# 4 Engine Japanese Heavy Bomber



## V-1710 (Jul 1, 2006)

What was the story with the 4 engine JAAF bomber (Kawanishi?). Very few were built, had some problems?


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## plan_D (Jul 1, 2006)

Kawanishi was a company, the only four-engined aircraft they built was the H6K 'Mavis' which was a flying-boat. The four-engined bomber that you may be refering to was the Nakajima G5N _Shinzan_ or 'Liz' in Allied terms. I don't know why it's bombing operations were minimal, if at all existant, but I do know it was used as a freighter.


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## loomaluftwaffe (Jul 1, 2006)

there is also the G8N Renzan, it would have made a very good heavy bomber... had it not come too late or had unreliable Homare engines


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## Henk (Jul 1, 2006)

plan_D said:


> Kawanishi was a company, the only four-engined aircraft they built was the H6K 'Mavis' which was a flying-boat. The four-engined bomber that you may be refering to was the Nakajima G5N _Shinzan_ or 'Liz' in Allied terms. I don't know why it's bombing operations were minimal, if at all existant, but I do know it was used as a freighter.



Yes, The Nakajima GSN1 "LIZ" was the first Japanese four-engined operational type, was origanally designed by Mitsubishi copany as the GSM1, but was not successful. It was modified by the Nakajima company and put into production as the GSN1. Although designed as a heavy bomber it was never used as such.

_JANE'S FIGHTING AIRCRAFT of WW2_


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## V-1710 (Jul 2, 2006)

Thanks for the replies. Sounds like the G5N was originally designed by Douglas (as the DC-4E)! The G8N was the one I was thinking of.


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## Henk (Jul 2, 2006)

Douglas? What the hell?


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## V-1710 (Jul 2, 2006)

Did a Google search on the G5N. Seems that it was based on the experimental Douglas DC-4E, a large 4 engine transport that Douglas was working on in the late 30's. No airlines were interested, as it was too large and complex. Douglas went ahead on the smaller and less complex DC-4/C-54, and sold the one and only DC-4E prototype to the Japanese. The G5N bears more than a passing resemblance to the DC-4E.


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## Henk (Jul 2, 2006)

Sorry V-1710 I see no resemblance of a Douglas in the design of the "Liz". If some of the other guys have something to ad here? 

Oh V-1710 do you have any books of WW2 aircraft or any other source than the net? Doing a Google search and finding something there does not mean it is the truth though.


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## plan_D (Jul 2, 2006)

It's quite clear that the G5N was a development of the DC-4E. Henk, the internet is a massive source of information and very handy. Use sites of some crediability and generally you won't go wrong. It's always best to have books on the subject too, because they're a lot more detailed. 

Books can be wrong too, y'know ?


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## Henk (Jul 2, 2006)

Yup, I have seen a lot of books that talk a bunch of bull or name the stuff wrongly. Thanks plan-D I did not know that. Like you said if you use the web you must use a website that can be trusted for their info.


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## V-1710 (Jul 3, 2006)

After reading the G5N was a development of the DC-4E, I did compare drawings of the aircraft, and I see a great deal of similarity, particularly in the wings. The DC-4E was a much different (and larger) aircraft than the DC-4/C-54.


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## johnbr (Jul 4, 2006)

Technical Date on the G8n1 is Empty 38,360Ib loaded 59,084 Performance Max speed 320kt at 8,000m cruising speed 200kt at 4,000m Range normal 2,130 naut miles max 4,030 naut miles.Dimensions span 32.54 m length 22.935m height 7.2m wing area 112sqm Production four g8n1 were built between october 1944 and june 1945 by Nakajima Hikoki kk in their Koizumi plant.


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## Twitch (Jul 6, 2006)

Here's everything you want to know about Japanese heavy bombers but were afraid to ask

HEAVY BOMBERS
KAWASAKI 
By 1943 it was realized that the bombers active service were not adequate by the way the war was going. Like the Germans, the Japanese relied on twin-engine bombers early on but they’d now reached their maximum of technology and performance. A scant few bombers were able to cope with the speeds of American fighters and take damage. A true long-range heavy bomber was needed that could fly fast.

The Navy was committed to the G8N Renzan (Mountain Range), code named “Rita,” but was hampered by air raids. The Army liked the Kawasaki design for their bomber. Therein lie part of the problem. Here was country under assault day and night by air and they stubbornly chose to stay divided as rival service factions each demanded their own planes. Had they combined and concentrated their efforts it would have been realized that only one big bomber was needed.

The Ki 91 was to have a crew of eight or nine would have been housed in a pressurized fuselage 108.25 feet long. Four Mitsubishi Ha-214ru engines of 2,500HP each would have driven the plane to a maximum speed of 360 MPH. A wingspan of 157.5 feet was larger than the B-29’s as was weight calculated at 127,868 lbs. loaded. 8,818 lbs. of bombs could be delivered on a 2,796-mile mission and a maximum range of 6,214 was estimated with lighter ordnance loads.

The Ki 91 was to have five power turrets- one in the nose, one on the top of the fuselage, and two beneath the fuselage along with the tail position. All would be equipped with pairs of 20 mm cannon except the tail position which would have four 20 mms!

By early 1945 the prototype was progressing in assembly but a February air raid destroyed all the tooling and jigs for the production facility rendering the project futile that late in the war.

KAWANISHI
Another contender for a high-speed long-range bomber that was fulfilled by the G8M1 “Rita” was a Kawanishi proposal- the K-100 (Type17). This thing was small like the Mitsubishi Type 17 with a crew of four in a short 50-foot fuselage. Four Nakajima Mamoru-Kai 18-cylinder radials each with 2,300 HP mounted on the 75-foot wings. Weighing just 30,000 lbs. loaded this thing could scream with a 376 MPH top speed and cruised at 230 MPH for 3,450 miles range. A ceiling of 30,732 feet was projected.

Armament was just three 20 mm cannon a 1,760-lb. torpedo or bob of the same weight.

This one never proceeded beyond preliminary designs but the concept was solid enough.

MITSUBISHI 
Beyond the excellent G8M1 “Rita” 4-engine bomber tested in the post-war US, the G7M1 Taizan Type 16 project was drawn up for a high speed bomber able to carry a lighter payload shorter distances. A crew of five rode in a comfortable 65.6-foot fuselage. Four Mitsubishi Ha.42 Model 31 18-cylinder radials of 2,400 HP each turned on the 82-foot wings. All up the compact bomber weighed 35,200 lbs.

Like the Rita this ship would be quite fast at 345 MPH but with a shorter range of 1,726 miles. 

Defensive armament proposed was that of two 20 mm cannon and six 13 mm machine guns. Bomb load variables could be a 1,760-lb. bomb or torpedo, two 1,100-lb. bombs or six 550-lb bombs.

This project was cancelled due to shortages and long lead time to completion.

NAKAJIMA
Before ending this chapter there is one area left to touch upon- heavy bombers. Like Germany, Japan didn’t possess an early vision for their use. They certainly had the technology. Two good 4-engine bombers existed and could have been built but weren’t. One design never went to prototype stage but was awesome in scope, nevertheless.

G5N2 
Shinzan or Mountain Recess was code named “Liz” and had four 1,530 HP Mitsubishi Kasei 12 14-cylinder radials on its 138.25-foot wing. Seven to ten crewmen operated in its 101.75-foot fuselage. Maximum loaded weight was 70,768 lbs. with its 8,818-pound bomb load, which could be hauled to a ceiling of 23,440 feet. Maximum range was 2,647 miles. She could do 261 MPH at 13,450 feet. Defensively it mounted one 20 mm Type 99 Model 1 cannon in a dorsal turret; one 20 mm Type 99 Model 1 in the tail turret and one 7.7 mm Type 97 machine-gun in nose, ventral and waist positions.

Thought to have been inspired by a DC-4 purchased before the war, the first bomber flew in 1941. While it didn’t possess long range the Japanese did use the prototypes for transport duties during the war. Four G5N1s were built along with two G5N2s.

G8N1
The Renzan or Mountain Range, code named “Rita,” housed a crew of ten in her 75.25-foot fuselage while four 2,000 HP NK9K-L Homare 24 18-cylinder radials turned on the 106.75-foot wings. Normal and maximum weights were 59,084 lbs. and 70,879 lbs. 4,409 lbs. of bombs could be delivered but range was a whopping 4,639 miles. She would have been hard to intercept with a top speed of 368 MPH at 26,245 feet and a ceiling of 33,465 feet. 

Armament consisted of twin 20 mm Type 99 cannon in dorsal, ventral and tail turrets; two 13 mm Type 2 machine-guns in nose turret and one flexible 13 mm Type 2 machine-gun on each side of the fuselage. 

At least one of four built survived and was tested in the US. If this bomber had been expedited much earlier it would have proved a fine plane.

G10N1
The Fugaku or Mount Fuji was to be a super bomber on par with Germany’s Amerika Bombers. Named “Project Z,” Nakajima studied the requirements for an aircraft able to attack the continental United States from Japan on their own whim not due to official project request. His idea did draw interest from the military for further exploration.
Six 5,000 HP Nakajima Ha-505 36-cylinder radials were proposed but gestation on them was slow and six 2,500 HP Nakajima NK11A radials would have to be used to start. Dimensions are unknown but it would have had to have a wingspan similar to that of the six-engine Ju 390 at 165 feet and length of 112 feet. A crew of ten was suggested including one relief pilot.

The G10N1 would have cruised at 32,810 feet hauling its 11,023 lb. bomb load at 310 MPH with a range of over 12,000 miles! For shorter hops the payload could be as high as 44,092 lbs. With a top speed of about 400 MPH it would have been hard to catch. Even with the smaller engines speed performance would have been at least equal to the B-29’s 342 MPH top speed with a 265 MPH cruise. Proposed armament was four 20 mm cannon- one in the nose, one in a tail location, and two in an upper fuselage turret.
This never made it of the drawing board.

Had the G10N1 been produced it could have bombed the western US. Long-range heavy bombers, if committed to in 1942, could have been counter attacking Allied islands by late 1944.


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## Tham (Jul 21, 2007)

Kawanishi also built the H8K2, which was probably
the best flying boat during the war.

It also had the best defensive armament of any four
-engined aircraft to this day, whether bomber or flying
boat - no less than FIVE 20 mm cannons as their primary
defensive armament. Contrast this with the .303 "pea shooters" 
carried by British bombers and flying boats like the Sunderland.

It also had Mitsubishi Kasei 22 1,850 hp engines, compared
to the Sunderland's Bristol Pegasus XXII 1,010 hp engines,
and climbed almost twice as fast as the Sunderland.

H8k2

Kawanishi H8K - Wikipedia, the free encyclopedia


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## syscom3 (Jul 21, 2007)

If the Japanese had a credible 4 engine heavy7 bomber in the early part of the war.... boy would things have unfolded differently! (Allies still would have won though).


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## Graeme (Jul 21, 2007)

Another 4-engined Japanese bomber, the Mitsubishi Ki-20. (yes..I know, I know).
But it was still around in 1940!


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## Graeme (Jul 22, 2007)

Twitch said:


> MITSUBISHI
> Beyond the excellent G8M1 “Rita” 4-engine bomber tested in the post-war US, the G7M1 Taizan Type 16 project was drawn up for a high speed bomber able to carry a lighter payload shorter distances. A crew of five rode in a comfortable 65.6-foot fuselage. Four Mitsubishi Ha.42 Model 31 18-cylinder radials of 2,400 HP each turned on the 82-foot wings. All up the compact bomber weighed 35,200 lbs.



This is interesting. I concur that the majority of web sites describe the Taizan as a four engined bomber project, but some quote Rene J Francillion, calling it Mitsubishi's *twin-engined* Navy Experimental 16-Shi Attack Bomber project. The project was the same size as the G4M.


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## Soundbreaker Welch? (Jul 23, 2007)

Interesting if the Japanese had put forth a bomber larger than the B-29. Would it have cost them more than it cost us?


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## syscom3 (Jul 23, 2007)

Soundbreaker Welch? said:


> Interesting if the Japanese had put forth a bomber larger than the B-29. Would it have cost them more than it cost us?



Depends on what they would have used it for....Mine laying missions or harrasment bombings of the small islands might have paid some dividends.


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## Kiwikid (Oct 27, 2008)

Nakajima himself proposed the GN10 Fugaku as an interceptor fitted with 96 forward firing cannon around the circumference of the aircraft. This was because with 5,000hp engines it would have been able to overtake B-29s in level flight. 

It was a kind of metal storm concept


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## B-17engineer (Oct 29, 2008)

Here is what it looked like


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## Aurum (Jan 8, 2010)

If Japanese developed 4 engine bomber on the base of Kawanishi H8K flying boat in the same way as Short developed Stirling bomber on the wing of Sunderland flying boat they could have it already in 1942. 
By the way Kawanishi had partnership relations with Short company.

Such Kawanishi G5K 4 engine bomber could look like as on pic below




Characteristics could be even better than Liberator D had an in general close to Emily data.


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