Another airship underway: 1/144 Z XII Scratchbuild.

[MoFo]

I'm currently awaiting delivery of a large format resin printer, so while I wait, I've been designing another Zeppelin model to print on it: Z XII.



Z XII was one of the first Zeppelins built during the Great War and the only N Class Airship.  As an early war design, in many ways it bridges between the pre-war passenger airships and the war time bomber/reconnaissance airships.  It introduced changes such as the duralumin structure and central keel, but maintained the external keel of the passenger airships.  The gondolas were enclosed, with the front using a pusher propellor for the first time, while the airship lost the venetian blind-like array of tailplanes for a simpler, cruciform tail structure.  It had a successful career spent mostly on the Eastern Front, before being retired to training and development and, astonishingly, managed to survive the war.  It was the first airship to bomb Paris, the first to use an external 'sub-cloud car' for navigation, and it was the first aircraft to use a standoff guided weapon: the Siemens Torpedo Glider.  This is how I plan to finish my build, in a late-war sheme with dark envelope with a lighter top section, and a pair of torpedo bombs slung underneath.






...as seen here, which also happens to be my primary reference, using the excellent scale drawings contained therein.  The volume covers the history of all the early Zeppelins used in the war, with special focus on Z XII and the O Class ship LZ39.

[MoFo]

Sooo... how to design a model kit.



The first step was to scan the scale drawings, re-size them to the correct scale dimensions, then carefully trace the key dimensions - the outline of the airship, location of the tails, gas cell locations, etc.  This is a fairly slow, tedious task with a lot of time spent fretting over fractions of a mm (mostly needlessly) and wondering which side of a line to trace to.









This process also serves to get the gist of the shapes into my head.  It familiarizes me with the intricacies of the subject and just generally helps me get up to speed.



With that done, the actual design work can start.



A cylinder with the diameter of the envelope was extruded for the nose, then excess was cut away to form each individual facet.







The same process was repeated for the tail.  There's also quite a bit of cross-checking with the scale drawings and with reference photos, to ensure the creases are formed in the right locations - it's not just a simple 17-sided structure.







...and then a simple loft in between the two sections to finish the raw shape of the envelope.







With that done, I turned my attention to the keel, creating a loft to form the front end:



 



...then the back...

 



...then the transition sections...

 



Before completing the centre section:

 



Which seems fairly straightforward, but required a bunch of planning, tweaking and revision.  The loft tool is powerful - it can make complex 3d shapes - but it's also kind of dumb and doesn't always do what you want it to.  It needs to be able to connect each vertex - each 'point' - from one sketch to a matching point on the next sketch.  Try to loft a square into a triangle, for instance, and things can go haywire. 

[MoFo]

Next, attention moves to the tailplanes.  These were sketched out, then more complete detail drawings made, before the actual modelling was begun.

 

First, the framing is extruded:


 

Then the 'fabric' is extruded - slightly thinner than the framing, to give slight relief.


 

Then various details added - the rudder trailing edged were chamfered to a thinner edge, fillets added to the tailplane leading edges, control horns(?) added, etc.  And the same process was repeated for the horizontal tailplanes.


 

The envelope was copied, then a thin shell is created as the basis of the framing detail.  The frames were then marked out and the areas between cut away from the shell, leaving a series of thin 'rib tape' rings, which are then merged with the original (correct size) envelope:


 

And finally, detail areas were cut out from the almost-complete envelope: windows, the gun platform, rigging points, etc.

[GazzaS]

That is very interesting.  And impressive.  I'm looking forward to watching this come together.  How long will it be from stem to stern.

[MoFo]

About 110 cm or 44 inches.

[lone modeller]

That will be impressive when finished. I admire anyone who can handle the programme for 3D printing - it is certainly adding a new area to our hobby.

Stephen.

[KiwiZac]

Fascinating stuff! I enjoy seeing projects like this in such detail, thank you for sharing so much of this journey.

I admire anyone who can handle the programme for 3D printing - it is certainly adding a new area to our hobby.

I'm learning CAD for just that purpose, but it isn't as easy to pick up as I'd initially thought.

[kensar]

1/144 scale and still 44 inches long!!  These things must have been quite a sight in the air.

[Dirigible-Al]

Hi MoFo.
The N Class is a great choice, a really cool looking Zeppelin. Will it have any of the SSW Torpedo Gliders attached?
Alan.

[Beto]

What a great (in many senses) project!!! - Greetings!

Maybe I'm wrong, but I prefer to say it now that the problem can be addressed... in the last render the rings don't seem to be equidistant lengthwise as I think they should be. Have you checked that?

Cheers,
Beto

[Alexis]

This is going to be good !


Alexis

[RAGIII]

Like all of the others I will say this is/ will be an impressive build! Looking forward to your progress.
RAGIII

[MoFo]

Sorry for the delay in responding.  I've been moving house. 

That will be impressive when finished. I admire anyone who can handle the programme for 3D printing - it is certainly adding a new area to our hobby.

Stephen.

Thanks.  CAD isn't hard per se, it's just a different skillset to be learned.  It's like airbrushing, or model building - the fundamentals aren't all that hard to understand, but mastering them takes time and patience.  It's a really cool feeling to design something on your PC and then hold it in your hand once printed, though.

Fascinating stuff! I enjoy seeing projects like this in such detail, thank you for sharing so much of this journey.

I admire anyone who can handle the programme for 3D printing - it is certainly adding a new area to our hobby.

I'm learning CAD for just that purpose, but it isn't as easy to pick up as I'd initially thought.

I'm hoping it will serve as a bit of a tutorial for anyone interested in the digital side of things, rather than just showing a completed model as "here's one I made earlier".  If there's anything you want to see in more detail, LMK. 

One of the biggest hurdles I found with learning CAD was simply figuring out how to think about applying steps.  I did a lot of design, then undo because I'd done things in the wrong order, then re-do because inserting a process broke all the other operations.  Not a terrible way to learn though - once you've thorn away six hours work because you messed something up on the first step, you tend to remember that lesson! 

1/144 scale and still 44 inches long!!  These things must have been quite a sight in the air.

They were ridiculous.  They were basically the size of battleships, floating in the sky.  And this is a 'small' one - the Hindenburg is 5'8" in 1/144.

Hi MoFo.
The N Class is a great choice, a really cool looking Zeppelin. Will it have any of the SSW Torpedo Gliders attached?
Alan.

Yeah, it is cool with the gondola underneath.  Next up will be one of the pre-war passenger ships, with the ridiculous-looking mass of control surfaces.  They look like Venetian blinds!    And yes, the plan is to have the gliders underneath.

What a great (in many senses) project!!! - Greetings!

Maybe I'm wrong, but I prefer to say it now that the problem can be addressed... in the last render the rings don't seem to be equidistant lengthwise as I think they should be. Have you checked that?

Cheers,
Beto

Thanks!  And grrr!  But thanks!  I appreciate the criticism.  Good eye - the spacing was indeed wrong.  That's what I get for just following the drawings, rather than double checking the measurements.  They should be spaced 10m apart (that's one of the defining characteristics of the N class - it was the first Zeppelin to adopt the standard 10m spacing), mine were not only uneven, but the wrong spacing.  Fudge.

So, it's fixed now (will update later), but what seemed like a simple fix - just adjust the spacing - essentially involved re-building the entire airship.  The cool thing (and the curse) about Zeppelins is that they're quite 'mathematical' in their design.  Everything is spaced at even distances (to the meter, even if those measurements aren't all the same).  Everything lines up (the gun platform aligns to a main station; the rigging and struts line up with stations), which makes it easier to draft... but if something is off, it has ripples through the rest of the work.  So in this case, a 'simple' re-work of the stations meant re-designing the envelope gondola, the envelope itself, and the gun platform, plus all the location points for the struts, rigging and external gondolas (gondolae).  About the only things that didn't need altered were the tailplanes.  Sigh.

(but I do appreciate it - I've seen another Zeppelin being built elsewhere that has the ribs in the wrong locations, and it drives me nuts!)

This is going to be good !


Alexis

I hope so.

Like all of the others I will say this is/ will be an impressive build! Looking forward to your progress.
RAGIII

Thanks.

[Ringleheim]

I really enjoyed watching this come together with the CAD design work.  Very nice job!

I would LOVE a 44 inch sized zeppelin kit!  I know there are a couple on the market now, but they are quite small and that defeats the point.

As someone above said, an object of this size would be something like 1.5 football fields long.  You can only imagine it slowly and quietly moving through the sky towards its target.  It must have been an early form of psychological warfare.  I know I would be scared silly seeing this thing slowly coasting towards its target!

Good luck with the project and I look forward to seeing more progress!

[MoFo]

I would LOVE a 44 inch sized zeppelin kit!  I know there are a couple on the market now, but they are quite small and that defeats the point.

That could be arranged...