Japanese BI I-25 in 1/72

[oztruck]

Ok this is what I have got to fit into my dry area.

2 x 7.2 stick batteries
2 x electric motors and gear boxes
2 x ESC's
2 x Air pumps
1 x receiver
4 x servos
And still leaving enough room fo my ballast tank





Will it all fit?

[oztruck]

This is a mock up of how it should look like. There is still other other vital parts that I need to find room for. The auto trim leveler, the fail safe, the emergency ballast blow gas and the ? for the recovery float.

[oztruck]

OK, did a bit more on the hull detail while the glue was setting up on the water tight thingy.





Knowing how much space I had to have for the ballast tank and limited to an overall length of 28" (the hull shape thins each end)
all I had to do was move things around till it all fitted and could be easily worked on.
The ballast tank bulk heads and the communication tube were set in place and made fast with super glue and epoxy, also some plastic glue.
They were set aside to dry and while they were drying I made the retaining/strengthening parts that the lids bolt against.







So far I am happy with the way it is working out and looking forward to getting it wet again but this time with the drive unit installed.

[oztruck]

I forgot to mention that I am using the 1/16" push rod seals and the 1/8" prop seals that Caswell sells and DM produces on this project. At least I know that they will work without leaking.

[redboat219]

Wouldn't it have been easier just to go with a dry hull with this boat?

[Outrider]

If I ever get around to it, I'm using a Gato SD, as David suggested. The Wiz posted somewhere that he thought all he'd need to do is lengthen the ballast tank on the Gato SD to get it to support Lindberg's monster. The scratch-built system is interesting and I'm glad to watch it being built, but I'd rather get the SD and be done with it. I think a dry hull would be a problem for this kit, since it's polystyrene and not built with any R/C use in mind.

[oztruck]

Outrider, I would love to be able to use one of David's SD on this but at the moment it is out of the question. After seeing there build quality in person (one of my club members just got one) and using some of there other products has got me dreaming of one day getting my own SD from Caswell.

The Lindberg kit is very heavy especially above the water line and need a lot of volume in the ballast tank to get it to sit at the correct water line. So it would need extra ballast area in the Gato SD. But that is nothing that the "Wiz" could not handle.

redboat219, I don't think a boat this size made of plastic would be strong enough to handle the extra weight needed, and it would limit any future additions or alterations to the monster. The way it is going to be set up is flexible enough to allow me to change any thing inside the hull without any damage to it. I could even replace my water tight thingy with a good SD when things change for the better.

[redboat219]

Ok.

BTW, Ever considered getting a 1/72 aircraft kit to place on the ramp to spice up the look while running on the surface?

The 1-25 carried the Yokosuka E14Y floatplane http://en.m.wikipedia.org/wiki/Yokosuka_E14Y

looks similar to the Arado ar 196 carried by the Bismarck. So if you could find one in 1/72 you can dress it up to look like an IJN plane.

[oztruck]

I have a "Glen" on order, hope to have it soon. Fujumi do a very nice 1/72 scale Glen and it even comes with a catapult.

[He Who Shall Not Be Named]

Wouldn't it have been easier just to go with a dry hull with this boat?

Would have been a complete nightmare.

David,

[oztruck]

OK back to it.

With the BOX all assembled and everything inside it working it is now time to test it.

I am going to test it the same way I tested my other one in the ALFA.

Here in South Australia our water quality is not all that good so most houses have large rain water collection tanks.
They are all about 6' deep or 2 mtrs.

The way I test my water tight thingy is to assemble it, run it, then drop it in the rain water tank with enough weight on it to keep it on the bottom.
I leave it there for 10 min then pull it up and have a look for water inside, if all is OK it then will go back in for a day or two.

24/48 hours at a scale 432 feet is in my opinion a good test. If it survives it is then put into service, if not ?????

[oztruck]

The WTT or water tight thingy is still being tested, because it is too cold and wet outside to get it out of the rain water tank.

I did a bit more detail work on the hull, hand rails, boarding ladders and Ariel mast

[He Who Shall Not Be Named]

I hate it when a post is simply praise with no constructive comment other than stupid gushing. Well ... I'm gushing, Oztruck!

What a magnificent accomplishment you have pulled off here -- you have turned what otherwise is a waste of plastic, into an interesting, well detailed, and reasonably faithful representation of a specific class of Japanese submarine.

Wow!

David,

[oztruck]

Thank you David, complements are always welcome and help to lift the standard of all of our model building.

But when it comes from the MAN it means a lot to me.

[oztruck]

OK, my WTT (watertight thingy) is now out of the rain water tank. It had a bit of condensation in the rear area and anything on the outside that was not plastic seems to have rusted but it looks like it could be ready to install into the sub after a bit of a clean up.

This is the rear area.

Here are the 2 drive motors and gear boxes, 2 ESC's, 3 servos- One for the rudder, one for the rear dive plane and one for the gas blow/recovery buoy, and the 2 Air pumps.

On the lid there is a section that is removable with 4 screws to help vent and dry the unit after missions and if needed make small adjustments to the control linkages. It also has a Schroeder valve to pressure test the unit.
The air hoses also exit through the lid







Here we have the center section or ballast tank.

The lid is made of 1.5mm clear plastic that I heated up and formed a raised section in it and that is where I installed the air outlet/inlet. This I thought will make it easer to remove ALL the air even in a 15 deg dive, because without it air could get trapped at one end of the ballast tank if it was not sitting flat.
Because each section has it's own lid I can add extra material under the ballast tank lid to give me more volume if needed.





This is the front section (Reactor room). Living in here is the 2 drive batteries, the front dive plane servo and the servo/mini switch for the 2 air pumps and of course the receiver. The lid on this section also has a removable panel and the Ariel cable passes through the gasket to the outside world. Under it is the twin recharging jacks for the batteries and a ready made power source for a vent fan to blow through the front hatch and out the rear hatch after a mission. The idea with this is to be able to service my water tight thingy without having to remove it from the hull.





Now I am off to install it in the hull, connect all the linkages and begin the fun part, TRIMMING IT.