When did pilots experience blackouts and redouts for the first time?

Question

I'm working on a semi-historical novel right now. There's an interesting dogfight inside, between two 1914-era planes.

While writing it I wondered if at the time, planes were fast enough for pilots to suffer from blackouts when diving, or from redouts when gaining heights very fast. It then led me to ask myself when these two phenomena were first experienced and if pilots of that time knew about it.

I remember Stuka pilots had a device to make their bomber regain altitude should they lose consciousness when diving, so at least in the 1930's it was a well known phenomena.

When did pilots experienced for the first time blackouts and redouts?

Answer 1

The table on the Wikipedia page for G-force shows that WWI fighter planes could pull 4.5-7G's.

Typical human tolerance on the body's vertical (up-down) axis is said to be in the neighborhood of 5G (and 9G for modern pilots with G-suits). Much less for redouts. So yes, this is something an experienced WWI fighter pilot likely encountered. However, it would have meant not only their bodies but their airframes were reaching their tolerance limits.