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spinglebout

Basic Data required for Project

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Hi everybody!
I'm new to Dropzone.. and I'm loving it so far. I'm a student of Aeronautical Engineering and I'm currently doing my final Project in Sport Parachuting. For kicks, I'll be doing my Tandem jump sometime next month(excited!):ph34r:

I need a some data for an analysis I'm conducting and I'd really appreciate any help from experienced skydivers out here.
Here goes:

For a Performance Design - Velocity (Expert level)
- At what altitude would an average 150lb person deploy his parachute? (Mean sea level)
- What would the inflation time be?
- At what airspeed would he be travelling (MSL)?

If possible could I have the above values for a PD-Navigator (Student level) and a PD-Stiletto as well?

Thanks! :)

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For a Performance Design - Velocity (Expert level)
- At what altitude would an average 150lb person deploy his parachute? (Mean sea level)

An average 150lb jumper wouldn't be jumping a velocity ;)
But generally, anyone jumping a high-performance canopy like that opens a little bit higher than 'mandatory', because generally these type of canopies open relatively slow, you need more altitude to deal with opening issues, and oftentimes these jumpers have specialized gear that takes a bit of time to stow away (RDS). I don't think many of these jumpers open below 3000ft (above the ground, not MSL unless you're in The Netherlands... ;))

- What would the inflation time be?

Skydivers don't usually use 'time' as a reference, but altitude. A velocity could take up to ~1000ft to open I believe, but presumably someone who jumps them can provide a more accurate answer.

- At what airspeed would he be travelling (MSL)?

Before or after opening? Before opening if you did a 10sec freefall or more, generally you're travelling at 120mph-ish. After opening, it depends on the wingloading (jumper + equipment weight in lbs/sqft of the canopy) and how you're flying. if you're hanging in breaks you do down relatively slow, if you're doing a high-performance turn on a canopy like a velo, you can beat 13m/s...

If possible could I have the above values for a PD-Navigator (Student level) and a PD-Stiletto as well?

A student would open higher, starting at 5000ft and moving down slowly, and a navigator, like most student canopies, opens fairly quick.

A stiletto is for a jumper with 300-500 jumps or more, presumably this jumper is free to open at 2000-2500ft. A stiletto generally opens fairly slow, so in between the nav and the velo.


ciel bleu,
Saskia

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I have some very specific examples based on GPS recordings and video. But it is specific, not average, and maybe not typical.

I weigh 170 and fly a Pilot 210.

If you want a couple of examples let me know.
Instructor quote, “What's weird is that you're older than my dad!”

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This is the real world, not academic engineering.;)

Opening altitude can be anywhere from high enough (USPA recommended minimum 2500') to exit altitude. It depends on what the jumper wants to do.

Opening time/altitude will vary from jump to jump. Any differences in canopies are qualitative, not quantitative. Fast opening, medium opening, long opening. These overlap and again vary from jump to jump within a range.

We don't live in the world of standard atmosphere/pressure or MSL. We live in the world of humidity, wind and weather. And for the most part precise canopy speeds aren't measured but each individual canopy and jumper combination would be slightly different based on drag, variation in canopies and line sets, etc.

We can give you classroom numbers.;)

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

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Opening altitude takes license level, the skydiver's own feelings on the subject and other variables into consideration. This is not specific to the canopy they're flying. Also we measure altitude in AGL (Above Ground Level,) not MSL. So where I live I always say we're starting around 12000 even though it's actually 17000 MSL.

When I was a student I felt uncomfortable deploying below 5500 because that's what they had me at in AFF. It got moved down during my coaching and got moved down a bit more as my jump numbers went up and I got my B license. These days I pull at 3500 and that's pretty comfortable for me. I'm not afraid to go lower if the need arises -- I know there's a guy above me, for example, and don't want to give him a face full of parachute. If that ever actually happened, I would yell at the guy when we got to the ground, for being directly over me 2000 feet below our agreed-upon break altitude. Someone would have to actively be TRYING to do that, though. It's not like I can't take steps to prevent it from happening.

If I hit 2000 for any reason and still haven't deployed, I'm going directly for my reserve parachute.

The reason for that is I have actually had my parachute snivel for over 1000 feet. Actually I've never seen the one I'm currently on go more than about 700, but I have seen at least one 1200 foot snivel on a rental chute. If I deploy my main below 2000 feet, I'm risking a 2-out malfunction (AAD Fire.) If I ignore that and deploy my main anyway and there turns out to be something wrong with it, I have no room to cut it away.

Average person's going 120 mph on deployment. I weigh 210 and usually average about 130. Before I lost weight, got a baggier jumpsuit and learned the body position to fall more slowly, they clocked me at 170 a couple of times. My coaching jumps were full of jumps where I'd tell the coach "I fall like a bat out of hell!" They'd say "Don't worry, I can keep up!" (Spoiler alert, they couldn't.) So there was a lot of fall speed work with my coaches and in the tunnel.

My D license buddy was allowed by his license level to pull as low as 2000 when I asked him about his deployment altitude. It's been moved to 2500 now, but it was 2000 when I asked him. He said no way he'd every pull that low. He told me he wanted lots of room to deal with it in the event of a malfunction. So he usually pulls where I do. But he's on the ground a couple minutes before I am, after he does that.
I'm trying to teach myself how to set things on fire with my mind. Hey... is it hot in here?

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spinglebout

Hi everybody!
I'm new to Dropzone.. and I'm loving it so far. I'm a student of Aeronautical Engineering and I'm currently doing my final Project in Sport Parachuting. For kicks, I'll be doing my Tandem jump sometime next month(excited!):ph34r:

I need a some data for an analysis I'm conducting and I'd really appreciate any help from experienced skydivers out here.
Here goes:

For a Performance Design - Velocity (Expert level)
- At what altitude would an average 150lb person deploy his parachute? (Mean sea level)
- What would the inflation time be?
- At what airspeed would he be travelling (MSL)?

If possible could I have the above values for a PD-Navigator (Student level) and a PD-Stiletto as well?

Thanks! :)



Wow, sounds exciting.

Um, where are you a student at?
And what is your .EDU Email?

C
But what do I know, "I only have one tandem jump."

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mattjw916

Quote

If I hit 2000 for any reason and still haven't deployed, I'm going directly for my reserve parachute.

I hear people say this a lot but under pressure muscle memory wins and they almost always go for their main handle.



That wouldn't be terribly surprising. I'm going to do my best to avoid finding out. Not hitting 2000 feet while still in freefall and not ever having an AAD fire on any jump I was conscious on are two of my long term goals in the sport.

Others include never causing harm to others because I was being a dumbass and not dying of anything would be embarrassing to have on my grave. First time I flipped a step-through back through the lines, the canopy went over my head and I suddenly realized that "ZP" means "ZP." I thought "It'd be funny if this is how I died in the sport of skydiving..." Now that would be an embarrassing thing to have on a tombstone!
I'm trying to teach myself how to set things on fire with my mind. Hey... is it hot in here?

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spinglebout

Hi everybody!
I'm new to Dropzone.. and I'm loving it so far. I'm a student of Aeronautical Engineering and I'm currently doing my final Project in Sport Parachuting. For kicks, I'll be doing my Tandem jump sometime next month(excited!):ph34r:

I need a some data for an analysis I'm conducting and I'd really appreciate any help from experienced skydivers out here.
Here goes:

For a Performance Design - Velocity (Expert level)
- At what altitude would an average 150lb person deploy his parachute? (Mean sea level)
- What would the inflation time be?
- At what airspeed would he be travelling (MSL)?

If possible could I have the above values for a PD-Navigator (Student level) and a PD-Stiletto as well?

Thanks! :)



Welcome to the board. Quick questions to clarify (I can not help you with much as a student to the sport).
You need to define "opening" for accurate numbers. Do you require time from pilot-chute deployment to full canopy inflation or do you mean time from line-stretch to full opening? A quick and dirty way would be to try and use video to measure the times (theres a LOT on youtube). My videos on a PD-Navigator260 are not useful since the video loses me after pull. But as an engineer you need to define your parameters.

I can not speak for an "average 150lb" person deploying, it may be better to actually use the MODE altitude since data collection on a large enough sample would yield outliers from "cross country" flights which may deploy up or over 10,000 to low pull altitudes.

Airspeed in MSL? Under terminal "boxman" student freefall conditions your non-scientific-average is around 120mph or roughly 200ft/s (1000ft/5.5s). Some folks probably have altimeters that calculate fall rates that may be useful. Under canopy I believe its roughly 1000ft/minute IIRC. Your ground speed would depend on canopy type and wind conditions.
You are not the contents of your wallet.

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CSpenceFLY

***Why not give a little information about yourself?

Sparky


I think you were thinking what I was thinking.

Ya, I think its pretty apparent she's really a lawyer for the Crown Prince and looking to stick it to PD for the mental anguish he suffered in that recent near death experience.

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Divalent

******Why not give a little information about yourself?

Sparky


I think you were thinking what I was thinking.

Ya, I think its pretty apparent she's really a lawyer for the Crown Prince and looking to stick it to PD for the mental anguish he suffered in that recent near death experience.

More like for the packer, who now has to hitch hike without thumbs...










~ If you choke a Smurf, what color does it turn? ~

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Well.. I was referring to MSL because the inflation-force calculation diagnostic tool that I am using requires altitude in MSL
I am still learning about a lot of new terms and concepts and I hoping once I'm more well versed on this subject (which should be very soon) I would be able to ask more informed questions :)

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dragon2

For a Performance Design - Velocity (Expert level)
- At what altitude would an average 150lb person deploy his parachute? (Mean sea level)

An average 150lb jumper wouldn't be jumping a velocity ;)
But generally, anyone jumping a high-performance canopy like that opens a little bit higher than 'mandatory', because generally these type of canopies open relatively slow, you need more altitude to deal with opening issues, and oftentimes these jumpers have specialized gear that takes a bit of time to stow away (RDS). I don't think many of these jumpers open below 3000ft (above the ground, not MSL unless you're in The Netherlands... ;))

- What would the inflation time be?

Skydivers don't usually use 'time' as a reference, but altitude. A velocity could take up to ~1000ft to open I believe, but presumably someone who jumps them can provide a more accurate answer.

- At what airspeed would he be travelling (MSL)?

Before or after opening? Before opening if you did a 10sec freefall or more, generally you're travelling at 120mph-ish. After opening, it depends on the wingloading (jumper + equipment weight in lbs/sqft of the canopy) and how you're flying. if you're hanging in breaks you do down relatively slow, if you're doing a high-performance turn on a canopy like a velo, you can beat 13m/s...

If possible could I have the above values for a PD-Navigator (Student level) and a PD-Stiletto as well?

A student would open higher, starting at 5000ft and moving down slowly, and a navigator, like most student canopies, opens fairly quick.

A stiletto is for a jumper with 300-500 jumps or more, presumably this jumper is free to open at 2000-2500ft. A stiletto generally opens fairly slow, so in between the nav and the velo.




Thanks so much for the information! It really helped!
And yeah I was looking for the airspeed at the moment of canopy extraction. Basically, the pre-inflation fall rate! :)

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Well air mass-density will probably be a factor you will have to contend with (seach for "density altitude" here for lots of discussions on that topic). For example, Florida DZs are pretty much at sea level (+/- 20 meters), so more dense due to altitude compared to, say, most inland DZs. But Fla is generally warmer and more humid than most other US locations, and those factors lower air density.

But you probably don't want to model all the possible variations. Maybe define one "standard" ground level set of conditions (say: 100 meters ASL, 25 degrees C, 50% humidity) and then go from there. Deployment altitude above that ground level at 900 meters (~3,000 ft) where you expect it will be about 6 degree C cooler (2 degrees per 300 meters). (Relative humidity will be higher due to the temp change, but actual water content will be the same.)

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