A U-Boat In Ireland

[The Boattrainman]

This is what a 900ml Piston Tank looks like.




It's the spindle that's scary, it adds considerably to the length.




To set the Piston Tank anchor tightly, a 12mm by 15mm brass bush is made.




It matches the diameter of the raised piece at the end of the motor, and butts up against the battery tray plate.




I discarded the Piston Tank holding surrounds and made my own, there's fours holes for the full length threaded rods, and four for the holding rods a bit further out so that they can take 4mm bolts.




I'm using a feature of the tank, the three metal longitudinal straps, I've cut three notches per plate to hold the tank in place. The plate at the inlet end has a matching 10mm hole drilled.




The plate is screwed towards the tank jamming it up against the brass bush at the motor end.




The inlet hose is attached, and led through the receiver tray and through the motor plate.





And finally the end cap, all fits so far.




Here is the total tech rack, the Piston Tank dominates, and the spindle sticks out through the battery tray by about 25mm, but as the WTC is curved out at the ends, there is room (just about).




It's all fitted into the WTC, battery end first........




........Piston Tank and equipment trays................




................to the end cap, which closes with a twist,




The Boattrainman

[HardRock]

Very well done.

[reddevil]

Neat and nice. Keep in mind that as the tank intake is ASTERN, the tank starts filling from STERN, and that will affect the way the sub dives because the stern gets heavier first, so starts to dive sooner at that head.

[The Boattrainman]

Thanks guys.

Always an issue when the inlet is facing the rear, and it's such a large single tank, I've squeezed every cm of space to give me the biggest volume possible. I looked at all the options, 2 X 450ml tanks counter firing towards each other, trying to route the inet hose to the front but then the problem is the spindle firing towards the end cap with issues there etc. etc.

Anyway, I have a trick or two if there is significant issues with the aft section going down first..............!

Rob

[The Boattrainman]

As spring finally arrived in Ireland, there was gardening and other outside stuff to do, so finally getting back toU557.

The two 5000mah Lipos are modified to accept my standard Deans type connectors, the interconnectors are just too big, so standard 30amp single connectors are encased in heatshrink.




The are held in under the battery tray by a hook and loop strap, the connectors come up through small holes, and they pass tightly into the WTC.

[The Boattrainman]

The time has come to attach the end bayonet cap to the rear hull, but first there's lots of holes to be drilled in it, horrible job.

As the end cap has a weird shape, the 15mm plastic tube surrounds to be filled with epoxy are cut to the shape.




Here are two examples, one of the four tech rack rods filled with epoxy and the inlet for the on/off switch with additional Bluetac to stop leaks which will picked away when the epoxy is solid.




The red cables taking 12v outside the WTC and the white cables for the speaker are soldered to1.5mm pins pushed through the cap





The usual plastic surround is made and filled with epoxy.




The cables get a surround on the outside as well to be filled with slow curing epoxy, and the brown wire is an external extension to the Receiver aerial.




Still holes are needed for the fore and aft dive planes and the two prop shaft tubes, the cap will be like Swiss cheese when finished.

The Boattrainman

[The Boattrainman]

Almost there, here is the end cap, at 1,3,6 and 12 O'clock are the tech rack rods sticking through the end cap with bolts and epoxy surrounds. The three brass tubes in a row are forward and rear dive plane push rod exits and the rudder pushrod exit in the centre. The aluminium tube at the top is for the On/Off switch push rod and the larger brass tube is the water inlet for the piston tank. All that's left is to put prop tubes on the shafts.




The inner side of the end cap is a mess, luckily the cover plate will cover all these openings.




And when fitted to the rear hull section, it'll be tricky to get to all the parts.




The Boattrainman

[The Boattrainman]

I finally got the rear hull attached to the end cap, a combination of plastic pieces as shims and lots of epoxy, the hull break is not too bad but needs work.

I managed to drive pins through the hull into the raised ridge on the end cap for stability and strenth.




The end cap is seated on a series of plastic shims, the gap between them was filled with epoxy and the cap fitted.




Now to set the shafts in place.

[The Boattrainman]

The intermediate shafts are standard 3inch items from Model Bits.



As usual they are surrounded by a resin filled outer tube.



Both inside and outside the end cap the shafts get collars and 4mm O-rings, lightly compressed to the end of the shaft at both ends. I pressure tested these and once the tubes are filled with grease there are no leaks.

[The Boattrainman]

The wiring can now be tidied up, 12v down the starboard and aerial extension down the port.




The rear light can now be sorted, it's a brass etch stuck to the deck.




A 2mm LED is inserted through a hole into the unit.




A plastic surround is the added and filled with epoxy encasing the wiring and the capacitor that reduces the voltage.




The Boattrainman

[The Boattrainman]

The rear light is pure white, but reflecting off the inside it appears off-white which is great, I don't like pure white on period vessels.


The hull break is better with lots of sanding and fillets of styrene.




Here are two final shots of the end cap and through hull openings, all 13 of them (4 pushrods, 4 tech rack rods, 12v/speaker, piston tank water inlet, aerial extension and 2 prop tubes, I'm looking forward to my next project with just one!




All tided up when the rear cover plate is attached, the pushrod exits hade LED bezels as surrounds and the prop shafts have 10mm washers for a neat finish. No one will ever see the inside of the boat, but it's better than looking at the messy end cap!




The Boattrainman

[cgbillb]

Rob
I believe you are wrong, in stating that “The Wolf Pack, a Collection of U Boat Modelling Articles “

Is sort of a Bible for U-Boat nerds.Your build log is the only Bible any modeler needs, great work
This will be my bible for my U-92 printing it off now
Thanks for all the great information
Bill

[The Boattrainman]

Hi Bill,

Thanks for the kind words, if you root around the forum, there are amazing builds out there, even if it's not the exact sub you are making, the advice is great, and Mr. Merriman is always on hand to steer in the right direction.

As a matter of interest, what point are you starting out from, I presume it's the 1/48 Arkmodel kit, I hope you're not starting on converting the Robbe one as I did, it's a severe tect of patience!

Rob

[The Boattrainman]

I found these pushrod terminators online, handy as I want the screws pointing upwards for convenience.


Here are the four pushrods without bellows exiting the end cap, top left is to the on/off switch, then left to right, rudder, rear planes and fore planes.




The fore plane reverse throw mechanism and the rudder pushrod mechanism.




Here's the whole rear section with pushords...............





......looks roomy but it's very tight for access in there.

[cgbillb]

Rob
Yes it is a

1/48 Arkmodel kit,

and I have a problem right out of the box, here is a photo of my rudder linkage, not going to work, thinking of designing one like yours. Any ideas.
Bill