Why Did It Take So Long to Invent X?

rootsofprogress.org

Usually it's economics and/or need.

The first jet engines were invented in the late 20s to early 30s, almost simultaneously in Britain and Germany.

But it was easier, and cheaper, to continue building propellor-driven planes until the extreme pressures of WW2 nearly 20 years later pushed people into a change-over from ICE+propellor to the more expensive jet.

Thanks Simon, any good articles on this point about jet engines? I'm collecting analyses of specific inventions.

This one tells about how the Germans and British were almost simultaneously inventing the jet: https://www.thoughtco.com/history-of-the-jet-engine-4067905

This one tells of Whittle's difficulties in Air Force resistance, also the new jets were extremely costly and required whole new areas of metallurgy and turbine design: https://frankwhittle.co.uk/challenges/

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