What's the real difference?

[PhreeZone 15]

Well.. since you want info from a website hows PD's website?

What is the difference between a tapered, elliptical, or semi elliptical canopy? back to top

These terms refer to the shape of the wing when viewed from above. Any canopy that is not rectangular can be called either semi-elliptical or tapered. The amount of taper affects the canopy handling and performance, though in combination with several other parameters.

While the term elliptical is often used to describe some canopies, no skydiving canopies are truly elliptical. The curve in a canopy is approximated by a series of straight-line segments, and they do not form a true ellipse. What we are really dealing with here is the relative degree of taper from one canopy to another. This involves not only how much taper there is, but where it is located. Some canopies are more tapered than others, regardless of whether they are called "elliptical" or "semi-elliptical.”

PD prefers to use the word "tapered” for several reasons. As soon as skydivers began using the word “elliptical,” many people created the idea that every "elliptical" canopy will have certain specific characteristics, some good and some bad. In reality, a non-rectangular canopy may not have any of those characteristics. We like the term “tapered” because it simply means “not rectangular,” while the term “elliptical” implies certain things about a canopy that may or may not be true.

Rather than the actual shape of a wing, most jumpers are really interested in performance characteristics: how does the canopy open, fly and land? These characteristics are influenced by taper, but not totally dictated by it. The degree of taper is part of a whole package. Airfoil, aspect ratio and trim angle are also very important. Wing loading, or body weight compared to canopy size, is actually the main factor that determines canopy speed. The degree of taper generally influences the responsiveness of a canopy, though other variables come into play. This is why it is not necessary for a jumper to know exactly how tapered or “elliptical” a particular canopy is. The proof is in the performance, and in the handling.

Therefore, it is best to read descriptions of the various canopies, and try demos of those that might suit your needs. Dealing with all the different terminology used can be confusing. Just remember that this terminology is often just one company's choice of packaging, rather than actually describing something different or new. Every company wants their products to be viewed as different from another. These types of word plays are one way to achieve that. In the end, the canopy’s performance in the air is what really matters.

http://www.performancedesigns.com/faq.htm#5


But then again what do I know, I've only worked on half the mentioned canopies, inspected the other half while attaching them to rigs or test jumping them.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[rgoper 0]

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Taken from the flight profile info: The Sabre2 from Performance Designs is a slightly tapered, zero-porosity nine cell canopy.

Other canopies that are marketed under terms like this: Safire, Hornet, Sabre2, Lotus.

i posted that, to counter this remark.

--Richard--
"We Will Not Be Shaken By Thugs, And Terroist"

[andrewstewart 0]

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yep, but i've jumped each and every one of the canopies in disscussion here at one time or another.

Well seeing as literal interpretation seems to be the theme of the evening, that means you have jumped a Sabre2, Crossfire2, Safire, Stilleto, Lighting, Tri', VX, Hornet, Lotus, and BASE canopies.

Not bad for someone who's profile says they have 300 odd jumps.

Bleh! I'm going to bed.

- Andrew

[skybytch 259]

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Terms such as "semi-elliptical" and "tapered" are simply marketing speak.

Yup. From what I've gathered over 6 years of selling gear, any canopy that isn't "square" - all cells the same length from leading edge to trailing edge - can be called "elliptical." (rounds excepted, of course)

The differences between what are called "tapered" or "semi-elliptical" (Sabre2, Safire and Safire2, Spectre, Omni, Omega, Hornet, Silhouette, etc) and what are called "elliptical" (Crossfire, Cobalt, Stiletto, Heatwave, etc.) are in the degree of "taper" and in the line trim. "Tapered" canopies are less aggressive than "elliptical" canopies, so the marketing-speak makes a valuable distinction. But technically I believe they are all "elliptical", especially when compared to the traditional "square" shape of canopies like the original Sabre and the Triathlon.

[rgoper 0]

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Well seeing as literal interpretation seems to be the theme of the evening, that means you have jumped a Sabre2, Crossfire2, Safire, Stilleto, Lighting, Tri', VX, Hornet, Lotus, and BASE canopies.

haven't jumped the lightning, VX or lotus, or any base canopies, i was under the impression we were originally disscussing the Sabre2, and Crossfire2, my mistake. and by the way, i just had my first cut-away on jump # 475, i don't update my profile like i should, it's said 300 for 6 or 7 months, heck i don't know. i'm not trying to be a canopy guru here, i'm merely trying to give you research information. it's funny that PD would make the remark(s) about "tapered" semi-elipitical, etc...but no other manufacturer speaks in those terms. i've heard people refer to certain canopies in way different terms, so all we have is the data that each manufacturer posts about their equipment. if you ask a question in this forum, such as you did, you've got to know your going to get varying opinions. hope all of this helps. take care, be safe.

--Richard--
"We Will Not Be Shaken By Thugs, And Terroist"

[quade 4]

http://ltp.arc.nasa.gov/aero/events/collaborative/help.html

quade -
The World's Most Boring Skydiver

[rgoper 0]

so does this mean a semi-elipitical is an elipitical, or a tapered an elipitical as well, or not? by now, i'm all confused.

--Richard--
"We Will Not Be Shaken By Thugs, And Terroist"

[PhreeZone 15]

Semi-elliptical and Tapered are just terms used to describe a wing that is not a full elliptical (No skydiving canopy is truely elliptical to the extent of the word, they are all partially elliptical) but a wing that has a degree of ellipticalness less then the full extent. Remember, anything that does not have all ribs the same width is elliptical in the sense of the word and its marketing terms.

Some canopies like the FX/VX are called fully elliptical, but their taper angle is closer or in some cases less then a canopy marketed as tapered.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[rgoper 0]

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Some canopies like the FX/VX are called fully elliptical, but their taper angle is closer or in some cases less then a canopy marketed as tapered.

so does this statement hold true for my Cobalt, or is it a semi-elipitical canopy? the manufacturer's are talking "in circles" if you ask me. PD is the only manufacturer i've found so far that uses the term "slightly tapered" if it is in fact semi-elipitical, or fully elipitical would this statement not be missleading?

--Richard--
"We Will Not Be Shaken By Thugs, And Terroist"

[quade 4]

Well, if they (any of them really) wanted to be perfectly honest, they'd include a planform diagram and let you decide what shape it is.

quade -
The World's Most Boring Skydiver

[crazy 0]

For technical reasons, there are no elliptical canopies. Canopies are not rigid wings and it would be too difficult to build a real elliptical. So, all non rectangular ram air parachutes are tapered. As many people already said on this thread, "elliptical" is only a good marketing word.
Fully elliptical (sometimes) means tapered on the leading edge and the trailing edge, with a constant aspect ratio on each cell, both in width and thickness (shorter cells are narrower and thinner).
Semi elliptical means many different things and is almost useless marketting terminology.
Anyway, taper is only a contributing factor among many others for the flight characteristics. Some very high performance canopies are almost rectangular. The structure, the trim, the airfoil, the thickness and the nose can be much more important than the planform.

come

[PhreeZone 15]

Tapered and Semi-elliptical are just marketing terms. All they do is describe canopies that are not as elliptical as other canopies. Its like marketing a Mid-sized car, its only slightly smaller then a full size, but they want to market it to a different market.

At one point CobaltDan said on here they could have marketed the Cobalt as Semi-elliptical, but chose not to for marketing reasons.

Semi-elliptical = marketing term
Tapered = Marketing term
Elliptical = Any non square canopy. This inclues every thing from the Stiletto to the VX to the Parafoil to a Hornet to a Spectre (Just the end ribs are shorter then the rest on the Spectre).

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[Zennie 0]

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so does this statement hold true for my Cobalt, or is it a semi-elipitical canopy? the manufacturer's are talking "in circles" if you ask me. PD is the only manufacturer i've found so far that uses the term "slightly tapered" if it is in fact semi-elipitical, or fully elipitical would this statement not be missleading?

I've also heard the Sabre2 be referred to as a "light elliptical". Don't take marketing-speak as gospel, you should know better than that. I can't tell you how many times marketing has said our software does XY & Z with features AB & C and when we get wind of it we blow a gasket. And of course then we have to cover for marketing's screw-up (or lies, take your pick).

Anyway, I think the source of your confusion is that there's a difference between "elliptical" in the geometric sense and "elliptical" in the context of describing parachute design.

Think of it in terms of "squares". What we call "square" canopies aren't true geometric squares... they're rectangles. If you had an aspect ratio of 1:1 the flight characteristics would be... um.... interesting. Nevertheless, everyone, even the parachute manufacturers call them "square" canopies.

And how about "rounds"? They're a little closer to the mark, but some aren't truly round in the geometric sense either. Actually, I guess I think of a round as a half-sphere, really, and that isn't even always the case.

Same deal with ellipticals.

As Andy described, a true geometric ellipse is a non-circular, non-edged planar shape which is symmetric across both axes along the entire length of both axes.

An ellipse in parachute-speak is what others have said... pretty much anything that isn't a "square" or a "round". They aren't true geometric ellipses, but to describe they're shape as more akin to an ellipse than a rectangle would probably be accurate.

Anymore when I hear elliptical I think more in terms of its performance characteristics than it's shape (other than maybe aspect ratio). A "light elliptical" or "slightly tapered" canopy means performance will be a little more docile. An "elliptical" is more mid-end and "highly elliptical" or "extreme" canopies are on the high-performance end of things.

Clear as mud?

- Z
"Always be yourself... unless you suck." - Joss Whedon

[SkymonkeyONE 4]

I moved this thread to G&R because it is really a discussion on "hardware" if you will.

As to Richards question about the Cobalt: lay your canopy flat on the ground and check it out. the canopy is generally straight in the three center cells, then both the front sides sweep back. The same is true to rear, only to a greater degree. Is it a true ellipse? No, but it is fully tapered.

Chuck

[cobaltdan 0]

"At one point CobaltDan said on here they could have marketed the Cobalt as Semi-elliptical, but chose not to for marketing reasons."

more like for educational reasons. marketing wise it would probably have been better for us to play the game and call one cobalt semi tapered and another identical version elliptical. sounds familiar: alpha and space. the alpha and space were identical canopies, the alpha marketed as an elliptical swoop machine to be used at high wingloadings, and the space marketed as a tapered begineers canopy to be used at light loadings. both were very succesfull. when i founded the american division of atair i decided that i did not like the fact that misinformation ruled (elliptical issue, manufacturer mis-sizing of canopies & wingloading charts so under rated no one adheres to) in the industry and decided to simply try to educate. basicallky call elliptical canopies elliptical and try to educate that whether a given design is a student canopy or a pocket rocket is a function of the sum of many design variables, and that the only thing you can assume about a design because it is elliptical is that potentially it is more efficient, nothing more.

our first year, people did not want to hear this. there were violent responses telling us we are going to kill people putting beginners on ellipticals. people could not even assymilate the information that we already had a 6 year track record with beginners on our elliptical space canopy. at the time elliptical was so ingrained to everyone as synonomous with high performance and certain negative traits.

its very exciting for me as i believe the education level of most jumpers has gone way up over the last 3 years. they have more understanding for the equipment they jump.


"Semi-elliptical = marketing term
Tapered = Marketing term
Elliptical = Any non square canopy. "

well put phree.

btw there are no "fully" elliptical skydiving canopies. no "true" ellipse planforms.

understand that wether a canopy is considered high performance or low performance is again the sum of many design variables. as someone pointed out an extreme canopy such as the vx is actually much closer to square than many "tapered" begineers canopies.

sincerely,

dan<><>
atair aerodynamics
www.extremefly.com

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[rgoper 0]

Dan:

it sounds to me like the manufacturers are developing these canopies, shaping them anyway they wish, and calling them something else other than they are for "sales pitching" let's break it down a little, either the canopies are semi-elipitcal, or elipitical, why don't YOU guys make up your mind. it's the information that the manufacturers are putting out that gives the sky diving community the information we have, and use, and swear by. miss inform one of us, we miss inform others. i've been to every canopy manufacturers website you can think of, and i've seen the following terms used: truely elipitical, fully elipitical, semi-elipitical, slightly tapered, if the canopies are not of this geometric origin, why are you guys using this termonology? your Cobalt is described on your website as an elipitical, then you come here to this forum, and say there are no true elipiticals, why don't you say that on your web-site? a little clarification would be appropriate here. if the canopy is not an elipitical, don't call it that. Sabre2 describes it's canopy as "slightly tapered" when i do research on a canopy, i go to their websites, and talk to the people in the office, just like i've done with you in the past, i've obtained my information from the manufacturer(s), and now i see that everything you hear and see is not to be believed. this may be good this is coming to light, as i can now see that canopy manufacturers are using "altered information" just to sell canopies? i'm dissapointed, to say the least.

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"At one point CobaltDan said on here they could have marketed the Cobalt as Semi-elliptical, but chose not to for marketing reasons."

your words dan? you guys need to get your facts straight, and stop telling the public what "you think" they may want to hear to sell them equipment. double standards are a thing of the past, or they should be. "clear as mud" right??

--Richard--
"We Will Not Be Shaken By Thugs, And Terroist"

[PhillyKev 0]

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el·lip·tic Pronunciation Key (-lptk) or el·lip·ti·cal (-t-kl)
adj.
Of, relating to, or having the shape of an ellipse.

I don't see what the manufacturers were doing as misleading. They used an adjective to describe their canopy. That's like saying they misled you by calling something high-performance, or even a new design.

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and now i see that everything you hear and see is not to be believed.

[PhreeZone 15]

Richard, do you understand why no canopy can be a true ellipse? Even Paragliders are not true ellipses and they are elliptical in shape. They have more taper to them then any skydiving canopy does.

>if the canopies are not of this geometric origin, why are you guys using this termonology

The people that deisgn airplane wings do the same thing. Look at a flight manual and see the terms used by the designers. Same thing, slightly tapered, elliptical. Unless its all straight lines and all ribs are identical, its not a straight wing.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[rgoper 0]

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Richard, you you understand why no canopy can be a true ellipse?

this IS NOT my point of contention, let's all be SURE we understand that. my problem is with the manufacturer's putting information out there contending that they are true elipiticals, when there not. consider this my last word on termonology matters.

--Richard--
"We Will Not Be Shaken By Thugs, And Terroist"

[Samurai136 0]

Marketing makes things easier for non-technical minded buyers to understand. One of my jumper friends is a stellar free-flyer but she doesn't understand the technical differences between different canopys. She loves her Spectre107 (flight and landing characteristics) and but only understands that my landings and swoops are different from hers because the Samurai "has airlocks and is elliptical".

"truly", that's enough.

Ken

"Buttons aren't toys." - Trillian
Ken

[Zennie 0]

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if the canopy is not an elipitical, don't call it that.

It is an elliptical. It is not an ellipse. There is a difference. "Elliptical" is an industry standard term (again like "square" and "round") to describe a general platform design. It has nothing to do with geometry.

I've never had trouble parsing through marketing-speak. I've always known what they were talking about.

In any event, why does shape nomenclature matter so much to you? It's irrelevant.

I could care less what they call it as far as shape goes. That's because I'm interested in flight characteristics, not whatever shape they declare it to be. They could call it penguin-shaped for all I care. If it flies the way I want it to, I'll buy it.

- Z
"Always be yourself... unless you suck." - Joss Whedon

[Hooknswoop 19]

To keep things simple for myself, I put canopies into one of three catagories, based on planform.

1. Square: No taper, leading or trailing edge.

2. Semi-elliptical: Trailing edge tapered.

3. Elliptical: Front and trailing edge tapered.

The degree of tapering and if the thickness of the cells decreases as the ribs get closer to the end cells are also factors of the design.

Hook

[PhreeZone 15]

Where does the Spectre fit in? The corners are rounded and there for the end ribs are shorter then all the others. Same with the Sabre2 and I'm almost positive the Lotus. I'll need to look at a Hornet this weekend to see if its front edge is altered.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[Spy38W 0]

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as i can now see that canopy manufacturers are using "altered information" just to sell canopies? i'm dissapointed, to say the least.

Maybe this will work for you. Lets say that instead of developing the terms Tapered and Slightly elliptical the manufactures created an "E#" representing the degree of ellipsicity. Then PD could say the Saber 2 has a E# of 3, while the Stiletto has an E# of 9 (or whatever.)

--
Hook high, flare on time

[Spy38W 0]

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this IS NOT my point of contention, let's all be SURE we understand that. my problem is with the manufacturer's putting information out there contending that they are true elipiticals.

Yeah, who can forget when they pulled the wool over our eyes and said we were jumping SQUARE parachutes.

--
Hook high, flare on time