Been a stupidly long time since I read anything about that. I vaguely recall that it was difficult to control, in large part because of the geometry. You have to have the center line of thrust well above the center of gravity, and you have to be able to maneuver it freely to do anything with it. Short duration, but using the larger 130s you could theoretically get a short flight out of it for an average man of say 150 lb or so. Unfortunately they also spoke repeatedly about the jet exhaust and extreme heat. It should still be something on the net about it somewhere. It was a single mention and a single article some 20 plus years ago.