You would use an airfoil suitable for flying wings. They tend to curve up at the back. One of my gliding instructors used to fly this flying wing with reasonably good performance (35:1 glide ratio):

* https://en.wikipedia.org/wiki/Marske_Pioneer

Note the comment about the narrow centre of gravity range. The instructor said that wearing his heavy boots would change the flying characteristics enough that he could notice.

So such things exist and are at least somewhat practical.