what is an eliptical?

[NtheSeaOrSky 0]

I have tried to find out info online, but am becoming frustrated. Please help. What are the differences in an eliptical canopy and the one I am jumping as a student? Im assuming it is higher performance, but I would like details. Thank you in advance!

[riggerrob 643]

Elliptical is fancy marketing jargon for tapered canopies. To date I have not seen any canopies that conform to a geometry textbook definition of elliptical .....
As a student, you are probably jumping rectangular canopies (ie. all the ribs are cut from the same pattern) that have straight leading an trailing edges.
By 1990 most manufacturers had rung all the performance and handling they could out of rectangular canopies, so they started test jumping tapered canopies. A common feature of tapered canopies is that the end cells are smaller than the center cell. Smaller end cells help performance by producing smaller wing tip vortices, which produce less drag, which leads to a faster or flatter glide. This why top blade running competitors jump tapered canopies. The flattest gliding para-gliders are tapered so radically that they ceased looking like parachutes a long time ago.
Incidentally, a para-glider designer named John Bouchard claims to have invented elliptically tapered canopies. The first tapered parachute was the Blue Track introduced by Parachutes de France in the late 1980s.
Smaller end cells also help tailor handling. With a smaller end cell to d rag around the outside of a turn, a tapered canopy can turn quicker. That is why the first generation of tapered canopies (Blue Tracks and Stilettos) were aimed at the crotch rocket sector of the skydiving market.
Canopy planforms vary widely within the "elliptical" category. Some have all the taper on the trailing edge (ie. Diablo). Some have all the taper on the leading edge (Swept Wing Jedi). Some have mostly rectangular cells in the middle with only a few tapered cells near the wind tips (Stiletto and SET 400) and some have every cell a different size (Icarus). All these different patterns drive up the cost of manufacturing "elliptical" canopies.
But nowadays the term "elliptical" covers dozens of different can)opies designed for most types of skydiving. You can buy elliptically tapered canopies for tandem, student, casual weekend or blade running skydiving.
The list of market sectors that don't use ellipticals is shorter (reserves, BASE and Canopy Formations) because these are the only sectors where on-heading openings are life-and-death matters.
Accuracy competitors experimented briefly with wedge tapered canopies back in the 1980s, but most accuracy competitors still jump canopies that look the same as they did in the late 1970s.

[PhreeZone 20]

Excellent reply Rob! Your knowledge never ceases to amaze...
I'm not sure what to put here right now.....

[NtheSeaOrSky 0]

So its not so much that the canopy is "eliptical", but the charateristics of the tapered cells that affects the performance? So crisper turns are possible with the taper design, and does that also make the angle of approach on landing smaller ( due to the flatter glide )?
Thank you for your replies (and patience)

[riggerrob 643]

Yes, an elliptically tapered canopy can glide flatter than a similar sized and loaded rectangular canopy.
For example: if you take similarly sized and loaded Sabres (rectangular) and Stilettos (tapered) they will have the same forward speed, but the Stilettos will return to the DZ from worse spots than the Sabres.

[cobaltdan 0]

as rob pointed any canopy that does not use the exact same rib for every rib is elliptical.
"top blade running competitors jump tapered canopies."
interesting note many 'top blade running' canopies are not very elliptical. ie a vx or fx are quite square on the list of 'elliptical' canopies. these canopies increase their glide (swoop) with other variables, ie. increased speed and decreased spanwise airfoil distortion. lots of variables affect the efficiency of a canopy. planform (the projected shape) is just one of them.
"para-gliders are tapered so radically that they ceased looking like parachutes a long time ago" they also look different due to their significantly larger aspect ratio. competition wings almost look like banannas.
'a para-glider designer named John Bouchard claims to have invented elliptically tapered canopies. The first tapered parachute was the Blue Track' introduced by Parachutes de France in the late 1980s.
actually it was the volplane canopy from pioneer patent # 3,524,613I in 1968. designed by jim reuter and greg yarbonet. this was the very first production canopy to have greg's invention of the >slider<. btw greg is also credited with designing the first paraglider (at least in this country).
"now adays the term "elliptical" covers dozens of different can)opies designed for most types of skydiving. You can buy elliptically tapered canopies for tandem, student, casual weekend or blade running skydiving."

great point. there are too many misconceptions about 'ellipticals'. without knowing the other design variables of the canopy you can not assume anything about a canopy because it is elliptical other than it is more efficient than the same canopy square. it is the combination of design variables that determine if it is a pocket rocket or a student boat.
sincerely,
dan
atair

[Jimbo 0]

Since we've learned that the term 'elliptical' can mean anything from a tapered leading edge, to a tapered tail, to a completely tapered wing, I'm curious - how are Cobalts designed?
Thanks Dan,
Jim

[cobaltdan 0]

center 3 cells are equal cord, outer cells have a linear taper both nose and tail.
sincerely,
daniel
atair

[rogue108 0]

Rob, that was an excellent response. I now know why eliptical canopies are more efficient and have different turn rates as compare to square canopies.
Now my question...What are the effects of just tapering the leading edge, trailing edge or both edges? How do manufactures decide on how much tapering to use? How does it affect flight, turning, openings?

[riggerrob 643]

Diablos have straight leading edges - and all the taper on the trailing edges - because that configuration results in more openings on heading.
For a more detailed explanation, you will have to ask leading canopy designers like Bill Coe, Gyro, Bryan Germain and the dudes from Parachutes de France.
Hey guys?

[Geoff 0]

PD have an FAQ on their web site (new since I last looked) which addresses this question and largely agrees with Rob.
Geoff

[bigdad510 1]

Can someone tell me about PISA Heatwave 135 characteristics. Thanks

Brad

[dragon2 2]

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Can someone tell me about PISA Heatwave 135 characteristics. Thanks

You jump it and you don't KNOW?

It's an elliptical HP canopy, a 135 is already very small for your low jumpnumer, let alone a hp canopy!

Here are some reviews: http://www.dropzone.com/gear/Detailed/64.html

ciel bleu,
Saskia

[mjosparky 4]

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You jump it and you don't KNOW?

It's an elliptical HP canopy, a 135 is already very small for your low jumpnumer, let alone a hp canopy!

Like I've said before, skydivers refuse to learn from the pain of others.

My idea of a fair fight is clubbing baby seals

[bigdad510 1]

I asked the question to get different opinions. Yes its in my profile because I'm going to jump it to see if I like it. I've made quite a few jumps on a hornet 150. After talking to a lot of the o'l timers, I asked them about the Heatwave 135 based on my flying characteristics and landing ability.

Now after spending countless hours reading threads on here, I already know the reposne that I'll get, but I'll say it anyway. Personal ability differs from person to person. So I try not to judge people based on numbers. I have participated and taught many extreme sports and I have learned that yes, experience comes with time, time=experience. However, people progress at extremely different levels.

Even though it may not seem, I am a cautious skydiver, but that is all relative. "Cautious" doesn't really mean too much when "circumstances" have never been experienced.

So, be my guest, and talk about the low jump numbers vs. canopies. Too many times in all my extreme sport teachings, I have found that yes there is a norm, but the two don't always equal each other.

Blue skies everyone. Oh, and if it scares the shit out of me, I know when to quit.

Brad

[mjosparky 4]

Hey Bigdad,

You are all grown up, go for it. What is the worst that could happen.

My idea of a fair fight is clubbing baby seals

[bigdad510 1]

The worst that can happen is I can die. Hell that could happen before I even get to the drop zone (chances are higher any way)

No seriously, I see a lot of posts in here that seem like they come from younger people, whcih I am not. I think you guys are a little harsh (but I understand why) sometimes on the newbies. Some of us newbies have military experience, but we don't count it, Pride I guess. I can't speak for everone, just myself.

I do see people making poor choices at the dropzone, but I've noticed its because they don't talk to people. If they do, they don't like what they have to say so they don't listen anway.

Rest assure, my decisions are thought out. But I really do appreciate your concern. Without skydivers like yourself, there would be a lot more casualties.

Thanks!

Brad

[bigdad510 1]

I do have a question in general about elipticals. As far as there pack volume and packing procedures. Is there anything more specific to them then squares?

Brad

[Samurai136 0]

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I do have a question in general about elipticals. As far as there pack volume and packing procedures. Is there anything more specific to them then squares?

A Standard Pro-Pack will do.

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Rest assure, my decisions are thought out. But I really do appreciate your concern. Without skydivers like yourself, there would be a lot more casualties.

Try to avoid aquainting yourself with the calculated, pre-planned error in judgement. I can tell you from experience they hurt.

If it looks low, opt for the safest landing you can take (wing level over head).

"Buttons aren't toys." - Trillian
Ken

[dragon2 2]

You have no clue what canopy you're flying yet you're sure you'll be fine.

Sure.

Go away.

ciel bleu,
Saskia

[3331 137]

Read about the Elliptical canopy here

I Jumped with the guys who invented Skydiving.

[JohanW 0]

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Now after spending countless hours reading threads on here, I already know the response that I'll get, but I'll say it anyway. Personal ability differs from person to person.

I'll bite.

See you in Incidents.

Johan.
I am. I think.

[phoenixlpr 0]

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Read about the Elliptical canopy here

Wingload seems to make big effect on flying characteristics.

There are amazing all-around airfoils around.

[mjosparky 4]

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Rest assure, my decisions are thought out. But I really do appreciate your concern. Without skydivers like yourself, there would be a lot more casualties.

It would make my day if something I posted here kept one skydiver from dying because of a recreational activity.

You say your decisions are “thought out” but I question if they are well thought out. A 135 Heatwave is a fully elliptical High Performance canopy. Jumping one at 1.22:1 would be questionable for someone with 300/400 jumps if they have been making 100 jumps a year. You profile indicates you have made 136 in 10 years. That’s only 13 canopy landings a year on average. You are honestly moving into a really dangerous area. I have several hundred more jumps and 3 times the years in this sport and I would not put myself on a 135 pocket rocket. From my experience level right now it would take me at least 1 year and 100/150 jumps on progressively smaller canopies before I would jump your heat wave. Its not that I am a bad canopy pilot its just that a 135 is a long way from where I have ever been.

I know that nothing I say is going to stop you from jumping the Heat Wave, but maybe something I say will stick in you mind and at the right time it will slow you down and maybe back you up a bit. I hope so.

My idea of a fair fight is clubbing baby seals

[Ron 10]

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I do see people making poor choices at the dropzone, but I've noticed its because they don't talk to people. If they do, they don't like what they have to say so they don't listen anway

Just like you are doing?

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Rest assure, my decisions are thought out. But I really do appreciate your concern. Without skydivers like yourself, there would be a lot more casualties.

Your choice may be thought out, but it is a bad choice.

Less than 150 jumps over 10 years...I assume you are including military jumps...I have military jumps and they will not help with an eliptical canopy at all.

Your choice is poorly made.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334