TFA is one of the best!
Quick question: in hand-to-hand combat, without using the force, who would win and how: Darth Vader vs. Chewbacca?
It depends on what you mean by not using the force. The force means extra agility, speed, enhanced senses kind of like a spidey sense, telepathy and telekinesis which can be use in a number of ways, especially against normal humans and normal humans and aliens with human level durability. Without any of that, a Jedi or Sith is basically a normal person so they would get killed by Chewie. I assume they still know some form of martial arts, but again, meaningless when fighting something much bigger and stronger, like a Wookie.
Even under those conditions, I think comic book Vader wins that fight.
Movie Vader might win because he's still a robot, but Chewie should be very strong, so it could go either way. I don't know enough about Chewie's fight experience, but his main weapon is a long distance bowcaster , so he must be good from a distance and have good vision, but he might not be very skilled in H2H combat, if he was, he would also use a close range weapon as a backup, so I'll give the fight to Vader, because of fight experience, close combat fighting skills, and robotic enhancements.