i-400: giant scale with Seirans

[locoworks]

I may be wrong, but

I may be wrong, but I seem to recall Lyle Jansma was working up drawings of this boat in CAD several years ago. You might contact him and see what he worked up.

There is another chap who made some 1/48 white metal castings for the IJN subs. substuff@aol.com Chris I think?

Soar art is releasing a 1/144 scale I-400 soon. nice but too small imho.

1/30 1/32 scale is good for this boat, plenty of room for large batteries
Mylo
Yes the Seiran was used as a bomber scout plane etc & with floats could land & be retrieved buy the sub.
The seiran could also be launched without the floats with a bomb "bolted" to the fuselage to be used as a kamakazi weapon.

[dietzer]

Gary,

I was hoping you had

Gary,

I was hoping you had found a set of plans that I had not heard of. Oh well.

Before you try drawing your own plans, I suggest you try buying a copy of the same plan I bought on ebay. Ebay seller "great_plans" sells many ship plans on ebay, including one he calls 'Plans Japanese WW2 submarine aircraft carrier "I-400" '. He does not currently have one listed on ebay, but it was listed a few days ago, and he relists them rather frequently. The plans are in 1/120 scale.

I purchased a copy of these plans about 15 months ago. They matched pretty well with the 1/160 scale plans that came with the Hasegawa wooden I-401 kit which has long been out of production. The plan sheet from great_plans is not perfect, and it is missing some detail, but I think it might be the best set of plans for the I-400 class that is currently on the market. Of course, that may not be saying much...

With the 1/120 scale plans from great_plans, I think you could build a decent 1/96 scale I-400, but it would be difficult to build anything much larger than 1/72 scale from these plans as there are not enough hull stations. If you are truly set on building a 20' model, you will definitely have your work cut out for you in drawing up plans. You would definitely want to get the 1/350 scale Tamaya kit that others have already mentioned in this thread.

If you are serious in building a 20' model (which I cannot recommend), I would suggest you try to find and contact the japanese artist who did the 3-D models of the I-400 for the book "3D CGI I Type Submarines, ISBN#4-575-47600-5. Some one with that good of a CGI model might be able to produce hull stations for you. Good luck in finding him, though, as the book is entirely in Japanese...

BTW, you are probably already aware of it, but there is a good Japanese navy bulletin board at:

http://www.j-aircraft.org/smf/index.php?board=5.0

You might find some good I-400 advice there.

Hope this helps,

Carl

[dietzer]

Mylo,

The I-400 class was specifically

Mylo,

The I-400 class was specifically designed for a top-secret mission. That mission was to fly the Seiran in to the Panama Canal and destroy the locks by dropping torpedoes or bombs. By destroying the Panama canal, it would take ships from the east coast an extra 2-3 months to sail around South America to reach the pacific. Thankfully, the war ended before the I-400 class could be deployed on this mission. It would not have changed the outcome of the war, but it could have dragged it out a few more months.

You are correct about the floats. It could be flown back to the sub and dis-assembled and stowed back in the I-400's aircraft hanger. But it was well understood that the mission to the Panama Canal was likely a suicide mission in that it would be unlikely that the sub could be found by the planes after the raid. In my opinion it was equally unlikely that the I-400 could remain undetected that close to the Panama canal long enough to launch all three of its planes...

Get the book mentioned earlier in this thread. It is a fascinating read!

Carl

Gents,

Excuse my ignorance as to the use of the Seiran, but.....just how was this thing used ? Single aircraft raid on unsuspecting U.S. merchant shipping in kind of a quick strike surprise attack, or was it primarily a recon plane for it's mother sub ? Also, with it being float equipped, did it land near it's launching sub after it's mission to be craned back onto the catapult ?

Very interesting and unique piece of military hardware, both the sub and plane combo.

Mylo

[ghethco]

I-400 History, etc.

Carl -- thanks for all the info, bound to be helpful. Can't say I blame you for being skeptical about this project. I'm still a bit skeptical myself!

PaulC -- thanks for the tip, I'll try to contact this guy.

I'm don't have much doubt I can produce a workable hull in this size. The part I'm more concerned about is propulsion. I'm not sure if there is anything suitable made for this purpose, and I don't have machining equipment to make or adapt anything else. Though I've been drooling over a certain mini-lathe for some time now...

Anyone know of a good source for larger motors & ESCs made for model boats? Like I said, I don't care if this thing is underpowered, as long as it can slowly maneuver, hopefully even with a little wind/chop.

I'm used to being told "it can't be done". I got a lot of that when I began work on the Horten 229 (see http://www.wingsontheweb.com/ho229/). For me, that's a great motivator!

As someone already posted, the background of the I-400 is a fascinating story. This was the largest submarine built during WWII, but so secret that we didn't know about it until the surrender. Here are some links that will give you an idea:

http://en.wikipedia.org/wiki/I-400_class_submarine

http://www.armorama.com/modules.php?op= ... e&sid=2631

If this piques your interest, buy the new book, which has a lot of newly discovered details, "I-400]http://www.nasm.si.edu/[/url]



Gary

[raalst]

I'm not convinced propulsion is

I'm not convinced propulsion is the problem,
you could even mount an (electrical?) outboard motor in the
hulll out of sight.

what will be a problem is how to turn. you'll need 40 feet at least
for a turn. you'll need sideways thrusters.

and how to assemble this hull from it's 3 parts? in the water ?
getting something 20 feet long in the water might prove a challenge as well, even if the joints can bear it...

But don't be discouraged by all this, if you pull this off it will be
a globally unique model.

[mylo]

Ideas for thought:

I think

Ideas for thought:

I think that having the centre section, however long that may be, have all the water tight "guts" in it with simple wire connections to the fore and aft sections as needed. The assembly would be better done on dry land with the components mating up with indexing pins, along with some general pissing around. This might be one of those models where you have to go out with a buddy/wife/spouse/hired hand, in order to launch it. Assemble it on dry land, two people carry into the water, much like a big, kind of awkward canoe. Once in the water, put the plane on the catapult. I would suggest making the hull free flooding or you'll need a 20 ton crane to lift it. Plus, with a free flooding hull, the mating of the sections would be much easier as I would have the bow and stern components totally free flooding....no problems with trying to get a perfect water tight seal between the sections.

I would have a hull mounted bow thruster because as mentioned, getting a model of this size to turn, and turn quite sharply, would have to be considered. With a bow thruster, a few quick and easy bursts could get the model pointed into the wind quite easily not to mention overall control during sailing.

The bottom line is that unquestionably, this model CAN be built, it's a matter of how committed the builder is. What a unique modelling and engineering challenge. If it's your passion to build.....build it.


....well, ...I have my own project to get going on.


I'd like to see pics of this thing in the water in a couple years.


Mylo

[anonymous]

Gent´s,

i am just now redrawing

Gent´s,

i am just now redrawing the bulkheads is this is done and the rest of the plan from the i400 i can change to any scale. May we make a community projekt?


I look that i get the plan asap ready

Gantu

To to pic´s of the model if i have it right in mind was taken from a webside long time ago. But that was from a museum somewhere?

[herrmill]

1-400 Project

Gary,

There's a chap from NZ who is working towards building a 1/96 I-400 that would be a great assist to you in terms of plans & research material. I've been talking to him since January after meeting on the J-Aircraft forum & have I sent you a PM with his contact details.

BTW, Hasegawa recently released a kit that he is using for reference. You'll find for info & photos of this over in Sub Pirates static model section.

Your project sounds like a lot of fun!

Chuck

[ghethco]

Re: "Community Project"

Hi guys,

While I like the idea of a community project, I have to say I've not had good experiences with this in the past. The last one I was involved in, I ended up doing 99% of the work and the other guys got the benefit In this case I ended up pulling the project back in and making it more or less proprietary.

I'm in the R/C model airplane kit business, I design and sell kits of unusual subjects, see http://www.wingsontheweb.com. I will most likely keep the Seiran design proprietary as there may be some hope of selling a few kits. The i-400 is another story. I can't imagine too many people crazy enough to attempt it in the scale I'm talking about! So, I'm comfortable sharing whatever I come up with with the community. The CAD drawings can always be scaled as gantu suggests.

I've already started some tracing just to get a better idea of dimensions, but please share what you have gantu, you may be able to save me some trouble. What I was thinking of doing is CAD tracings of the 3-4 sets of drawings I've collected and comparing them to each other and to existing photos to try to arrive at something that is better than the sum of parts.

Mylo and raalst -- thanks for the thoughts and suggestions. Yes, I was thinking free flooding definitely, as much as possible. Though I was hoping to have most of the working bits in the aft section, having the middle section (with the hangar) just a shell and the bow section having the catapult and (now) thrusters (great idea).

And raalst is probably right, propulsion is likely not to be a big issue, just have to find and install the right bits.

Thanks again guys,

Gary

[herrmill]

1-400 Project

Gary,

There's a chap from NZ who is working towards building a 1/96 I-400 that would be a great assist to you in terms of plans & research material. I've been talking to him since January after meeting on the J-Aircraft forum & have I sent you a PM with his contact details.

BTW, Hasegawa recently released a kit that he is using for reference. You'll find for info & photos of this over in Sub Pirates static model section.

Your project sounds like a lot of fun!

Chuck

[anonymous]

Hi gary,

i know that in

Hi gary,

i know that in the naval historial center there have a lot of pic´s and infos about the i400. You can get copys from there? Did you allready have cad olans fron the i 400 because i start drawing the plan into vector.

Gantu

[shadowpeo]

These are a set of

These are a set of plans I have, the are obviously not full size as the full size files are huge, these are much smaller, and the dimensions of the image is reduced as well so its not the 1/72 you see in the image (yes the original ones are 1/72)





EDIT FIXED IMAGES SO LINKS ARE ABLE TO BE CLICKED FOR LARGER IMAGE

[ghethco]

Drawings...

Yes, I have some scans of those drawings. I've heard they were made using info from the captured submarines. I can see already that there is a lot of disagreement on the slimness/fatness of the stern and bow, and also on the shape of the bowplanes.

Gary

[anonymous]

Gents,

thats why we have to

Gents,

thats why we have to get those pitures from the naval historial center to get many details out of those pic´s.

Gantu

[dietzer]

Those scans are the same

Those scans are the same plan set sold by 'great_plans' on ebay.

I'd be willing to work on a community project. I've got a lot of I-400 references, and also have the wooden 1/160 scale Hasegawa I-401 kit w/plans.

BTW, is the guy in NZ that's an I-400 expert named Art? Art is a great guy! I'm going to have to email him again, I haven't chatted with him in a while...

Carl