Author Topic: 3D Printed WWI Drachen Observation Balloon.  (Read 1134 times)

Offline MoFo

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3D Printed WWI Drachen Observation Balloon.
« on: January 05, 2021, 07:48:41 AM »
1/144 (they're surprisingly large), designed in Solidworks and printed on my Photon. 

The full balloon is done in two halves so it's a simple assembly.  Roughly placed together here, but after grinding out the base and giving the halves a quick sand, it's a perfect fit.  (the halves are hollow, with 2mm thick walls so it's very robust, but the base of each half cupped slightly when curing.  easy to remove with a dremel, though) 

 

I've given it a subtle droop with some puckering underneath the main ballonet, as was typical in-flight.  My first pass was straight, more or less per the drawings, but it felt a little 'wooden', so I re-built the model with a slight curve and some weight and shape to the fabric sections to give it a little life.  Fairly pleased with the result:



Note the small hole on the side, necessary as a vent hole during the printing process.  It'll be simple to plug, either with a length of styrene rod, or I may apply some tape over it and back-fill with a dab of UV resin.  A bit of a necessary evil, but it's certainly easier than filling/sanding the seam lines if it were a plastic kit.

Oh, and for the 3D printing nerds out there, the sections were printed straight on the build plate at .05mm layer height with mid-level anti-aliasing.  There is some slight voxellation on it, but either a light pass with some fine sandpaper, or a coat of levelling pimer (like Tamiya or Alclad) and it should be good to go.

Next up: drafting the various rigging lines and figuring out a way to depict them.  Debating between etching them, or having them laser cut in card stock.  PE would be more 'traditional', but laser cutting should be faster and more forgiving, and if it's impregnated in CA, every bit as strong.

And, while all airships have, err, a 'certain shape', this is far and away the most explicitly phallic model I've ever seen!  :o

Offline aircooled

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Re: 3D Printed WWI Drachen Observation Balloon.
« Reply #1 on: January 05, 2021, 10:16:51 PM »
Nicely done! Do you have any in-progress pics while it was in the printer? I've just acquired a Photon Mono myself. Seems there is a little bit of magic involved with orientating the part on the build plate and properly supporting it.

Offline William Adair

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Re: 3D Printed WWI Drachen Observation Balloon.
« Reply #2 on: January 05, 2021, 11:08:03 PM »
That looks amazing.  I've often thought how nice it would be to make one of those.

Offline Alexis

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Re: 3D Printed WWI Drachen Observation Balloon.
« Reply #3 on: January 05, 2021, 11:24:59 PM »
Different , what is the over all length ?

Alexis
Hurra ! , Ich Leben Noch
Body and life is a vessel we use to travel the planet . Femininity is the gift , The miracle comes from what we do with it .

Offline MoFo

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Re: 3D Printed WWI Drachen Observation Balloon.
« Reply #4 on: January 06, 2021, 10:32:24 AM »
Length is about 20 cm or 7 1/2", from tip to tip, though it'd technically be shorter in flying orientation (but taller) as it sits at an angle.

Do you have any in-progress pics while it was in the printer?

No, but I took a couple of screen caps in the slicer for you.  Printed straight on the build plate, no supports necessary (apart from a small bit of webbing added in the CAD to help support the end cap).  I do a lot of printing directly to the build plate - there seems to be a weird phobia about it - since it gives a cleaner mating edge and saves print time.  The only precaution needed is to add a vent hole near the bottom layers, to allow air/resin to escape and reduce suction forces.  You will also have to deal with the 'elephant foot' on the initial layers from the increased exposure time, but I've been playing with the "Bulge Buster" app to eliminate that effect.





(the main section was hollowed in CAD, hence the smooth interior; the end cap was done in the slicer, so it's rougher)

Offline gbrivio

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Re: 3D Printed WWI Drachen Observation Balloon.
« Reply #5 on: January 06, 2021, 04:29:31 PM »
Unusual, even not the first Draken balloon on the forum it's always a fascinating subject. Looking forward for your progress.
Ciao
Giuseppe

Offline Alexis

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Re: 3D Printed WWI Drachen Observation Balloon.
« Reply #6 on: January 07, 2021, 12:13:27 AM »
Thanks for the reply , 20 cm is a good length .


Alexis
Hurra ! , Ich Leben Noch
Body and life is a vessel we use to travel the planet . Femininity is the gift , The miracle comes from what we do with it .

Online RAGIII

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Re: 3D Printed WWI Drachen Observation Balloon.
« Reply #7 on: January 07, 2021, 02:43:23 AM »
Very cool project. I am afraid the Tech is above Me but I look forward to your progress!
RAGIII
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"Don't slop it on" Lynda Geisler

Offline aircooled

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Re: 3D Printed WWI Drachen Observation Balloon.
« Reply #8 on: January 07, 2021, 06:59:44 AM »
Length is about 20 cm or 7 1/2", from tip to tip, though it'd technically be shorter in flying orientation (but taller) as it sits at an angle.

Do you have any in-progress pics while it was in the printer?

No, but I took a couple of screen caps in the slicer for you.  Printed straight on the build plate, no supports necessary (apart from a small bit of webbing added in the CAD to help support the end cap).  I do a lot of printing directly to the build plate - there seems to be a weird phobia about it - since it gives a cleaner mating edge and saves print time.  The only precaution needed is to add a vent hole near the bottom layers, to allow air/resin to escape and reduce suction forces.  You will also have to deal with the 'elephant foot' on the initial layers from the increased exposure time, but I've been playing with the "Bulge Buster" app to eliminate that effect.

(the main section was hollowed in CAD, hence the smooth interior; the end cap was done in the slicer, so it's rougher)

Thanks for the tip on bulge buster. Downloaded. I'm going to give it a shot. Coming from a FDM printer, the idea of having to print a bunch of supports and elevate a part off the build plate seems pretty foreign.

Offline petrov27

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Re: 3D Printed WWI Drachen Observation Balloon.
« Reply #9 on: January 07, 2021, 07:44:17 AM »
very cool - looks great! Any chance when finished you might sell the stl files for others to print it?

Interesting point about printing directly on the build plate - I have avoided that entirely so far due to the strange stuff that happens sometimes to the initial layers but maybe will try again
-Patrick

Offline MoFo

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Re: 3D Printed WWI Drachen Observation Balloon.
« Reply #10 on: January 07, 2021, 10:23:37 AM »
Coming from a FDM printer, the idea of having to print a bunch of supports and elevate a part off the build plate seems pretty foreign.

I guess it's the same idea as a raft on an FDM print (which seems dumb now that we've got Buildtak and PEI).  But really, there's no reason not to print directly on the plate when you think about it - the 'reason' is that you want to minimize peel forces by reducing the cross section of the base layers... so instead you should print a raft with an even bigger cross section?  It makes no sense.   (don't get me wrong, rafts definitely have their use, but 'never print on the build platform' is silly)

very cool - looks great! Any chance when finished you might sell the stl files for others to print it?

I'm not really keen on selling the STLs, but I am willing to sell individual prints.