Landships II

Members Login
Username 
 
Password 
    Remember Me  
Post Info TOPIC: Dicke Bertha / Big Bertha 3d model


Corporal

Status: Offline
Posts: 11
Date:
Dicke Bertha / Big Bertha 3d model
Permalink   


Hello,

I am in the process of modelling this fascinating, historical gun in SolidWorks. Have attached raw renders of the current state. Comments are welcome; there are still a lot of details missing and/or unclear, but at least the overall proportions are way better than the Takom kit. My sources are the nice drawings from this forum (uploaded by Arie Dijkhuis) and the model from the Paris Army Museum, that I went to see earlier in the year.

I have been fascinated with this weapon of mass destruction ever since seeing a photo in Guinness Book of Records, Danish edition ca. 1972, that turned out to be Cherubin's wooden full-size model.

Cheers,
Steen



Attachments
__________________
Drawing 3d models of military and naval hardware


Legend

Status: Offline
Posts: 1673
Date:
Permalink   

Have you read M. Romanych & M. Rupp's monograph  "42cm "Big Bertha" and German Siege Artillery of WW1"?

Marc Romanych inhabits this forum from time to time and may be able to help with some of the details of the 42cm M-Gerät.

Your model would make a great first  (and the most important) step in the production of a cardmodel of the M-Gerät.

I agree the Takom model just doesn't look quite right to me although I find it's hard to identify exactly where the Takom model is 

in error.

Regards,

Charlie

 



__________________
MLW


Lieutenant-Colonel

Status: Offline
Posts: 151
Date:
Permalink   

To my knowledge, Arie Dijkhuis' drawings are the best available. He created plans for the two initial prototype guns sent to the field in August 1914 and the later production models built in 1915. There have been a few other people who embarked on projects to create detailed drawings, but as far as I know they never published anything.

Regards,
Marc

__________________

Regards, Marc

Digital History Archive



Corporal

Status: Offline
Posts: 11
Date:
Permalink   

Hello Charlie,

Yes, I have read Marc's book - it gives a great overview of the whole weapons system with all the different variants. 

To my eyes, the Takom model have a trail and a trunnion that are too sleek, and the trunnion is mounted too far forward and too low. And the blast shield is too vertical.

I have done a quick Photoshop mock-up of what I think is a more correct geometry:

Cheers,
Steen



Attachments
__________________
Drawing 3d models of military and naval hardware


Corporal

Status: Offline
Posts: 11
Date:
Permalink   

Hello Marc,

Thanks for your post. I enjoyed your book about the Berthas a lot. 

From an engineering perspective, I am really keen to know more about the firing procedure for big mortars in detail. I wonder if you know of any sources...?

The Paris model has a front platform (in front of the shield), which I didn't model. I wonder what this was for, and how widely it was used, because in all the many images have seen, it only appears in a couple?

Cheers,
Steen



__________________
Drawing 3d models of military and naval hardware


Legend

Status: Offline
Posts: 1673
Date:
Permalink   

Tackling the firing procedure from a different direction. The 42cm M-Gerät used cartridge cases (big ones) for

obturation. The case has a primer in the centre of the bottom - http://www.kaisersbunker.com/cc/cc16.htm.

By analogy with other Krupp guns it's likely that the primer was activated by a spring loaded firing pin.

The Krupp system was to cock and fire the gun/howitzer from a  lever on the right side of the breech - this lever

had a ring for a lanyard. I think I've got some breech images of a 21cm Morser which possibly isn't too dissimilar

to the M-Gerät. 

Regards,

Charlie

Later... first image is the back of the breech block in a 21cm Morser - the central firing pin assembly is obvious.

The second image is the right side of the breech. The opening lever is at the top with the firing lever immediately

below it. The M-Gerät seems to have had a crank handle on the top right side of the breech ring to open/close the breech. 

 



-- Edited by CharlieC on Monday 5th of September 2016 11:50:14 AM



-- Edited by CharlieC on Monday 5th of September 2016 01:34:11 PM

Attachments
__________________


Legend

Status: Offline
Posts: 1360
Date:
Permalink   

Steen's renders look excellent! Far better proportions than the Takom model. For some time I was trying to create my own plans of the Bertha, and had been in correspondence with Arie a few years ago (he very kindly sent me early drafts of his work on the Bertha). I missed the plans he uploaded here last year, but attached is basically as far as I got.



Attachments
__________________


Corporal

Status: Offline
Posts: 11
Date:
Permalink   

An update showing the current state of the Solidworks 3d model with new renders. I am looking for info on the brackets used to guide/attach the ammunition tray to the breech. Several pics shows a flat-ish, detachable bracket mounted on the breech, but the Aberdeen Bertha had what looks to be guide wheels mounted in a horizontal plane. How did these engage the ammunition tray? Can anyone shed light on these devices....? confuse



Attachments
__________________
Drawing 3d models of military and naval hardware


Legend

Status: Offline
Posts: 1360
Date:
Permalink   

Superb progress, Steen! I wonder if those horizontal wheels are nothing to do with the ammunition tray but were, rather, to help guide the barrel into the cradle during assembly? Just a thought.

__________________


Corporal

Status: Offline
Posts: 11
Date:
Permalink   

Thanks Roger
Interesting thought that the guide-wheels could be for some other purpose; although they do seem slightly underwhelming for guidance of a 13 t barrel. Again, this is a detail that I have only seen pictures of on the Aberdeen Bertha, all other guns, that I know of, have a flat-ish, T-shaped bracket....?

__________________
Drawing 3d models of military and naval hardware


Corporal

Status: Offline
Posts: 18
Date:
Permalink   

Beautiful impressive work and very welcome. Although I have already built the TAKOM kit and were able to adjust a few details, based on your excellent drawings I will make a new model.

Big Bertha was a "secret" weapon and just a few usable photo's exists. As with many photo's taken the perspective is almost everytime from a standing uprigth position. Sometimes photo's published are copies from copies loosing details. Printing quality can be poor as well.....

Success,

Harry

__________________


Corporal

Status: Offline
Posts: 11
Date:
Permalink   

Thanks for your comments Harry
I also bought the Takom kit with the intention of redesigning the parts that needs improvement using CAD, but there are so many details that are dodgy, that it is very hard to decide what to keep and what to redesign, so the project hasn't taken off yet....!

__________________
Drawing 3d models of military and naval hardware


Legend

Status: Offline
Posts: 1360
Date:
Permalink   

Steen Winther wrote:

Thanks Roger
Interesting thought that the guide-wheels could be for some other purpose; although they do seem slightly underwhelming for guidance of a 13 t barrel. Again, this is a detail that I have only seen pictures of on the Aberdeen Bertha, all other guns, that I know of, have a flat-ish, T-shaped bracket....?


You're right, looking more carefully (rather than making a knee-jerk reply without looking!) at the large Aberdeen photo, I see the horizontal wheels are actually attached to the rear face of the breech-ring, not to the cradle and thus cannot have the purpose I speculated upon. Perhaps, though, they were to loop cables around as part of a sort of windlass-type setup for pulling the barrel into the cradle during assembly?



__________________


Corporal

Status: Offline
Posts: 11
Date:
Permalink   

Just a little update showing my findings regarding the accuracy (or lack of same) of the Takom Big Bertha model. The attached drawing shows just how much too long both the trail and the barrel are, making the overall size much too large. I am presently reverse engineering the Takom kit in CAD with the intention of revising the most glaring mistakes in order to produce a more accurate model.



Attachments
__________________
Drawing 3d models of military and naval hardware


Legend

Status: Offline
Posts: 1360
Date:
Permalink   

Fantastic progress, Steen! I must say that after my initial enthusiasm at the release of the Takom model a couple of years ago or whenever it was, I've become very disillusioned by it. There are so many errors, not least of which being that it's basically over-sized quite apart from proportional errors, detail errors etc., that it's impossible to modify it to make it accurate, you may as well build one from scratch.

After doing a comparison using Photoshop, I'm pleased to see that my old scale drawings (well, early stages anyway, I never finished them) are very close to yours in overall proportions...

Seeing as you're working up your drawings in a CAD programme, are you considering using it as a basis to get all the parts 3D-printed as a kit?



Attachments
__________________


Corporal

Status: Offline
Posts: 18
Date:
Permalink   

Beautiful work Steen. Impressive.

"Hope you will be able to do a Gamma gun as well.wink"

Success,

Harry

 

 



__________________
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.

Tweet this page Post to Digg Post to Del.icio.us