The Dial Plate, Gauge Face, etc.
The appearance of the faceplate is critical to the illusion of flying a real plane. Fortunately, making a truly first rate faceplate is pretty straightforward these days. Most are simply white lettering on a black background with a few colored arcs to depict operating ranges and limits. Back in the old days, we made such things with black Krylon spray paint (because it was cheap), white dry-transfer lettering (because our hand printing was wretched), and clear Krylon spray paint (because the press-on lettering fell off if we didn't, and, oh yes, because it was cheap). You can make the faceplates the same way, adding some color arcs by hand if your hand is steady enough. (Mine isn't).
A better way:
Use your favorite drawing program to create the image of the faceplate. Use your color printer to print the image onto adhesive backed paper. Trim it, remove the protective backing and stick it on your simulated instrument. Voilá! Instant wonderfulness!
Adhesive backed paper is available from most office supply stores. It's a full sheet of the same stuff used for self adhesive labels, but is not scored into small labels. If the cost of this stuff puts you off, regular paper and double stick tape works just fine.
If you want to put a protective layer over the faceplate, a light coating of matte finish, non-yellowing urethane varnish works well. A heavy coat my cause the ink to bleed, so use the varnish sparingly.
If you don't have a color printer, you can do as I did. Use TurboCAD to generate a black and white image, then add the color arcs by hand with a colored marker. (And even if your hand isn't steady enough, the black background hides your mistakes.)
The turbine temperature gauge as an example:
I started out with a picture I found on the web, rather poor quality, but having enough detail to act as a rough guide. I used a pencil to extend the marking lines several inches. This allowed me to use a protractor to measure the angle of each mark relative to a horizontal reference line. Measuring these angles is important because this particular gauge is very non-linear. I wanted to capture this non-linearity for my simulated gauge. I then made some length measurements of the markings. This required some adjusting as the picture was not to scale.
With the measuring done, I launched TurboCAD. I first drew three concentric, temporary construction circles. The first had a radius equal to the distance between the faceplate center and the inner end of the radial markings on the faceplate. The second had a radius equal to the distance from center to the far end of the minor markings. The third had a radius equal to the distance to the far end of the major scale markings.
I then added radial lines from the circle center on each angle measured from the picture. Line weight was made heavier for the lines that will become the major scale markings. I selected the inner circle in TurboCAD "trim" mode. This made the circle a reference for cutting lines. As I subsequently selected each radial line at a point inside the inner circle, TurboCAD deleted the portion of the line inside the circle. Using a similar technique I trimmed the outer portions of the radial lines using the other two construction circles. Trimming completed, I deleted the circles.
I added a circular arc touching the inner ends of the scale markings. This is the arc I later colored by hand. I added the numbers and lettering as simple labels, adjusting font size and position by eye. I placed a small circle in the center. This is used to center the faceplate on the body of the simulated instrument.
Up to now everything had been done in black. After first noting where the center was located in TurboCAD's drawing world, I selected everything and changed the color to white making everything disappear. I placed a black circle centered on the faceplate center, and filled the circle with solid black. I moved the now solid black disk behind the other drawing elements, and all the lines and text reappeared as white on black. Although TurboCAD does support color, I do not have a color printer connected at present, so I printed the image and added color on the operating range white arc by hand.