Hello, Leif!
Thanks for your post. You're quite right, of course, to point out my other thread on papermodelers.com and the links to Richard's engines and your own propellors. I'll try to answer all your questions the best I can, and I'm grateful for the opportunity for some discussion.
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Your wing design is beautiful, and the translucent effect is very effective. It would be interesting to know a bit more about paper thicknesses involved to get that effect, also about the thickness of ribs & spars.
Thank you. I was a bit intimidated by the airfoil, but I'm satisfied with the results. Translucence is, I feel, the key to a realistic model of a fabric-covered aeroplane and card is a medium uniquely suited to achieving the desired effect, providing you also adequately replicate the underlying structure. I've seen some truly remarkable trompe l'oeil techniques on plastic models, but the illusion of an opaque surface painted to look like a translucent one is only viable if point-of-view is limited. Only a truly translucent surface will look translucent from any angle.
The wing skins are "regular" cardstock, single thickness. I confess to not paying much attention to weights - I generally use what I can buy at the local craft or office supply store. It's probably 80lb; I estimate the thickness to be .008" / .2mm. The ribs are quadruple thickness, or 1" scale. Intermediate spars are the same, and the two main spars are eight layers or 2" scale.
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I admire the way you managed the wingtips (after so many testbuilds, I'm tipping my hat here!). How did you really go about achieving that - are the wingtips built as separate parts, or are they part of the big wing covering piece? How does one arrive at the exact shape, and/or how did you shape them? And no additional cuts necessary, I take it? Is there a possibility to see what they look like unfolded?
Thanks for that - they were a challenge to be sure! Here is the wing skin; it's one piece, but as you can see there are long cuts along the outermost rib to allow the tip shape. The black background is just to make it easier to see the shape, as the underside color is very pale and I try not to use any black outlines on light-colored parts:
[Blocked Image: http://i16.photobucket.com/alb…op/WingSkinBlkBckgrnd.jpg]
Essentially, the upper surface of the wingtip is simply rotated away from the main surface by increasing degrees from about half-chord forward. It is common to see wing skins that have spanwise wedge-shaped cuts from the tip inward; we all know how this allows the tip to taper from full height down to an edge. This is really no different - imagine rotating each section of the tip away from the wing to close up those wedges. The obvious advantage to this method is that the cut is nicely hidden along the outermost rib. See a recent discussion we had here about this very topic.
The underside of this particular wing was especially troublesome due to the complex airfoil shape. You can see where it was necessary to relieve the bottom skin from both front and back, leaving only a very small section attached.
In the build sequence, the tips are formed first by gluing these cut edges together. This is done before any of the wing structure is added. As for how I arrived at the final shape - it was simply an educated guess followed by a LOT of trial-and-error!
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The wings look a little greenish in one photo, but you only used that one layer, right?
As I mentioned, all of this is designed in PhotoShop. I don't use any modeling software; everything is drawn from three-views, photographs and other references. I create the parts digitally for precision and repeatability, but I also use surface texturing to enhance the effect of seeing underlying texture through the fabric. If you look closely at the wing skin above, you'll notice that the ribs are highlighted and the spaces between them slightly shaded. If the finished wing is backlit, you'll see the structure show through and it will be dark compared to the rest of the wing. If the finished part is lit from the front, however, the ribs show lighter indicating the sagging fabric between them. I feel the best effect is achieved by combining an accurate interior structure (where possible), translucent skin and skillful coloring.
[quote]The reason I ask is that the modeling of wires & structural members seen through varnished fabric is a particularly interesting problem.
It's actually the thing that has always most appealed to me about modeling in card. I know you've been working on this issue from a graphic perspective and there's certainly merit there, but to me the great advantage of card modeling is that you don't have to represent the appearance of translucent fabric because cardstock is already translucent.
Thanks again for your thoughtful post. I'm glad for the opportunity to talk about these things in detail.
Eric
