Open Broadcaster Software, or OBS is a free and open source program that allows you to record what's happening in your screen, including games and flight simulators. In fact, you can not only record videos but you can actually stream them directly to YouTube or Twitch. That's actually its primary function!
This is a companion discussion topic for the original entry at https://www.helisimmer.com/tutorials/recording-with-open-broadcaster-software/