Ever hear the phrase "Balls out" when referring to pushing something to the max? Comes form the balls of the centrifugal engine governor. At maximum speed the balls extended all the way outward giving us the term "Running balls out."
edit: I once said this phrase at a work meeting and someone objected to my use of a crude term which I then explained much to everyone's surprise. They thought it had something to do with testicles.
While fun and satisfying, this is extremely unlikely to be true.
The first attested use is from 1945, on the nose of a P-47 Thunderbolt flown by Captain Milton Thompson of the 509th Fighter Squadron. And his art was exactly what you'd expect: a charging bull with the words "balls out".
Definitely a fun note :). I think I heard it first from a Jay Leno youtube video where he was showing his amazing collection of steam powered machinery.
This is from the article, but governors also played a role in kicking off modern control theory!
"""
In 1868, James Clerk Maxwell studied when these oscillations grow or die away in his paper “On Governors”[https://www.damtp.cam.ac.uk/user/gold/pdfs/teaching/old_lite...]. This became one of the beginnings of modern control theory.
"""
Example, throttle controls on a Dogulas DC3. All engine controls forward is the typical convention for full power. (At sea level, neglecting the altitude effect on required engine fuel/air mixture.)
There is also a steam engineers term called "high-balling" which referred the little ball in the steam pressure gauge used in the early days. So high-balling was travelling at high speed.
Euphemisms are weird, what was originally intended as a way of saying a thing without actually saying that thing, becomes the unspeakable thing in the first place. and the original meaning fades.
The one I like is why do we use birds to refer to female anatomy? I also heard something the other day and had an epiphany, but the sort you can't really tell anyone. "Oh... it means pouch that makes so much more sense, it's not a cat."
Every source I can find says it was a mid century phrase first found written in the 1960s from pilots. Pre aircraft locomotives would have been steam driven. Largely operated by a complex series of valves, mostly rotating so no wall to push them to. They did have a governor balanced by rotating balls, which when at full RPM would be fully extended, or: balls out.
https://en.wikipedia.org/wiki/Centrifugal_governor
edit: I once said this phrase at a work meeting and someone objected to my use of a crude term which I then explained much to everyone's surprise. They thought it had something to do with testicles.