Backfly Exit order?

[ubisunt 0]

Hi,

My searches to this question on forum came up empty and I have had conflicting advice from experienced jumpers...

When moving from belly to practicing backflying (no headup]\head down) ...what is the correct exit order please? Some say exit with other flat fliers, others say to exit with freefliers? Lets assume backfly is stable but certainly not expert.

Head\Feet perpendicular to jumprun is a given.

Many thanks in advance.

[Trafficdiver 8]

Backflying is freeflying so at most DZ's I go to it is after belly fliers. Large groups first, smaller after.

Keep in mind you can reach high speeds on your back if you fold at the hips.

[Joellercoaster 6]

Backfly can range between the speeds of belly and sit depending on what they're doing, and falls roughly vertically - to be honest the question has never come up, but I'd put them out between belly and freefly groups.

The "large to small" part comes naturally, since I don't think I've ever seen a dedicated flat-fly group larger than two.

Keep in mind that the (modern) exit order thing is mostly based on the group's behaviour on the hill; I would guess that backfliers aren't in the super fast-fall backfly of the recovery position on exit.

I guess this means treat them as a belly group, but put them out at the end of the belly section of the load just in case?

--
"I'll tell you how all skydivers are judged, . They are judged by the laws of physics." - kkeenan

"You jump out, pull the string and either live or die. What's there to be good at?

[ghost47 18]

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Keep in mind that the (modern) exit order thing is mostly based on the group's behaviour on the hill

I always thought the modern exit order had to do with how long the jumper was exposed to the relative wind, and trying to ensure adequate horizontal separation. Can you elaborate on your statement above?

[Joellercoaster 6]

We're talking about the same thing - and in retrospect, I realise that my way of saying it is jargon-heavy and less useful to a beginner.

So: for the non-4-way-obsessed, the "hill" is RW-speak for the time when you are travelling partly in the same direction as the plane, while your velocity changes (due to friction and gravity) from horizontal to vertical.

Faster-falling groups are faster-falling because they have less air resistance. Friction due to air resistance is what dissipates forward speed, so freefly groups travel further in the direction the plane is going before they are completely vertical.

This is why we put them out after slower-falling groups: to ensure that groups are separated by as much horizontal space as possible.

--
"I'll tell you how all skydivers are judged, . They are judged by the laws of physics." - kkeenan

"You jump out, pull the string and either live or die. What's there to be good at?

[Deimian 43]

Isn't it also because slow-falling groups stay more time in the air, and drift a bit further with it? That was my understanding at least, even though I always wondered how big of a difference it makes.

[Thijs 0]

Joellercoaster

So: for the non-4-way-obsessed, the "hill" is RW-speak for the time when you are travelling partly in the same direction as the plane, while your velocity changes (due to friction and gravity) from horizontal to vertical.

Faster-falling groups are faster-falling because they have less air resistance. Friction due to air resistance is what dissipates forward speed, so freefly groups travel further in the direction the plane is going before they are completely vertical.

That might technically be correct, but it not the reason why belly goes out first. Your reasoning doesn't work when a plane is dropping with a tail wind.
The longer an object stays in freefall, the more it will drift according to the winds at that altitude.
If you would drop a freeflyer and a belly flyer from a helicopter which is flying without moving forward (so there is no hill), they would still open at different locations, simply due to the different amounts of time they are exposed to relative wind.

[EvilGenius 0]

I believe both factors are important, there are some great animations illustrating this here...

http://diverdriver.com/freefall-drift-simulator/

[JohnMitchell 16]

Joellercoaster

Keep in mind that the (modern) exit order thing is mostly based on the group's behaviour on the hill; I would guess that backfliers aren't in the super fast-fall backfly of the recovery position on exit.

I guess this means treat them as a belly group, but put them out at the end of the belly section of the load just in case?

The "hill" part you talk about is correct. It's how much forward throw one gets after exiting the airplane, and is directly related to your terminal velocity speed, regardless of wind drift, etc. A good backflyer can fall at belly speeds, but can easily go faster. I vote the idea of them getting out after belly, but before sit/head-downers.

Once again, beginning freeflyers of any discipline, try to face perpendicular to the jump run line. That way, if you backslide (very common while learning), you won't slide up or down the jump run line into someone else's airspace.

[timrf79 0]

Back flyers should go out after Bellly, before FF.
However there should be good separation.

Reason being that some back-flyers fall SLOWER than Belly, others fall faster.

However I think in average back-flyers fall comparable to belly.

Related note, back-flying basics should be learned in a tunnel. Then in the sky with a friend that goes belly and looks at body position and can keep an eye on heading and movement.

[Alexg3265 0]

Thijs

***So: for the non-4-way-obsessed, the "hill" is RW-speak for the time when you are travelling partly in the same direction as the plane, while your velocity changes (due to friction and gravity) from horizontal to vertical.

Faster-falling groups are faster-falling because they have less air resistance. Friction due to air resistance is what dissipates forward speed, so freefly groups travel further in the direction the plane is going before they are completely vertical.

That might technically be correct, but it not the reason why belly goes out first. Your reasoning doesn't work when a plane is dropping with a tail wind.
The longer an object stays in freefall, the more it will drift according to the winds at that altitude.
If you would drop a freeflyer and a belly flyer from a helicopter which is flying without moving forward (so there is no hill), they would still open at different locations, simply due to the different amounts of time they are exposed to relative wind.

If the plane had a tailwind, itd be flying backwards... so thats not going to happen. slower freefall speeds equals less horizontal travel after leaving the plane, higher freefall speeds body positions mean youll travel horizontally with the plane longer... once free of the intertial momentum, you're all in the same airmass and affected by winds aloft the same... so, sure a really slow belly group could possibly end up on top of a really fast freefly group due to differences in time exposed to upper winds.... but jumprun on high wind days, should be into the winds aloft and the separation to make this happen would have to be way too close anyways. This is assuming the lower group isnt opening and flying up jump run of course. Opening altitudes can be considered but in my opinion, are worthless.. you get distracted and can easily blow through your "opening altitude". Kind of makes me nuts listening to people trying to organize the load by opening altitude... what if you have a cutaway?what if you dump early or a little late?.... horizontal separation is key. When in doubt give it a couple more seconds...

I was that kid jumping out if his tree house with a bed sheet. My dad wouldn't let me use the ladder to try the roof...

[KBUDA 19]

This isn't trying to contribute to the specific discussion at hand, but I do want to point out that my dropzone always does an East to West jumprun due to air traffic from DIA. Headwind or tailwind, the jumprun is always the same and can vary greatly in ground speed. FYI.

[JohnMitchell 16]

Alexg3265

If the plane had a tailwind, itd be flying backwards...

Umm, are you sure you know what a tailwind is? It's the same as flying your parachute downwind. You're going faster across the ground, but you're still moving forward through the air. You ain't flying in reverse.

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once free of the intertial momentum, you're all in the same airmass and affected by winds aloft the same... so, sure a really slow belly group could possibly end up on top of a really fast freefly group due to differences in time exposed to upper winds....

A bit of a possibility, yep.

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. This is assuming the lower group isnt opening and flying up jump run of course.

One of my pet safety peeves. After opening, your spot is less important than "Where's the next conflicting freefall group?"

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Opening altitudes can be considered but in my opinion, are worthless.. you get distracted and can easily blow through your "opening altitude". Kind of makes me nuts listening to people trying to organize the load by opening altitude... what if you have a cutaway?what if you dump early or a little late?.... horizontal separation is key. When in doubt give it a couple more seconds...

Absolutely. Premature openings, hard pulls, malfunctions, distracted jumpers; all make vertical separation unreliable. Longitudinal and lateral separation are the only ones you can count on, and that's only if people work together to make it happen.