Deploying from a track...How does this change anything?

[Chris-Ottawa 0]

OK, so, I was just reading the thread about the Spectre slamming a guy and it was raised that it could have been linked to tracking at pull time. Time and time again, I come to this and think...how the hell does that change ANYTHING. Maybe it is strictly my inexperience speaking, but theoretically, you are changing only the direction of the relative wind to the canopy, btu truthfully, the relative wind stays the same, only your orientation to the ground changes.

Here's the way I'm thinking of it, please correct me and provide input to help me understand why everyone thinks it's bad to track when dumping:

Tracking is simply going to convert some of your vertical speed into horizontal speed. This would mean that instead of your PC deploying straight up, it will deploy say, 35ish degrees off of "straight up". Now, some might say well look, it's deploying is a different direction, but that doesn't matter. It is still deploying DIRECTLY into your burble, just as it would from a flat freefall. Some might also say, well deploying in a track exposes the nose of the canopy to more wind...to that, I say not a bit. No matter what, you will still hang 90 degree to your canopy during deployment (Picture the letter "T"). Also, consider a hop and pop. You are still experiencing "throw" from the plane, which would be barely different than deploying from a track, I don't hear people saying you shouldn't do H+P's because you might have a hard opening. Granted the speeds are slower on H+P's.

As a side note...I'd say about 80% of my jumps are ended directly from a track and I've jumped Sabre 2's, Spectres, Cobalts, and and a Katana. Not once did I have a hard opening, or even one where I was like, geez...that was firm. I was even practicing "wingsuit pulls" with my Cobalt 105 and had no issues. On any jump that isn't solo, I'm tracking and the only "deceleration" I normally do is the time it takes me to reach one hand up to stabilize myself and the other to pull, I do not "flare out".

So, that being said, please enlighten me and help me understand why some people think this changes things. I'd like to consider other aspects that I may not understand or be thinking as a possibility. I truly am interested to know what I'm not thinking of. I'm looking to be schooled on aerodynamics and the relative wind if that's what needs to be....

"When once you have tasted flight..."

[stayhigh 2]

Cobalt opens nicer in a track...

but if you have something like this one,

http://www.youtube.com/results?search_query=cobalt+skydiving&search_type=&aq=f

good luck to that guy, it seems like any body position will slam your ass huh??


so i guess it all depends on your canopy,
when i was jumping safire and sabre i did try to slow down,
but once i was jumping crossfire, i was always trying to get it open faster by tracking faster.

and now i have cobalt which opens like SHIT unless i track hard and dump so there, here is your answer.... do whatever works for you durning pull time...

and experiment with packing as well, I did not believe in super tight roll of tail, but with cobalt you have to roll the PISS out of tail or mine slams the fuck out of me..

Bernie Sanders for President 2016

[brettski74 0]

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It is still deploying DIRECTLY into your burble, just as it would from a flat freefall. Some might also say, well deploying in a track exposes the nose of the canopy to more wind...to that, I say not a bit. No matter what, you will still hang 90 degree to your canopy during deployment (Picture the letter "T").

Let me start by saying that I don't know the reasoning behind the "don't deploy in a track" advice, however, while there is some validity in what you're saying, you're also missing something. When you deploy falling straight down, the forces of drag and gravity are acting in roughly opposite directions and your body and the deploying canopy are in roughly the same relative positions as they will be when the system stabilizes. When you deploy in a track, the canopy starts deploying behind you. Somewhere between your throwing of the pilot chute and achieving stable canopy flight, your body needs to transition back underneath the canopy. Exactly how this transition occurs and what effects it can have on the opening I'm not qualified to say, but I could see at least two effects that might change things.

First is that as your body starts to transition back down underneath the canopy, it will exert a some force on the nose of the canopy drawing it forward. Granted, the relative drag of your body as compared to the canopy will mean that your body should be affected by this more than the canopy, but since neither of you are fixed in any way in the air mass, both will be affected.

Second, as you start to swing back under the canopy, the load will be shifted toward the front of the canopy, meaning that the load on the rear suspension lines is reduced.

There may be other differences that I haven't thought of, also.

[Gato 0]

http://www.youtube.com/results?search_query=cobalt+skydiving&search_type=&aq=f

There ya go.

(I think he's referring to the second video on the list - that's some ugly shit.)

T.I.N.S.

[stayhigh 2]

no i was referring to that video, even his nice opening are scary and just wrong looking.

to gearless chris.
get rid of that shit. dude and how many more time are you gonna look up at that thing??? until it breaks your neck??? how bout you start looking out at the horizon while opening and trying to keep your spine straight.

Bernie Sanders for President 2016

[freeflyit 0]

Yo Chris,


>>I've jumped Sabre 2's, Spectres, Cobalts, and and a Katana
Try a Sabre 1.

[peek 20]

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OK, so, I was just reading the thread about the Spectre slamming a guy and it was raised that it could have been linked to tracking at pull time. ...how the hell does that change ANYTHING? .... please enlighten me and help me understand why some people think this changes things.

Because I believe most of us fall faster while tracking than in (belly to earth) formation skydiving. I certainly do. (See Andre's description of his fall rate in the other thread.)

But this belief seems to be changing. (I have read comments from some people that they believe that they fall slower in a track.)

And, the reality may be changing too, depending on the type of skydiving one is doing.

[Chris-Ottawa 0]

Hey Brettski,

I understand your logic, but I tend to want to disagree.

If there was no such thing as relative wind and it always came from straight down, then I would agree with the "swinging" theory. When you deploy, your canopy comes out EXACTLY in line with the relative wind no matter the direction of travel. As you slow down, the relative wind direction changes, as does your body in reference to the canopy. Think FJC..and the throw of the airplane....You change positions, but you're really only staying flat to the relative wind.

The fact of the matter is that the canopy will always deploy exactly in line with the relative wind. Until I see video of someone getting their canopy to deploy against the relative wind, this is what I will believe...

The ONLY ONLY ONLY thing I can associate a "hard opening" and tracking to is the distance you swing to change direction. Easiest to think of deploying from Head down, you will be swung upright and it may "seem" like a harder opening, but it's just the amount of swing the body perceives.


Peek:
You may be correct. I know that my fall rate drastically drops in a track. I have a very shallow, slow track. I can get into the high 70MPH range without trying too hard, but I'm definitely travelling more horizontally. I don't doubt a steep or head down track is gonna get you a slammer because you're using the parachute at it's unintended limits.

"When once you have tasted flight..."

[councilman24 36]

You and I certainly have higher airspeed when tracking. All these skinny, tall, tight suited youngsters may slow down.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[phoenixlpr 0]

Never mind. They think that tracking involves higher deployment speed.

I've attached two jump profiles: WS was a wing suit jump with a Triathlon160, other was a hop and pop with a Cobalt Competition 105.

[jakee 1,255]

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The ONLY ONLY ONLY thing I can associate a "hard opening" and tracking to is the distance you swing to change direction.

Nah, it's just because most people dive instead of track.

Do you want to have an ideagasm?

[Carrapeta 0]

I fly a sabre (1) and have yet to have a hard opening. . . I ALWAYS pitch in a full track and even in full flight when I wingsuit, never an issue.

It seems that if you really are tracking/flying well, your vertical speed will be slower than in a typical boxman. Even more so in a wingsuit.

This goes for BASE as well I've pitched in full flight for all (a whole whopping 6) of my WS base jumps and, honestly I prefer it.

Maybe people are tracking more headlow than they realize and are getting whacked from the "increased" speed that could create. . .

I dunno sh*& anyways, just my thoughts on the matter

If your gonna be dumb ya gotta be tough.

Your mom goes HandHeld

[phoenixlpr 0]

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It seems that if you really are tracking/flying well, your vertical speed will be slower than in a typical boxman. Even more so in a wingsuit.

FYI your canopy knows nothing about vertical or horizontal speeds. The relative wind matters...

[headoverheels 291]

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Because I believe most of us fall faster while tracking than in (belly to earth) formation skydiving. I certainly do. (See Andre's description of his fall rate in the other thread.)

But this belief seems to be changing. (I have read comments from some people that they believe that they fall slower in a track.)

And, the reality may be changing too, depending on the type of skydiving one is doing.

A good flat tracking position gives a lot more speed, but descent rate is lower. If you watch the on-level video of the 400-way break off, those departing in a track fell slower than the center formation. This tended to be the case, even when we did a steeper track, as requested by later waves so that they could see us ahead of them (and not above).

[peek 20]

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Never mind. They think that tracking involves higher deployment speed. I've attached two jump profiles: WS was a wing suit jump with a Triathlon160, other was a hop and pop with a Cobalt Competition 105.

Could you explain those? I'm not sure what you are trying to tell us.

[phoenixlpr 0]

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Could you explain those? I'm not sure what you are trying to tell us.

Both opening was soft. WS opening had even less vertical component.

[brettski74 0]

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When you deploy, your canopy comes out EXACTLY in line with the relative wind no matter the direction of travel. As you slow down, the relative wind direction changes, as does your body in reference to the canopy. Think FJC..and the throw of the airplane....You change positions, but you're really only staying flat to the relative wind.

That is not correct. The main drag force on your d-bag and canopy pull directly in line with the relative wind, but that doesn't mean that is where the canopy/d-bag will be. There are other forces acting on the system and the system does not react instantaneously to those forces. Gravity is acting so as to pull the jumper and canopy off of this line. To see this, consider the gravitational and drag forces on the load and canopy separately. Given the relative sizes of the forces involved, this difference is probably small, but it will be there while the system is undergoing angular acceleration.

[Carrapeta 0]

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It seems that if you really are tracking/flying well, your vertical speed will be slower than in a typical boxman. Even more so in a wingsuit.

FYI your canopy knows nothing about vertical or horizontal speeds. The relative wind matters...

Well, correct me if I'm wrong (I usually am)BUT, wouldn't the relative wind be different between a track/WS flight than a normal boxman body position??

If your gonna be dumb ya gotta be tough.

Your mom goes HandHeld

[brettski74 0]

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Never mind. They think that tracking involves higher deployment speed.

Why not? While your descent rate in a track may be lower, and should be if you're good at tracking, your airspeed may well be higher. For example, my stable box position falls at around 120mph. In a decent track, that might fall to 100mph, but if that's managing a 45 degree glide angle as some people have noted is possible in a decent track, that gives me a combined horizontal+vertical speed through the air of around 140mph.

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I've attached two jump profiles: WS was a wing suit jump with a Triathlon160, other was a hop and pop with a Cobalt Competition 105.

Your data only shows the vertical descent rate, not the total combined airspeed, which is what your canopy will deploy into.

[peek 20]

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For example, my stable box position falls at around 120mph. In a decent track, that might fall to 100mph, ... was a hop and pop with a Cobalt Competition 105.

As a large and heavy person, I would not have expected that. What is your body size, shape, and weight?

[pchapman 261]

1) Good question Chris. I do sometimes wonder to what degree "deploying in a track = harder opening". I'd also like to know what others have experienced.

2) The normal reason why that is said is because vertical speed isn't changed (much) but extra horizontal speed is added, giving a higher overall airspeed. Which clearly increases opening forces in general.

3) Yeah the idea that "the relative wind changed" doesn't make much sense; the canopy is still deploying along the relative wind. (I'm not including Brettski's ideas in this - that's a separate issue.)

4) I agree Chris that if someone's Spectre "slammed" them, that's because of something other than a normal, proper track away from a typical formation.

5) I figure the body position thing is significant factor in peoples' perception.
The more one swings, the harder the opening feels. Like students who dump while somewhat head down -- a big swing makes them feel a lot more whipped around. So if in a track one is just slightly head down from level, but the canopy will deploy with the relative wind up and slightly back, that's more of a swing than for someone not tracking who is level or a little head high. (I'd say all this is more of a factor if the peak of the opening shock is near the beginning, before one has swung much.)

6) I agree on a good long track one can get some low vertical speeds. (I'm light & tall and also get down into the high 70s mph on a dive dedicated to a track.)
I've never tested it, but it seems to me it takes some time to get that going. On a quick little track away from a small RW jump I doubt that people typically have reduced vertical speed much.

7) Brettski's thoughts are interesting. I'm not sure there's anything in it, but it's an idea to explore. The idea is that if the opening isn't vertical so one will get some other factors, like the jumper weight returning towards the vertical, which he suggested loads the front lines more. Or one could say it introduces rotation into the situation, or creates a more dynamic angle of attack situation. Off the top of my head I still think any effect would be small and could usually be neglected, but who knows. (So now someone has to do high speed hop and pops both in a normal head up position and diving downwards, to see if the canopy pitching forward vs back makes any difference.)

8) Occasionally there will be confounding factors like not tracking long enough after a freefly jump. One might still be slowing down and have a harder opening simply because one hasn't been slowing down for long enough. E.g., if one tracks a short X seconds, brakes for a few seconds, checks the alti, waves off, and dumps, sure the opening could be softer than if one just tracked X seconds and dumped.


So the question is, just what happens to the vertical speed, typically, for short tracks? A few people may be diving away at extra vertical speed, but for the rest, is the speed largely unchanged from regular belly to earth freefall? Does it start to slow a bit simply due to exposing more area (lower legs out, not arched)? Or does it slow much more due to the lift from a good track?

If there isn't much slowing for the situations most people are thinking of, then the added horizontal speed in the track will increase the airspeed and presumably result in a harder opening.

The airspeed certainly doesn't change as much as we might think by seeing the numbers. Even knowing Pythagoras, when we see say 115 mph vertical and 30 mph horizontal, it "feels like" we'd be talking about a lot of extra speed. But root (115^2 + 30^2) = an airspeed of 119 mph. Faster, but not hugely so.

If one did slow a bit vertically in that track, to 110 vertically, then in that particular case the overall speed is 114 mph, essentially unchanged from normal freefall.

[Chris-Ottawa 0]

Lots of interesting things to ponder Peter...Thanks for your post. I'm actually surprised of the direction this thread has taken. I expected my "theory" to be completely wrong and as such, get shot down quickly. It's actually providing some practical information. I expect a full writeup on your testing Peter! Haha.

Brettski, I now understand what you're referring to. I agree the effect would be very little, but you could be onto something. I agree that gravity would be pulling you down and could be putting slightly more tension on the A+B's, but I still can't imagine that gravity would override the relative wind. I mean that in the sense that there's no way you'd be "pulled" enough to bring slack to the C"s and D's for example. I know that's extreme, but it's easier for me to reference that way. I just can't wrap my head around the fact that gravity would essentially make the canopy "dive" into the relative wind while it's deploying any more than if you were perfectly vertical.

Interesting discussion anyways, lets keep it going.

Thanks!

"When once you have tasted flight..."

[pms07 3]

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OK, so, I was just reading the thread about the Spectre slamming a guy and it was raised that it could have been linked to tracking at pull time. Time and time again, I come to this and think...how the hell does that change ANYTHING. Maybe it is strictly my inexperience speaking, but theoretically, you are changing only the direction of the relative wind to the canopy, btu truthfully, the relative wind stays the same, only your orientation to the ground changes.

Here's the way I'm thinking of it, please correct me and provide input to help me understand why everyone thinks it's bad to track when dumping:

Tracking is simply going to convert some of your vertical speed into horizontal speed. This would mean that instead of your PC deploying straight up, it will deploy say, 35ish degrees off of "straight up". Now, some might say well look, it's deploying is a different direction, but that doesn't matter. It is still deploying DIRECTLY into your burble, just as it would from a flat freefall. Some might also say, well deploying in a track exposes the nose of the canopy to more wind...to that, I say not a bit. No matter what, you will still hang 90 degree to your canopy during deployment (Picture the letter "T"). Also, consider a hop and pop. You are still experiencing "throw" from the plane, which would be barely different than deploying from a track, I don't hear people saying you shouldn't do H+P's because you might have a hard opening. Granted the speeds are slower on H+P's.

As a side note...I'd say about 80% of my jumps are ended directly from a track and I've jumped Sabre 2's, Spectres, Cobalts, and and a Katana. Not once did I have a hard opening, or even one where I was like, geez...that was firm. I was even practicing "wingsuit pulls" with my Cobalt 105 and had no issues. On any jump that isn't solo, I'm tracking and the only "deceleration" I normally do is the time it takes me to reach one hand up to stabilize myself and the other to pull, I do not "flare out".

So, that being said, please enlighten me and help me understand why some people think this changes things. I'd like to consider other aspects that I may not understand or be thinking as a possibility. I truly am interested to know what I'm not thinking of. I'm looking to be schooled on aerodynamics and the relative wind if that's what needs to be....

If you aren't going faster in a track then when you are stable face to earth, then you probably need to work on your tracking skills. Just saying...

[brettski74 0]

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As a large and heavy person, I would not have expected that. What is your body size, shape, and weight?

I'm about 5'9", average build and currently about 185 pounds. Note that I'm rounding off those speed numbers for simplicity. 118mph is probably more representative of my neutral fall rate on my belly. I fall a lot slower in a hard track. Somewhere within the 97-105 range would be typical of my descent rate at the end of tracking away from a 4-way if I'm not being lazy. If I'm really working, I have a few jumps where I've gotten it under 90, but that's the exception. Anything under 95 more than likely required some hard work while tracking and was probably a longer track than a typical 4-way break off.

[fasted3 0]

I think you would understand this better if you weighed 200 lbs. or more. I can pull in a track and fly like a bird, but I've got to work at it. I can get slammed in a lazy track. IMO that is where a lot of this comes from, not to say that it couldn't happen to a lighter person in a bad enough track.
That is something to point out about pulling in a track: It can be dangerous if done really wrong. Pulling in a track is certainly possible, even to get soft openings, but a hard opening is nothing to mess around with. and a beginner could hurt themselves trying this.
I don't think it's hard to learn to do it right, and I can easily see where you are at since it works so well for you, but it's not as easy for everybody.
You've probably done a lot of tracking jumps; some jumpers only ever track at the end of a skydive and just dont get the vertical drop in speed that you are used to. I think everyone benefits from tracking dives and they are fun too. A bird pull at the end, and the opening should be no harder than a RW jump, but only when vertical speed is reduced.
Only when good tracking skills are developed should this be tried.

But what do I know?