DC-3 (Again)

[Gil]

Hello All,

I've been working on this design off and on for several years now and recently decided to make another attempt at getting somewhere with it. It didn't take long to become totally mired in details that either weren't obvious in the documentation or was completely wrong. Most of the time has been taken in staring at photographs to get the details right. Just remember one thing, "there is no such thing as accurate documentation" and that also includes any of my own personal output as it's also based on the "drivel in - drivel out" principle (I am doing my best to get it right though). The fuselage has been completely redrawn so many times now that I've lost count. Each time the fuselage is redrawn the wing fillets have to be completely redone and so on..., Some of the shapes look deceivingly simple until you start designing it and soon find out that this bird has some areas which must have taken a lot of super fudging to get them right. The aim is to get the wrinkles in the same place as the full scale model. Funny thing that...,

I personally like this bird (a lot) and for one design to span from its first flight in December 17, 1935 till the present gives an amazing amount of latitude for just one basic airframe. I'm just doing the DC-3 design currently but will have additions for the C-47 and foreign manufactured birds also. I've given some thought to the distribution of the finished model and haven't come to any real conclusions yet. The scale will be 1:32 and 1:24 with the larger size model a simple enlargement of the smaller one.

The photo below is a tease render of the fuselage front view.

+Gil

http://img340.imageshack.us/img340/1584/frontviewr2v13kd9.jpg

[Leif Ohlsson]

I'm happy to hear you've moved the DC3 from the backburner, Gil. As for the intricacies, I can fully empathize - I once made a simple 3D model of it for the Xplane flight simulator, so I have some idea of what you're up against, particularly in the cockpit area, the fuselage-fin area, and the wing-fuselage fillets.

But it it a beautiful aircraft, and so unique in its versatility. In the sim version, I've flown it several times across the Atlantic (by way of Iceland, Sondre Stromfjord, and Goose Bay, which was the classic route for the DC3 transports during the war), and have fond memories of that.

As you know, I would be among those first in line to savour a civilian or neutral model of this classic. A "white" version with the rivet lines would be an ideal first step, since the DC3 appeared in so many liveries, and national & company markings.

So, here's hoping a few more steps in that direction will be taken by you.

Leif

PS. Anticipating your reply - no, the 3D model in the Xplane sim is altogether much too simple for anything you would need. It wouldn't be of any help at all. You are already way beyond that. But here's another teaser (from the Farm Security Administration collection of colour slides at the Library of Congress). Looks a little bit like a BIG card model, doesn't it? Note the intricate shaping above the cockpit side window, just to highlight an example of what you are saying:

http://www.papermodelers.com/gallery/data/532/medium/1a35284v.jpg
(http://www.papermodelers.com/gallery/showphoto.php?photo=338)

[Gil]

Hi Leif,

Yes, it's been awhile since I left off from the last go at it. My skills have improved in the interim to the point where they aren't the limiting factor any longer. Funny you should post the very picture where the people are riveting the glazing frames into place. It is that very column which holds much of the secret to getting the nose joggled into the main fuselage correct. If you look closely at the post in front of the sliding window you will notice that the frame from the nose to the cabin roof angles back ever so slightly through that post. This is something not well contained in any of the "view" drawings. The other point that's not well documented is that the frame side section for the sliding window is flat to accommodate the window. Most sectionals show it round which it isn't. Sorry for the slight rant but those two items chewed up nearly a days worth of work to get right. In many respects this work is identical to sculpture and has all the same nuances. It takes a while to get it to look right you just need to keep chipping away at it. Rhino has a good set of filleting tools that make fairly short work (well almost) of most normal filleting work. The wing fillets took some time before the right combination fell into place. Most of the time all you have to do is to study the airplane very carefully to see how the metal was shaped and fitted followed by using Rhino as the Electric English Wheel for shaping surfaces to airframes...,

+Gil

[Leif Ohlsson]

I know - and it took me way longer than a day to get that particular section reasonably right!

How about this for synchronicity - right at this very moment George on this site uploaded a tip (http://www.papermodelers.com/forum/showthread.php?t=380) which is a goldmine, Flight International cutaway drawings! Here's their DC3:

http://www.papermodelers.com/gallery/data/532/medium/DC3.jpg (http://www.papermodelers.com/gallery/showphoto.php?photo=340)

The source is: http://www.flightglobal.com/StaticPages/cutaways.html, and their section for civil aviation 1903-1948.

I have uploaded this image to my galleries, but it is such a pity that the site doesn't allow showing the full image. So go to the original source.

Leif

[rlwhitt]

Gil,

I'm rooting for you to get this one out there as well. This is one of my all time favorites and would love to attempt to do a repaint in Piedmont Airlines livery. This was a regional airline (later bought out by USAir) that started in the city near where I live and operated DC-3s in the early days, so it'd be a cool build for me.

Good luck!

[Gil]

Looking for detailed photos of the landing gear I happened upon the following site. High resolution close-ups are the stuff model designers only dream of and then every once in a while something like this comes along...,

http://www.primeportal.net/hangar/mark_hayward/c-47a_skytrain/index.php?Page=1

+Gil

[Leif Ohlsson]

Many thanks, Gil!

http://www.papermodelers.com/gallery/data/532/Gear.jpg

Until now, this was the best I've been able to find. Yours, of course, is a great improvement.

Leif

[blueeyedbear]

The first flight I ever made on an airliner was on DC-3 in Mohawk Airline livery, from Watertown, NY to Boston. This was in '54 or '55. I would love to see a Mohawk DC-3, or any of a bunch of little operations in that era.

I've flown in lots of airliners since then, but there is still nothing like sitting in your seat, leaning back at an angle, while waiting for a tail-dragger to get airborne!

Bob

[Gil]

Hi All,

Seems this bird brings out a lot of memories for a lot of people. A pretty good reason to model such a well received bird with as many plumages as one can ever dream of.

Work on the engine nacelle skins has, as usual, taken more time than anticipated. One thing about Rhino is that more you use it the better you become. New learning experiences always seem to be just around the corner. Needless to say I've learned several new and valuable things about this software over the last several evenings.

The photo below shows the Port Engine Nacelle surfaces. I spent several hours in getting the render to look just so for the teaser shot. Upside of spending the time is that it can be used on all the other assemblies at show and tell render time...,

Oh yeah, it's the Pratt & Whitney version. Pilots who flew the Wright Cyclone version were renowned to have kidney problems for some reason...,

+Gil

http://img120.imageshack.us/img120/1716/enginenaceller2v17copyrh6.jpg

[Gil]

http://www.master194.com/maquettes/madman/dc3/images/conclusion/image002.jpg

The above is a plastic model build (good grief!) but with an extreme twist that Leif Ohlsson will enjoy immensely. Helps if you parle francais but there's enough images to more than explain the build. A build done well whether in plastic or paper is always a pleasure for a dyed in the wool modeler. Now to do this using card as the base..., Hmmm...,

http://www.master194.com/maquettes/madman/dc3/index.htm

+Gil

[Leif Ohlsson]

I was wondering all the time how did he manage those rive lines. And the answer, of course, is something Gil and others have mentioned a number of times - grandmothers cake-baking tool, made into a jeweler's (and modeler's) dream tool:

http://www.master194.com/maquettes/madman/dc3/images/collagealu/image020.jpg

It strikes me that the technique for getting that alu finish, the tape (also mentioned by Gil & others), would be even better on card models. It would enable you to fill & sand all glue joints without risking the pattern. Then just tape them over with alu.

http://www.master194.com/maquettes/madman/dc3/images/collagealu/image008.jpg

But a lot of work, of course. And it kind of defeats the purpose of card modelling, being able to print & paint patterns on parts BEFORE you assemble the model.

[Gil]

But a lot of work, of course. And it kind of defeats the purpose of card modelling, being able to print & paint patterns on parts BEFORE you assemble the model.Or does it? If you print on aluminumized card stock is it any different than applying it over the card stock? I've been thinking about building the substrate out of 0.5-1.0 mm card stock, soak with nitrate dope, fill with gesso and sand. Applying aluminum foil over the gesso surface is the art of metal leafing the glue is called size. For this application it would be scaled up to an industrial level from that used in metal leafing.

Panel lines and rivet detail remain problematic. Models with pounce wheel applied rivet detail look essentially that. Rivet detail depends greatly on the sun, angle to the surface, it's relative reflectance and surface textures. This is the stuff that renderer's have to deal with..., and may be what is needed for an interim solution. Render the surface with raised rivet and depressed panel line detail (including overlapped seams) as a gray scale only overlay which is then printed on the aluminumized card stock which is then sized to the waiting surface. Compound surfaces would need to be shaped prior to being mounted after which the surface detail would applied in the form of a clear decal...,

Ultimately applying the gray scales to a photographic mask on the surface for chemical etching would be the end of words for this thought train...,

Of course this is only the gist of the idea and a mountain sized load of work stands in between this and seeing if it actually works...,

Interesting idea though...,

+Gil

[Gil]

Hello All,

Seems the harder one attempts to shut out the World the more the World intrudes..., Kind of like the line from the stage production "Oliver", "Stop the World, I want to get off"...,

Finally eked out a little time to draw a few more items on the nacelle and blew a whole lot of time messing with the material and render settings so it looks pretty (I am a sucker for that part of it). Added the external exhaust manifold, hub and tire.

I've been experimenting with rivets. No surprise but when applied as a 3D entity on the surface they make reality pop completely out of the display. After that experiment it won't be any surprise if real panel lines do the same thing. It finally occurred to me that good renderer's are fully capable of capturing the real world to good effect. Capturing that "picture" and applying it to a flattened geometry is the end goal of all this "directed messing about"...,

Below is another teaser shot.

+Gil

http://img184.imageshack.us/img184/7641/enginenaceller2v19adc9.jpg

[Darwin]

If I might point out, the tool Leif is using has more to do with sewing than baking. It is a seamstress' seam marker, and can still be obtained in the notions section of most department stores. It's a good item for any modeler's toolkit, regardless of the medium of choice. Closely related tools with many modeling applications are seam guides (poor man's calipers) and seam rippers. The sewing section is a good place to look for handy-dandy tools with modeling applications....nearly as good as the fly-tieing section of a sporting goods store.

[Leif Ohlsson]

Credit where credit is due - Gil's the one who's been plugging various seamstress' and jeweler's tools...

Leif

[Gil]

A little detective work on the net provided the following derivation:

Pounce:
A fine powder formerly used to smooth and finish writing paper and soak up ink.
A fine powder, such as pulverized charcoal, dusted over a stencil to transfer a design to an underlying surface.tr.v., pounced, pounc·ing, pounc·es.
To sprinkle, smooth, or treat with pounce.
To transfer (a stenciled design) with pounce.[French ponce, from Old French, from Vulgar Latin *pōmex, *pōmic-, from Latin pūmex, pumice.]

A sheet of paper with a pattern traced on it is sprinkled with pounce powder. The pounce wheel is then used to trace the pattern onto another surface. It pierces the paper through which a small bit of the pounce powder is transfered to the surface below. In short a precursor to carbon paper.

The wheels are widely available from a number of sources but need to be modified to apply a more rounded rivet type pattern to the surface. One issue is that the spacing is limited to just two choices. One enterprising modeler made his own from a selection of watch gears to obtain scale distances for the rivet pattern.

I've used these in experiments on aluminum tooling foil. The effect is Ok but will not pass the macro lens examination effect. These experiments were the beginning of the present garden path I happen to be on...,

A set of Pounce Wheels:

http://www.micromark.com/prodimgs/15200.jpg

[Gil]

Messed a bit with Rhinos decal placement software. Came away slightly on the unimpressed side but that's most probably due to the fact that I didn't really know what I was doing more than half the time while attempting to use the tool. This is par for the course as usual...,

After messing about I found the easiest way to obtain a decent looking line was to project the panel lines onto the surface followed by the pipe tool to "cut" a channel out of the surface. This effectively separates the panel by a known distance (similar to "scribing" the surface). Once that's done the surfaces are split and the tubes are deleted leaving the separated panels. An offset surface must be performed prior to this to obtain a neutral gray-black under surface for a better render effect. In any event that's a high level rundown of the method shown below. Next comes rivets. Hopefully I'll figure out some way of automating that, otherwise it is really going to be painful..., Ciao!

+Gil

http://img252.imageshack.us/img252/7182/enginenaceller2v20wor6.jpg

[Leif Ohlsson]

You are really enjoying this, aren't you, Gil!

L.

[Gil]

Hi Leif,

Yes, this is a nice project. Skinning a DC-3 to create a 2D enviroment map for use as a layer in Photoshop for repainting is the intended goal. This idea goes back to a Natural Aluminum Finish tutorial I did several years ago in which the reflectance patterns painted onto the surface were dependent on the subjects environment. Environment reflectance maps are now available in the form of High Dynamic Range Images (HDRI). Think of a ground plane combined with a hemispherically shaped dome onto which is placed a "fish eye lens" photograph of a particular place. The HDRI image is then projected onto the subject to produce the reflectance map. The 3D image so created is then used as a texture map layer for the various unrolled surfaces.

The entire process is based upon the 3D surface of the subject down to the panel and rivet detail. One complaint is that you only get one lighting setup per snapshot which is true but this can be fudged some by softening the shadows and playing with an interesting feature called Ambient Occlusion. Very desirable results can be produced through a judicial combination of these effects.

What meets the eye is not always what is seen...,

+Gil

[John Bowden]

Gil,

Like many others I eagerly await the results...................

I am glad you have started this bird back up, but, and there always is a but ain't there................ will this help jump start your C-5 design too?

john

[Gil]

Hi John,

The good news is that I haven't initiated any new projects lately. The bad news is that the existing list is depressingly long...,

The C-5B is files are safely stored in an archive. The C5 surface detail at any conceivable scale size is low enough to not require things like rivet detail. Just achieving a believable fuselage shape in paper is challenge enough...,

+Gil

[Gil]

Panel lines that work are actually pretty simple. Projected lines onto the surface then used the single rail command to form a very small rectangular polysurface line on the surface. The polysurface line was then assigned a somewhat transparent shiny black material in the object editor. This was repeated for each panel line shown below. This allows the surface shape to be left whole which is preferable. The panel lines can then be handled as a layer group making things a lot easier. Another item is the background image has been assigned in the renderer and can be seen in the reflected surface of the image. For a surface to be perceived as metallic aluminum it must reflect something...,

+Gil

http://img469.imageshack.us/img469/9650/enginenaceller2v21wxc3.jpg

[Willja67]

Looks great Gil. Maybe I would find the answer if I looked through the entire thread but do you have any of the rendering plugins for Rhino or are these done with the Render that comes with Rhino?

[Gil]

Will, It was rendered using the Flamingo Raytrace plugin.

+Gil

[Gil]

Hello All,

Finished some experiments on achieving rivet line detail and came up with a method that's not too difficult to achieve. The results below show an artifact of a low resolution image for the reflected environment but it's enough to show the effect of both the rivet and a the panel line detail. The rivet detail is accomplished by laying down the row as an "array along a curve" which is a projected curve on the nacelle surface. Although a little tedious it is simple and can be retained within a 3D layer...,

+Gil


http://img517.imageshack.us/img517/6071/rivetdetailr2v22wdb9.jpg

[Leif Ohlsson]

That is just great . For once, aircraft rivets like they should look - possibly recessed just a tiny bit, but not protruding. Actually, they need not be that much recessed, just a shift in colour is enough. After all, they are made not to create air resistance.

L.

[maurice]

I think this is how you are supposed to be seeing them.
Recessed the way that you are seeing them they would be lethal sources for crack propagation.

[Gil]

http://img105.imageshack.us/img105/9650/c47askytrain42of44uz9.jpg
Rivets are a very distinct detail of the DC-3 requiring a certain amount of attention to their detail in order to obtain the right look...,

Rivet patterns and the size and type of rivet used varies according to the airframe support structure underneath and in some cases a unique purpose on each aircraft. Notice also from the image above the way in which the skin overlaps in a typical shingle pattern "over" down to bottom, fore to aft and that not all rivets are round headed.

In general flush head riveting was considered too expensive for use in transport aircraft production until the 1950's when jet powered transport aircraft mandated their use. High performance fighter aircraft of this same general period used flush riveting for the performance gain giving this genre of aircraft a sleeker look...,


+Gil

[shrike]

And just as a aside, there are a few aircraft whose performance can be increased by replacing specific lines of flush rivets with button head rivets

[Lex]

Gil, I've never managed to get Rhino to render panel lines, yours is a really nice idea!! Great rendering!

[wunwinglow]

I seem to remember they flush-rivetted a Spitfire, test-flew it, then progressively glued split peas over it, in different locations, to see there flush mattered and where it didn't. Might be an apocryphal story...

Tim

[Leif Ohlsson]

OK, I'm glad to admit it - you never get too old to learn. Could not believe a DC3 really looked like that close up, even though I studied the photos Gil provided earlier closely. Just didn't register. Too much looking out the window of contemporary commercial jet airliners prejudiced me, I guess (although it hasn't been that many occassions).

Leif

[Gil]

Thanks for the huzzahs. I am actually beginning to understand how to use Flamingo, Rhino's advanced renderer (now that's scary). I find that my usual problem is not reading the next paragraph, so to speak, for the explanation. Doing so saves so much time..., (Total Attention Deficit Disorder in action I am sure).

Always remember that the render engine needs surfaces to render. A line or point will not render because it has by definition zero surface area. It can be "shown" in the rendered image meaning that it cannot be represented as an "illuminated object" and will not be smoothed or anti-aliased by the render engine. Rhino is great at very small surface detail and Flamingo faithfully renders it. The reason for using a rectangular cross section surface is to insure that it's surface is well above the surrounding surface at all points. A single surface parallel with the larger surface will tend to "melt" in and out on curved surfaces causing unwanted artifacts in the rendered image. Below is a render using the Rhino Render engine of the same geometry as used earlier in thread.

http://img256.imageshack.us/img256/3060/rivetdetailr2v23wsx8.jpg

I think what Tim was referring to was an attempt to prevent separation of the laminar airflow on the Spitfire. The split peas acting as turbulators. Any of you who have dabbled in high performance gliders are probably familiar with the following explanation:

http://www.mh-aerotools.de/airfoils/turbulat.htm

+Gil

[maurice]

Tim
Not an apocryphal story. Once the boundary layer has transitioned to turbulent flow you might as well save on production costs and time and peeling half peas off in stages showed where flush riveting was necessary and where effort could be saved.
Fully equipped with peas the Spit lost 22 mph in top speed.

Shrike
And for the same reason that golf balls have dimples.

Gil

No, turbulators explain Shrike's point and why golf balls have dimples but that was not the purpose of the peas test with the Spit. That was intended to establish the areas that retained laminar flow.
Models and golf balls are operating in a totally different range of Reynolds numbers to full size aircraft and, as in this case, the relative importance of some effects can change dramatically between small and large flying objects.

[Gil]

http://img504.imageshack.us/img504/5766/rivetdetailr2v24wky5.jpg

The rivets from the earlier experiment were applied to projected rivet lines on the nacelle skin using the "array along curve" command in Rhino. Transverse ring bands were done first providing correctly rotated rivets for the horizontal rivet lines. Again these were stored as a separate layer in Rhino. Apologies again for the low resolution HDRI dome image.

Beginning to look like a real aircraft skin...,

+Gil

[Leif Ohlsson]

Apologies again for the low resolution HDRI dome image

No apologies necessary for this, Gil - it looks astounding indeed!

Leif

[John Bowden]

Gil it's beautiful.............but the polished mirror finish looks more at home on a Reno Mustang rather than a Gooney Bird.

But it would look fantastic in Delta Air Line livery.

john

[Gharbad]

There's a DC-3 on the cover of my local airport's magazine.
It's a very nice looking plane.

[Gil]

Glad you guys like it. I'm kind of partial to it for all the above reasons...,

Many of the DC-3s were only painted to accent the aircrafts aluminum art form when first put into service by the airlines. That's the look I'm after. Down the line from here I'll apply a paint pattern to the surface for one of the early adopting airlines, probably do the City of San Francisco, United Airlines Mailiner Service. American DSL's are also prime candidates (have to add the sleeper widows to the fuselage).

Rhino's rendering abilities have been one of it's more maligned attributes but with the release of version 4 and Flamingo version 2 McNeel and Associates is catching up fast. I seem to be getting happier all the time with it...,

I'm taking a small break to do something else for the next several days...,

+Gil

[Gil]

Guess who got a new render/shader?

+Gil

http://www.papermodelers.com/forum/../gallery/data/500/medium/Rivet-Detail-r2-v28wa.jpg (http://javascript%3Cb%3E%3C/b%3E:;)

[Leif Ohlsson]

Is that pretty, or is that pretty...

Goes for the intricacy of the parts design as well.

Leif

[willygoat]

There is a C-47 at the museum I work at. If you'd like some detail shots let me know. I should be able to get in it and get some shots too.

[Rick Thomson]

Gil it's beautiful.............but the polished mirror finish looks more at home on a Reno Mustang rather than a Gooney Bird.

But it would look fantastic in Delta Air Line livery.

john

John,

you never made the acquaintance of the Base Chief Warrant Officer at CFB Cold Lake during the 70's early 80's, our two Dakotas Pinocchio and Dolly's Folly(see link) were kept ultra shiny as were the T-33s. Any airman on his sh*t list was given a buffing machine, and a bunch of polish to use over the weekend.

Airliners.net | Airplanes - Aviation - Aircraft- Aircraft Photos & News (http://www.airliners.net/search/photo.search?aircraftsearch=Douglas%20CC-129%20Dakota%204M%20%28DC-3A%29&distinct_entry=true)

Rick