i-400: giant scale with Seirans

[ghethco]

I became quite captivated with the i-400 and the Seiran aircraft ever since (20 years ago) I walked past the huge fuselage of the Seiran at the NASM Garber Facility and the docent casually mentioned "That thing was designed to be launched from a submarine!!!"

I've recently been building electric R/C airplanes and it hit me that it might be feasible to build an i-400 large enough to have a workable R/C Seiran.



OK, get ready... the scale I'm thinking of would be a Seiran in the 30" wingspan range, and the i-400... over 20 feet long! I figure, broken into three segments, it will fit in the back of my truck.



I'm not thinking of making the i-400 submersible, just a big model ship. But it MUST have a working catapult and be capable of launching the Seirans!

Am I totally off my rocker??? OK, don't answer that, I know the answer already

Gary

[dietzer]

I've always wanted to build

I've always wanted to build one of the I-400 series! Good choice!

Have you found plans of the I-400? If so, what plans are they, and what scale are they?

Thanks,

Carl

[anonymous]

Hi

all plans in the net

Hi

all plans in the net are not original because the original not exist anymore. Those plans in the net not so scale, but olivier and me try to recreate a new one.


Gantu

[mylo]

Gary,

Off your rocker ??

Gary,

Off your rocker ?? .....not a chance. I LOVE the idea. I forsee it being quite costly, but not a crazy thing to do. If I was doing it, I would build it and keep it as a complete one piece model, however long. I would then get a separate trailer for it, kind of like a sea doo trailer but extended a little longer, so that you can literally launch your sub from a boat launch. Turn some heads, big time plus just way less messing around. Experience has taught me that when things are a pain, you're MUCH less likely to do it. In other words, you probably wouldn't get your real cool sub in the water as much as you think if you have to build it and wrestle with getting it in the water all in one piece (and not sink) everytime you go to play with it.

What scale will that be ?

....my 2 cents worth.

REALLY like the idea.

Mylo

[ghethco]

i-400 plans

Hi Gantu & Dietzer --

The side view I posted above is from the new book: "I-400: Japan's Secret Aircraft-Carrying Strike Submarine" by Henry Sakaida, Gary Nila, and Koji Takaki. This is the side view, the book also has top, front and rear views also. These drawings may not be exact, but they look better than anything I've seen before. I think they are definitely good enough to build a model from. The Seiran drawings in the book are excellent.

Unlike the i-400, a Seiran survived the war intact and has been fully restored. It's on display at the NASM Udvar-Hazy Center at Dulles Airport.

This is going to be a long-term project, and I can't even really get started yet because I have a couple of other projects to finish first. Ever since I got the new book, I've been daydreaming about this project here and there.

Mylo -- I like the trailer idea, unfortunately though I don't have any place to conveniently store such a trailer. I have a small house and yard and a garage already full of equipment and models. I'll think about it though. Hmm... I wonder if the sub would even fit in my garage at full size...

I would definitely use foam or whatever to make sure the model never sinks! I built a Robbe U-47 a few years back and ended up having to retrieve it from 20 feet of water with scuba gear!

Gary

[ghethco]

Tamiya 1/350 scale i-400

Tamiya makes a 1/350 scale i-400 kit, I just bought one from a guy in Hong Kong. I don't know how long it has been available, I don't remember seeing it before. Aoshima made a 1/700 scale i-400 kit years ago and also a 1/72 scale Seiran. Those kits are crude and probably hard to find now. I bought three of the Seiran kits with a dream of building a 1/72 i-400 to go with them But like I said the kits are crude and would have needed a lot of work to make a presentable model. SkyWave made a better 1/700 scale i-400 years later. 1/700 is too small to do anything interesting!

Tamiya sponsored the restoration of the NASM Seiran and produced a really first-class 1/48 Seiran kit which I snapped up at the first opportunity.

Gary

[locoworks]

If I go by your

If I go by your idea of a 30" span on the plane, that works the sub out at around 1/16 scale & 25' long, about 2'6" beam, you could if you are a small frame sit inside it.
Yeah yer mad but I like it!
might be a small problem getting it to the scale water line!
have you thought of propulsion yet? 24V system.
makes my inprogress 1/30 model now look very small
Gantu I have drawings that seem to be ok according to the pictures I have seen over the years & in the I-400 book.
Tony

[ghethco]

Hi Tony,

What do you mean

Hi Tony,

What do you mean by 'a problem getting it to the scale waterline'? I would think it would just be a matter of the right amount of lead and foam in the right places.

Can you give me more info on the drawings you have? All the line drawings I've seen have been crude. The color profile I posted here is the best thing I've seen.

I'm planning to transfer everything to CAD, drawings of both the sub and the Seiran.

Gary

If I go by your idea of a 30" span on the plane, that works the sub out at around 1/16 scale & 25' long, about 2'6" beam, you could if you are a small frame sit inside it.
Yeah yer mad but I like it!
might be a small problem getting it to the scale water line!
have you thought of propulsion yet? 24V system.
makes my inprogress 1/30 model now look very small
Gantu I have drawings that seem to be ok according to the pictures I have seen over the years & in the I-400 book.
Tony

[locoworks]

ghethco
What do you mean by

ghethco
What do you mean by 'a problem getting it to the scale waterline'? I would think it would just be a matter of the right amount of lead and foam in the right places.

Yes correct but the amount of lead required is going to be a lot.
Unless you go for a free flooding hull.
PM coming your way.

[ghethco]

i-400 construction method

Here's what I'm thinking for building the sub. Make bulkheads every 12-18 inches at the right shape, jigged to a keel to insure proper orientation. Fill in the spaces in between with foam and shape. Lay up fiberglass over the foam. Dig out or dissolve the foam with gasoline as necessary to install equipment or trim her for the right 'float'. Double the bulkheads at the 'break' points, use bolts to hold the three pieces together.

I would appreciate some pointers on where to get electronics & motors that would be big enough to move this beast! I don't care if it is fast, just needs to be able to sail out and "bring her about into the wind"...

Gary

[locoworks]

Re: i-400 construction method

Here's what I'm thinking for building the sub. Make bulkheads every 12-18 inches at the right shape, jigged to a keel to insure proper orientation. Fill in the spaces in between with foam and shape. Lay up fiberglass over the foam. Dig out or dissolve the foam with gasoline as necessary to install equipment or trim her for the right 'float'. Double the bulkheads at the 'break' points, use bolts to hold the three pieces together.

I would appreciate some pointers on where to get electronics & motors that would be big enough to move this beast! I don't care if it is fast, just needs to be able to sail out and "bring her about into the wind"...
Gary

Gary
I procured an electric wheelchair for my project, 2 electric motors with g/boxes, & the electronics (single lever left right forward & reverse)to drive the thing. Trim pot to set max speed as well
modern scooters have wheels to steer this one relys on the electronics to shut down 1 motor & spin the chair from the motor on the other side, or 1 into reverse & 1 forward.
Perfect for a tank or a sub & its a 24V system

[anonymous]

Hi

to do a good

Hi

to do a good plan it´s good to have a side, topview and crooscutingsection so it´s possible to recreate a plan. I will ask olivier may we do this plan with all bulkheads? If this i done i have here a guy he do cnc me bulkheads from wood very cheap so i don´t need to use a saw. A good scale for the sub would be 1:60 or 72 scale.







Gantu

[ghethco]

Hi Gantu,

Can you tell us

Hi Gantu,

Can you tell us where the pictures were taken and the scale of the model?

Yes, 1/72 would be a great scale for a static model, but too small for a flyable R/C Seiran!

The drawings I have do show 3-views, but they don't show cross-sections. I can do without these, but it would be easier if I have them as long as they're accurate.

[quote]Hi

A good scale for the sub would be 1]

[mylo]

Gents,

Excuse my ignorance as

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

[PaulC]

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.