Kawanishi KX-9 (Army "TB" Super Heavy Bomber)

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Hello people i´m looking for drawnings or artist inpressions of the Kawanishi tb bomber
It was ment as an after thought for the G10N Fugaku, im very interested in ww2 Japanese aviation.
Especially in unbuild projects,so i can use some pics of Japanese never were bombers like the tb
bomber.
cheers T-50
 
According to this site, this is what the TB bomber would have looked like:
http://xh2002.blog.hexun.com.tw/37222394_d.html
 

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The more I look into this, the more I'm convinced the elliptical winged bomber is not the TB and, instead, was simply one of the initial Fugaku design drafts. This is born out by the illustration in Minoru Akimoto's All the Experimental Aircraft in Japanese Army shows the TB as a slender fuselage, long span, 4-engine bomber. Kawanishi's design was based on super long range aircraft like the Gasuden Koken and the A-26 (Ki-77). This is born out by the involvement of the Tōkyō Teikoku Daigaku (Tokyo Imperial University) with the TB project. The Tōkyō Teikoku Daigaku was also involved in the development of the Koken and Ki-77 and thus had the most experience with long range aircraft operating in the sub-stratosphere.


It is certainly possible that Kawanishi's 19-shi bomber was a Fugaku proposal but because of that, I wouldn't separate it from the Fugaku program. And since the Fugaku program was not initiated because of a Shi specification, it honestly wouldn't be accurate to assign 19-Shi to the design.



Stargazer2006 said:
According to this site, this is what the TB bomber would have looked like:
http://xh2002.blog.hexun.com.tw/37222394_d.html
Click to expand...
 
And here is the TB from Akimoto's book. This design very much ties in with what the IJA wanted in terms of their version of the Fugaku. Light defensive armament flying at extreme altitudes which would render interception very difficult. And since the IJN stomped on the IJA's Fugaku design philosophy seems only right that the IJA dominated Gunjūshō would seek to give the IJA their desires since the Gunjūshō controlled both the IJA and IJN and thus could instruct Kawanishi to work on the TB despite Kawanishi being exclusive to the IJN.
 

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Hikoki1946 said:
And here is the TB from Akimoto's book. This design very much ties in with what the IJA wanted in terms of their version of the Fugaku.
Click to expand...

So the Army wanted 4 engines only? I thought all Fugaku proposals had 6 engines...
 
At the time the Army was involved in the Fugaku project, yes, their idea used six engines. The Ju 390 is the best example of what the Army wanted their Fugaku to look like. Their philosophy of high flying, light armament still applied.


The change in engines was no doubt Kawanishi's idea. I suspect this is because they had experience with four-engine designs, not six. They felt making the TB a sub-stratosphere bomber, with all the associated technology for that, would give the range without the need for two more engines. This entire concept for the TB fit into what the Army wanted, high flying, light armament.



Stargazer2006 said:
Hikoki1946 said:
And here is the TB from Akimoto's book. This design very much ties in with what the IJA wanted in terms of their version of the Fugaku.
Click to expand...

So the Army wanted 4 engines only? I thought all Fugaku proposals had 6 engines...
Click to expand...
 

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In reply 102 -April 2010- in the "G10N1 Fugaku derived projects" thread
Blackite writes that the drawing of the so called eleptical winged bomber
was made for use in the magazine Mach club-Soku around 1965-1974.
He describes it as a fake or private venture.(invention?)

In my opinion ,Robert C.Mikesh was put on the wrong track by this drawing when he
used it for the creation of the sideview in "The Japanese Giants" two part article for Wings/Airpower.

The sideview is the same,exept for a few very minor details , and the caption reads
Kawanishi 19Si Super heavy landbased attack bomber , designated TB.

Based on this info i'ts safe to assume that the eleptical winged bomber
was not the long searched for TB...
 
The 19-shi elliptical bomber, as you suggest and to which I agree with, is not the TB.


Now, we have the question on if this bomber was, in fact, made up for the magazine or as suggested, a possible contender as a private venture (much like the Fugaku with Nakajima).
 
Oh this one. Many thanks. :)
High winds means Kyofu(強風 strong wind).
 
The main gear looks like it was lifted off a Stirling and otheral it has a very Liberator look to it.
 
simmie said:
The main gear looks like it was lifted off a Stirling and otheral it has a very Liberator look to it.
Click to expand...
Yes I think so, too. Very good artistic impression! Landing gear length was very long.
Conslidated and Kawanishi were both flying boat maker.
 

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Kawanishi TB(1) from All the Experimantal Aircraft in Japanese Army.
Kawanishi TB was a competitor of Fugaku. TB’s planner was the Cabinet Planning Board(企画院,Kikakuin), former of the Ministry of Munitions of Japan(軍需省,gunjusho), but according to various documents at the day, the IJA apparently joined the planning of TB secretly.
TB’s design was a joint work between Tokyo Imperial University Aeronautical Research Institute and Kawanishi.
The basic design policies for TB were as follows.
① Use established technology, do not use technology which need research and development (R&D).
② Institute member Tanaka(田中敬吉) takes charge of the engine, engine is selected among Mitsubishi’s engines and apply some modification. Number of engine for TB is four.
③ Institute member Ichiro Tani(谷一郎) (developer of laminar flow LB wing) takes charge of wing aerodynamic design. TB use LB series laminar flow wing.
④ Do not use pressurized cabin, use Oxygen discharge from the Oxygen tanks when high altitude flight to realize light weight fuselage. Oxygen discharge technology is based on the research result of Institute member Taichi Ogawa(小川太一).
⑤ Apply the research result of Institute member Nagai(永井) for engine oil degradation through 60hours flight.
⑥ Institute member Hidemasa Kimura(木村秀政, Kokenki, A26 and YS-11 designer) and Kawanishi take charge of overall design.
⑦ Kawanishi take charge of fuselage, tail stabilizer, engine nacelle aerodynamic design, overall structure and eqipments.
Institute member Ogawa(小川) take charge of design integration, Kawanishi assist Ogawa.Wind tunnel test result of TB wing as stand-alone units showed very high performance, lift drag ratio was 30 to 35, which could get 12,000km range.
The basic design finished in the first of January 1944.
 
That is my contention that this bomber, if not a post-war creation, was one of the proposals submitted for the Project Z which got rejected. Question is, who proposed it? Kawasaki was involved with the Fugaku project. Perhaps it was theirs?



Justo Miranda said:
Project "Z" ???
Click to expand...
 
Hikoki1946 said:
That is my contention that this bomber, if not a post-war creation, was one of the proposals submitted for the Project Z which got rejected. Question is, who proposed it? Kawasaki was involved with the Fugaku project. Perhaps it was theirs?



Justo Miranda said:
Project "Z" ???
Click to expand...
Click to expand...
TB was proposed by the Kikakuin(Cabinet Planning Board) (and perhaps the IJA secretly) as a realistic America bomber.
http://en.wikipedia.org/wiki/Teiichi_Suzuki
 
Heyas, Blackkite!


My question was about the elliptical winged 6-engine bomber. :)


It has been mentioned as showing up in a post-WW2 magazine. So, is possible it was lumped into the initial Project Z proposals and if so, who designed it? If Kawanishi wasn't involved in the Fugaku and Kawasaki was, then could it have been a Kawasaki concept? Or...just something made up post-WW2 for the magazine?



blackkite said:
Hikoki1946 said:
That is my contention that this bomber, if not a post-war creation, was one of the proposals submitted for the Project Z which got rejected. Question is, who proposed it? Kawasaki was involved with the Fugaku project. Perhaps it was theirs?



Justo Miranda said:
Project "Z" ???
Click to expand...
Click to expand...
TB was proposed by the Kikakuin(Cabinet Planning Board) (and perhaps the IJA) as a realistic America bomber.
Click to expand...
 
Hi!
I believe that the elliptical winged 6-engine bomber was a after war work.
But I don't know who designed it.
 
Correct Hikoki,

I think we need to find the original text from the Mach club magazine
or a good translation of it.I'm close to the point to accept that the concept
is made up hence the date of publication..

Beside ,maybe it's good to know that the photo of the 6-engined Ju 390 is a fake.
There never was a RC+DA registration. The photo of an in flight Ju-290
was retouched with 2 additional engines and a bit more wing spanto let
it look like a 2e Ju-390.
The long fuselage in front of the wing is an indication of the trick..

I found this in fo in : Luftfahrt History nr.4 Messerschmitt Me 264 & Junkers Ju 390
Horst Lommel - Lautec medien,Siegen ,Germany
 
I am leaning in that direction, too. It would seem that it only appeared in that magazine and hasn't shown up in the surviving Fugaku documents and plans. I guess we can't completely rule it out.


I've attached what appears to be the entire page (I only recall seeing the upper portion, without the text at the bottom) from that magazine (or, at least another source that drew off it)?



blackkite said:
Hi!
I believe that the elliptical winged 6-engine bomber was a after war work..
Click to expand...
 

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A possibility. Though, the only manufacturer that had a long relationship with Heinkel was Aichi. Still, the Manchukuo puppet state's Manchukuo National Airways who operated the He 116 was certainly not in a position to argue with the Japanese if the military chose to take the two planes to study.


But, yea, your idea has merit. The Japanese had access to the He 116 which was a relatively successful design so it wouldn't be far-fetched to think that, if this 19-shi bomber was a Fugaku proposal, scaling up the He 116 was certainly a plausible concept.



Justo Miranda said:
Maybe a He-116B evolution?
Click to expand...
 
While the Nakajima engineers had their doubts about
the technical feasibility for the construction
of such a wing planform with six engines..
 
Japanese text explained about this drawing that "this drawing is said as a one plan in Fugaku planning phase".
Trere are no description about this drawing's desinger or maker.
備考 means remark.
Remark described only general description about Fugaku project that we already know very well. No description for this drawing in remark.
 

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lark said:
While the Nakajima engineers had their doubts about
the technical feasibility about the construction
of such a wing planform with six engines..
Click to expand...
Yes. We already know that Fugaku had a wing root strength problem, but this shape weakend the strength of wing root!
I used to read following text in some document.
"Nakajima enginner said that they never think about such a complicated elliptical wing shape. It's very hard to fabricate."
Please remember that Fugaku was born from Nakajima's private venture.
 
So, lets sum things up. We have come to a consensus that the elliptical winged bomber was, indeed, a part of the initial Project Z "brainstorming" and was rejected. What we don't know is who proposed it (IJA or IJN) and that might not be known at all.


As for the TB, that has been resolved also.


This leaves, then, the G9K. As Blackkite posted, it was a Kawanishi bomber project. This brings up some questions. One, what date was this bomber proposed? If prior to the Nakajima G8N, why did the IJN not call it the G8K as it would have followed the Mitsubishi G7M? Or, to kick something around, was the G9K a follow-up design to the G8N the latter of which was initiated in September 1943? I can't see the Kawanishi K-100 having been given the G9K designation (as alluded to by some authors) since it was canceled so fast.
 
Good question. But I can't answer, because the information is from Japanese wikipedia. ;)
If possible, anyone please answer ED's sharp question.
 
Kawanishi TB(2) from All the Experimantal Aircraft in Japanese Army
TB ‘s planning was finished in 14th of January 1944.
In the afternoon of 17th of January 1944, the Cabinet Planning Board(企画院) explained the plan to Takamatsunomiya(高松宮,brother of an emperorthe Emperor of Japan Hirohito, the IJA commander), the First Sea Lord Osami Nagano(軍令部総長永野修身) and the IJA and the IJN’s persons concerned in official residence of the First Sea Lord.
In 26th of January 1943, there was a meeting to compare Fugaku and TB in the IJN Air Service office and in 27th same meeting was held in the IJA Air Service office.
In the first of February 1943, there was a meeting of the IJA/IJN aeronautical technical committee, Fugaku was selected as the America bomber, TB lost the race.
 

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Very interesting blackkite!

Does the "Kawanishi TB(2)" in the title indicate a footnote, or the fact that it was the second Kawanishi project with that designation?
 
Sorry for your confusion.It's footnote for me. ;D
So my next post for TB will be TB(3).
 
Kawanishi TB(3) from All the Experimantal Aircraft in Japanese Army
TB’s name in the Kawanishi office was KX-9. Kawanishi proceeded TB design as if it was a cargo aircraft to keep secret of her mission. TB was a very well‐proportioned and aerodynamically sophisticated aircraft with slim fuselage and very large wing. The engine were takeoff power 2000hp class Mitsubishi A20(MK9,( HA43)) air cooling radial 18 cylinders or Nakajima Homare (NK9,(HA45) type 20, with reduction gear ratio change, three stage supercharger(the first and second stage were turbo charger, third stage was mechanical supercharger), inter cooler and force cooling fan. The propeller was constant speed 4.8m diameter four blades. The wing was LB type laminar flow wing, aspect ratio was 12.48 dihedral was 6 degree. The area of tail stabilizers were very small to realize light weight, low drag and minimum inherent stability. The fuselage was designed as slim as possible, and only 2.33m maximum diameter fuselage realized. The fuselage had perfectly circular cross section, no step cabin wind shield, pressurized cabin made of synthetic resin nevertheless inverse initial design policy and 50L liquid Oxygen tank for the failure of pressurized system to keep 20hour flight with 6 crews at 8000m altitude. Also the cabin had 6 beds for over 60hours flight time.
 
This is a very interesting contribution Blackkite..
Keep up the good work.
 
Good information, indeed, on the TB. ;D


Still have the G9K mystery to solve, though.
 
Many thanks my dear lark, Ed and Star!
I will try to keep posting thids topic. And I believe we can see better TB shape near future by brainstorming. ;)
 
Kawanishi TB(4) from All the Experimantal Aircraft in Japanese Army
Fuel tanks were located upper middle of the fuselage, large bomb bay which could accommodate four 1500kg bombs was located lower middle of the fuselage. Most difficult problem was the main landing gear accommodation compartment because It’s structurally and aerodynamically difficult to find accommodation space of large main landing gear which support gross weight 74 ton aircraft. So following solution was selected that use 4 Shinzan’s tires for main landing gear(diameter : 1650mm, breadth : 60mm, each), two tires are dropped after take-off. This method was same as Fugaku’s one. Maximum bomb carrying capacity was 6ton, minimum capacity was 2ton. (1500kg bomb×4 or 800kg bomb×4 or 500kg bomb×4 or 250kg bomb×9 in bomb bay, but in case of close bombing mission, 60kg bomb×100 or 1500kg bomb×10 could carry under the wing.) The armaments were remote controlled 13mm gun at each side of the fuselage and remote controlled coaxial 13mm gun at the tail.(total 4×13mm gun, each gun had 300 bullets).
 
Kawanishi TB(5) from All the Experimantal Aircraft in Japanese Army by Minoru Akimoto(秋本　実)
The telecommunication equipment of TB was a 2-shiki Kuu 3-go radiotelegraph. TB also had a return to base direction finder. But there were no radar in TB.
The maximum loadage of fuel(56500L), methanol(1000L) and oil(1500L) was 44ton. TB carried 40L of drinking water and 60kg foods for three days flight by 6 crews. Because of her large size, take-off was a big problem for TB. Following take-off methods were considered.
① Normal take-off
② Rocket Assisted Take Off
③ Electric car assisted take-off
④ Slanting run way take-off using mountain slope
But each method had merits and demerits.
Take-off run with 70ton weight by normal take-off method was 1600m.Using RATO(thrust 3 ton) or electric car : 1000m
Take-off run with 74ton weight by normal take-off method was 1900m.Using RATO(thrust 3 ton) or electric car : 1200m
Take-off run with 78ton weight by normal take-off method was 2300m.Using RATO(thrust 3 ton) : 1500m Using electric car : 1400m
TB was more realistic plan than Fugaku, but might be lost the race by political reasons.(Chikuhei Nakajima's political power?)
 
Kawanishi TB(last) from All the Experimantal Aircraft in Japanese Army by Minoru Akimoto
TB’s specification
Engine : Air cooling radial 18 cylinders take-off power 2100hp class with turbo charger × 4
Span : 32.4m, Length : 28.0m, Height : 7.0m, Wing area : 220.0 square meter,
Empty weight : 26.5ton with bulletproof rubber 2.3 ton,
Gross weight without bomb and fuel 17 ton(Normal state) : 45ton,
Gross weight with 2 ton bomb and 44 ton fuel(Over loaded state) : 74ton,
Wing loading : 336.36kg/square meter(when gross weight was 74 ton),
Power loading(when gross weight was 74ton and with take-off power) : 8.81kg/hp,
Maximum speed(Normal state) : 325kt(601.9km/h)/12000m,
Service ceiling when after 6000n.m.flight, Gross weight become 50 ton : 12700m,
Range(take-off weight 70 ton(with 4.6 ton bomb)) : 11000n.m.(20372km)
Range(take-off weight 70 ton(with 3.2 ton bomb)) : 11600n.m.(21483.2km)
Range(take-off weight 74 ton(with 4.6 ton bomb)) : 11950n.m.(22131.4km)
Range(take-off weight 74 ton(with 3.2 ton bomb)) : 12400n.m.(22964.8km)
Range(take-off weight 74 ton(with 2 ton bomb)) : 12800n.m.(23705.6km)
Range(take-off weight 74 ton(with 1.5 ton bomb×10 under the wing and 1.5 ton bomb ×3 in the bomb bay)) : 7000n.m.(12964km)
Range(take-off weight 78 ton(with 4.6 ton bomb)) : 13000n.m.(24076km)
Range(take-off weight 78 ton(with 3.2 ton bomb)) : 13500n.m.(25002km)
Range(take-off weight 78 ton(with 2 ton bomb)) : 13800n.m.(25557.6km)
Armaments : 13mm gun×2(fuselage both side), 13mm coaxial gun×1(tail)
Crews : 6
Remark : Range was calculated using following conditions.
① From take-off and following 20hours : cruise altitude under 8000m with 190kt(351.8km/h) speed.
② After 20 hours from take-off : cruise altitude 11000m with 220kt(407.4km/h) speed.
③ Bombs and bullets are consumed after 6000n.m.(11112km) flight.

操縦席 : Pilot seat, 無線航法士 : Radio operator/navigator, 乗員仮眠用ベッド : Crew nap bed, 機密室隔壁 : Pressurized cabin bulkhead, 胴体内タンク : Fuselage tank, 翼内タンク : wing tank, 桁 : Girder, 側方銃座遠隔方式 : Remote controlled side turret, 爆弾 : Bomb, 機内配置略図 : Simplified inner fuselage general arrangement
 

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Existing TB 3-side view's propotion is obviously strange. Fuselage length(28m) is too short compared with wing span(32.4m).
Correct propotion is as follows. But fuselage diameter is still too slim, perhaps wing area is too large(wing chord is too long) and nose is little long?.
I only extend the existing TB plan view to longitudinal direction using Microsoft Word, free soft GIMP2 that Jozef taught me and free soft Jing. ;D
 

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blackkite said:
Exising TB 3-side view's propotion is obviously strange. Fuselage length(28m) is too short compared with wing span(32.4m).
Click to expand...

For a long-range bomber a wing with a high aspect ratio may be a good choice, I think. And the B-24 had a
span/length ratio of 1.55 (here it is 1.16).
 
Jemiba said:
blackkite said:
Exising TB 3-side view's propotion is obviously strange. Fuselage length(28m) is too short compared with wing span(32.4m).
Click to expand...

For a long-range bomber a wing with a high aspect ratio may be a good choice, I think. And the B-24 had a
span/length ratio of 1.55 (here it is 1.16).
Click to expand...
Yes! Also tapered wing is very important to reduce wing root bending moment due to lift. If you have large wing surfece apart from the fuselage such as Republic XF-91, wing root bending moment due to lift will be very large for such a long span wing.
 

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