Speedometers in formats other than round with a needle sweeping around a central pin are common enough. There are horizontal 90° sweeps, 180° sectors with or without something in the middle, drums vertical and horizontal, rotating dials, and ribbons. I'm sure there are others I can't think of right now. Odd-format tachs are less common: but I'm thinking in that direction for the Morris Minor. It's got a central round speedometer with inset fuel gauge, and I'll want battery, temp, oil pressure, and a tach in front of me. I'd like to do something in the idiom of the immediate post-WWII era, but also with a touch of idiosyncracy to it. The plan is for a resin panel that fits in place of the driver's side glove box door and holds a glass window, with all the above gauges behind it. Beyond that I'm suffering a temporary imagination loss: I can't see how those would be arranged in the strange triangularish space - but that will come. Now, I've got an 80mm VDO tach in the car, and I'm wondering if its movement could be used to drive some sort of odd-format tach, a ribbon or a drum or something just a bit unusual. Is this sort of thing viable? If so, can someone throw me something to get the old creativity going?
Perhaps it'd be easier to settle on the shape of the tach or the style first, or is that the problem-can't settle on the style/shape? Seems to me like it'd be easier to figure out how to make it work after settling on the design. Horizontal seems sounds interesting, but maybe hard to read. Maybe something with an odd sweep like this: http://www.google.com/imgres?imgurl=http://www.airminded.net/nstdd25/d25nat_airspd_ind.jpg&imgrefurl=http://www.airminded.net/aeroncac3/c3borneo.html&usg=__Y8AEJ618-icFaY4u41XUsu4YWQc=&h=732&w=800&sz=61&hl=en&start=45&zoom=1&um=1&itbs=1&tbnid=N-e5lGfy9m0e7M:&tbnh=131&tbnw=143&prev=/images%3Fq%3Dairspeed%2Bindicator%26start%3D42%26um%3D1%26hl%3Den%26safe%3Dactive%26sa%3DN%26ndsp%3D21%26tbs%3Disch:1&ei=5upmTezGBYr2swOdht2oBA You mentioning WWII made me think of altimiters...the kind that have a "vertical roll" (if that the right way to describe it...) with a solid line on the lense face. Having a really hard time finding any images of those.
How about creating an original style Alta rev counter like this http://www.mmoc.org.uk/viewtopic.php?f=19&t=22703&hilit=rev+counter&start=0
Many British aircraft such as the Avro Anson, Airspeed Oxford etc used a verticle rolling style mechanical engine RPM instrument that should adapt. These are still reasonably common and often turn up in collections. Should still be a few floating around in S.A, luck with it.
1970-71 Ford Torino's had a different style tach. <iframe width="560" height="315" src="http://www.youtube.com/embed/LfTRhQyp1EQ" frameborder="0" allowfullscreen></iframe> http://www.youtube.com/watch?v=LfTRhQyp1EQ