Kirby told me at his forum at the 2005 Airadventure that he has his Red Bull single seater pointed just enough forward as to sustain a hover for a time. He still gains lift from his airfoil. He said that his thrust is not greater than the weight of his plane.

The folks at Jim Kimball Enterprises stated they are developing a Pitts Model 12 that should have a positive thrust/weight design. See jimkimballenterprises.com for the latest.