A Meshula Labs production
by Nick Porcino
The Original Series U.S.S. Enterprise
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Building TOS nacelles by Nick Porcino (c) 2000
Making an accurate model of the Enterprise's nacelles is greatly aided by understanding how the original model was put together. I'll describe each of the major assemblies in turn.
The Nacelle Barrel: From the rear edge of the nacelle strut forward, the nacelle is a lathed untapered wooden tube.There are three chamfered rings forward of that, and another small ring with a beveled front edge that the domed nacelle caps are attached to. There are three thin rectangular plates which bridge the front ring to the front of the nacelle barrel. These plates match the curvature of the nacelle barrel when viewed from the front. The rest of the barrel, from the nacelle strut back, is a tapered, rolled steel tube. You can just make out the dozen or so finishing nails which hold the tube to the forward section. A red rectangle is painted on the bottom of the nacelle, beginning at the front of the rolled tube section and stretching back a ways. There is also a darker grey section on the bottom of the nacelle beginning at the ring holding the nacelle dome cap on. It is currently restored as an actual marking, but it is not clear if it was originally blurry weathering or if it was originaly a marking. There were darker weathering bands on the barrel located where they appear in the current restoration but apparently not as dark as that. There is a very small yellow light on the top of the ring holding the dome cap.
The Nacelle Dome Caps: The nacelle caps are joined to the bevelled front ring by three small clamps shaped like a fat "8" with a screw in each hole. These clamps used to be covered by small wedge shaped covers, although the current restoration does not have them. The cap itself is a frosted plexiglas dome of a diameter only slightly less than the diameter of the ring it is afixed to. Note that the caps in the Trials and Tribbulations model are too small. Underneath the dome are twelve tapered aluminum vanes. The vanes are fixed to the dome by a screw in the very front of the dome. (This screw was hidden by decorative spikes for the pilot episode.) The vanes don't move. Just behind the vanes is a round tray holding a number of Christmas light bulbs. This tray spins (at I believe one turn per second), giving the nacelle caps their characteristic animation. The flashing effect is of course achieved by the bulbs being momentarily occluded by the vanes. The five brightest lights were orange, and there were a roughly equal number of red, yellow, and blue bulbs as well, although these did not contribute to the effect as much as the orange bulbs.
The Aft Caps: The aft caps are separated from the nacelle barrel by two rings with a slight gap between them. The tapered aft cap itself has very fine ribbing oriented along the axis of the nacelle. There is a small globe embedded in the nacelle cap.
The Intercoolers: The two intercoolers on the top of the nacelle and the intercooler in the grove on the nacelle's inboard side were all pulled from the same mold. There are five half round dowels glued on top of them which extend over the full uncurved portion of the intercooler. The gap under the inboard groove's intercooler is open, but the gap under the two ventral intercoolers is occupied by a panel covered with small pyramids. I believe they are arranged in a 4 x 27 grid. There is a small half round dowel mounted forward of the two ventral intercoolers.
The Inboard Groove: Aside from the previously mentioned intercooler, the inboard groove also has a long detailed plate filled with a tight pattern of circular holes. The pattern is interrupted where the intercooler is attached. Each section of holes in the plate is bordered by two long half round dowels on the top and the bottom. At the front end of the detailed plate is a small block. Near the front edge of the small block are two small bumps.
Constructing a nacelle dome cap: Make three nested domes. Between the second and third nested domes, create a fourth nested dome with 36 sections. Remove 2 of every 3 sections, leaving you with the 12 vanes. Colour the vanes black. Colour the two outermost domes orange (rgb = 240, 100, 60), 30% ambiently lit, and 25% transparent (where 100% transparent is invisible). To both these orange domes, apply the nacelle cap texture as described below. Create a small orange plate behind all these domes so that the interior of the nacelle does not show through. Make this plate 100% ambient. Afix the vane transparency map to the vanes. In the map, black is the most transparent. Make the last dome 100% transparent. This last dome gets the most complicated texture treatment. The first layer is an alpha layer that masks the nacelle itself. The second layer is the colour layer. This texture also has its own alpha channel. The final layer is an ambience layer which is the alpha layer recycled. It is set to be 2000% (or 20x) overbright to show through all the other layers and tie the effect together. Here is the result which you can see approximates the appearance of the special effect quite closely:
Final result:
Vane transparency map:
The nacelle cap texture (color/alpha). The two should be combined into a single 24/8 image. The way this texture works is that the alpha channel in the texture allows the 25% transparent orange of the underlying dome material to show through.
Here are the light textures. The light texture itself needs to be these two combined into 24/8 image. The alpha texture also needs to exist on its own to work as the ambience and alpha layers.
