1/250 scale Zeppelin beta builder(s) wanted...

[Kugelfang]

Hello all,

This is my first design effort. It's a 1/250 scale airship, the LZ-17 Sachsen. At this scale it's almost 25 inches long so it is fairly big. I don't think it's a difficult build, though. It was mostly a learning project for me but I hope it produced something that other modelers will enjoy.

https://drive.google.com/file/d/0B9jtsIgx34oidHNLN1dwMTFPTmc/view?usp=sharing

I'm an inexperienced builder so I'd really appreciate feed back as to what you liked, what you did not like and what would make the design more enjoyable. There's no rush. Though I am eager to incorporate feedback and wrap it up and go on to another design. I'd particularly like feedback on the fit of the parts. My biggest concern is that the internal formers don't allow enough play for the thickness of paper used for the envelope covering. My intention is to use 67# card when I get around to building it. Print area is 7x10 inches so I think it should work for US Letter or A4 size sheets.

Thanks,

--jeff

[Rubenandres77]

I don't have much time, so I guess I won't be able to help you in the test build.

But let me tell you that the artwork looks really wonderful, the subtle texture of the fabric is very nice.

The triangular internal support looks like a great idea to hold the structure. I'm sure it will make for a sturdy model.

The graphic instructions are wonderful, and seem easy to follow. I wish more designers would make instructions like those.



Just a couple of notes:

I notice that the size of the pages is 7X10 inches (about 17.7 X 25 cm).
I can guess that it is because you wish to avoid the problem of Letter vs A4 size? If that's the intention, an additional note on how to print correctly would be welcome to avoid confusion, as many people use "fit to page/actual size/etc" as their defaults, and that can alter your desired print size affecting the scale.

I like a lot when the designers put some sort of measure in the kit. In your case you put the half inch corner to know that is printed at the correct size. That's good. Please take into account that the imperial system is used but only a handful of countries. Sometimes those of us living under the metric system also thank a decimal guide ;)

Why no copyright/credit notes? Since you designed this nice kit, you deserve to be acknowledged. :) Is both a way to protect your work, and for others to recognize your dedication.

I really wish to see this build. Looks like a very nice kit.

Regards :)

[missileer]

I would enjoy completing a Beta Build on this model I really love airships. If you don't mind it taking 3 or 4 weeks, I will be happy to sign on. The reason for the delay is another project (a diorama) that will be going on at the same time. Let me know if this time frame works for you.

John

[Kugelfang]

Thank you, gentlemen.

@Ruben, Thank you for the kind words and all your suggestions will be incorporated in the final version. I remember back in the 1970s when President Carter tried to get the US to move to the metric system. It all made perfect sense then and even more sense now. I think there are only two countries on earth that still officially use Imperial. Since I've lived all my life in one of them I tend to forget there even is another system!

@John, a 3 or 4 week time frame is fine by me. I am so slow at printing and assembling that I'm sure you'll still beat me by a country mile!

--jeff

[DougH]

A quick google and Myanmar and Liberia came up as the other countries using the Imperial system besides the USA

[snowmanX]

I am not an experienced builder but built Ralph Currells Graf Zeppelin and I think this is something I can build.

Charming model and a beautiful documentation. And not many models of the older Zeppelins which makes this kit unique in that way. I will try to have a build done by Christmas and advise of any issues I come across. Please post about any issues that are reported by other beta builders.

[ringmaster]

Those are the best instructions I've ever seen. It is a course in paper modeling. Good work.

[douglasmarrel]

Oh, if only I wasn't a never finish anything kind of guy :).Love zeppelins

[herky]

A quick google and Myanmar and Liberia came up as the other countries using the Imperial system besides the USA

did you miss the UK??:)

[CharlieC]

did you miss the UK??:)

Not true - the UK's official measurement system is metric but there are special dispensations such as the road signs which still use miles. There was a recent article in our local Oz papers about what Brexit will mean for measurements - there are the Poms who want to go back to the Imperial system when England leaves the EU.

Regards,

Charlie

[Kugelfang]

Thanks again for the comments, fellow paperists. They are appreciated. I will certainly pass on any build feedback I receive.

@douglasmarrel: "finish" ??? New word to me. I have no idea what it means ;-) . Go on... you know you want to....

My understanding is that Myanmar, while not officially using the metric system, mostly uses traditional Burmese units. So that leaves the US and Liberia as the Imperial holdouts. Not too long ago I was conversing with a British couple who were renovating their home. They mentioned that when ordering new drapery, the height was typically measured in meters, but the width was measured in inches. Who knew drapes could be so complex?

--jeff

[Rubenandres77]

One curious thing to mention:

Although here in Colombia we use metric, in almost all our life, we still use "letter" size paper for common use (office, photocopies etc.). And it is very very hard to find A4 paper in reams. If not impossible. To get "A" sizes I've had to buy the whole big pages and cut them to size.

Another extended use we make of the imperial system is in the fuel. It is still measured in gallons.

[Kugelfang]

I just uploaded a revised version of the beta kit. Added some 'about' information, copyright, etc., added a few fold indicators which may not have been obvious. Also revised the scale markings to indicate both inches and centimeters.

Are the cut and fold lines self evident in this kit? Would it be worth the time to create a cut/fold diagram? They seem obvious to me but I've been staring at this thing for days and days now.

Thanks,

--jeff

[ringmaster]

I am worried about attaching the gondolas to the keel, no instruction is given leaving the builder on his own. Parts PO-1 and PO-2, the airscrews do not have printed front sides, although they are visible.
Vertical rudders are generally called elevators in English.
Beautiful model.

[Kugelfang]

More feed back! I love it!

Good point on the propellers. I'll incorporate that. The 'horizontal rudders' (s.07) should be renamed elevators. Not sure why I wrote it that way but I'll make the change. (I'm not thoroughly convinced that 'horizontal rudder' would be an inappropriate term for 1914, but 'elevator' is certainly the more accepted current term.)

Ah, the gondolas. Yeah.... From what I can tell from photographs, they were suspended under the central keel by three pairs of cables and then had aluminum girders attached fore and aft to provide stability. I think the best representation would come from using thin lengths stiffened thread or wire. To be honest, I've yet to decide how to do it. I suspect anything in paper would be so fragile as to be pointless. There's also something that extends from the engines in the gondolas to the airscrews. I can't determine if they were chain driven or had some sort of shaft (probably).

Recently I've come to believe that the front gondola had a windshield attached to it. Perhaps the rear gondola did too, but I think that's less likely. Such a windshield is probably in the works. One of the things I found challenging about this model is that the zeppelin itself is large. But that means that fine detail parts are super thin and fragile.

Thanks!

--jeff

[Diderick A. den Bakker]

I love Zeppelins. Had a quick look at your design, and miss tabs needed to 'close' the various segments of the envelope, so they become 17-sided tubes?

[herky]

Not true - the UK's official measurement system is metric but there are special dispensations such as the road signs which still use miles. There was a recent article in our local Oz papers about what Brexit will mean for measurements - there are the Poms who want to go back to the Imperial system when England leaves the EU.

Regards,

Charlie

thats interesting as all the time i was there we used inches,feet.miles
pounds and ounces.metric might be official but no one has told the population:)

[JohnM]

Right ol' mixup here now. We buy petrol by the litre, but still drive by Miles per hour and miles per gallon. Signposts still give distances in miles (I've not seen a Km one yet). Most modern(ish) cars have digital mileometers with both available, but everyone I know still switches them to miles. Of course the old bangers that I mostly drive don't have the Km option anyway.

Most shops pretty much sell everything in Kg/gm weights and most liquids are now in litres, but there are many street markets where the Costermongers are doggedly hanging on to Pounds and ounces. They've tried to force them to change to metric by taking them to court, but I don't think there's been a successful prosecution yet. Pounds, Shillings, and pence are long gone now though, and it's only ol' duffers like me that object to paying £1.50 for a sixpenny ice cream cone.:rolleyes:

Here in Wales all the signposts have to be bi-lingual as well. By the time you've read through the Welsh to get to the English words ... you've gorn past it anyway.:rolleyes:

Listening to the rumblings here ... if UK do ever actually achieve Brexit (I'm not convinced I'll live to see it happen) I reckon the Taffs won't be too far behind the Jocks with our own independence referendums.

[herky]

:)Right ol' mixup here now. We buy petrol by the litre, but still drive by Miles per hour and miles per gallon. Signposts still give distances in miles (I've not seen a Km one yet). Most modern(ish) cars have digital mileometers with both available, but everyone I know still switches them to miles. Of course the old bangers that I mostly drive don't have the Km option anyway.

Most shops pretty much sell everything in Kg/gm weights and most liquids are now in litres, but there are many street markets where the Costermongers are doggedly hanging on to Pounds and ounces. They've tried to force them to change to metric by taking them to court, but I don't think there's been a successful prosecution yet. Pounds, Shillings, and pence are long gone now though, and it's only ol' duffers like me that object to paying £1.50 for a sixpenny ice cream cone.:rolleyes:

Here in Wales all the signposts have to be bi-lingual as well. By the time you've read through the Welsh to get to the English words ... you've gorn past it anyway.:rolleyes:

Listening to the rumblings here ... if UK do ever actually achieve Brexit (I'm not convinced I'll live to see it happen) I reckon the Taffs won't be too far behind the Jocks with our own independence referendums.


I remember long after decimal currency in uk we were on an excersize taking ATC up snowdon.There was a pub in Betws-y-coed who still qouted all his prices in pounds,shillings and pence:)

[THE DC]

This is a great team effort.

Its appreciated.

[missileer]

Jeff,

Did you have a building sequence in mind for the forward section. It appears that you would first have to assemble f.03 to e.04 and then e.04 to f.04 to get the perfect alignment you will need to attach f.04 to f.05 later in the build.

Since there were no tabs, I tried starting with gluing the bottom side of e.04 to f.03 while both parts were flat. Then I began curving both parts by gluing the next tab on f.03 and so on. This did not work well. So now I am starting with making rings of all the parts and then I will start with e.04 working forward.

If neither of these methods were intended, please let me know let me know your assembly thoughts.

John

[Kugelfang]

@John: I imagine the front section would be easier to build from front to back. E.g., form the front cone e.01, attach f.01, attach e.02 then f.02, etc. Though, I haven't built anything in seven years so this is just how I intend to attack it. It may change. My first thought was to use butt joints with joining strips but I've added tabs anyway. They can always be cut away.

A new version has been uploaded with changes suggested in this thread (mostly minor): the aforementioned tabs to the envelope sections, fold marks in areas that may be confusing, simplified scale markings, both sides for the propellers.

The page size has been changed from 7x10in to 8.5x11in, though the print area has remained at 7x10in. I found that my printer drivers(?) just couldn't deal with a custom page size. I think this should maintain A4/US Letter compatibility.

--jeff

[missileer]

Jeff,

After studying the drawings again, it appears to me, that the whether you work from the front or the back, you will always have to glue the connector ring to the top of the envelope ring first ( f.01 to e.02; f.02 to e.03; f.03 to e.04). You might use that as a cautionary note.

Regards,
John

[Kugelfang]

John,

Earlier you said that when you started by gluing e.04 to f.03 and working your way around from the bottom that it did not work well. What was the issue? Was it fit? Did the shapes seem off?

I cut out the parts for the nose section late yesterday and will probably start gluing today. Once I had the parts in hand and did some dry-fitting, that sequence seemed to make perfect sense so that's how I intended to start.

Thanks,

--jeff

[missileer]

The problem was trying to curve two separate pieces at the same time and keep everything aligned. It was not a fit problem; it was a builder problem. After trying the assembled ring method on the foremost connector ring, I agree that the best method is the one you are going to use. I am in the process of reprinting the connector rings and have arrived at a gluing process that will work for me. As soon as I have the connector rings on e.04, e.03 and e.02, I will post photos of the four separate envelope rings before assembling the foreword section.

[Kugelfang]

Yeah, I came to the same conclusion. I've started a build log on the forum to keep me motivated.

--jeff

[missileer]

This first photo shows the process that I used to connect the glue strips to the envelope strips. I creased both type strips and then glued the glue strip to the envelope strips before I closed the envelope ring.

[missileer]

I closed the rings with a butt joint using a piece of scrap. I am in the process of gluing the former ring (f.04) onto e.04.

[missileer]

For some reason, I cannot post with photos. I'll try again tomorrow.

[Kugelfang]

Ouch! f.04 was a deal killer for me.

I continued building over the weekend but quickly found that my fear that the internal formers were going to be too large proved true. I need to reduce them in order to get them to fit into the envelope cylinders.

Is there any rule of thumb when designing internal parts to allow for paper thicknesses? Like... circular formers should have a diameter equivalent to 98% of the diameter of the 'outside' parts?

Fit issues are particularly labor intensive revisions to make considering my design process but I don't know how to solve them without iterative test builds. Any advice would be appreciated. (Actually... I should have known better than to do all the graphics before ensuring the parts fit together!)

--jeff

[Rubenandres77]

...
Is there any rule of thumb when designing internal parts to allow for paper thicknesses? Like... circular formers should have a diameter equivalent to 98% of the diameter of the 'outside' parts? ...

You may wish to have a look at the first post in this thread:
http://www.papermodelers.com/forum/tips-tricks/3177-making-paper-cylinders-ledge-full-inner-layer.html
Although it is applied to a different challenge, I think the explanation
on how to compensate for paper thickness may be useful for your case. :)

[thorst]

You need to account for the paper thickness in mm, not in %. That means that you need to set the scale for your model before designing the actual parts. In general, I use 0.1mm thickness per 100g/m² (that means 0.2mm for 200g/m² and so on). In most cases, the outline of the parts you want to print is the shape of the part in the neutral axis (see here: https://en.wikipedia.org/wiki/Neutral_axis). So assuming you design a cylinder with a diameter of 100mm with the formula

part_length=2*r*Pi

and don't account for the paper thickness, the outer diameter of the cylinder will be 100mm + paper_thickness , the inner diameter will be 100mm-paper_thickness. A former should thus have the diameter 100mm-paper thickness.

On the other side, you may want to have a cylinder with the outer diameter of 100mm. Then you need to take it into account before calculating the length: D=2*r=100mm=2*r_neutral_axis+2*paper_thickness. The length of the part needs to be 2*r_neutral_axis*Pi, and the diameter of the former is 100mm-2*paper_thickness.

When modeling with 3D-software, you can just trace the part directly in the neutral axis and add half of the paper thickness in each direction. This way, you can account for the paper thickness when designing formers of irregular shapes.

[Kugelfang]

Thanks for the links and explanations. I'm using 65# cover stock (so a thickness of ~ 0.198mm). Since my model is actually polygonal in cross section rather than circular, are there any calculations to determine tolerances for the corners of the polygon? Do creases affect the Neutral axis? Or is this usually not a factor?

The above questions are for future reference.

In this case I think an empirical process is going to work better for me. While I could revise the original 3d model to a high level of tolerance to account for the paper thickness, I can't really export only the revised parts to the SVG format for the paper model. I'd have to export the entire model to ensure that all the parts are printed at a consistent (though not necessarily accurate) scale. With Wings3d, that is an art, not a science--scale consistency is the BIGGEST challenge in this work flow. It also would set me back all the way to the beginning of layout and graphics in Inkscape.

Instead, it's probably a more effective to make minute reductions of the formers in Inkscape, print and assemble to determine when I've reached a good fit.

Oh, well, it is a learning project, after all.

--jeff

[thorst]

If you want to use your current Inkscape files, I would try to offset the outlines of the formers by ~0.1mm to the inside for cylindrical sections, and to about 0.3mm for the front formers. At the formers in between, just use values in between. That's just an estimation, you'll see if it works later.

In general, I found the method of adding half of the thickness in each direction to work well also for folded parts. Trying to draw even more exactly quickly leads to cases where the design accuracy is less important than printing- and building accuracy. So just try if it fits together after using the method above, and then tweak it slightly if it doesn't work.

Thorsten

[Kugelfang]

I got lucky. Looks like the first size reduction I made will work. I'll be able to tell for sure once I assemble the rear portions. But for now... back on track.

(Also uploaded the revised version to the link in the first page of this thread.)

--jeff

[missileer]

Jeff,

Thanks for the update and discussion of the sizing problem. I found that I had to trim the connecting rings and make some spacer cuts in f.04 to make it fit. I thought that I had really lost my cutting skills and was going to beg off on the beta build. I'll download the update and try again.:)

John

[Kugelfang]

Hi John,

Never assume I know what I'm doing! If there's a problem in building, more than likely it's because I messed up the design.

I appreciate you taking on the build.

--jeff

[Don Boose]

This and your other dirigible build thread are exceptionally informative. Great Imagineering, engineering, math, and rollation.

Don

[Tino]

Not true - the UK's official measurement system is metric but there are special dispensations such as the road signs which still use miles. There was a recent article in our local Oz papers about what Brexit will mean for measurements - there are the Poms who want to go back to the Imperial system when England leaves the EU.

Regards,

Charlie

Really they want to do that? They should also forbid the EU to use the english language! :)


I would like to build this model but with the available time that I have and the Akitsushima very far from finished I cant for now.

[missileer]

Jeff,

Now the glue strips are slightly too short and the formers slightly too small in diameter. Circumference wise, the former f.04 is approximately 1/4 inch too small. I am using 65# (or 176 g/m) paper.

John

[Kugelfang]

Hi John,

I'm not seeing that issue on my end. Actually, I don't recall reducing parts f.01 through f.03 (the glue strips) only the round formers since that was where I was having problems. Former f.04 fit quite snuggly for me when using the reduced sizes. Is it possible your printer was not set to 100%? Do the scale marks measure at 1cm and .5in correctly?

My WIP build is printed directly from Inkscape so I printed out a page from the pdf to compare to the Inkscape print out and I'm not seeing any size difference there, either. You've got me puzzled.

I just uploaded the latest version where I reduced the triangular keel parts (fk.01 - fk.03) a bit more because they would not fit through the formers. On the second page of the instructions there should be a version number (v.2016####). The latest is v.20161113. The changes that have been made since the initial upload are that the scale marks have been redesigned, parts f.04 - f.24 have been reduced in size by 2% and parts fk.01 -fk.03 have been reduced by ~ 5%, in addition fk.01 and fk.03 have had cut-outs added to help the flaps fit into fk.02 better.

--jeff

[missileer]

Jeff,

If you are not seeing the problem, then it has to be on my end. I am going to print the whole package again, using your latest upload. I will then check all pages to make sure that they line up (I thought that I did the last time, but maybe I missed something). I have never had a problem before, but Murphy's law says the if anything can possibly go wrong, it will! :)

John

[missileer]

Jeff,

Forgot to ask: was this set up for A3 or A4 printout?

[missileer]

Jeff,

I think that I found the problem (Murphy's law is alive and well). My printer was set to "Fit to Page". I don't remember ever selecting that; it must have been a WWII retired Gremlin. :)

John

[Kugelfang]

Hi John,

You may want to wait to reprint if you've not already done it. Yesterday I woke up with the feeling that uploaded an incorrect page with the last of the round formers on it. Due to that pesky day job I didn't have an opportunity to verify. I'll do that today.

Re A3 or A4: Neither, actually. Being in the US I designed for Letter (8.5x11in). But the printable area is set to 7x10in so it should fit A4. I suspect your printer probably defaults to something other than Letter so it automatically gave you the 'fit to page' option in order to fit the printer default page size.

Yeah... Murphy and his law are my boon companions!

--jeff

[Kugelfang]

Doh!

I see you're in Annapolis. We're near neighbors. I'm in Silver Spring. I assumed since you asked A3/A4 that you were outside the US.

--jeff

[Kugelfang]

False alarm on my part regarding uploading some wrong pages. The download is current.

--jeff

[missileer]

Roger that. I am in the process of building the forward section again.

John