage sides and cockpit hatches
(H8K2, H8K3 and H8K4).
External load: two 800 kg torpedoes, or eight
250 kg bombs, or sixteen 60 kg bombs or
depth-charges (H8K1 to H8K4).
H8K1
H8K2
H8K3
H8K2-L
Dimensions:
Span
124 ft
124 ft
124 ft
124 ft
Length
92 ft
92 ft
92 ft
92 ft
Height
30 ft
39 ft
30 ft
30 ft
Wing area
1722 ft2
1722 ft2
1722 ft2
1722 ft2
Weights:
Empty
34,176 lb
34,176 lb
40,939 lb
37,258 lb
Loaded
54,013 lb
54,013 lb
54,013 lb
58,825 lb
Maximum
68,343 lb
68,343 lb
68,343 lb
66,138 lb
Wing loading
153.1 kg/m2
153.1 kg/m2
153.1 kg/m2
166.8 kg/m2
Power loading
4.0 kg/hp
3.3 kg/hp
3.3 kg/hp
3.6 kg/hp
Performance:
Maximum speed
234 kt at 5,000 m
252 kt at 5,000 m
-
227 kt at 4,000 m
Cruising speed
160 kt at 4,000 m
160 kt at 4,000 m
-
160 kt at 4,000 m
Climb to
16, 400 ft
16, 400 ft
-
13,123 ft
in
14 min 33 sec
10 min 12 sec
-
10 min 37 sec
Service ceiling
25,032 ft
29,035 ft
-
-
Maximum range
3,888 naut miles
3,862 naut miles
-
2,397 naut miles
Production: A total of 167 H8Ks were
built by Kawanishi Kokuki K.K. in their Naruo and Konan
plants as follows:
1 H8K1 prototype (Dec 1940)
2 H8K1 pre-production aircraft (1941)
14 H8K1 production aircraft (1941-42)
112 H8K2 production aircraft (1943-45)
2 H8K3 prototypes (1944)
(2) H8K4 prototypes modified from H8K3 frames
(1945)
