It is obvious that electronic computers very quickly grew out of the stage at which they were only capable of solving simple arithmetical problems, however lengthy the problems might be. It was not long before the programmers tried supplying their machines with problems that mathematicians had never yet dared to tackle. Among these problems, for example, is the expression of complicated chemical and biological processes in mathematical terms. In such cases, equations with 200 unknown quantities are frequently involved; mathematicians will know what that means. In the same category are precalculations of the dimensions of aircraft parts. When we spoke in the last chapter of the air resistance to rigid and retractable under-carriages, we made the problem sound much, much easier than it really is. These calculations are so complicated that no one could be found who was prepared to grapple with them. For many years, therefore, planes were designed and tried out in the wind tunnel on the trial-and-error principle of "sooner or later it'll fly."
Today, dimensions of every detail in the design can be worked out in advance - with electronic computers. But even they need hours or days to do the job, so complicated are the technical and mathematical problems involved, so extensive the programs necessary for them.