ZRS5:U.S.S. Macon

[Gil Russell]

A preliminary glimpse into the design phase of a 1:200 scale paper model of the U.S.S. Macon. The main hull surface is now complete with large detail projected onto the hull. All surfaces are developable or can be unrolled into a flat planar surface suitable for modeling in paper or depron. Upper fin is identical to port and starboard horizontal fins. Lower fin is a separate design as it was widened in the original to obtain enough space for an auxillary control room. Finished model will be slightly under 120 cm in length and will have F9C-2 aircraft for hangar and trapeze. Attached image has been given a little help in Photoshop to make it slightly more appealing.

-Gil

http://img129.imageshack.us/img129/9563/maconaftstb3vt.jpg

[Charles Adams]

WOW! You've obviously had some practice at this. Nice! :)

Could you tell us a little about how you make a "developable" model in CG? What software, techniques, etc.?

I know how to build the basic hull and project the markings and other details onto it. But I have never dabbled in paper modeling so I don't know all the tricks to developing paper surfaces from CG models.

Thanks! :D

PS What's depron???

[Gil Russell]

Hi Charles,

I use Rhinoceros 3D (Rhino 3D) to develop 3D models. There are a lot of different 3D apps around but I find Rhino alone is the most productive for doing 3D models. It has a surface develop command which will take a developable surface and "unroll" it on a flat plane. This command is the Holy Grail for paper model design. Note that any use of Nurbs meshed surfaces is off limits as they can't be unrolled. 3D modeling and rendering of a design allows the designer to "render & sculpt" the model to accomodate the fact that it is made from paper. After the unrolling the models surfaces they are then opened in PhotoShop where coloring, weathering, and other special effects are accomplished. It's then printed and built.

Depron (or Zepron as it is sometimes called) is a closed cell styrofoam sheet material used mostly in Europe as a floor underlayment and as an insulation material. It comes in thicknesses varying from 2 to 6 mm and can be ordered in North America from various sources (URLs below). Many people in the RC community have been using it to make aircraft using an enlarged paper model as a template. The resulting aircraft are very light, strong and use modest motive power. Besides that they look great and build fast. The material is easily worked and bonds well using PVA (white glue) adhesives.

http://www.airdyn.com/zepron.htm

http://www.depronusa.com/


-Gil

[CanisD]

That will be one spectacular model when finished. Are the Sparrowhawks going to be built in the same manner? With the Macon you could have one on the trapeze and another on the skyhook, or maybe have one be an F9C, the other an XJW-1.

[Charles Adams]

Thanks for the tips! I also use Rhino and am getting really good at it and I agree with everything you said about it. I simply love this program! I know some 3D modelers aren't crazy about it, but I have not used any other program that is more perfect for physical modelers who want to use the latest "power tools" to make their patterns. When it comes to pattern making, mesh modelers can't seem to hold a candle to spline modelers.

I've been drafting for 20 years now and can develop 2D patterns for just about anything I want to build. But using a 3D program really takes things to the next level, doesn't it? Yet there is so little info on either subject for modelers. For the last 6 months, I've been working on a multi-volume book called "Drafting and Pattern Making for Modelers" in which I share my experience and techniques for creating blueprints and construction patterns. Vol. 2 will talk about how to make patterns for 3D models and also how to use 3D tools for developing patterns for physical models.

Even though I have been using these tools for a long time, I am not a paper modeler, that's why I was curious about paper modeling techniques. I have heard of special programs created for developing mesh models. Some of the work required to develop complex paper models is pretty sophisticated!

Rhino's tools for this are not perfect. They won't develop compound curves or certain complex surfaces. They also won't do anything with a mesh. I have found the "unroll" function somewhat tricky to use. When the interface asks for the "direction to unfold" that seems a little strange!

I had never heard of depron. From the links you posted, it appears to be a soft closed-cell foam with a skin. I recognize this from the little foam gliders I used to have while growing up. This stuff does not seem to be suitable for carving, though, since it is soft. Can you use a hot wire cutter on it?

[Gil Russell]

Hi CanisD,

One thing that I forgot to mention is that the model will fufill being either the Akron or the Macon. Several small changes makes this possible.

The F9C-2 Sparrowhawk is being designed by another individual as part of a joint project. The wing span is 38 mm so it is on the "small" side.

The only other aircraft flown on a regular basis from the Macon was the NY-1 which was used mainly as an air taxi to transfer personnel, mail and a limited amount of supplies between the ship and the ground. The models target is to show it in its intended rolls as an airborne aircraft carrier.

Now who will build a scale USS Patoka?

-Gil

[CanisD]

The Waco XJW-1 replaced the N2Y-1 on the Macon in 1934. The NHS has photos of it here. (http://www.history.navy.mil/photos/ac-usn22/j-types/xjw.htm) It was bought off-the-shelf from the civilian market since it fit the door and the N2Y's were considered worn out.

Akron moored twice to the Patoka, but Macon never did. There's a model of the Patoka and Shenandoah at the San Diego Maritime Museum, photos located at Steel Navy (http://www.steelnavy.com/PatokaAO9bc.htm)

I think the biggest changes besides the name on the hull of course, are the engine outriggers. Macon's were more streamlined and she also had different propellers. The condenser panels differed at times as well. Akron had several new versions which were smaller than the originals, though they didn't replace all the sets. Macon removed the third pair aft when they were considering removing two of her engines to extend her range.

[Gil Russell]

Hi All,

For some reason I missed Charles last post. Sorry Charles, all my fault.

I agree with your assessment. People that don't like Rhino tend to be more into the Nurb type package which does not apply well to the real World of engineering and production processes. They also dislike AutoCAD and other drafting packages. If the object is animated characters Nurbs is the way of the World. But building set items that will suspend disbelief requires near parametric quality that can easily be generated by Rhino. Rhino's real strength is in it's ability to enable quick prototyping and what if viewing before the fact.

The surface development facility in Rhino becomes second nature once one takes the time to experiment and fully understand it's limitations. This also extends to the way in which the model is designed which can become a problem when it's not a requirement. In other words the model is designed from the beginning with only surfaces which can be developed. This is not always easy and sometimes requires several test subjects to work out the details.

Paper doesn't stretch very much (5% at best) so tolerances have to be fairly tight to make everything fit (this is one of the items which a card model is measured by). Things like card thickness have to be taken into account and a small amount of fit tolerance dialed in. The model is finished using a paint program like paintshop of photoshop where coloring, panel lines, rivet detail, weathering and the like are added. This is where cardmodeling can really have an effect that would be extremely difficult to achieve through traditional modeling techniques. Glues used are PVA (Poly_Vinyl_Acetate) types with Aleenes Tacky Glue being very popular. I use the cheapest PVA I can find thinned with a little water applied with a hypodermic bottle, a small fork made from a large needle eye on a handle or a small paintbrush.

Another form of cardmodeling doesn't utilize computer generated paint but more traditional methods and is generally called multimedia cardmodeling. Think of this as being similar to the methods used in architectural models. A card model can be sanded just like a wooden one it just needs to be sealed with nitrate dope or hard lacquer first. Methods of inkjet printing on tissue paper make applying lettering and insignia fairly easy.

So, in a nutshell, that's a high level view of card modeling in general. Note that paper is highly available, cheap and easily worked and doesn't necessarily have to be the main element of construction. The fact that you can print out your parts and laminate them to the right thickness card or board is a very attractive modeling technique for just about anyone.

-Gil Russell

[Charles Adams]

Card modeling seems like a special art form unto itself. I think a lot of neat things can be done with it. :)

A potential disadvantage I see with paper models, however, is their susceptibility to moisture. As with wood, the model must be sealed. But, even then, you can't seal every portion of the paper (back side, inside surfaces, etc.). Therefore, humidity will take its toll on a paper model over time. . .

[Gil Russell]

Charles,

For most models that need not be touched by sandpaper I seal with a coat of acrylic matte followed by a coat of gloss arcrylic followed by a misting of acrylic matte if a dull coat is desired. This method thouroughly penetrates the paper with an acrylic matrix making it fairly impervious to moisture. No this treatment doen't bother the print quality although the whiteout caused by the first coating of matte acrylic will cause the onset of an angst attack, it totally disappears with the acrylic gloss coat...,

-Gil Russell

[Goncalo Mendes]

Hi CanisD,

One thing that I forgot to mention is that the model will fufill being either the Akron or the Macon. Several small changes makes this possible.
(...)

Now who will build a scale USS Patoka?

-Gil

I'm working on it, by five years now. No date to finish it...

Goncalo

[Digger]

I can't believe I didn't notice this thread till today. How far from finished is the model? And how can we get a copy? I've already built the Macon in 1:350 scale, but would love to have one in 1:200 scale (Akron too), as most of the paper zepps I've built (or will be soon) are in this scale. :cheers:

[Gil Russell]

I can't believe I didn't notice this thread till today. How far from finished is the model? And how can we get a copy? I've already built the Macon in 1:350 scale, but would love to have one in 1:200 scale (Akron too), as most of the paper zepps I've built (or will be soon) are in this scale. :cheers:


Hi Digger,

I put it on hold for the time being. The preliminary design study has been finished and there's no reason it can't be done in card at 1:200. Texturing the surface still remains an interesting task as does the selection of the underlying card to print it on to obtain the "look".

Best regards,

Gil Russell

[jejeusn]

Gil
Do have any updates to your 1/200 Macon project?

[Gil Russell]

Still safely moored in a back-up file waiting for a reluctant administration to appropriate funds sufficient for finishing construction...,

Gil Russell