Fugaku : Z-plane, G10 or G12

[Justo Miranda]

May be Kawanishi "Gunzan" or project Z? ???

 

[blackkite]

Thanks Justo!

Brief history of Z／Fugaku project
(1) 1943/1/28 : 4 engine and 6 engine large bomber plan(including gun ship variant and cargo variant) was made by Nakajima aircraft
private venture.(Engine was HA177,Mamori engine variant? Take off power is unknown.)
(2) 1943/2/16 : 4 engine and 6 engine large bomber plan was made by Nakajima aircraft private
venture.(Engine was double BH(HA54),take off power was 4,400hp each.)
(3) 1943/3/5 : Temporary 6 engine(HA44,take off power was 2,600hp each) bomber plan(including cargo
variant) was made by Nakajima aircraft.
(4) 1943/4～1943/6 : Basic design for Z-plane was performed by Satoshi Koyama,Yasuo Naito,etc
in Nakajima club.
(5) 1943/6/8 : 'Z-plane design explanation' was made by Nakajima aircraft.(final Z-plane plan)
(6) 1943/8 : 'Winning strategy or Winning game plan(必勝戦策)' was made by Chikuhei Nakajima.
(7) 1943/9 : Z-plane was selected as IJN and IJA joint research program, IJN insisted that service
ceiling was 15,000m with light armament, IJA insisted that service ceiling was 10,000
with heavy armament. Finally IJN's plan was selected with range was
18,520km(15,000n.m)
(8) 1944/1 : IJN and IJA compared with Fugaku and Kawanishi TB, selected Fugaku, although JJN
hoped TB.
(9) 1944/1 : Named this plane as Fugaku(富嶽). Established Fugaku committee, chairman was
Chikuhei Nakajima, members were Kugisho, IJA aircraft technology research institute,
Central aircraft research institute, Tokyo imperial university, Nakajima Aircraft,
Mitsubishi Aircraft, Sumitomo Metal and Hitachi.
(10) 1944/3/14 : Fugaku committee offered to IJN and IJA following two stage developing plan for
Fugaku because of the delay of HA54 development.
①Realize HA44 engine×6 bomber.
② Realize HA54 engine×4 bomber or HA50 engine×6 bomber.
(11) 1944/8 : IJN and IJA stopped Fugaku project followed the fall of Saipan island .

We have not seen the official drawing of HA54×4 Fugaku still now.

 

[lark]

Dear Justo and Blackkite
The 6-engined bomber should be an 'after the war' and
highly speculative design.Drawing was published in a Japanese
magazine mid sixties..
I'll try to comeback with more info which I have somewere in my files..

 

[blackkite]

Dear Justo and Blackkite
The 6-engined bomber should be an 'after the war' and
highly speculative design.Drawing was published in a Japanese
magazine mid sixties..
I'll try to comeback with more info which I have somewere in my files..

Thanks lark!
It had single propeller, considering this feature, the engine was HA44 or HA50.

 

[blackkite]

I must say my compliments to Blackkite and Justo Miranda for their awesome pics and info! this topic is getting more and more interesting by the hour.
I made a model of the fugaku couple years ago,but with this new info I going to plan to build a new Fugaku model.
But more accurate than the previous model

Hi T-50! We look forward your new work about this beauty. Please take care that 50% under carridge of Fugaku were dropped after take off.
I think it's one of the magic of Fugaku's high performance.

 

[lark]

About the elliptical winged design.

From the book:Kyojin-ki Monogatari (Giant plane story)
by Minoru Akimoto- Publ Kojin-sha 2002
cited by Ryushuke Ishiguro on J-aircraft.

"...There was a time when a drawing of an elliptical-winged aircraft with six
engines was called 'Fugaku'.The drawing was put in the magazine "Soku" of Mach Club as
'G10N1' around 1965..."
"Later this drawing was introduced in other magazines..."
".. The source of the drawing was a famous engineer professor.There are stories that this was
the early design of Fugaku or 'Z'plane,but Nakajima had never thought of using elliptical wings.The idea that this was TB is not correct because TB had four engines. Therefore this drawing of the
eleptical-winged airplane maybe only an imaginary concept or a very private sketch..."

So far the above mentioned sources...

 

[Justo Miranda]

It may derive from Heinkel He 116B...

 

[blackkite]

Thanks a lot lark and Justo.
I introduce you two books.

①IJN & IJA Experimental Aircraft(日本軍試作機). FUTABA-SHA(双葉社),Tokyo,2005/2/25.ISBN978-4-87357-233-8
This book shows the blue print of final Z, 4 engine(HA54) bomber, Temporary 6 engine(HA44) bomber, CG(Shinden,Reppu,Senden,Kitsuka,
Ki-64,Ki-87,Ki-94,Ki-91,Ki-93,Ki-88).
FUTABA-SHA has some Nakajima Aircraft original documents for Z/FUGAKU.
(Z project plan explanation, Temporary 6 engine bomber explanation, Z-plane design calculation report,etc). Please confirm attached picture.

②All the Experimental Aircraft in Japanese Army(日本陸軍試作機大鑑).KANTOSHA,Tokyo,2008.(Minoru Akimoto,秋本実) .ISBN4-575-47587-4
This book include the precise description and drawings for Z/FUGAKU,Kawanishi TB,Ki-117,etc.

 

[robunos]

It may derive from Heinkel He 116B...

From 'Warplanes of the Third Reich'. page 324 :-

"In 1936, Deutche Lufthansa (DLH) began to display
an interest in the possibilities of direct mail services
to the Far East. The route contemplated...
crossing the Pamir Mountain range...
dictating a service ceiling in excess of
25,000ft...
Heinkel initiated the design of a four-engined
longe-range monoplane specifically to meet
DLH's needs."

"Two of the He 116A-0 aircraft had, in the meantime,
been ordered by the Japanese, these being registered
J-BAKD and J-EAKF and named Nogi and Togo
respectively...
arriving in Tokyo on April 29th, 1938...
These were subsequently operated...
over the Tokyo-Hsingking route."

So the He 116 would have been available for study in Japan,
bearing in mind the original purpose of the design
was for a long-range, high-altitude mail carrier...


cheers,
Robin.

 

[blackkite]

Hi Robin! I thank you very much for your quick action.
I confirmed that your information is true by my No.1/No2. bible.
Nogi was from "Maresuke Nogi(乃木希典)".
http://en.wikipedia.org/wiki/Nogi_Maresuke
Togo was from "Heihachiro Togo(東郷平八郎)".
http://en.wikipedia.org/wiki/T%C5%8Dg%C5%8D_Heihachir%C5%8D

 

[T-50]

found additional stuff

Hi Justo Miranda could you please tell the title and the author,publisher of this book,i want this book adding to my own collection
cheers T-50

 

[T-50]

Dear Justo and Blackkite
The 6-engined bomber should be an 'after the war' and
highly speculative design.Drawing was published in a Japanese
magazine mid sixties..
I'll try to comeback with more info which I have somewere in my files..

Hello Lark I cant wait for the info!

 

[lark]

Afternoon T-50..

See my 2e post on March 13 please..

 

[T-50]

Hi! 4 engine bomber and another picture of final Z. Enjoy.
Source:Japanese experimental aircraft,Futaba-sha,Tokyo

I ask my self why has the aircraft on the first blueprint pic a strange jumbo jet like back?
was this space mend for extra fueltanks?

 

[blackkite]

Hi T-50 san! According to your question, we are approaching to some facts about Z/FUGAKU variants.
Now we are discussing about 4 engine bomber.
This design was proposed in 1943/1/28, earlier than final Z(proposed in 1943/6/8).We already know that the basic design for Z-plane was performed by Satoshi Koyama,Yasuo Naito,etc in 1943/4～1943/6(in Nakajima club). So this design was pre-Z plane. This aircraft had double propeller, the engine was HA54(5,000hp in take off). The propeller diameter was 4.8m, then we can calculate following dimension of this 4 engine aircraft.
Wing span:about 70m to 75m(perhaps 72.5m same as Z(Ohta)), length:about 50m.
Fuselage was bigger than final Z, I can't understand the meaning of this fuselage shape. Final Z was very slim. I feel that engine nacelle shape and wing tip shape were similar to DC-4E.

 

[blackkite]

Hi Fugaku structure and Z-Koizumi(Nakajima IJN aircraft design department) structure.Enjoy!
In Fugaku drawing, I realize following items.
①The engine is BH(HA44, 18 cylinder, 2,500hp in take off), so this was the Fugaku first stage
plan offered by Fugaku committee. Fugaku second stage plan had six HA50 engine(22 cylinder
2 array, 3,500hp intake off, almost same power of P&W R4360 WASP majors 4 array 28
cylinder) or four HA54 engine(36 cylinder 4 array, 5,000hp in take off).
②This plan has a passage tube between fore pressurized cabin and aft pressurized part.
In Z-Koizumi drawing, I realize following items.
①The engine is HA54 with double propeller(contra rotating propeller).
②It had drop tire.
③The armament included torpedo.
④This plan had remote controlled 20mm cannon turret.
Source:Goodbye air battle ship Fugaku(さらば空中戦艦富嶽),KOJINSHA(光人社) TOKYO,2002/2/16, Yoshiro Ikari(碇義朗), ISBN4-7698-2335-5 C0195

 

[blackkite]

Hi Z Gun Ship and Z Cargo Variant!. Enjoy!
Source:Goodbye air battle ship Fugaku(さらば空中戦艦富嶽),KOJINSHA(光人社) TOKYO,2002/2/16, Yoshiro Ikari(碇義朗), ISBN4-7698-2335-5 C0195

 

[blackkite]

Hi! Final Z 3-side view and picture. Enjoy!
But engine and propeller are apparently mistake. Final Z had double propeller.
Source:Militaly Aircraft Development Story(軍用機開発物語), Kojinsha Tokyo(光人社), Takeo Doi(土井武夫), ISBN978-4-7698-2334-6 C0195.

 

[mz]

I remember reading about a microwave weapon, but can't find the page anymore (not a forum, anyway, wikipedia has more at http://en.wikipedia.org/wiki/Secret_and_special_weapons_in_Showa_Japan ). Anyway, for close range work against people. Perhaps behind cover / inside buildings? I don't think it has anything to do with Fugaku.

 

[blackkite]

I remember reading about a microwave weapon, but can't find the page anymore (not a forum, anyway, wikipedia has more at http://en.wikipedia.org/wiki/Secret_and_special_weapons_in_Showa_Japan ). Anyway, for close range work against people. Perhaps behind cover / inside buildings? I don't think it has anything to do with Fugaku.

Thanks a lot mz. Very interesting information!

 

[T-50]

Hi Blackkite very interesting pics from the final version of the Fugaku.I saw on the underside of the wings two pods,they looked as two jet engines it seemsthat these engines where to support the Fugaku at takeoff.
If they were really incorporated into the design,its a very interesting and advanced part of this final design!

 

[blackkite]

Hi Blackkite very interesting pics from the final version of the Fugaku.I saw on the underside of the wings two pods,they looked as two jet engines it seemsthat these engines where to support the Fugaku at takeoff.
If they were really incorporated into the design,its a very interesting and advanced part of this final design!

Oh! I realize now. You are very sharp eyed, too!!

 

[airman]

really nice !

i have a doubt :
Kawanishi Type 17 Experimental Ground Bomber (K-100) was directly connected with derived projects of Fugaku or was an other different project ?

 

[blackkite]

really nice !

i have a doubt :
Kawanishi Type 17 Experimental Ground Bomber (K-100) was directly connected with derived projects of Fugaku or was an other different project ?

Kawanishi 17-shi land base bomber(K100,torpedo bomber) was a twin engine bomber which could operate as a dive bomber. The size of K100 was smaller than 1-shiki land base bomber(G4M), larger than Ginga(P1Y). K100's engine were Nakajima Mamori-kai(護－改)(Modified Mamori). (Mamori was a 14 cylinder engine). The shape of K100 was similar to Ginga land base bomber, and engine nacelle was very big.But Nakajima stopped Mamori-kai's development and IJN decided that next land base bomber was Renzan 4 engine bomber.
Kawanishi terminated K100 experimental production.
Wing span:21.6m, Length:15.0m, Height:6.07m, Wing Area:64m2, Empty Weight:8,550kg, MTOW:16,000kg, Engine:Nakajima Mamori-kai air cooling radial 18 cylinder engine(2,300hp in take off), Max speed:606km/h(325kt)/7,600m, Service Ceiling:11,200m, Range:5,556km(3,000n.m.), Wing Loading:211kg/m2, Crew:4, Armament:20mm×3. Torpedo:800kg.
Expected K100's performance surpassed B-25 and B-26 very much.
IJN ordered Mitsubishi to study land base bomber with same specification as K100, too.
Source:My No.2 Bible.

 

[airman]

really nice !

i have a doubt :
Kawanishi Type 17 Experimental Ground Bomber (K-100) was directly connected with derived projects of Fugaku or was an other different project ?

Kawanishi 17-shi land base bomber(K100,torpedo bomber) was a twin engine bomber which could operate as a dive bomber. The size of K100 was smaller than 1-shiki land base bomber(G4M), larger than Ginga(P1Y). K100's engine were Nakajima Mamori-kai(護－改)(Modified Mamori), air cooling 18 cylinder engine(2,300hp in take off).(Mamori was a 14 cylinder engine). The shape of K100 was similar to Ginga, and engine nacelle was very big.But Nakajima stopped Mamori-kai's development and IJN decided that next land base bomber was Renzan 4 engine bomber.
Kawanishi terminated K100 experimental production.
Wing span:21.6m, Length:15.0m, Height:6.07m, Wing Area:64m2, Empty Weight:8,550kg, MTOW:16,000kg, Engine:Nakajima Mamori-kai air cooling radial 18 cylinder engine(2,300hp in take off), Max speed:606km/h(325kt)/7,600m, Service Ceiling:11,200m, Range:5,556km(3,000n.m.), Wing Loading:211kg/m2, Crew:4, Armament:20mm×3. Torpedo:800kg.
Expected K100's performance surpassed B-25 and B-26 very much. Source:My No.2 Bible.

thanks blackkite, i hope to see , in future, a picture of K-100 !

 

[blackkite]

Hi airman! There are no K100 drawings in my books and Japanese internet site.
The wing of K100 was little larger than Ginga's wing. Aspect ratio was 7.3. Dihedral of wing inner part was 0°, outer part was 5°.
Sweptback angle was 30°!? Source:My No.2 Bible.

 

[T-50]

I saw on one of the drawings send by Blackkite a to me very simple type of bombsight,was a no more advanced design of a bombsight? I know the Japanese have captured a US Norden bombsight and copied,so I can imagine that they designed a new type bombsight based on the norden type and placed it on board the Fugaku.
I ask my self were the Japanese planning a bombsight based on radar for the Fugaku,like the radarset on the B-29?

 

[blackkite]

I saw on one of the drawings send by Blackkite a to me very simple type of bombsight,was a no more advanced design of a bombsight? I know the Japanese have captured a US Norden bombsight and copied,so I can imagine that they designed a new type bombsight based on the norden type and placed it on board the Fugaku.
I ask my self were the Japanese planning a bombsight based on radar for the Fugaku,like the radarset on the B-29?

Sorry. I'm not sure about bombsight of Fugaku. I will study.
The National Institute for Defence Studies in Tokyo has the "Winning Game Plan,必勝戦策". I will try to get the copy of 必勝戦策.
http://www.nids.go.jp/english/index.html

 

[blackkite]

Hi! She has contra rotating propeller, so the engines are HA54.
But Fugaku committee offered four HA54 engine Fugaku as the second stage of Fugaku project.
She might be the ultimate Fugaku, not Z-plane because she has B-29 like cabin.
Source:I forget the source of this drawing,sorry. Perhaps from some Japanese internet site.

 

[Skybolt]

Blackkite-san, the last transparency you posted is a modern or a wartime one ?

 

[windswords]

"She might be the ultimate Fugaku, not Z-plane because she has B-29 like cabin."

I have always wondered about this. Some drawings of G10N show traditional cockpit and others look like the B-29. Is that a fact that a B-29 style cockpit is someones post war imagination of what might have been?

 

[blackkite]

Hi Skybolt-san! Thank you very much for your attention for Fugaku.
Unfortunately I forget the source of this drawing. I imagine that you think that this drawing’s structure and equipments arrangement are proper from your professional viewpoint.
I think this drawing is after war work, because six HA54 engine Fugaku was not offered by Fugaku committee to IJN and IJA. I think that this drawing was cooked up by similar drawing of B-29 or B-36.(If not so, I am terribly sorry for the writer. ;D)
Hi windswords-san! I don’t think so, because there is a Fugaku drawing in my No.2 bible which has the B-29 type cabin. My No.2 bible was made by all Japan line up.(Tadashi Nozawa, Mitsubishi Heavy Industries, Kawasaki Heavy Industries, Fuji Heavy Industries, etc)
It might be true that all of Fugaku’s drawings were burned out and we can’t see the official blue print of Fugaklu. But It’s impossible to erase memory of engineers who engaged in Fugaku project. They must be remember the detail of Fugaku’s data very clearly. This is the reason why I believe Fugaku’s B-29 style cabin is true.

 

[blackkite]

I saw on one of the drawings send by Blackkite a to me very simple type of bombsight,was a no more advanced design of a bombsight? I know the Japanese have captured a US Norden bombsight and copied,so I can imagine that they designed a new type bombsight based on the norden type and placed it on board the Fugaku.
I ask my self were the Japanese planning a bombsight based on radar for the Fugaku,like the radarset on the B-29?

Hi! I can't find any evidence of Japanese radar bombsite project.
Yes Japan copied Norden bombsight from B-25. It was completed in January 1944, called 4-shi automatic bombsight for 4-shiki heavy ;D bomber Hiryu(飛竜).There were 17-shi bombsight(90-shiki bombsight) picture(right) and night bombsight picture(left) in Z-plane cabin drawing.
Bombsight=爆撃照準器
http://gunsight.jp/b/1/sight-a.htm

 

[T-50]

Hi Blackkite San this is very interesting stuff you send me,thanks! this was for the Japanese optical industry a very usefull gift although the Americans didn't want this to fall into the hands of the Japanese.
with this new data they could develop their own very advanced bombsights

 

[blackkite]

From "富嶽(FUGAKU)" ,Author:Maema Takanori(前間孝則),Kodansha(講談社) Tokyo
published in 1991.ISBN4-06-205543-0 C0095 P2000E(0) 　　　　No.(1)

In November 1942, Chikuhei Nakajima called twenty Nakajima's elite engineers to the Nakajima club, explained that
①Japan would lost the war by strategic bombing to Japan using B-29 and B-36 from 1944.(He already knew B-36 at the day!)
②The only way to win the war was strategic bombing to the United States by transoceanic large
bomber with 5,000hp engines, which speed was higher than American fighter.
③This plan was already explained to the JIJA and IJN.
④Study how to realize this bomber as the secret private venture, keep secret.
⑤ Named secret study party as “Winning game, guard Japanese sky research party(必勝防空研究
会) ”, leader was chief engineer Satoshi Koyama(小山悌).
Then the conceptual design began by the secret party, the chief of fuselage study was Shinobu Mitake(三竹忍)(Shinzan chief designer), the chief of engine study was Tanaka Kiyoshi(田中清史)(Mamori(護) engine and NBD engine chief designer). The engine designing team started discussion between Kotani(小谷)(Section manager), Tanaka(田中), Nakagawa(中川)(chief designer of Homare(誉) engine), Inoue(井上) and Kudo(工藤). They discussed about several engine types.
Tanaka and Kudo recommended 4 array 36 cylinder HA54 engine.(tandem double HA44 engine)
BTW Nakagawa argued against this engine that cooling would be the big problem, too risky.
Nakagawa insisted 4,000hp 26 cylinder!!(2 array 13 cylinder) engine which diameter was rather
bigger than HA54. Finally Tanaka and Inoue agreed Nakagawa's plan. The 26 cylinder engine plan
was explained to Chikuhei by Koyama. BTW Chikuhei rejected this 4,000hp engine and ordered to Koyama ”Don't be less than only 1hp from 5,000hp”.

Mitake studied 26 aircraft types based on Chikuhei's idea for the answer of Chikuhei's order.
They were from small plane to large plane, carrier base bomber, torpedo bomber, attack bomber, twin engine bomber, long range bomber, gun ship and cargo plane. At the time, Nakajima's design for the aircraft were based on British R&W report and NACA's report for wing section. Yasuo Naito(Desiger of Saiun's laminar flow wing and past war T-1 trainer) made his own chart for the aircraft basic design from the British R&W report and NACA's report. Naito helped Mitake's study, he thought that among 26 types, the final 3 types were very difficult to design. They were very big long range bomber, gun ship which had 20 cannon located under the fuselage to shoot American fighter and cargo plane to carry soldiers to the United States.
Finally Mitake and Naito merged these 26 types into one long range bomber.

 

[blackkite]

From "富嶽(FUGAKU)" ,Author:Maema Takanori(前間孝則), No.(2)

The results of basic design for Z-plane(Final Z-plane) performed by Satoshi Koyama,Yasuo Naito,etc in Nakajima club in 1943/4～1943/6 were as follows.
Wing span:65m, Length:45m, Height:12m, angle of ground position:9 degree?, Wing area:350m2, Maximum wing chord length:9m, Dihedral:3.5 degree, aspect ratio:12, Taper ratio:1:5, angle of incidence:6 degree, horizontal tail stabilizer area:60m2, Vertical tail stabilizer area:40m2,Distance between main wheels:9m, Fuselage fuel tanks capacity;42,720L, Wing fuel tanks capacity:57,200L,
Wing loading:457kg/m2, Power loading:5.3kg/hp, Empty weight:67.3ton, MTOW:160ton, Engine:six double BH(HA54) 5,000hp in take off, 4,600hp/7,000m, Propeller:3 blade contra rotating 4.8m diameter, Maximum speed:680km/h/7,000m, Service ceiling:12,480m, Take off run:1,200m, Range:16000km with 20 ton bomb.

 

[blackkite]

Hi! Radio controlled Z/Fugaku flying model. It's 1/15 scale model. (Cooperator: Fuji Heavy Industries )
http://www.nextftp.com/ty2/plink12.htm
http://sky.geocities.jp/fukiagerc/ivent_syokai/2009_5_2ivent/fugakuwo_tobasou.html

 

[airman]

Hi! Radio controlled Z/Fugaku flying model. It's 1/15 scale model. (Cooperator: Fuji Heavy Industries )
http://www.nextftp.com/ty2/plink12.htm
http://sky.geocities.jp/fukiagerc/ivent_syokai/2009_5_2ivent/fugakuwo_tobasou.html

The nose is very similar to G5N Shinzan !

 

[blackkite]

Yes I think so.

 

[T-50]

Its a nice piece of work this RC model but it has some G5N Lizzy features,but nevertheless its a huge and beautiful RC plane!