Hi Zeb, I appears you are cleverer than I, so don't discount your abilities.

1: On Slide rules: They are simple scales for adding and subtracting logarithms with scales in "real" numbers.

They do not add, subtract regular numbers. Because of that you have to manually write-down what you are doing, and split calculations into their sub-components, then utilise the slide rule to multiply, etc. by adding the logs of those numbers, etc. That keeps the Slide Rulers directly in touch with their calculations in a way that no computer really does. It is a great tool to help you quickly do the calculations, without taking the calculation into a black-box and just giving you an answer.

2: When you understand what you are doing, you then can write it onto and Excel spreadsheet, programable calculator, or whatever and repeat the calculation many times, even using finely changing variables to iterate to an optimum design.

This is where slide rules become obsolete, although a much speedier way of helping you when doing the basic calculations a smallish number of times.

3: Then (the really clever bit!) you can turn the program inside-out to write it so it will iterate to the optimum, so you input the answer, and it tells you the parameters to get there!

I am at the "Stage 2 level" above, but have had "Mathematicians and computer boffins" write software for stage 3, in my various jobs of a few decades ago.

That was what we called Computer Aided Design before PCs were invented... (Apple, Commodore and the rest!). The programme was on a dedicated huge magnetic disc cartridge, and ran on a computer that was like 10 metal wardrobes in a large room. (Like a school classroom). It took 20 minutes to set-up, then we were allowed 3 runs of 15 mins max. (in the middle of the night). to do the calculations. But it cut a 4 year design and development into 2 years, so was easily justified.

Now you could use your "phone" and get an answer in seconds, if you had "the app"! But you need not understand how the answer was produced... Is that progress?

K2