onyx quad cell

[cobaltdan 0]

pictures have been posted at:
http://extremefly.com/aerodynamics/canopies/onyx.html
sincerely,
dan

[Viking 0]

OMFG!!!!!!!
I WANT I WANT!!!!!
but really dude that looks like a badass canopy!!
I swear you must have footprints on the back of your helmet - chicagoskydiver

[prost 0]

Looks interesting. Different way of attaching the cross bracings. Dan, do you want to send out some demos?
William

[rgoper 0]

Dan:
i swear, that is one B.A.D. canopy design, i can see the humour in it! about those demos.............
Richard
"Gravity Is My Friend"

[rhino 0]

I WANT ONE TOO!!!!!!!!!!!!!!!!!!!!! How much are they??
Blue Skies .....

[PhreeZone 20]

Rhino... Pros only is what the page said so unless you got really good recently and joined the Pro tour....

[rhino 0]

Phree,,
I have a job.. Can't afford to join the pro tour.. But I fly those parachute things REALLY well.
Blue Skies .....

[polarbear 1]

Interesting...
I have a question. The front of the quad-cell looks kind of like
[/ I \] - Figure 1 - Very bad computer drawing
The two outer sub-cells are triangular, while the two center sub-cells are quadrilaterals. Quadrilaterals don't have much torisonal rigidity. Would you have better luck attaching the cross-bracing at the top of the non-load bearing rib, rather than outboard of the top of the non-load bearing rib, sort of like
[/I\] - Figure 2- Another bad computer drawing
In this case, all four of the sub-cells are triangular, which should have better rigidity then the quadrilateral case. Any thoughts?
Note to canopy designers...if you use my idea, I expect credit - you heard it from polarbear on DZ.com!

[prost 0]

Then it would be like an fx out without the middle closed of cell.
William

[Hooknswoop 19]

Bear- that is how the FX/VX/Velocity are built, except they have two non-load bearing ribs per cell, not one like the Onyx.
I still dis-agree that canopy cells are counted by the number of top-skin seams, irregardless of the bottom skin seams or the number of non-load bearing ribs per cell. One non-load bearing rib per cell=standard design and one cell, two non-load bearing ribs per cell=tri-cell like in the FX/VX/Velocity. I looked at the Onyx and I call it a cross-braced standard designed cells.
Hook

[crazy 0]

Are the cross ribs continuous?
Do you have any front view to compare the distorsion with other cross braced canopies?
What's the anticipated release date?
Nice canopy!
Come

[cobaltdan 0]

hi everyone thanks for the feedback.
polarbear: i) its not a bad computer drawing, it is extremely accurate and takes into consideration an imposed tension pattern, material stress and inflation. it was done on the most sophisticated program used in the industry http://www.extremefly.com/aerospace/products/parachutes/ataircad.html
the web site movie is a flash jpg made from the cad fliles. the files are very high resolution and are difficult to make nicely readable in a jpg flash movie.
as far as the center cells being trapezodial. because of the way a canopy loads trapezoids have more rigidy than squares which is what is present center of a tricell. as far as your idea of attaching the diagonals to the nonload rib top seam: the problem is to create any kind of a resonable span between line groups the diagonal rib angle would be too acute to function. the beauty of the quad cell is that you can maintain an equal to larger span than a tri cell while reducing spanwise airfoil distortion and creating a more rigid design with a fully rounded in flight nose.
hook: again the purpose going to a cross brace design is to reduce spanwise airfoil distortion. of interest is only the top skin airfoil profile. 3 divisions tri cell, 4 divisions quad cell. but what ever you want to call it , it has advantages.
demo's : not yet. it is our policy once we have completed inhouse testing to release the canopies to our pro flyers only. the canopies are jumped usually for a full season, when they have loged enough jumps without any issue they are released for sale. we are extremely diligent and cautious in our testing regimen.
come: yes the diagonals are continous to the tail, non stressed areas are cut out to reduce pack volume. if i were producing a tri cell i would not have continous diagonals to the tail basically because they do not do anything, reducing airfoil distortion on the back half of the canopy does little to increase performance. additionally because the height of the rib decreases as you go back on the cord, the diaginal angle gets too acute to function, they do not reduce distortion only increase pack volume.
on a quad cell, there is a constuction issue in than you only want to want to end an i beam seam on a spanwise tape. as such in the curent prototypes i have run the diagionals all the way to the tail. comparision pictures: yes we have video with the fx and vx and velocity, i would like to take stills in the next month or so.
sincerely,
dan

[polarbear 1]

OK, I'll buy that.
By the way, I didn't mean that YOUR drawing was bad, I meant my depiction of the front of the cell in my previous post was bad. Your drawing was very nice!

[polarbear 1]

FX/VX and Velocity each have a square shaped cell in between the triangular ones. Again, the square will not have much rigidity compared to the triangle shape.
My idea was to have NO quadrilateral sub-cells; all of them were triangular.
I agree that 1 cell should be defined to be between two load-bearing ribs. I use the term "tri-cell" and "quad-cell" to designate different construction methods, and I ONLY use them becasue they are terms everyone recognizes. Extremes and Velocitys are not "21" or "27" cells, they are 7- and 9- cell canopies with tri-cell construction. The Onyx is a 9-cell canopy with quad-cell construction.

[rgoper 0]

Dan:
if you need a "test jumper" just let me know! i won't even charge ya nothing!! J/K it really looks like Atair could have a winner here, i like the concept. maybe by the time it's released, i'll be able to fly one!
Richard
"Gravity Is My Friend"

[crazy 0]

Quote

FX/VX and Velocity each have a square shaped cell in between the triangular ones. Again, the square will not have much rigidity compared to the triangle shape.
My idea was to have NO quadrilateral sub-cells; all of them were triangular.

here are the different structures:
0) [ | ] old traditional design
1) [/| |\] tri-cell with non continuous cross-braces (fx, vx, velocity, chaos, ninja)
2) [/ | \] quad-cell with continuous cross-ribs (onyx)
3) [/|\] polarbear-cell
If the main objective was to reduce the lateral sliding of the whole top skin above the bottom skin, you woul be right. But the main objective is to have a top skin as flat as possible.
As the distance between the loaded ribs is the same in all the cases, the angles in 3) are much more open than in 1) and 2). The force transmited by the cross rib has a vertical component and an horizontal component. Only the vertical component is good. The 3 or 4 small bulges in 1) or 2) are better than the 2 big bulges in 3).
However, the vertical position of the unloaded ribs in 1) is directly controlled by the cross braces (and a little bit by the bottom skin). In 2) the vertical position of the unloaded rib is like in 0), except that the cross ribs reduce by 50% the lift pulling that rib up.
If you really like ASCII art, there are plenty of unexplored possiblilities :-)
- suppress the vertical loaded rib on 1) and 2)
- replace the vertical unloaded ribs by oblique ribs
4) / /\ \ no more useless vertical ribs
5) / / \ \ with irregular spacing
- use mixed ribs (vertical ribs forking at the bottom, or cross ribs sewed on the unloaded ribs rather than on the top skin)

6) 
[ | ]
[/\ ]
7)   
/  |   |  \    
/  / \ / \  \

You can even exaggerate and have something like a middle skin, kind of bottom skin with a huge distorsion, and cross or vertical ribs on top of it.
Come
PS: Personally i don't like the name "quad-cell" because vertical unloaded ribs are completely different from cross-ribs.

[polarbear 1]

Yeah, that all makes sense. I can dig it.
I don't really go with "quad-cell" or "tri-cell" either...but I don't know what else to call it. I guess I'll use quad-cell so people know what I am talking about.

[cobaltdan 0]

note on the non loaded vertical of a quad cell, it does differ quite a bit from the non loaded vertical on a standard bi cell. if you draw a cross section of the cell and add little arrows to show the tension vectors you will notice that the top skin between the diagonals carries a greater tension this reduces the spanwise distortion. the nonloaded vertical in a quad cell is basically to keep an acceptable bottom skin shape.
sincerely,
dan