DKM Bismarck by MikeConnectrix - Scale 1:150 - 3D printed - RADIO

[MikeConnectrix]

Hi,

 

It's been a while but I have been doing stuff since completing the Tirpitz model.

 

Bismarck and Tirpitz are brother ships (German navy ships are male whereas most other navies ships are female so grammatically not a sister ship). So making a 150 Scale model of Bismarck should be no harder than upscaling the Tirpitz Model 133% and modifying a few parts right???

 

Wrong

 

This is a complete re-design correcting some minor issues in the hull and making it more friendly for remote control use.

 

1:150 versus 1:200 doesn't sound like much of a difference.

 

 

My wife is quite displeased. Where are you going to keep that?

[MikeConnectrix]

The hull is printed in PETG, I used a layer height of 0.3mm with organic supports on hull 1 and 8. I don't recall using supports on any of the other sections.

 

The hull pieces are printed from the bulkhead upwards so there is no issue with build plate adhesion even though some parts taper out from the first layer (Like Hull 2 in the picture below)

 

Hulls 1 and 8 are printed from the open end so there is a risk of instability due to the small amount of bed contact. I did have an issue with Hull 1 lifting slightly, you can see the gap when it is glued to hull 2. This is easily filled and the deck will be laminated with a detailed deck plate so should not visible going forward.

 

Mating hull parts have a joiner that is attached to the bulkhead on one of the parts using JB Weld and M3X10mm machine screws.

 

 

This is then JB Welded to the other part

 

 

Etc etc..

 

 

 

Edited Sunday at 11:01 AM by MikeConnectrix
Spacing

[MikeConnectrix]

Hulls 4 and 5 are connected by a double sided joiner as the print direction on the hull pieces changes direction.

 

 

The joiner is attached to Hull 5 with JB-Weld and aligned using the tabs printed into the hull piece.

 

 

[MikeConnectrix]

Hulls 4 and 5 were right at the extent of my printers bed in width so I elected to split the pieces with PrusaSlicer vertically using 1.75mm dowel joiners.

 

There is steel keel stringer epoxied into a channel at the centreline when the hull is fully assembled so the chances of this join leaking when assembled is low.

 

 

 

Hull 6 Bulkhead has an oil reservoir for the prop-shafts that will feed into the prop tubes which needs to be glued into position.

 

 

[MikeConnectrix]

The keel stringer is a simple black steel M3X20mm flat bar with some angle grinder cuts to get the correct profile.

 

Measurements of this are not critical. If its 5-10mm shorter  or has the corners rounded to get a comfortable fit it is of little consequence. Weight is not an issue. This thing will need a ton of it to settle at the right level.

 

Here is a pre-oxidised version of it:

[Ian_Grant]

There seem to be more and more 3D printed ships showing up here. I've started one too. It's interesting.

My hull section #4, a 22 hr print, seems to have warped as it cooled even though I added inner and outer brims.

Trying to decide how to proceed......

 

Do you plan to have the turrets rotate? Access along the hull inside looks to be restricted by your joiners.

 

Looking forward to more!

 

ian

[MikeConnectrix]

Hi Ian,

 

A lot of work goes into designing the models so that they print well and look OK. This one will be a mix of resin and FDM prints so its a case of PETG where strength is needed (even though it looks stringy and rough) and Resin print where detail is needed.

 

I printed the hull pieces at 0.3mm layer height so they don't look as good as they could but largely this will be covered with PLA deck veneers and filler/paint. The appearance could be improved by printing at 0.2mm but then your time for each section goes up. I think the longest one on this was 18 hours, but at 0.2 it was over 24. 

 

My easy solution to cutting my print times in half was to just build another MK3s

 

One difference between the Tirpitz Model and this model is that the main deck structure is incorporated into the hull files. The Tirpitz model has a tendency to warp until all the deck plates are glued in. This one is rigid as anything and apart from one piece lifting slightly from the bed I haven't encountered too many issues.

 

The turrets are already done, I just haven't detailed them yet. The mains have traverse and elevation, the secondaries just have traverse (considering elevation in the 150's but there is not much room in the turret). All up it will be around 30 servos. The bulkheads/joiners have large apertures in them so passing wiring should not be an issue.

 

I did have an issue with one pair of 150's where the bulkhead is directly underneath it and while I put in relief for the turret into the bulkhead I did not put enough to actually fit the turret. (The servo, by necessity due to the turrets size, protrudes outside the turret basket.) I have since altered the bulkhead file but for this one a dremel was my friend.

 

Mike

 

 

Edited 16 hours ago by MikeConnectrix
Spelling

[Ian_Grant]

Thirty servos!!   Just how long is this model? My 1/150 HMS Lion from WW1 is about 54" long; I used mini servos for turret traverse. It would be impressive to have elevation too but the turrets from the 70's are solid wood (this is a "restoration" build on one of my teenage builds). There is plenty of room in fact I was planning to add smoke but the smoke unit I bought has a mind of its own as far as actually making smoke.

 

Looking forward to your build..........

 

Ian 

 

ps: if you click on "follow" at the top of your log, you'll get automatic notifications if someone adds a comment.

Edited 1 hour ago by Ian_Grant

[MikeConnectrix]

In the lead photo:

• Tirpitz is 1:200 = 125.5cm=49.4 inches
• Bismarck is 1:150=167.33cm=65.9 inches

Maybe not 30 servos. I can definitely see 27.

 

I will be using a 3 channel controller  Rudder/Throttle and Main Fire control director. Everything else will just follow that based on compass input.

 

 

 

 

[yvesvidal]

1 hour ago, Ian_Grant said:

 It would be impressive to have elevation too.

The old Lindberg Bismarck kit had a clever way to elevate the guns while rotating them. Look it up.

 

Yves

[Ian_Grant]

13 hours ago, MikeConnectrix said:

I will be using a 3 channel controller  Rudder/Throttle and Main Fire control director. Everything else will just follow that based on compass input.

 

Extremely cool tech! Are you a fellow retired engineer? I used an Arduino to control the oars in my RC Roman galley, writing code to read the throttle and rudder inputs and control the oars via two servos per side; one for the fore-aft motion and one for up/down. The model can't overcome much of a breeze, and I found even my oversized rudders couldn't steer her at her slow speed. She's on the shelf until I have more time and ideas. Writing the code was fun, even though I was a hardware guy all my career. 😏