Thursday, June 7, 2012


My vertical speed indicator (VSI) is one of the most important displays, indicating whether I'm ascending or descending. My model reads in the standard Feet Per Minute (FPM), 500, 1000, 1500 and 2000. I know a decent ascent rate will be on the order of 1000FPM -- same for descent until about the last mile down, when I want to cut it drastically to land at closer to 100FPM -- but those numbers don't mean much to me, viscerally. Naturally MPH (miles per hour) is more intuitive, so I've printed a ring as a mockup, that translates FPM to MPH (turns out 2000FPM is about 20mph, and so on, but still I do like the larger numerals). Not so important for ascent, but landing is hitting the ground at the MPH indicated, and I'd prefer to keep that at something less than 5MPH or a little over at most -- it will be like being in a car crash at that speed (though I do have an idea for an airbag-like impact cushion that could be deployed with pressurized gas in a real emergency). So, this ring is a mockup around the VSI; when I have the numerals properly aligned, I'll print the final image, laminate it, and fix it to the VSI so that it doesn't obscure any other dials. The whole instrument display will be rebuilt pretty soon into a flyable configuration, but for the moment I'm learning a lot from thinking about these issues. Lower photo shows the whole red-lit panel, and another is a low-res image of a pressure test being shot for a magazine coming out in August.

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