horizontal speed on tracking

[Hooknswoop 19]

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I know that I am a noob here, but I would tend to question some of your numbers.

My Alti-Track shows deployment altitudes that are much lower than I pitch, it seems to record the altitude I am in the saddle. I know that I come out of the track and slow before I pitch. There has to be some time there that recorded free-fall time is not tracking. Trimming off seconds from exit to track and from track to pull seems to be needed in your calculations.

I exited in a track and pulled in a track.

Derek

[Hooknswoop 19]

Those that do not believe it is possible should get out of the way of those doing it.

You do not believe it is possible. That is OK. That in no way means it is not possible. How else can you explain 102 seconds of freefall from 13,500-2,100 feet?

I once wore a belly cam for a state record attempt jump. After the jump we were watching the video and people simply could not believe how long or how far I was tracking.

Realizing what is possible is the first step to improving your tracking.

Derek

[RB_Hammer 0]

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I exited in a track and pulled in a track.

Derek

Got it. Been working on getting in the track right after exit. Still can't get that good tracking position and forward speed right away yet. I do love to practice it though.

How far after you pitch in the track do you think you continued to have significant horizontal movement when you pitch?

What about the deployment altitude? Does the Pro-Track record deployment pretty accurate? Like I said, I know my Alti-Track records it as right around the altitude time I am in the saddle, which with my Spectre, is usually 800-1000 feet lower than when I pitch and deployment starts.

Not being critical here you understand, just trying to get my mind around this.

"I'm not lost. I don't know where I'm going, but there's no sense in being late."
Mathew Quigley

[Hooknswoop 19]

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How far after you pitch in the track do you think you continued to have significant horizontal movement when you pitch?

Not much, the canopy I was jumping opened quickly, about 300-400 feet.

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What about the deployment altitude? Does the Pro-Track record deployment pretty accurate? Like I said, I know my Alti-Track records it as right around the altitude time I am in the saddle, which with my Spectre, is usually 800-1000 feet lower than when I pitch and deployment starts.

Fairly accurate because of the quick openings.

Derek

[jakee 1,558]

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120mph AIRSPEED gives you v*sin(x) vertical speed and v*cos(x) horizontal speed. So a 120mph max track at 45 degrees would give you an 85mph fall rate, an 85mph horizontal speed.

How sure are you that you can get your vertical velocity anywhere near that slow? I seriously doubt anyone can do that without a wingsuit. The physics you're proposing just don't make sense. Your body is not all that great of an airfoil with respect to creating a lot of lift. I know it's easy to fly fast horizontaly in a track, but that doesn't have a whole lot to do with "lift" like you see with an aircraft wing. It mostly has to do with the fact that the relative wind is glancing off your body at an angle.

Dude. Learn more, talk less. Seriously.

I can get whole dive averages in the low 90's in jeans and a long T, low 80's in BM Pantz and low 40's in an intermediate wingsuit.

And y'know what the kicker is? There are lots of people out there who are much, much better at it than me.

Now, if you still think that the effect of a good track on your normal fallrate is 'negligable' then you really, really need to get an experienced person to show you what a good track is.

Do you want to have an ideagasm?

[kallend 2,105]

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There is no way in hell that someone is slowing down to 70/80mph without a wingsuit.

How can you explain 102 seconds of freefall from 13,500 feet to 2,100 feet in an RW suit? How could I fool a Pro-Track into logging more free-fall time than actual time? How could I fool the exit or opening altitudes?

That's why I wanted to see the data for myself. No offense, but I just don't believe that it's possible to slow your decent rate down near wingsuit speeds. It just does not make sense.

On what DATA do you base your scepticism? I can get freefall times in excess of 1m30s from 13,500ft in my RW suit when tracking.

Just because you can't do it doesn't mean that others can't.

...

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

[darkwing 5]

Too many people here are saying/implying/concluding that low rate of descent is necessarily connected with high horizontal coverage.

As skeptical as I am about 1:1 glide angles, I am not doubting the freefall time issue.

-- Jeff
My Skydiving History

[JohnMitchell 16]

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Just because you can move sideways, doesn't mean you're generating enough lift to slow your decent rate to sub-terminal (~120mph).

Generating a force perpendicular to the airflow is the very definition of lift, isn't it? I'll grant you that we are poor airfoils, but even wingless bodies can develop lift. Remember the Dyansoar project, the lifting bodies developed and tested by NASA? They, and we, use the strong vortices created by the high angle of attack, to develop lift. It's not a good L/D ratio, but it works. Look at the F-18. Those chines up by the cockpit are there just for that, to create vortices to create lift at high alphas.

I'm guessing you don't track that well yet. Work at it and you may find the "magic" we've experienced.

[billvon 3,063]

>Remember the Dyansoar project

The Dyna-soar (X-20) was a sailplane compared to some of the other lifting bodies they tested! The HL-10, M2-F2 and M2-F3 all looked like flying bathtubs. Heck, _I_ look more aerodynamic than the X-24A. (see below.) It looks like a big sausage.

[JohnMitchell 16]

[Eule 0]

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Jump run was 1/2 mile west of the DZ and into the wind (South), I opened 2 miles to the East of the DZ. [....]
Exit:13,500
Deploy:2,100
Free-fall time: 102 sec
By my math that equals 76 mph avg speed and a 1.158:1 Glide ratio.

I'll try not to get this one backwards...

13500 - 2100 = 11400 feet vertically
11400 / 5280 = 2.159 miles vertically

102 sec * (1 hour / 3600 sec) = 0.02833 hour

2.159 miles / 0.02833 hour = 76.2 mph vertical

2.5 miles / 0.02833 hour = 88.2 mph horizontal

2.5 miles / 2.159 miles = 1.16:1 glide ratio

Track angle from horizontal = arctan(2.159/2.5) = 40.8 degrees

Track length = sqrt(2.5*2.5 + 2.159*2.159) = 3.30 miles

Speed along track path = 3.30 miles / 0.02833 hour = 117 mph

So yeah, I agree with your numbers.

Eule

PLF does not stand for Please Land on Face.

[PWScottIV 0]

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Generating a force perpendicular to the airflow is the very definition of lift, isn't it?

Yes, but what's your frame of reference? If it's the jumper, then yes, it looks like you're developing a tremendous amount of "thrust" upwards, but if you look at the whole picture (i.e. you're primarily plummeting toward the ground), the picture doesn't look so great.

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I'll grant you that we are poor airfoils, but even wingless bodies can develop lift. Remember the Dyansoar project, the lifting bodies developed and tested by NASA? They, and we, use the strong vortices created by the high angle of attack, to develop lift. It's not a good L/D ratio, but it works. Look at the F-18. Those chines up by the cockpit are there just for that, to create vortices to create lift at high alphas.

I don't think you can use that as a comparison, as our velocity is WAY below the speed of sound, which is the region where I'm pretty sure that effect becomes functional. Correct me if I'm wrong, but I think the primary(possibly the sole) reason for the chines on the F-18 was for stability in high speed flight. It's also an air foil, which you've all ready conceded the human body does not excel at.

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I'm guessing you don't track that well yet. Work at it and you may find the "magic" we've experienced.

Well I'm definitely not slowing my vertical decent rate down to anywhere near 70mph, but I do actually have a pretty decent track. To practice, I do a max track at the end of pretty much every jump, but on several tracking dives I've done, watching my horizontal speed relative to the ground, I'm definitely fucking booking. I've become pretty good at adjusting my attitude to optimize my glide. I can feel when I "stall" by flattening out too much, and I can feel when I'm diving too much and not preserving my altitude.

I've never actually had a whole lot of interest with tracking, aside from it's ability to save my life, but I think I'm gonna work on getting some real data for myself to see what I can do.

And the "magic" you've been experiencing might very well be the same "magic" that Throttle Body Spacers do to give you more hp in your car... Not saying that what you're claiming is definitely untrue, it just doesn't make sense to me. I'd like to see some REAL scientific data supporting the claim... Unfortunately all I've seen so far is several people "claiming" it is true, but don't have any REAL proof. (someone saying that they used to have the data, but it got corrupted, really isn't good enough) Not that it doesn't exist... I just haven't been presented with it yet. I'm really all ears though, so if someone has undeniable proof I'd be ecstatic.

Gravity Waits for No One.

[jakee 1,558]

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Well I'm definitely not slowing my vertical decent rate down to anywhere near 70mph, but I do actually have a pretty decent track.

Are you reducing your descent rate by much at all? From what you've posted on this thread it doesn't sound like you are. You probably don't have nearly as good a track as you think you do. Are your legs straight and locked, toes pointed, pushing down on the air? Are your arms straight, roughly by your side (not above and behind) pushing down on the air? Is your torso completely de-arched, shoulders hunched/ rolled, chest/ sternum sucked 'up'? Does your tracking position take noticeable physical effort to hold the optimum shape?

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To practice, I do a max track at the end of pretty much every jump,

With your jump numbers that really is only a tiny amount of practice.

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I've become pretty good at adjusting my attitude to optimize my glide.

Without a proper frame of reference, how do you know? Try begging/ borrowing/ bribing a really, really good tracker on your DZ to go and do a two way with you. Fly relaxed side by side until a certain alt where you both punch it out. Once you've watched him disappear into the distance above you then come back and talk about vert speed.

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I'd like to see some REAL scientific data supporting the claim... Unfortunately all I've seen so far is several people "claiming" it is true, but don't have any REAL proof.

What do you want me to do, post a photo of my pro-track? If I post a photo of the 84mph Ave I got with BM Pantz how would you know that it wasn't really a wingsuit dive? Alternatively you could just trust the several people with several thousand jumps who've all told you that you're wrong.

Do you want to have an ideagasm?

[NewGuy2005 53]

HooknSwoop: Thanks for the explanation. I will continue to try and perfect the technique.

[billvon 3,063]

>I don't think you can use that as a comparison, as our velocity is WAY >below the speed of sound, which is the region where I'm pretty sure that
>effect becomes functional.

Well, the M2-F1 glided at about 110mph - very similar to human wingsuits.

>It's also an air foil, which you've all ready conceded the human body
>does not excel at.

That's the POINT of lifting bodies. They are awful airfoils. But they are just good enough to get some glide (around 3:1) and to land. The idea was to design the Space Shuttle like this, but they added wings since the lifting bodies were just too hard to land safely.

[JohnMitchell 16]

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but if you look at the whole picture (i.e. you're primarily plummeting toward the ground), the picture doesn't look so great.

don't think you can use that as a comparison, as our velocity is WAY below the speed of sound, which is the region where I'm pretty sure that effect becomes functional.

And the "magic" you've been experiencing might very well be the same "magic"

1- Didn't say it was a great L/D ratio, but it's there.

2-Those weren't supersonic either. All subsonic, like Billvon said.

3-Lot of people said the Wright Brothers were magic.

People have offered you all kinds of protrack data to crunch. I would accept 99% of Kallend's data and conclusions very readily. But you can keep saying that man can't fly.

[PWScottIV 0]

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Are you reducing your descent rate by much at all? From what you've posted on this thread it doesn't sound like you are. You probably don't have nearly as good a track as you think you do. Are your legs straight and locked, toes pointed, pushing down on the air? Are your arms straight, roughly by your side (not above and behind) pushing down on the air? Is your torso completely de-arched, shoulders hunched/ rolled, chest/ sternum sucked 'up'? Does your tracking position take noticeable physical effort to hold the optimum shape?

Yes, when I'm in a good track my legs are tight together, legs locked straight, toes pointed, I'm fully de-arched and straight (except for bending at the waist to adjust my attitude), my chest is cupped as much as possible, my shoulders are hunched, and my arms are straight to my side with my palms facing down (I know some people swear by having their palms up, but I like the ability to use my hands to make small adjustments and it seems to work best with my hands cupped down). I know I'm not very experienced, but I know I don't suck at it.

No, it doesn't seem like it takes a lot of physical effort to hold the position, but I'm on pretty decent shape too, so I'm not sure that I'd feel fatigued in any position if it only lasted for a minute or so.

I'm gonna do a few jumps tomorrow where I get out at the end of the load and track up jump run to see how much distance I can get. I'll try to find references on the ground as I exit and deploy and check the distance on Google maps. I haven't done any tracking jumps where I just go in one direction for the whole jump because I usually cover a lot of ground very fast. I'm gonna track along a river bed we have, so if/when I land out, I'll have a safe place to land.

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With your jump numbers that really is only a tiny amount of practice.

I know. I'm still a total newb.

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Without a proper frame of reference, how do you know? Try begging/ borrowing/ bribing a really, really good tracker on your DZ to go and do a two way with you. Fly relaxed side by side until a certain alt where you both punch it out. Once you've watched him disappear into the distance above you then come back and talk about vert speed.

Yep, I agree. I've been on a few tracking dives with others, but the other jumpers haven't been all that good at tracking compared to to me, so I'd definitely like to find someone to jump with who knows their shit...

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What do you want me to do, post a photo of my pro-track? If I post a photo of the 84mph Ave I got with BM Pantz how would you know that it wasn't really a wingsuit dive? Alternatively you could just trust the several people with several thousand jumps who've all told you that you're wrong.

Nobody has sent me any protrack data... Just numbers that they remembered... But you're right, if they did there wouldn't really be any way of knowing if they were flying a wingsuit or not...

Gravity Waits for No One.

[cpoxon 0]

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I may be wrong...

In the 70mph and 80mph range. Increasing drag will decrease vertical speed. Increasing lift will increase glide ratio. (Does this also decrease vertical speed? If so, then will increasing drag and lift dramatically decrease vertical speed?) I am very interested in this topic because I love tracking.

I agree, you are wrong. There is no way in hell that someone is slowing down to 70/80mph without a wingsuit. Anyone who says so is either lying or fooling themselves. Digital logging altimeters show speeds that slow sometimes, but it's only due to fluctuations in air pressure caused by variable airflow and burble around the unit.

Here you go. Here are some graphs from jumps during the recent sequential record in Z-hills. In 1923 there is 13 seconds between 78 and 91 where the sustained fall rate is in the mid 80s and you can see the speed bleeding off from 120 in the previous 17 seconds.

In 1928 you can see the speed decreasing over 28 seconds to a minimum of 77.5mph.

Unfortunately I don't have any data from World Team, where I was in the first group breaking off tracking for even longer, due to a problem with my Neptune which required it to go back to the facotry :-(

I'm 5' 11" and weigh about 192 lbs with gear and lead.

Skydiving Fatalities - Cease not to learn 'til thou cease to live

[pchapman 279]

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Nobody has sent me any protrack data... Just numbers that they remembered...

There's some learning going on in this thread!

Anyway, what the heck, here are a couple graphs to provide examples of the kind of tracks that people are talking about.

The "j1368" one is a straight track. RW suit, no booties, skinny jumper. Even in the reduced air density at altitude, true vertical airspeeds are consistently in the 76 to 82 mph range.

"j1544" is for another dive where I did a 180 turn which caused a spike in speed. It compares GPS output to Protrack data. (Raw protrack data reworked to provide a 3 second centered average rather than it's normal 6 second lagged average.)

Although there is some confusion during the turn, the GPS seems to confirm that the Protrack is not totally out of whack during long, steady state flight.

Of course I can't prove I didn't just spend all afternoon creating fake graphs. :)

[Butters 0]

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I may be wrong...

In the 70mph and 80mph range.

I agree, you are wrong. There is no way in hell that someone is slowing down to 70/80mph without a wingsuit. Anyone who says so is either lying or fooling themselves. Digital logging altimeters show speeds that slow sometimes, but it's only due to fluctuations in air pressure caused by variable airflow and burble around the unit.

Either alot of people are lying or I wasn't wrong. Now I need to find a really good tracker at my dropzone to teach me so that I can become a really good tracker.

"That looks dangerous." Leopold Stotch

[kallend 2,105]

With all due respect, you have no idea what you are writing about.

PS both Darkwing and I are physics professors, Billvon is a professional engineer.

...

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

[OSOK 0]

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I'm gonna do a few jumps tomorrow where I get out at the end of the load and track up jump run to see how much distance I can get.

Ok, I was staying out of it until now. Take this any which way, but for someone with a head as big as yours, you need to re-think certain things. I think instead of sounding like a badass, saying others dont track as well as you (with your jump numbers i seriously doubt you know what a good track even feels like), you should go back to square one and realize that tracking back up jump run is not safe.

Seriously, humble down a bit before it's too late.

[PWScottIV 0]

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I may be wrong...

In the 70mph and 80mph range. Increasing drag will decrease vertical speed. Increasing lift will increase glide ratio. (Does this also decrease vertical speed? If so, then will increasing drag and lift dramatically decrease vertical speed?) I am very interested in this topic because I love tracking.

I agree, you are wrong. There is no way in hell that someone is slowing down to 70/80mph without a wingsuit. Anyone who says so is either lying or fooling themselves. Digital logging altimeters show speeds that slow sometimes, but it's only due to fluctuations in air pressure caused by variable airflow and burble around the unit.

Here you go. Here are some graphs from jumps during the recent sequential record in Z-hills. In 1923 there is 13 seconds between 78 and 91 where the sustained fall rate is in the mid 80s and you can see the speed bleeding off from 120 in the previous 17 seconds.

In 1928 you can see the speed decreasing over 28 seconds to a minimum of 77.5mph.

Unfortunately I don't have any data from World Team, where I was in the first group breaking off tracking for even longer, due to a problem with my Neptune which required it to go back to the facotry :-(

I'm 5' 11" and weigh about 192 lbs with gear and lead.

Ok, well I just didn't think it was possible to slow down to that speed... Here's a max track I did on jump 29. I was working on transitions from sit to belly to back flying during the jump and then I did my track at the end like i usually do. I apparently got down to 74mph... I have several other jumps where I got down to mid 70s too.

Gravity Waits for No One.

[PWScottIV 0]

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I'm gonna do a few jumps tomorrow where I get out at the end of the load and track up jump run to see how much distance I can get.

Ok, I was staying out of it until now. Take this any which way, but for someone with a head as big as yours, you need to re-think certain things. I think instead of sounding like a badass, saying others dont track as well as you (with your jump numbers i seriously doubt you know what a good track even feels like), you should go back to square one and realize that tracking back up jump run is not safe.

Seriously, humble down a bit before it's too late.

There's NOTHING wrong with getting out last and then tracking UP jump run (not down), in the same direction the plane is travelling. And sorry to break it to ya, but I do have a good idea of what a good track feels like. Maybe not as much as the "experts" such as yourself, but good none the less. I don't think I'm a baddass. And anyway, how does tracking well make someone a baddass?

Gravity Waits for No One.

[PWScottIV 0]

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With all due respect, you have no idea what you are writing about.

PS both Darkwing and I are physics professors, Billvon is a professional engineer.

Ok, that's good to know because I frequently hear BS from people who know next to nothing about aerodynamics... I currently operate an engineering company and my dad was an aero engineer for Douglas and Boeing aircraft for 45 years. Don't get me wrong, as I'm not claiming to have any serious knowledge of aerodynamics and I've never worked on any such projects, but I'm not clueless either.

Gravity Waits for No One.