Time since introduction of the first mass-produced helicopter (Sikorsky R-4)

Time since introduction of the first mass-produced helicopter (Sikorsky R-4) (80 y)

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Neat Ratios ...

Time since introduction of the first mass-produced helicopter (Sikorsky R-4) (80 y)

is 1/50 of Time since earliest wheeled vehicles (4,000 y)...more
is 1/40 of Time since the start of the Iron Age (3,200 y)...more
is 1/25 of Time since the birth of Hero of Alexandria (2,014 y)...more
is 1/5 of Time since the death of Shakespeare (406 y)...more
is 1/4 of Time since the birth of Euler (316 y)...more
is 2/5 of Time since the first iron steamship crossed the English Channel (202 y)...more
is 2/5 of Time since the first passenger steam railway service (199 y)...more
is 1/2 of Time since the publication of Volume 1 of Marx's Das Kapital (157 y)...more
is 1/2 of Time since the birth of physicist Marie Curie (157 y)...more
is about as big as Lifespan of human being (80 y)...more
is 2 x Time since first Apple Macintosh Computer launched (40 y)...more
is 40 x Lifespan of rat (2 y)...more

If this was a standard unit ...