you mean to say if i leave a 17+ second gap for separation no one will throw me out the plane?!

[Newbie 0]

this is related to the Kallends post on separation. Going through the separation between groups/solos, it gives an example where you would have to leave 17 or more seconds for separation.
Is that realistic in terms of will i be allowed to do this (im not talking realistic in terms of Kallends calculation, i believe him to be spot on) if im doing a solo after a 3 way free fly will the other people in the plane not just decide to toss me out the door? Will the pilot not start to shout obscenities in my general direction?

I know that last year, Empuria was putting freeflyers out first (are they still doing that?) - if this is still the case, then i could see Kallends example of separation being necessary. Has anyone left this sort of length of separation and got other jumpers/the pilot moaning at them for taking too long?

"Skydiving is a door"
Happythoughts

[diverdriver 7]

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I know that last year, Empuria was putting freeflyers out first (are they still doing that?) - if this is still the case, then i could see Kallends example of separation being necessary. Has anyone left this sort of length of separation and got other jumpers/the pilot moaning at them for taking too long?

I had a jumprun where we had 45 seonds in between groups! It totally can be done and HAS to be done for safety. If your pilot is yelling at you to go then maybe you counted slow. Your pilot should be the one to help you decide group seperation because they -should- be able to tell you what the ground speed is. That is the basic way to determine good seperation. Unfortunately some people count slow.

But yah, if you are supposed to give 17 seonds between groups then do it! Your life depends on it possibly.

Chris Schindler
www.diverdriver.com
ATP/D-19012
FB #4125

[Push 0]

If someone is cursing at you for trying to be safe, that person needs a smack. If you want to be really curteous, inform them that you will take a long separation delay before the load takes off. I can understand getting angry if you wasted half a jumprun, but according to Dr Kallends presentation the jumprun is over a minute! Maybe, if you're last, you might need to request a go-around, but if those folks can't stomach that, then they need a reality check.

This sport kills if you do it wrong, just read the Incidents forum, or this. Would you let someone pressure you into buying an 84 VX at 200 jumps? Why would you let people pressure you into not getting adequate horizontal separation? If anything, the latter is even more potentially deadly, cause a freefall collision will likely take you and another person out.

-- Toggle Whippin' Yahoo
Skydiving is easy. All you have to do is relax while plummetting at 120 mph from 10,000' with nothing but some nylon and webbing to save you.

[darkwing 5]

absolutely, do it. This is one reason that you should have this understood BEFORE takeoff, to prevent idiots from screaming at you.

-- Jeff
My Skydiving History

[Rdutch 0]

this year at Skyquest there was 70mph uppers, we had to give 25 second seperation. It was cool to watch the previous team exit and just fall straight down.

Ray
Small and fast what every girl dreams of!

[billvon 3,111]

>if im doing a solo after a 3 way free fly will the other people in the
> plane not just decide to toss me out the door? Will the pilot not
> start to shout obscenities in my general direction?

They might try; it is your responsibility to say no. It's happened to me a lot when I take lower experienced groups up at the WFFC - people start screaming for us to go when I have the nerve to check the spot and wait 8 seconds before starting the climbout. I have found that the following strategies work:

- Count on your fingers so it's obvious what you're doing.

- Giving them the one finger gesture is also a way of communicating that you will not leave without safe separation.

- Taking off your helmet and saying "What? Huh? Could you say that again?" both gives you more time and discourages them from doing that in the future. In severe cases, have a short discussion about exit separation with them; this will guarantee you sufficient separation, and will result in their friends putting pressure on them to not talk to you during jumprun.

[dcgilbert 0]

OK, this is my 'pre-second' (yeah, I know) post here after lurking for quite a while. Assuming the airspeed of the aircraft is still 80 knots or so, why would jumpers fall straight down? I'd expect them to be pushed behind the aircraft by the realtive wind- which is still 80 knots. I've read the separation article, but I still would expect jumpers to drift away from the plane at 80 knots, at least until they get out of the higher speed uppers. What am I missing?

[Rdutch 0]

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OK, this is my 'pre-second' (yeah, I know) post here after lurking for quite a while. Assuming the airspeed of the aircraft is still 80 knots or so, why would jumpers fall straight down? I'd expect them to be pushed behind the aircraft by the realtive wind- which is still 80 knots. I've read the separation article, but I still would expect jumpers to drift away from the plane at 80 knots, at least until they get out of the higher speed uppers. What am I missing?

I can't exactly explain, because I actually don't know. Theoretically your correct, I think that maybe it has something to do with drift. They didnt exactly fall straight down, but it definitely wasn't a fast drift. Maybe someone like diverdriver could explain in real terms why we have longer /shorter seperation's, and why even with airspeed being airspeed, seperation's change.

Ray
Small and fast what every girl dreams of!

[billvon 3,111]

>Assuming the airspeed of the aircraft is still 80 knots or so, why
>would jumpers fall straight down?

They wouldn't. If you looked out the door they'd fall away like they always do, towards the tail of the plane. However, as they got farther from the plane, they would start to see less and less of those uppers, so they won't be pushed or pulled the same way the plane is being pushed or pulled by the winds. If you were looking out the door of the plane, you'd see them "slide back" just a bit towards the plane, as opposed to a normal jump run where they seem to be going away from the plane at 80kts.

In the worst case, 80 kt uppers and 80 kt airspeed, you'd see them slide significantly back under the plane by the time they opened. To an observer on the ground (where the wind is presumably 10 kts or so) they would see the plane "hover" and all the jumpers fall down the same path towards the ground. Under those conditions, there is no safe amount of time you can wait, since everyone follows the same path. In the real world if you allowed a minute or so between groups, that would give the previous group time to descend 1000 feet or so to give you some horizontal separation (although you can't always count on that.)

[dcgilbert 0]

Got it. Thanks.

[kallend 2,146]

Quote

this is related to the Kallends post on separation. Going through the separation between groups/solos, it gives an example where you would have to leave 17 or more seconds for separation.
Is that realistic in terms of will i be allowed to do this (im not talking realistic in terms of Kallends calculation, i believe him to be spot on) if im doing a solo after a 3 way free fly will the other people in the plane not just decide to toss me out the door? Will the pilot not start to shout obscenities in my general direction?

I know that last year, Empuria was putting freeflyers out first (are they still doing that?) - if this is still the case, then i could see Kallends example of separation being necessary. Has anyone left this sort of length of separation and got other jumpers/the pilot moaning at them for taking too long?

I do physics, not psychology

...

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

[markbaur 0]

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In the worst case, 80 kt uppers and 80 kt airspeed, you'd see them slide significantly back under the plane by the time they opened.

If the winds decrease as altitude decreases, but are all from roughly the same direction, the jumpers would continue to drift downwind, though not as fast. Jumpers wouldn't slide in the direction of flight.

Are you describing some kind of illusion, which causes folks in the airplane to think they are seeing a forward slide?

Mark

[billvon 3,111]

>If the winds decrease as altitude decreases, but are all from roughly
> the same direction, the jumpers would continue to drift downwind,
> though not as fast. Jumpers wouldn't slide in the direction of flight.

Correct; but they would slide back under the plane relative to a group of jumpers who jumped in normal (i.e. no/light wind at altitude) conditions. The only time you'd see them actually pass under the plane going forwards is if you jumped in winds so strong that the plane was backing up (possible but rare) and winds at opening altitude were light.

[jerm 0]

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- Count on your fingers so it's obvious what you're doing.

- Giving them the one finger gesture is also a way of communicating that you will not leave without safe separation.

- Taking off your helmet and saying "What? Huh? Could you say that again?" both gives you more time and discourages them from doing that in the future. In severe cases, have a short discussion about exit separation with them; this will guarantee you sufficient separation, and will result in their friends putting pressure on them to not talk to you during jumprun.

lol!! dude... i really have to get on some of your loads this year.... you organizing out of one of the tents?

Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time

[billvon 3,111]

>lol!! dude... i really have to get on some of your loads this year....
> you organizing out of one of the tents?

That's the plan, organizing with DJan's group again.

True story from last year:

I was doing a six-way from the casa; I had my chest mount camera on. Door opens and we set up inside the door. Green light comes on and I say "OK, move back, tighten up . . ." A woman immediately starts screaming "GO! GO!" I lean out to check the spot since I'm a 'floater.' I see the DZ, no traffic, so I give the count and go.

Afterwards she finds me. "Dude, you made like two groups land off, you took like 25 seconds in the door."

"Actually it was 5 seconds from green light to our group leaving, including the count."

"You didn't include your count and you spotted like forever . . ."

"Want to see the video?"

She thought about that for a second and just walked away.

[Clownburner 0]

Bwa-hahahahaha! That was hilarious!

Thanks for making my afternoon!

7CP#1 | BTR#2 | Payaso en fuego Rodriguez
"I want hot chicks in my boobies!"- McBeth

[diverdriver 7]

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Correct; but they would slide back under the plane relative to a group of jumpers who jumped in normal (i.e. no/light wind at altitude) conditions. The only time you'd see them actually pass under the plane going forwards is if you jumped in winds so strong that the plane was backing up (possible but rare) and winds at opening altitude were light.

There's one thing that I was thinking of that could give the illusion that the jumpers are "falling straight down" and that's a really good head down freefly group exiting. They present less surface to the relative wind so their relative change with respect to what the plane is doing through the air is less than a good 4-way team launching perfectly into the relative wind.

Chris Schindler
www.diverdriver.com
ATP/D-19012
FB #4125

[Jimbo 0]

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There's one thing that I was thinking of that could give the illusion that the jumpers are "falling straight down" and that's a really good head down freefly group exiting. They present less surface to the relative wind so their relative change with respect to what the plane is doing through the air is less than a good 4-way team launching perfectly into the relative wind.

Are you sure about that? The wind doesn't blow up and down, but rather from side to side. I would think that the FF group would present more surface to the relative wind, however due to the increased vertical speed they would spend less time in the wind. We talked about exit separation yesterday and I came away with the idea that it was time spent in the wind that caused drift, not area presented to the wind.

-
Jim

"Like" - The modern day comma
Good bye, my friends. You are missed.

[Push 0]

As I understand it, they're talking about the relative wind that you launch into when exiting. A 4-way would present their entire bodies to the wind, and a freeflier would not. More surface area, more wind drag, less plane throw.

-- Toggle Whippin' Yahoo
Skydiving is easy. All you have to do is relax while plummetting at 120 mph from 10,000' with nothing but some nylon and webbing to save you.

[diverdriver 7]

Exactly what Push said. When the free fly group exits head down they won't actually be "head down"to be into the relative wind. So, at first, they will present a small cross-section to the relative wind (parallel with the line of flight) and will go "with" the plane for a short time. Thus appearing to go "straight down".

[skr 1]

At the bottom of http://indra.net/~bdaniels/ftw/
are several articles on exit separation including three
by Bryan Burke, two by Bill Von, and a pointer to John
Kallend's simulator.

Separation Explained for Students
http://indra.net/~bdaniels/ftw/sg_skr_coach_weekend.html

contains a few pages on the physics of a typical situation,
and several pages on psychology - why stuff looks the
way it does to our untrained intuitions, how to expand
our intuitions, and how to learn how to do exit separation.

----

>Is that realistic in terms of will i be allowed to do this

>will the other people in the plane not just decide to
>toss me out the door?

>Will the pilot not start to shout obscenities

All that and worse will happen. The ongoing lack of
training on this topic is hard to understand.

OPEC changed the oil prices in 1973. Within a few
years multiple groups per pass was common. USPA
safety and training did nothing. Dropzone owners
and pilots did nothing. S&TA's and experienced
jumpers did nothing.

In the 90's several huge discussions happened on
rec.skydiving and a few DZO manager/thinkers like
Bryan Burke started working it out.

Now there is some awareness that exit separation
is an issue, but there is *STILL* no training
of new jumpers.

diverdriver is the only pilot I've ever heard of who
tells people about uppers and time between groups.

All other pilots I've ever seen either say nothing,
or are one of the people screaming go.

I think exit separation is one of the harder skills to
learn. Maybe someday people will be taught how,
but probably not any time soon.


"Don't hose the last groups out" translates to
"Just kill the people in the first ones instead".

Skr

[nightjumps 1]

I not only use time as a factor for separation, but the angle of the previous group as a gauge. I'll try to make this visual without a white board. If you were looking at an exiting group from the door, use your hand at a 45 degree angle out the back of the door. A forty five degree angle is equal in distant as it is to height. So, if the group has flown beyond the 45 degree axis (your hand), its safe to get out. Conversely, if they have been falling for a long time and have not exceeded the 45 degree angle, then the airspeed in relation to the ground speed would indicate that you should wait longer. Does that make sense? It's really demonstrated better graphically. Maybe you could explain it better.

[markbaur 0]

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A forty five degree angle is equal in distant as it is to height. So, if the group has flown beyond the 45 degree axis (your hand), its safe to get out.

After the previous group has been in freefall for about 10 seconds, they'll be falling at 120 mph, while the airplane continues at its airspeed of about 80. The distance will be less than the height, so the angle will be more nearly vertical. If the previous group ever got beyond the 45-degree angle, then sooner or later they'll be falling back through the 45-degree line into the unsafe zone. The longer they fall, the worse the separation gets. Does that make any sense?

One more time, forget that 45-degree angle stuff. It doesn't work, never has, never will. If you use the 45-degree method, you are relying on luck. Risky business.

Mark

[nightjumps 1]

Quote

After the previous group has been in freefall for about 10 seconds, they'll be falling at 120 mph, while the airplane continues at its airspeed of about 80.

Quote

Ok. I'm with you here.

Quote

The distance will be less than the height, so the angle will be more nearly vertical.

[dreamsville 0]

Diverdriver is right. One helpful rule-of-thumb may be "one-one-thousand, two-one-thousand," etc. thought/spoken at a continuous UNHALTING pace. Check it against a second counter/hand on watch/computer, then watch for visible horizontal separation at exit time to reinforce whether you are right or not.

Interestingly, there were 98 MPH (I don't think it was knots) at SDC last Sunday at 12,000ft. Were someone to be able to safely pull there, we figured that, even with the drop-off in winds at lower altitudes, one could easily drop 20 miles away and have altititiude to spare to return to the DZ on a cross-country. Unfortunately, it was 15 deg on the ground and no one had the nerve to jump those temps. Better to forgo than to return as a petrified block of ice.

The flip side of this is that on an upwind jumprun, the plane isn't moving so fast. Just watch the group ahead of you to see. Also, an OK track (although Rook Nelson may hit 50 or 60 mph) is going to take the edge of a dispersing formation (say, 15- or 20-way) much closer to you at pull time, so add horizontal separation for that.

Personally, I like to be aware of the winds and approx. speed at exit time as a better reference for my own comfort level. I've been 2+ miles west of Sebastian, Fla. (fortunately free fly coach and Harry were last out before students), I left early and pulled high, and got it wrong. With the winds we had, I could have been at least a quarter mile FURTHER away, pulled at 3,000, and still had altitude and time to spare. Oh, well.

As a last resort, step aside and indicate to the next group to go ahead if they've ants in their pants. I let some guy go past me at Pahokee out of the Casa, and we did a go-round right then. He landed between the town and the DZ and hitched a ride.
|

I don't drink during the day, so I don't know what it is about this airline. I keep falling out the door of the plane.

Harry, FB #4143