244:('heavenly mountain') carrier based torpedo bomber aircraft. The Navy requested this aircraft based on the Kasei, but Nakajima's Kenichi Matsumara insisted on using their Mamoru. The B6N first flew on 14 March 1941, demonstrating several problems, notably the poor engine reliability. With the delay of 2 years, by 1943 the engine had improved to the point where serial production was allowed to start, but after only 133 B6N1s had been delivered the Navy ordered the switch to the 1,850 hp (1380 kW) Mitsubishi MK4T Kasei 25. The rest of the 1,268 B6N2s were Kasei powered.
29:
228:
as Japan's first four-engine bomber and proved to be a disappointment. These problems were compounded by the unreliability of the early Mamoru engines, which had to be de-tuned and left the G5N1 underpowered. The G5N1's maiden flight was on 10 April 1941, and a further four prototypes were built with
233:
engines and redesignated G5N2s. Although the
Mitsubishi engines were more reliable than the original Mamoru 11s, further development was halted. Of the six completed Shinzans, four of them (two G5N2s and two G5N1s re-engined with the Kasei 12) were relegated for use as long-range Navy transports
216:
The Mamoru was
Nakajima's seventh air-cooled design, which led to its designation: N for Nakajima, K for air-cooled, 7 for the 7th design, and A for the major model number. Two sub-models were built with minor changes, the Model 11 for the Navy, and the Model 12 for the Army. Both produced
181:
At some 44.9 litres (2,740 in) displacement, it was one of the largest-displacement 14-cylinder radial engines in the world, rivalling the similar configuration
American 42.7 litre (2,600 in)
200:
engine, the Mamoru proved to be unreliable and was rarely able to operate near its design power. Designs based on the Mamoru were forced to use other engines, typically the less powerful
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engine was a 14-cylinder, air-cooled, two-row radial engine of 1870 hp. The
Nakajima model designation for this engine was
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the Mamoru. In an attempt to salvage the project, two additional airframes were fitted with 1,530 hp
Mitsubishi MK4B 12
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665:
558:
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508:
Francillon, Ph.D., René J. Japanese
Aircraft of the Pacific War. London: Putnam & Company, 2nd edition 1979.
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208:. Production of the Mamoru was ended by the Navy after only a few hundred production examples were built.
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engine of displacement levels, and was meant to compete with early 18-cyl engines, like the 53.6 L
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by the Army and "Mamori" or "Mamoru" by the Navy. According to unified designation code it was
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1,600 horsepower (1,200 kW), 2,500 rpm at 4,900 metres (16,100 ft)
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1,750 horsepower (1,300 kW), 2,500 rpm at 1,400 metres (4,600 ft)
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takeoff: 1,870 hp at 2,600 rpm, cruise: 1,750 hp at 2,500 rpm at 1,400 m
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The first application of the Mamoru was on the first prototype of the
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while it was an experimental project, in service it was known as the
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Pushrod operated overhead-valve system with 4 valves per cylinder
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14-cylinder supercharged, air-cooled two-row radial piston engine
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under the designation
Shinzan-Kai Model 12 Transport G5N2-L.
170:. The meanings of these two Japanese words are very similar,
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4 X 1,870 hp (1395 kW) Nakajima NK7A Mamoru 11
256:
1,870 horsepower (1,390 kW) at 2,600 rpm (take-off)
279:
1 X 1,870 hp (1395 kW) Nakajima NK7A Mamoru 11
178:, translates as 'to guard, protect, defend and obey'.
302:Specifications (Nakajima NK7A Mamoru type 11, 12)
224:. The G5N1 had been designed on the basis of the
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520:Goodwin, Mike & Starkings, Peter (2017).
297:(prototype) 2 X 1,870 hp Nakajima Ha-103
185:engine, of Soviet 41.2 litre (2,515 in)
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865:Aircraft air-cooled radial piston engines
237:The Nakajima Mamoru was also used on the
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16:1940s Japanese piston aircraft engine
13:
666:Imperial Japanese Army Air Service
390:Two-speed single stage centrifugal
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291:2 X 1,870 hp Nakajima Ha-103
196:Competing against the successful
524:. Sandomierz, Poland: MMPBooks.
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522:Japanese Aero-Engines 1910-1945
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174:translates as 'protection' and
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36:Nakajima Mamoru engine at the
1:
860:1940s aircraft piston engines
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38:National Air and Space Museum
365:870-903 kg (1,918-1,991 lb.)
7:
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453:Pratt & Whitney R-2800
183:Wright R-2600 Twin Cyclone
855:Nakajima aircraft engines
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61:Nakajima Aircraft Company
35:
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668:aero engine designations
494:translated at eudict.com
480:
470:List of aircraft engines
315:General characteristics
126:Ha-107, Ha-117, Ha-217
212:Design and development
350:44.9 L (2,740 cu in)
222:Nakajima G5N1 Genzan
356:1,380 mm (54.3 in.)
162:, and known as the
437:Comparable engines
84:Major applications
842:
841:
632:
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531:978-83-65281-32-6
423:Compression ratio
310:Francillon p. 433
191:Bristol Centaurus
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578:aircraft engines
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448:Mitsubishi Kasei
341:170 mm (6.7 in.)
332:155 mm (6.1 in.)
295:Mitsubishi Ki-67
263:Mamoru 12 Ha-103
202:Mitsubishi Kasei
198:Mitsubishi Kasei
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206:Nakajima Homare
187:Shvetsov ASh-82
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115:Nakajima Hikari
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70:Kiyoshi Tanaka
51:aircraft engine
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217:1,850 hp
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609:Ha-103 Mamoru
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514:0-370-30251-6
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464:Related lists
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458:Wright R-2600
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57:Manufacturer
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619:Ha-45 Homare
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503:Bibliography
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386:Supercharger
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346:Displacement
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283:Nakajima G5N
277:Nakajima B6N
271:Applications
241:
239:Nakajima B6N
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100:Number built
93:Nakajima B6N
89:Nakajima G5N
604:Ha-8 Hikari
410:Performance
849:Categories
476:References
396:Air-cooled
377:Valvetrain
370:Components
361:Dry weight
75:First run
354:Diameter:
307:Data from
134:Nakajima
67:Designer
575:Nakajima
516:. pg 425
432:See also
248:Variants
149:Preserve
756:101-200
443:BMW 801
266:As NK7A
204:or the
22:Mamoru
834:Ha-505
829:Ha-217
824:Ha-214
819:Ha-211
814:Ha-201
798:Ha-140
793:Ha-115
788:Ha-112
783:Ha-105
778:Ha-104
773:Ha-103
768:Ha-102
763:Ha-101
735:51-100
624:Ha-219
528:
512:
337:Stroke
242:Tenzan
176:Mamoru
172:Mamori
164:Ha-103
136:Mamoru
48:Piston
747:Ha-70
742:Ha-60
726:Ha-45
721:Ha-44
716:Ha-40
711:Ha-35
706:Ha-26
701:Ha-25
614:Sakae
481:Notes
405:0.578
321:Type:
231:Kasei
168:Ha-36
78:1941
44:Type
807:200-
696:Ha-9
691:Ha-6
686:Ha-5
681:Ha-1
674:1-50
599:Ha-5
526:ISBN
510:ISBN
328:Bore
132:The
104:200
427:6.5
193:.
160:NK7
156:NAK
851::
146:,
91:,
658:e
651:t
644:v
567:e
560:t
553:v
534:.
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152:)
143:護
140:(
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