What is it exactly that makes a parachute to...

[autoset 0]

... take you forwards instead of backwards when opening?

What is it exactly? The shape of the canopy? The length of the lines?

Forgive my amateur questions but I'm pretty much a newbie.

[BillyVance 34]

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... take you forwards instead of backwards when opening?

What is it exactly? The shape of the canopy? The length of the lines?

Forgive my amateur questions but I'm pretty much a newbie.

shape of the wing as well as the angle it presents to the wind.

"Mediocre people don't like high achievers, and high achievers don't like mediocre people." - SIX TIME National Champion coach Nick Saban

[BlakeWeston 0]

I'm also a newbie, so forgive un-thechnical terms...

To the best of my understanding....

Your canopy is not flat. Because the lines are different lengths, The A-lines being the shortest and the D and brake lines being the longest, the canopy has a 'slope' to it, with the furthest distance away from you being at the rear of the canopy. It could be this line length arrangement that helps maintain the passage of air from the front of the canopy to the back, i/e a forward direction. However, there is more. The way that a canopy flies relies somewhat on Bernoulli's [?] principle which states that [basically] a moving gas has a lower pressure the faster it goes. This means that the shape of your canopy is much like a wing in that the air that passes over the top of the wing travels faster than the air which travels along the bottom skin of your canopy. The faster the gas travels the lesser the pressure and so lift is generated. The inflation of the canopy after opening forms this wing shape which generates the lift and moves the canopy in a forward direction rather than backwards.

As I said, opening is a violent process, I don't know exactly what happens when, but I would guess that as the lines become taut, the canopy is pulled into the 'nose lower-tail higher' configuration which starts to generate the forward movement as the nose cells inflate to form the wing shape which further slows you down and provides forward movement and lift.

[If you want to go backwards, try stalling your canopy on either brakes or rear risers and you will find yourself moving gently backwards....but also a LOT down!! :-) ]

um, those are my thoughts anyway.

Always, always pay your Packer...

[bodypilot1 0]

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... take you forwards instead of backwards when opening?

What is it exactly? The shape of the canopy? The length of the lines?

Forgive my amateur questions but I'm pretty much a newbie.

You must have had a great FJC, huh?

You also stated in a past post, "Okay I'm a bit obsesed with safety as you may know from my other posts."

If your jumping and still asking these questions, maybe you need to take your FJC again, or get a better instructor to teach it?.......


Be safe
Ed

www.WestCoastWingsuits.com
www.PrecisionSkydiving.com

[floridadiver81 0]

i would agree with you too. i took my fjc 4 weeks ago but remember it like it was yesterday..and the instructor did go over the basic dynamics of the canopy..everything for the design of the ram air chute to the different stages of opening..to the airflow directions once the canopy is fully inflated. He told us that you fly forward due to the different lengths in the lines...as somone already pointed out. He didnt say anything about going backward though...im assuming becasue as students we shoudlnt be doing that anyway!

"Age has absolutely nothing to do with knowledge, learning, respect, attitude, or personality." -yardhippie
"Fight the air, and the air will kick your ass!!! "-Specialkaye

[Andy_Copland 0]

I also remember some of your posts and the whole "im obsessed about safety" thing. If you're obssessed about safety then why ask on a website, how do you know these peoples profiles are even accurate?

Instead of asking us arse holes on a website, go out and buy a book on canopy flight

1338

People aint made of nothin' but water and shit.

Until morale improves, the beatings will continue.

[billvon 2,435]

>What is it exactly? The shape of the canopy? The length of the lines?

Both. The trim of the canopy is such that the wing is tilted down towards the front. As the parachute begins to open, more air can escape out the back of the parachute than under the front of the nose. The reaction to all that air moving backwards is that the canopy moves forwards.

Once the canopy is flying, the downward trim of the canopy causes the lift vector to point slightly ahead of straight down. This generates lift going "forward" if you will. Drag and weight oppose that, and when all three are in balance, the canopy is in level (but descending) flight.

[Loonix 0]

Quite elitist attitude from you and several other posters.. They did cover this in my FJC, but didn't put much weight on it. I'd say leaving the hows and whys of aerodynamics out of the FJC does not mean it's a bad FJC. If you know how things are supposed to react, and what you can expect, you'll do fine. WHY it all happens, can be learned later. Remember that too much information can be just as bad as too little... I'd say there's nothing wrong with his question, and it does not neccesarily reflect any lack of knowledge of how to skydive safely.

[LloydDobbler 2]

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Quite elitist attitude from you and several other posters.. They did cover this in my FJC, but didn't put much weight on it. I'd say leaving the hows and whys of aerodynamics out of the FJC does not mean it's a bad FJC. If you know how things are supposed to react, and what you can expect, you'll do fine. WHY it all happens, can be learned later. Remember that too much information can be just as bad as too little... I'd say there's nothing wrong with his question, and it does not neccesarily reflect any lack of knowledge of how to skydive safely.

Yeah, I'll agree with Loonix here. I didn't learn too much about the aerodynamics behind canopy flight with my FJC - just the extreme basics, really. During that course, I learned things like what flaring does to your overall downward and forward motion...it was less about the scientific theory behind flight and more about what you'll specifically encounter when flying your wing. I've always thought of it kind-of like a driver's ed course - you don't learn how an alternator works during it, but you do learn how to drive the car.

That being said, autoset, Bill's great post above is succinct and tells you the basic mechanics of why a canopy moves forward upon opening. I wish I had his gift of consolidating paragraphs of important, detailed information into a few clear, concise, understandable sentences...but brevity just isn't my strong suit.

Also, I don't know what your experience level is - how many jumps (if any) you have. I can't specifically remember any of your other posts. So if you find yourself still interested in the "how does this work?" aspect of things, what I will suggest is this:

When you feel comfortable with it (being an AFF student is enough to worry about, usually, before you start getting into stuff like this), order a copy of Brian Germain's book "The Parachute and its Pilot." I learned more about the aerodynamics of canopy flight from that book than anywhere else.

If you're not at that point yet, wait until you get cleared for self-supervision, or until you've got your license, then pick it up. You'll find lots of stuff you hadn't thought about written in that book. It's good stuff.

Skies,

KC

[AggieDave 6]

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You must have had a great FJC, huh?

You take the time to go over the technical aspects of the aerodynamic properties of a modern canopy in your FJC? Jesus man, how long is your FJC if you include all this information you keep talking about in all these threads? Does it take a few days to complete your course?

Talking briefly about "its a RAM air canopy, which means it flies forwards...yada yada yada" is one thing. Getting into the technical aspects of HOW it flies forward due to line trim, etc is well above and beyond the infromation for a FJC and you know it. If you don't know it, I have to seriously wonder about your FJCs and you trying to push too much information down these poor guy's throats, then having them lock up and forget the important things about FJCs like how to pull and PLF.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[sundevil777 94]

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i would agree with you too. i took my fjc 4 weeks ago but remember it like it was yesterday..and the instructor did go over the basic dynamics of the canopy..everything for the design of the ram air chute to the different stages of opening..to the airflow directions once the canopy is fully inflated. He told us that you fly forward due to the different lengths in the lines...as somone already pointed out. He didnt say anything about going backward though...im assuming becasue as students we shoudlnt be doing that anyway!

Geez, cut the guy a break, eh!

He didn't have the same instructor as you. Some instructors would say that you were given too much information, that the FJC should only focus on the essentials, what they will need to know for the first jump and be able to remember - which isn't much for most students.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[fastphil 0]

Air...

[koppel 3]

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He didn't have the same instructor as you. Some instructors would say that you were given too much information, that the FJC should only focus on the essentials, what they will need to know for the first jump and be able to remember - which isn't much for most students.

One of the catch-phrases that I had drummed into me when I was doing my Instructors Course was "Must Know.......Should Know.......Could Know"


Give them the Must Know on the FJC with maybe a very small amount of Should Know if they show aptitude and are not being overloaded. Leave the Could Know for later

I like my canopy...


...it lets me down.

[bodypilot1 0]

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Quite elitist attitude from you and several other posters.. They did cover this in my FJC, but didn't put much weight on it. I'd say leaving the hows and whys of aerodynamics out of the FJC does not mean it's a bad FJC. If you know how things are supposed to react, and what you can expect, you'll do fine. WHY it all happens, can be learned later. Remember that too much information can be just as bad as too little... I'd say there's nothing wrong with his question, and it does not neccesarily reflect any lack of knowledge of how to skydive safely.

We aren't flying rounds during our first jumps anymore. Simple aerodynamics of why it a canopy goes forward is explained in a few minutes and is very easy to comprehend. It's never to much to learn as much as you can BEFORE you risk your life under something you know NOTHING about.....

Be safe
Ed

www.WestCoastWingsuits.com
www.PrecisionSkydiving.com

[bodypilot1 0]

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You take the time to go over the technical aspects of the aerodynamic properties of a modern canopy in your FJC?

Yes. Did you jump a round on your first jump?

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Jesus man, how long is your FJC if you include all this information you keep talking about in all these threads? Does it take a few days to complete your course?

My course involves 2 working tandems. Alot can be explained during the canopy control while under canopy. You can ask a few of my past students that post on here about the information I give and how simple it is to understand. My FJC isn't just hours of information and we jump, like some courses. They learn the dynamics of how and why it flies as we go through the first 2 jumps, then as they progress into the AFF portion, they learn how it can malfunction and how to deal with it. My ground FJC, after they complete 2 sucessful working tandems, takes about 2 or so hours, and then we dirt dive the AFF dive flow and jump.
The whole, "lets get this guy in the air so I can make more money and move on to the next student", isn't what my "private" course is about. It's one on one instruction with thourgh comprehension.

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If you don't know it, I have to seriously wonder about your FJCs and you trying to push too much information down these poor guy's throats, then having them lock up and forget the important things about FJCs like how to pull and PLF.

Simple questions during the training will let you know if they are comprehending the simple aspects of what your teaching. Having students jump just because you have finished your first jump course only leads to a student lack of knowledge and possible an injury or worse.....

And as far as them forgetting to pull? That's what I'm there for.

How many AFF jumps do you have Dave? If you have any, you'd know that not too much is going through their head at pull time, but lack there of........





Be safe
Ed

www.WestCoastWingsuits.com
www.PrecisionSkydiving.com

[AggieDave 6]

Every FJC covers the basics of modern ram air canopy flight, however, if they don't cover specifics about line trim and how that effects the opening sequence the course is unsafe? I'm glad that you're able to teach that in your private one on one course. I'm glad that you're able to spend that much time with each of your students. It would be nice if every single instructor was able to do that and that every single FJC student cared.

The reality is, and you know it, that going into detailed aerodynamics about canopy flight just isn't done and isn't practical for literally 98% of the FJCs out there. The basics that are covered are the basics and given as such to provide the student with the information they need to safely complete their first jump. Beyond that the FJC is only a foundation to build knowledge upon. I'm not telling you anything new. HOWEVER, saying that someone's FJC was unsafe (as you did for one you didn't attend or know for a fact what was or wasn't taught) simply because it was taught different then you teach your own specialized course is not only most likely not correct, but its unethical as an instructor. I doubt that you're an unethical instructor and I assume that you jumped the gun on this thread and mis-spoke.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[bodypilot1 0]

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HOWEVER, saying that someone's FJC was unsafe (as you did for one you didn't attend or know for a fact what was or wasn't taught) simply because it was taught different then you teach your own specialized course is not only most likely not correct, but its unethical as an instructor. I doubt that you're an unethical instructor and I assume that you jumped the gun on this thread and mis-spoke.

I didn't jump any gun or mis-speak. Maybe you should go back and re-read my post. Nowhere did I ever say it was unsafe.
Simple canopy aerodynamics during any FJC, on why a parachute flies forward instead of backward, can be explained in minutes.
Jumping something you know nothing about can kill you in seconds.


Be safe
Ed

www.WestCoastWingsuits.com
www.PrecisionSkydiving.com

[freeflysteve 0]

Because of the relative wind and that wonderful thing called gravity.

Swooping, huh? I love that stuff ... all the flashing lights and wailing sirens ... it's very exciting!

[popsjumper 2]

It appears that you and bodypilot are arguing over the depth of this instruction at the FJC.

Bodypilot is saying "simple" stuff and you are worrying on "detailed" stuff. You both agree that teaching the basic stuff is good.

2-3 minutes to explain the basics of how a ram air parachute works and 2-3 minutes to answer any specific questions for an FJC is quite sufficient. I find that knowing the basics of how the thing works gives the students some degree of confidence that the thing actually will work and takes some of the worry out of the process. Besides, it shows what's supposed to happen and provides a reference point for when you start talking about malfunctions.

My instruction for this part is very simple. I simply tell them that the parachute is designed to fly forward and that is what they should expect. Most students, by far and away, have no clue of fluid dynamics and don't even ask further. If I get an engineer or a pilot that wants the technical details, then I can go into more depth if necessary. After all, it's all about them and their comfort level, not about the time spent.

YMMV

My reality and yours are quite different.
I think we're all Bozos on this bus.
Falcon5232, SCS8170, SCSA353, POPS9398, DS239