wind behaviour around B`s

[Jhoek]

hello first post here on blinc

I`ve got a nice B being build nearby 300ft high , easy to get in , no security and a nice landing area. I`ve attached a picture (paint hehe ) of the situation

wind blue arrows
exitpoint marked als X
obviously jumping a B without wind is the best and only option most of the time, but im not sure about this B

exit1 is a crane near the building looks non jumpable with any wind... downdrafts updrafts and wind coming from any direction

but how about exit2 with the drawn wind direction? in my opinion the wind has got a clear path so when jumping from the corner you have wind coming from 135 degr. If this is true this building can be jumped with some wind, or am i totally missing something? turbulent wind coming from in between the gap of the two buildings? can anybody shed a light here?

thx
jelle

[QuickDraw]

Tom Aiello suggested using talcum powder to watch what the wind does, i would imagine that there are too many variables to give a precise answer.

Btw, i used to live in a block of flats (7th floor) when i was a kid,
i would drop balloons full of water out of the window and watch them on their way down.

Even now i remember they used to move in & out from the wall depending on if people had their windows open or not.

Just an observation you understand.

[Jhoek]

hehe think you might be right about too many variables.... powder sounds like a good idea thx

[eipmoez]

Hi,

I recommend getting a book called "Album of Fluid Motion" by Milton Van Dyke. I bought it after Tom Aiello recommended it in his article on getting into base, and especially the first two chapters are quite interesting.

It wouldn't contain pictures with your particular structure, but definitely pictures that combined could apply to your situation.

<disclaimer>
Pictures in a book provide no garantuees for actual wind-flows, and no substitute for common-sense and additional tests using powder on the exit point. Also, remember that the easiest situtation to comprehend is a no-wind situation, although that is not always garantueed to be the safest situation of course.
</disclamier>

I've actually been playing around with Fluid Dynamics in my work recently (computer graphics), and I've started thinking about writing a little application in which you can enter a little 2D height-map of structures, a wind-direction and a wind-strength, and it would draw the wind-flows. Perhaps it could even drop parachutes and simulate its flightpath when wind and canopy forward motion vectors are combined.

Would there be any interest in such an application? Of course it would be a grossly simplified model of reality, but could be fun to play with nonetheless.

Oh well... back to work.

Cheers,

Eipmoez

p.s. Ben je Nederlands of Belgisch misschien?

[Mac]

Tom Aiello suggested using talcum powder to watch what the wind does, i would imagine that there are too many variables to give a precise answer.

another one is to release helium balloons from the base of the B to see how they also react - this gives the advantage of not having to get to the exit point to initially check for possible wind problems.

Also take into account the complete environment the B is in, other buildings, enclosed areas like paths and roads, trees, basically anything and everything will effect the wind on an urban object and the environment you will be flying into - depending on where you want to land, where your outs are, what delay you are taking, where you exit, blah blah blah can all be effected in a jump with a more than zero wind condition. I mean no good in all being ok for the jump and opening, just to have you getting pounded and broken because as you come out of the wind shadow you get sudden accelleration and you get pounded into a concrete wall, spiked fencing etc.

HTH

[Faber]

looks like you rather want the wind abit from your right rather than straight from your back(guess as i can only see the Bs and not really your LZ)

So i guess my answer is it depends on your LZ...

take my answer by a grain of salt as i havnt done many B´s

[Mac]

take my answer by a grain of salt as i havnt done many B´s

but from the B I saw Faber do, he would probably agree that delay and conditions are something to really think about to make a safe landing to your LZ..................... Faber did ever so well to land into an area that really could have hurt someone........ without his skills he could of really got hurt............. nice one mate............. i still dont know how you made a "non injury" landing........

dont under estimate the urban jumps.............

[Faber]

cheers mate,i dunno my self how i made it,i can look at that vid again and again and still get swetty hands... But as the video shows there were PRECISE room for me to land really close to this 6-9ft fence whith trees all arround,sadly the video dont show that well how much i batled to get the canopy down,but it sure shows my first run after my broken leg

If i jump it again i sure will take a longer delay,unless we jump it to the other side were the road is

Besides thanks for GC at a concrete floor at 1,5-2 hours so that i could get my first B