Yet another method to calculate exit seperation

[speedy 0]

This was published in Freifall Express, the official magazine of the DFV (Germany's equivelent of the USPA).

---

When free fliers go before belly fliers.
Free fliers tend to have a freefall time of 50 secs, belly fliers 60 secs. Therefore free fliers will drift 1/5th less than belly fliers. Free fliers tend to have less forward throw than belly fliers. So lets take another 1/5th.
So if your normal exit seperation is 10 seconds, you have to add 2/5ths more when belly fliers go after the free fliers, which makes 14 seconds.

---

Not a literal translation, but what was put across.

The information to calculate this properly is freely available on the internet.

Time to start writing a letter

Dave

Fallschirmsport Marl

[RTB 0]

  Quote

---

When free fliers go before belly fliers.
Free fliers tend to have a freefall time of 50 secs, belly fliers 60 secs. Therefore free fliers will drift 1/5th less than belly fliers. Free fliers tend to have less forward throw than belly fliers. So lets take another 1/5th.

Wouldn't less forward throw make the distance larger in this case?
I thought belly flyers had less forward throw and FF more penetration into the wind on exit, i.e. more forward throw.

//r

[johnny1488 1]

Whatever they use to gauge separation, I think there should be some mention of wind speed and direction to determine time.

Johnny
--"This ain't no book club, we're all gonna die!"
Mike Rome

[speedy 0]

  Quote

Wouldn't less forward throw make the distance larger in this case?
I thought belly flyers had less forward throw and FF more penetration into the wind on exit, i.e. more forward throw.

Yes FF have more penetration into the wind. Therefore if they go first they will reduce the seperation. This was addressed in the article, but the method of calculating how much extra time you need between exits if FF go 1st is not addressed correctly in the article.

Dave

Fallschirmsport Marl

[speedy 0]

  Quote

Whatever they use to gauge separation, I think there should be some mention of wind speed and direction to determine time.

Of course wind speed (both uppers and lowers), aircraft speed, direction (cross or against the wind) all need to be taken into consideration.

The article was written by a FF'er that wanted to put forward a good reason to let FF'ers exit first. The reason was to avoid congestion in the landing area. This is not altogether a bad idea, but at least the method of calculating the exit seperation should have been properly presented.

Dave

Fallschirmsport Marl

[JohnMitchell 16]

  Quote

. Free fliers tend to have less forward throw than belly fliers.

]

Nope, Free fliers have more forward throw than belly fliers.

(edited for bahd spalling)

[billvon 3,102]

>The article was written by a FF'er that wanted to put forward a good
>reason to let FF'ers exit first. The reason was to avoid congestion in the
> landing area. This is not altogether a bad idea . . .

The additional 10 seconds of vertical separation you get means next to nothing. I have a 1.9 to 1 loaded canopy; I am going to be one of the first to land on most loads no matter where I exit. I know several freeflyers who have largish 7 and 9 cell canopies loaded around 1.2 to 1; they are going to land last no matter where they get out. Landing order is determined primarily by canopy loading and pull altitude, not by exit order.

[speedy 0]

  Quote

Landing order is determined primarily by canopy loading and pull altitude, not by exit order.

I agree, but would like to add, canopy skills also play an important role. I go last out quite often as tandem vidiot with my velocity loaded at around 2.0 to 1. Depending on the situation I decide when I land. That could be after the students with huge canopies.

as always edited for spilling.

Dave

Fallschirmsport Marl

[skr 1]

Besides differing forward throw and freefall drift
there is another reason not to put the fast fallers
out first.

They get to opening altitude 40 or 50 seconds
before the slow fallers do and spend a lot of that
flying up jump run to get back to the target.

With people commonly pulling between 3,000 and
4,000 ft that leaves some of them right in the kill
zone when the slow fallers start arriving and opening.

----

On another topic, I had emailed Bryan Burke to see
what he thought about this "Dealing with Uppers"
article

http://indra.net/~bdaniels/ftw/sg_skr_dealing_1_uppers.html

I ran into him at Lost Prairie and he said he may
experiment with putting ground speed vs seconds
tables in the planes. They already post the current
ground speed at the trailor loading area.

He also said they no longer fly jumpruns at less than
60 knots ground speed. If the uppers get stronger than
that they start flying various forms of cross wind
jump runs.

He's a very thoughtful guy and interesting to talk to.

Skr