I watched some videos on YouTube of pilots training and I noticed they always train to approximately notire than 9gs. Why do they train on 9gs and more / less?
Because that’s around what they’ll experience in flight. [Check out the Wikipedia page on g-loc.](https://en.m.wikipedia.org/wiki/G-LOC) An untrained person will pass out between 4 and 6 g. With the right equipment and training pilots can sustain close to 10 g for brief periods. So it makes sense for them to train at around what they will experience in in flight. The guy who does XKCD wrote a post about “[no-rules NASCAR](https://what-if.xkcd.com/116/)” where he discovers that the human body quickly become the weakest link if we try to design a fast accelerating contraption.
typical fighter jets can fly to 9g during the most extreme maneuvers, so obviously thats what theyll try to get the pilots to experience as well.
An airplanes ability to change direction is proportional to how much acceleration it can withstand. And the part of an airplane that limits its ability to withstand acceleration is its pilot. So the more acceleration the pilot can handle the faster the airplane can maneuver which helps it get out of dangerous situations much easier. So pilots are trained in handling more acceleration and also gets mechanical help from parts of their flight suit. But even with training and technology there is a limit to how much acceleration a human can handle before people black out. And most peoples limits are around 9g.