Still lacking any input from the witnesses of this jump. Maybe they're waiting until April 1? Anyway, as cool and easy as it looks in the video ... its not! The only guy I have heard of who tried to do this off a high building also landed on another one but died from the impact. He was found there some hours later.
The air flow around buildings can be very complex. If your kite sees less than stall speed, you will likely fall until you drop fast enough to exceed the stall velocity for your kite when you first launch. You can easily have this if you fly into rotor as well.. There can be tremendous uplift local to the side of the building. Then there can be rotor from wind shadow off other buildings and terrain. If you are trying to land on another building, the same bizarre factors might be present too, uplift, immediately downwind of a building side lots of nasty rotor. If you had to model it, it could get pretty complex. Flying into it, could be a suicidally exciting experience. Add to that the odds of hurting someone else on the ground, flying into high tension power lines, screwing up the depower of the kite to where you get dragged off or into something. The millimeter threading of that remarkable landing close to and between cars, fencing and steep walls is pretty amazing and apparently unrealistic. Here's a nice Catch 22 to go with this. Say your kite has a stall speed of 26 mph, as a guess or 30 ft./second. If you fly in during dead air, not rotor perhaps some thermals cooking off though, you have to be moving faster than that to stay aloft with steerage. You could easily be off the building LZ in bare seconds. The closer your head wind is to 26 mph, the slower you can land BUT the higher the mechanical turbulence. Tricky.
Checkout those caotic streamlines downwind of the tower. Those can run out a good long ways and can become even more confused with interactions with other structures.
From:
http://www.caebridge.com/urban-wind-...bine-placement
They even came up with a name for these confused winds that are cast off of a collection of buildings, "Urban Canyon Wind."
Tell me, you're coming in for a landing and you get caught in those uplift streamlines and get flown over the building and dropped over the other side into intense rotor. Having some fun now!
You want to stay out of those rotor or gyre zones downwind of the structures. Stalling to lofting to stalling kites, not a lot of fun.
From:
http://www.islandnet.com/~see/weathe...s/citywind.htm
A powered aircraft enjoying some time in the spin cycle courtesy of rotor or mechanical turbulence.
From:
http://www.atsb.gov.au/
Short version, don't try this regardless of our boys apparent prowess. From current indications, lacking confirmation, the most amazing and hazardous parts of this jump, happened only in a computer some place.