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My first choice would be to jump a 150 ft A with no wind. But this particular A could be jumped only at night in a constantly windy night (at dawn and sunset there is a 20 minutes window of no wind but you'd get caught, for sure). So, considering that is jumpable in 4 direction (more or less), and considering to jump it in SL (if you are not russian), what would be your preference?
A. cross wind, so you're able to turn 90 to the wind (if you fail, be prepared to hard landing...)
B. upwind, your flare will be better but in case of off heading (even if remote in SL) you could hardly strike and fall down
C. downwind, landing faster than desidered (plf training strongly required)
Thanks for your (serious) input

If one would jump this low object then what would one see on all 4 sides as in

What is the landing options around all sides..

Grassy fields flat.. no trees or power lines or houses and if its windy is there going to be issues with wind coming from these trees on the only landing area or is it perfect..

A few things to think about and i could list maybe 5 other things...

But i wont give away jedi skills online

You are right. When I wrote you can jump all direction I meant you have flat grassy field all around without trees, Powerlines, buildings. That's why that object is so interesting for a rookie.
No jedi skill needed (apart to reach the object itself).

Jumps in the sub-200' range are no
joke and very technical by nature,
hence not good for inexperienced.

I have done 160' B with a Troll 285
and a perfect Static Line - honestly
it all happened really very quickly!!


RE: exit direction

I prefer a tail wind because avoiding
an object strike is more important to
Me than wind direction for landing.

Wind Jedi Skilz needed.
Downwind: Too windy and your canopy wont a .have enough time to inflate. b. have enough time do do a recovery arc. c. both a. and b.
Take care,
space

I have a local 150 freesrander that I jump often.
I like a low tail wind or no wind.
I hope you are fast on the toggles.
last night I jumped it, pop toggles, keep one down to turn 90, then pull the other one down to flare. it's all over in 2 seconds. please dont think you can turn more than 90, or have any accuracy at that altitude. DO NOT JUMP a tailwind if the winds are over 5 or so, you wont recover from the surge before meeting the ground.

last night I saw some fucked up shit happen on a static line jump. apex method for sl, the first sl loop broke and caused the knot in the bridle to "jump" or pop back over a piece of allthread. catching the bridle loop on it. causing the bridle to break!

I here rounds are pretty reliable.

Whats that saying? If you gotta ask....?

Just because it is there and has a nice LZ does not mean You HAVE to jump it. I would recommend you find a higher A and work your way down until you feel comfortable with all kinds of wind conditions and how your canopy reacts. As soon as you've done enough jumps you don't even have to ask this question anymore.
Take care!

In my opinion, at only 57 jumps you really should wait on something this low.

How many jumps have you done turns below 75ft? Are you proficient at flaring turns? Understand that the canopy might not react the same way you think it will because it is still in the early stages of pressurization and flight.

What's the rush anyway? Are they moving this object? I would work your way towards something like this slowly with many practice jumps from various heights and conditions. Take some video of yourself on normal SL jumps and see just how quickly and cleanly you get to your toggles, how the long the canopy takes to recover from popping the toggles both partially and all the way, see how long it takes you to initiate a turn, etc. Like someone mentioned earlier things happen really fast and you have only seconds to deal with it so be prepared.
Also, I doubt that the winds are always 100% blowing at night. Meteorological patterns change and there are always windows of opportunity that open up that are different than the norm, it just takes patience.

Patience is a virtue that many newer jumpers seem to overlook.

Thanks everyone (except the ironic ones) for your inputs.
Just to clarify, I won't jump something just because is there, neither jump without the right progression and/or experience and/or optimal conditions.
But, since I live far from the few jumpers I trust to ask something, since I have not jump mates here around, since I'm ignorant on some physics topics... that's why I was asking some technical inputs.
By the way, i appreciate the ones who reminded me the dangerous consequences of a bad choice
Have a great ones

Wow!

Naod,
Knowledge is a like a tasty grape with bitter seeds. I personally didnt see any "Ironic" or even sarcastic responses to your post. That could very well be a sign of inexperience on your part. Be aware of that. Most of us had that low/nasty object down the road that keeps calling us with that whiny "nany nany nan neeee! You didnt jump me". It's how you handle the taunting from the low/nasty.
Take care,
space

do you have pictures of the bridle? where did it break? I'm a little suprised the attachment point didnt break at the canopy side, but the threaded rod was probably a little jagged.

the bridle is supposed to brake before the attachment point.

yea bryan, pm me your number, I'll send them to you. I posted them on facebook

serious question: what is the failure point of a standard bridle? in load/weight..

I've seen a s/l that didnt break, and ripped the attachment point clean off the topskin and left the bridle and pc hanging from the object.

All is dependent on the webbing, construction and bartack stitching (SPI) and load spread. RiggerLee could give us the actual tensile strength of the materials, I could also but I am not working directly in the field of rigging ATM.
The main thing to think about for normal jumping deployment forces is that the max loading occurs at line stretch. So a failure is not critical. Only costly. Early Ravens were notorious for failing at the PC attachment point. Beefing up the AP was standard back in the day.
I agree that it is cheaper for the AP or bridle to fail rather than the surrounding material and is a better design. But I only see it as a monetary risk using todays construction techniques. Meaning non life threatening. Just do a 3D model in your head. 1 line of force spread out to 4 and then back to 2. raise the tensile strength the further down the chain of applied forces over time and insert your weak link.
Take care,
space.

Type 4, 1" square weave has a tensile strength of 1000 pounds.

This 20 minute window at sun rise/set statement is absurd. Over the years I have pretty much seen every wind direction/speed (including calm) at every time of day/night. Generally it will be calmer during the night.

the bidle was attacheed above/beside a squre edge, to a round pole.
the pole was anchored to the square edge with U bolts.
when the bridle was tied in a knot for the static line, the loop in the knot was fairly large,(you could put your hand through it)
this caught up on the excess U bolt. causing the bridle to be hung from the knot loop,
and the pin side of the bridle to drag across the square edge, cutting the bridle.

So are you saying that that is the only pattern you see?
The 20min window is absurd?
I was like you once.
I came to Europe and being a flat lander, I had no understanding of the winds. Went to the famous Swiss Dam early morning with a Local. The winds were howling. The Local said lets gear up. I asked about the howling winds. He said they would stop in 20minutes. I was like "whatever". I noted the time and I geared up.
What do you suppose happened?
And why?
Why does the wind blow or not?

avenfoto was speaking of a predominate pattern. Are you stating that this does not exist?

Do you really think that wind is the results of chaostivity? (Those dang butterflies in China. Made me land in the trees again consarnit!!!).

So I will be direct in my question to you in relationship to your statement about the absurdity of avenfoto's statement.

The question is: Why does the wind blow?

Answer this correctly to get "credibility for advice" points.
Better yet, Do the same as 50cal BASE Academy students do. Make a presentation on why and share it.
Take care,
space

current conditions In Bad Toelz, Germany, predominate vs actual.
On a fair weather day, the winds should be blowing to the mountains at 1500 at 5-10mph. There is no wind. So I conclude that it is not a fair weather day and shite is gonna hit the fan in a coupla hours, I am observing the cloud types also BTW.
I will now check out out he forecast for the next hours to prove I am right. After I post this.

I meant to reply to Naod, not avenfoto.

Yes, I realize weather patterns are location dependent, if that was the point of all your stories.

I certainly haven't been everywhere, maybe i'm wrong, maybe there are place(s) where there are windows of calm wind at the same time every day... but i doubt it.

 
I am not sure if you are being sarcastic. But I will bite anyway. This needs to have its own thread though.

"maybe there are place(s) where there are windows of calm wind at the same time every day..."

Generally speaking, In a fair weather system, This is the norm, not the exception. Why? The calm (on the surface) that was spoken of around sunrise is due to a: a.temp inversion blocking the predominate winds on the surface. b. But as the sun rises higher in the sky, the ground heats up due to the sunlight. c. Creating thermic bubbles in the inversion layer that when d. they become buoyant enough, launch and e. destroy the inversion layer f. allowing the predominate winds to come down to the surface.

Since this common effect is based on sunrise, then yes, it is relatively at the same time each day. Same as with Mountain/Valley winds and Sea/Land winds. Each has their cycle based on sunrise with an inversion layer between the night and day winds.And not only that, the direction is pretty predictable as well.
I hope this helps.
Take care,
space

"Understanding the Sky"

Dennis Pagen



"In inversion layer contains stable air, as we shall see....If our happy bubble of air was rising in an atmosphere whose lapse rate cooled off less than 5.5deg / 1,000ft, then the bubble would be cooling faster than the surrounding air as it climbed and eventually it would reach a height where it was the same temperature as its surroundings, reaching equilibrium...Unstable air is just the opposite. If the lapse rate of the air cools more than 5.5deg / 1,000ft, a parcel of air forced upward will not cool as much as the surrounding air so it will continue to rise. Instability of the air means that it is out of balance, for the air in the lower layers is too warm for it to remain tranquil in the vertical dimension (note that horizontal wind blows in stable and unstable conditions).

Stable air - occurs when the lapse rate is less than the DALR (5.5deg / 1000ft).
Unstable air - occurs when the lapse rate is greater than the DALR."


That book is so awesome. I've been reading it some and thought this was relevant...at least to the past few posts

Nice! some people think that if one can predict winds or weather, That that one is a god, another type just think you got lucky and it is all random.. Some think a wind or storm just came out of no where. Some Hike down from ITW at 1600hrs only to meet the lokals who are going up. Because they dont under stand the winds, which are even posted on the wall in the Cafe'. Which I posted before on bj.com and my fb page. I am not a weather god. It is simple physics.
I would recommend that anyone who calls a concept absurd, do some research first. I promise that a storm that came from no where will never kill me like the Balloonpilot's witnesses claimed on dz. com.
@ themexican: there is a strong wind that starts at approximately the same time of the day. from the direction during fair weather. The name of the wind is called Ora, which in translation means on the hour or punctual. go figure that.
Thanks Zebu, Denis Pagen and themexican. Shall I post the Ora wind picto again?
Take care,
space.

And then there are those who think you have looked up the weather on a website or the phone or whatever.

Back before the turn of the century.At Lysebotn, I think it was 1997. I had brought a student of mine there. and I was acting as the overall knowledge dude for the summer. The Aussies and others would ask me in the morning what to expect with the weather that day. (I mention Aussies for a reason). I told them that it would rain about 1800 maybe 1830. They looked up and saw a few puffy clouds and thought maybe "fuck off". Well, they got nailed by rain between 18-1830. Nextday, the cycle repeats itself. And again and again. All while my student is watching my response to the questions. Well then I saw the next morning, that the clouds were forming 3 hrs earlier. S o when the question came again, I said it will rain about 1500. the "yeah right" look came up. My student gave me a look like "DoooD, you just screwed up"
While waiting in the BASE 1 pickup boat in a rainsuit at 1530 and picking these guys up. Petter said "you were wrong about the time. It was 1515 hahahaha!

My student asked me this. You dont speak Norge, you dont read it, you dont understand it, how can you know when it is going to rain without having access to a forecast?
I responded that the weather doesnt understan languages either. But they do give you signs.
No clouds at 0900, small clouds at 1200, med at 1500 etc = rain at 1800.
Next day, same program, and the next days.
So many peeps got wet because they didnt listen to the very advice they asked for.
The Next year, The Aussie crew would send some one to ask me the days weather, I would tell them and often I would hear "Tracy says rain at this time so rain gear everyone."
Take care,
space