Big way engineering

[kallend 1,644]

I have seen lots of articles on 4-way techniques, and quite a few on big way techniques from the point of view of the first-time participant.

Has anyone seen any articles about engineering big-ways? What are the advantages and disadvantages of different formation designs? Are some designs more stable than others? What about placement of trail planes and exit order? (I've been on a number of big ways where the trail plane exit order seemed counter-productive). Some organizers (such as Guy Wright) like a fast falling base, others (like Roger Ponce) don't. What is the reasoning behind these decisions?

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The only sure way to survive a canopy collision is not to have one.

[billvon 2,426]

>Has anyone seen any articles about engineering big-ways?

Nothing written that I've ever seen. Everything I know about designing big-ways came from talking to Kate, Tony, Roger, George, Dan BC etc. It's a pretty niche specialty I think.

> What are the advantages and disadvantages of different
>formation designs?

Large loops with a lot of open space - things like wackers - fall fast. Dense bases with a lot of zippers fall slowly. Airy formations with very long loops connecting both ends of something are very hard to build well, I think, because they rely on perfect spacing between people, and that's rare. Things like wackers work well because they can breathe, and can easily accomodate minor position discrepancies.

>Are some designs more stable than others?

I think it's a mistake to think in terms of structural stability. If your stability comes from the grips you're sorta doomed; a big way can't fly through people's grip strength, it has to fly because everyone flies their own position as if they weren't hanging on to anyone. Some things that make it more likely to remain stable IMO:

-A formation where slots relative to the base are easy to identify such that the jumpers can easily stay in them.

-Formations that are relatively in-facing. It's easier to resist a backslide than a sideslide.

>Some organizers (such as Guy Wright) like a fast falling base, others
> (like Roger Ponce) don't.

I was in the base for Roger's 120 ways last year and we were hitting 135 in the base before anyone docked. OTOH the base of the Airspeed 300 way 'base' was rarely over 115, and even the base 16-way rarely exceeded 125. And airspeed was determined to have a fast base. Sometimes it's hard to predict.

[kallend 1,644]

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>Has anyone seen any articles about engineering big-ways?

Nothing written that I've ever seen. Everything I know about designing big-ways came from talking to Kate, Tony, Roger, George, Dan BC etc. It's a pretty niche specialty I think.

> What are the advantages and disadvantages of different
>formation designs?

Large loops with a lot of open space - things like wackers - fall fast. Dense bases with a lot of zippers fall slowly. Airy formations with very long loops connecting both ends of something are very hard to build well, I think, because they rely on perfect spacing between people, and that's rare. Things like wackers work well because they can breathe, and can easily accomodate minor position discrepancies.

I've noticed that too - also wackers seem to handle the almost inevitable wave better (last guy just gets bobbed up and down, but the wave can't propagate any further). With loops, a wave just keeps on going until the jumpers actively damp it out.


I was on a big way a couple of weeks ago that combined all these elements - zippers on the base, loops and wackers. Fall rate was quite variable depending on whereabouts in the build we were. Almost seemed guaranteed to cause us problems.

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>Are some designs more stable than others?

I think it's a mistake to think in terms of structural stability. If your stability comes from the grips you're sorta doomed; a big way can't fly through people's grip strength, it has to fly because everyone flies their own position as if they weren't hanging on to anyone. Some things that make it more likely to remain stable IMO:

I wasn't so much thinking of structural rigidity or strength, as much as aerodynamic stability. If you consider the formation as a large pin-jointed structure , do some configurations just fly better than others?

I doubt anyone has ever looked at it from this point of view.

[loudtom 5]

"Any comments about exit order? Again, I was on several (many) jumps where trail plane floaters were expected to dock before the first and second row divers (this with both Otter and Caravan), and ended up having to fly around them. Seemed bass-ackwards to me. AFAICT It seems to be the consequence of doing run-outs rather than exit frames during the dirt dive.

[katecooper 0]

Re. Trail plane floaters docking before or after divers from the same plane.

my 2 cents worth....

I find that a firs or second row diver from a trail plane can almost always take a cleaner line to a base than the floaters from the same plane. Peel off the floaters with the super floater from the lead and the first divers take the straight line to the chunk, often docking before divers in the lead plane. It works well, at least is has for me.

Hope that helps.
kate

[kallend 1,644]

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Re. Trail plane floaters docking before or after divers from the same plane.

my 2 cents worth....

I find that a firs or second row diver from a trail plane can almost always take a cleaner line to a base than the floaters from the same plane. Peel off the floaters with the super floater from the lead and the first divers take the straight line to the chunk, often docking before divers in the lead plane. It works well, at least is has for me.

Hope that helps.
kate

Thanks - I'm glad I'm not just hallucinating. Now the harder question - how does a pawn like me get to convince a "name" organizer that they've got it wrong?

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The only sure way to survive a canopy collision is not to have one.

[katecooper 0]

Not a problem--I'm sold!

Oh, you meant ANOTHER organizer...

Well, it's as clear as day to me, it's physics. But Without knowing who you are talking about (honest) I'd say that the more formations they play with, the more the three dimensional aspects of the exit and first 3-5 seconds will come into play. It's like the matrix...

It also helps having done most of the different slots on a 100+ way. My views on floating trail planes, being in the base, short diving, super floating, late diving, etc are all tempered by experience in those slots. Variety is the spice of skydiving.

k8

[happythoughts 0]

The easiest way to look at the fallrate issue is by reviewing the video. If the outside people are spread out, and catching as much air as possible, then the base is going too slow.

If you see one or two people with their feet waving because they can't keep up, it is easier to have them add lead.

A good fallrate will help the divers because they can swoop longer (arrive sooner) without the fear of going low.

One weird thing that happens on occasion is when one side of the formation is lower than the other. This causes the formation to slide. One side of the formation is getting big and backing up while the other side is arching and putting their legs out. Both sides have the opposite opinion of what was going on.

[katecooper 0]

What I've found with fall rate is a faster fall rate tends to favor a one point skydive and a slightly slower fall rate tends to favor sequential dives. The reason being that most people are more open to the idea of putting on more drag (sleeve, t-shirts, larger suit) than more lead (I don't need weights--I can always arch!).

Both the GO FAST 300 way in Eloy and the 4 point 106 way in Crosskeys were done with what I consdered relatively slot fall rates, especially for the outermost rings, yet they were smooth and flat.

People adapt, the trick is to find out what they are going to adapt to the best.

Oft times I will start a dive with a faster fall rate and then ever so slightly slow it down later in the event as people get dialed in. It's worked so far. Your mileage may vary.

blues
k8

[flyangel2 2]

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It also helps having done most of the different slots on a 100+ way. My views on floating trail planes, being in the base, short diving, super floating, late diving, etc are all tempered by experience in those slots. Variety is the spice of skydiving.

Being a jumper that turns in applications to be on a big way, being able to do any of those slots is a dream for the organizer. I've turned many an application in with the question area that ask "what slot would you prefer" with "where ever you'd like me."

BTW Kate, great article about how to stay on big ways.
See ya in October for that shot

May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view. May your mountains rise into and above the clouds. - Edward Abbey

[mjosparky 3]

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Re. Trail plane floaters docking before or after divers from the same plane.

my 2 cents worth....

I find that a firs or second row diver from a trail plane can almost always take a cleaner line to a base than the floaters from the same plane. Peel off the floaters with the super floater from the lead and the first divers take the straight line to the chunk, often docking before divers in the lead plane. It works well, at least is has for me.

Hope that helps.
kate

I first ran into this in Texas for the state POP's record. I was a floater on a trail plane and docking in an outside wacker. I was leary at first but it worked great and after a couple of times really made more sense.
Sparky

My idea of a fair fight is clubbing baby seals

[happythoughts 0]

Everyone keeps saying "fast" or "slow" fallrates. These are kind of subjective. How many miles-per-hour are we talking about? I was recently on a 36-way where the organizer thought a "medium" fallrate was 108 and it was ok. Six people went low on the outside. We made it 114 and things got better. What is slow or fast?

[mjosparky 3]

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Everyone keeps saying "fast" or "slow" fallrates. These are kind of subjective. How many miles-per-hour are we talking about? I was recently on a 36-way where the organizer thought a "medium" fallrate was 108 and it was ok. Six people went low on the outside. We made it 114 and things got better. What is slow or fast?

On the Texas POP's loads, 62 way, I was on an outside wacker and my Pro Trac said I averaged 120 to 123 mph. on all attempts. The base was somke'n and it made everything on the outside much easier. I think 108 is way to slow but thats just my opinion.

My idea of a fair fight is clubbing baby seals

[rdesilets 0]

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Everyone keeps saying "fast" or "slow" fallrates. These are kind of subjective. How many miles-per-hour are we talking about? I was recently on a 36-way where the organizer thought a "medium" fallrate was 108 and it was ok. Six people went low on the outside. We made it 114 and things got better. What is slow or fast?

A few weeks ago I had the opportunity to take part in the New England 81-way record at Orange, MA. I was in the 8-way base with Guy Wright. We took an 8-way out the door (Otter) and Guy would "set the fall rate". Once we (the base) got warmed up (and some of use put on lead) we averaged 124 MPH. Prior to 'warming up', we were at about 114 and Guy told us all that this was too slow and we all needed to pick it up. This dive was a 1 point skydive.

If you are interested in the formation Guy (and others) designed you can see 2 photos here. Yahoo!

http://www.newengland100way.com

P.S. Kate, I can't wait until you set the dates for your next big way camp as I will be the first on the list.

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[happythoughts 0]

I have jumped with Guy on large stuff. Last time I was in a 4-way bridge attached to the mainframe attachment point. The initial base speed was 123 to 125. It was pretty easy to work with. I got moved back a few rows as we got bigger.

My routine fallrate is around 108 to 110. I prefer 112/113 for 20+ ways. 40 to 60-way is 116. Personal preferences.

Because I weigh 190 and can handle the push/pull of being in the base, I usually end up there with some extra weight. My favorite position is attachment point.

[kallend 1,644]

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I have jumped with Guy on large stuff. Last time I was in a 4-way bridge attached to the mainframe attachment point. The initial base speed was 123 to 125. It was pretty easy to work with. I got moved back a few rows as we got bigger.

My routine fallrate is around 108 to 110. I prefer 112/113 for 20+ ways. 40 to 60-way is 116. Personal preferences.

Because I weigh 190 and can handle the push/pull of being in the base, I usually end up there with some extra weight. My favorite position is attachment point.

I'm nearly always on the outside on account of weighing 150. Since we typically break off at 5k or above on big ways, my Pro-Track's averages include maybe 2500 - 3000 ft of tracking at the end of the skydive, and perhaps 5 - 6000 ft of swoop at the beginning. Consequently I find it difficult to figure a formation's actual fall rate from my own data.

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The only sure way to survive a canopy collision is not to have one.

[billvon 2,426]

> Since we typically break off at 5k or above on big ways, my Pro-
>Track's averages include maybe 2500 - 3000 ft of tracking at the
>end of the skydive, and perhaps 5 - 6000 ft of swoop at the >beginning.

Can't you download the data with that attachement? I believe that fallrate is sampled around 1hz, so you'd get reasonable resolution. I may do that after the Perris big-ways - Square 1 has an interface.

[kallend 1,644]

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> Since we typically break off at 5k or above on big ways, my Pro-
>Track's averages include maybe 2500 - 3000 ft of tracking at the
>end of the skydive, and perhaps 5 - 6000 ft of swoop at the >beginning.

Can't you download the data with that attachement? I believe that fallrate is sampled around 1hz, so you'd get reasonable resolution. I may do that after the Perris big-ways - Square 1 has an interface.

Yes, I too have an interface but I have been led to believe that the instantaneous values are prone to serious errors, and often show oscillations with a period of six seconds or thereabouts. I don't have any way of testing. Maybe Craig Poxon has some data on this.

My Protrack has clocked me at 224mph instantaneous on a RW jump. Somehow I think this is a little high.

...

The only sure way to survive a canopy collision is not to have one.