A few years ago, I forgot to lower my landing gear and was saved by the vigilance of a pilot holding short. After that, I began thinking about gear warning systems. My homebuilt Melmoth had none since I imagined that I would never make that mistake (or, to be more exact, never again, because I had already made it once, decades ago, in a Fournier RF-4).
The warning systems in many airplanes, for instance the Comanche 250 in which I learned to fly, consist of microswitches on the throttle and gear. They trigger a warning horn whenever the gear is up and the throttle is pulled back to idle. This is an imperfect system for several reasons. You could make a short-field approach with power, for one thing. For another, any approach to a power-off stall is accompanied by nuisance warnings.
