The game I currently am working on is quite heavy on all kinds of jumps, so I dedicated some time to investigate how to configure UE4 character jumps properly. Some random values I put in Jumping / Falling section of Character Movement component did not work well for me:
I drew a trajectory of my jumps before I started tweaking the config values. You may notice that they are not symmetrical – the reason for that is the character (a lamp in my case) speeding up horizontally during a jump. This does not make sense for projectile motion.