Kite Gliding Video - real or not? ... or a Turbulent Life

[ricki]

First checkout this intriguing video:


Then have a close look at the following.

Need some help, these two frames were taken during the jump over what appears to be 10 seconds of run time. A lot of changes went on with the cars during this 10 seconds. Lets say they cut out some video, so why not triple it to 30 seconds, long jump too.

Anyway in 10 to 30 seconds, some cars are missing (G for gone), some have changed into other body styles (C) and still others have appeared out of thin air (N for new). Missed labeling one too, there should be a G in the lower right hand corner of the roof where a fifth car change happened. There are still other things that stick out. That is some fast car moving, how about one of the many witnesses of this epic event help us to understand with an explanation?


Captured at 23 seconds


Captured at 13 seconds

[jaco]

no way this is real. just look at the angles and distance of the kite between the time of takeoff and landing

[ricki]

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.

[ricki]

Bob, I would like to say, yes, no one would try this. Reality is, some people imitate what they see regardless of common sense. This happens a fair amount in lesser degrees still with lethal potential. I doubt someone would jump off a 20 plus story tower in a dense urban setting anytime soon with a kite. Smaller buildings, maybe still with wind shadow problems, more likely. Look at all the folks out in squalls, doing tow ups and dying to try dune soaring with our tissue paper gear. Bad ideas but people like what they see, ignore common sense and just do it.

Again, someone already tried this from what I recall, years before this video. They killed themselves in a pretty nasty way, likely falling from a mid rise tower in a severe stall into another roof top. Or maybe when they put their kite up they were ripped off the roof and then dropped in an out of control stall or kite loop. Or maybe, he was flying until his kite fell into the wind shadow/dead air zone of a building upwind. I tried that once on a tandem condo soaring hang gliding flight with an instructor, we dropped like a rock and almost slammed into the roof of the building causing the dead air upwind.** The instructors idea, not mine. No one saw the guy go off the roof with the kite, he was found later on. Still trying to find the original post. Art copies life then?

Intriguing video comp nicely edited, but I would fess up, before someone not thinking very clearly tries some variant of this.





** We were trying to figure 8 down into the lift band from the tall condo to the right, in lighter cross winds. Trouble was, there was no lift band in those marginal conditions. We figured 8'd below the roof level and down several floors, then the lift turned off. That small six story building to the right cast a pretty nasty wind shadow down wind. We went into a power dive, barely cleared the roof of the lowrise building and did and skimmed in for an immediate landing on the water. The glider was setup with pontoons for water landings routinely. This was a very simple setting, nothing like one with a bunch of buildings. We were on a hang glider, still subject to stalls but able to come out of them light years better than a "kite" and a great deal more appropriate for flying.