So, there is this Swiss fellow named Ives Rossy who has developed a strap-on wing assembly complete with a small turbine engine.  His flight profile goes like this- He launches from a high wing single engine aircraft (a Pilatus) at altitude.  As he drops, he deploys the folded wingtips and achieves a stable glide. I can’t tell from the video, but I suspect that he starts his engine prior to leaving the plane.  Once he has his glide established he throttles up the engine and begins powered flight.  Clearly he is maintaining level powered flight and even appears to climb.  This is no mere glider. He ends his flight at altitude near the intended touchdown point and deploys a paraglider-type chute and lands by parachute. 

This is nothing short of amazing.  There are other video’s showing different flights and a few details of the wing.  As flying folk know, when you go aviatin’ you are actually flying the wing. Passengers may focus on the fuselage, but the pilot is busy up front making sure the airstream is moving over the wing properly. However, the fuselage is not just a cargo space or place to sit and leer at the stewtrons while munching pretzels.  Significantly, it connects the empannage, or tail assembly to the wing. 

The job of the empannage is to hold the vertical and horizontal stabilizers in place.  The horizontal stabilizer and its articulated control surface called the “elevator” is a concession to an unfortunate aspect of wing behavior.  A “normal” wing (i.e., a Clark Y) is just an oddly shaped truss built to develop a pressure imbalance in an airstream.  This imbalance gives rise to lift which counteracts the force of gravity.  But a normal cross section wing will also develop a pitching moment, or the tendency for the trailing edge to pitch upwards and the leading edge pitches downwards about the center of lift.  The job of the horizontal stabilizer downstream of the wing is to counteract this downward pitching moment. 

One of the critical design features of the flying wing was to counteract this downward pitching behavior.  One way to do it is to shape the trailing edge of the wing upwards to cause the airflow to impart some counteracting downward force on the downstream side of the wing.  So, if you look at the details of Rossy’s wing, you’ll see this upward curving lip on the trailing edge.  He is a clever boy.

My hat is off to this guy. Yves, my next glass of Fat Tire is in your honor!