6- and 8-cells

[lynxie 0]

Have you flown a 6-cell or an 8-cell canopy?

Or do you know how the open, fly and land compared to similiar canopies with odd cell numbers?

-- "If you can dream it, you can DO IT!" --

[Ron 7]

In my 11 years I think I have seen ONE 8 cell canopy.

I don't know anything about it, but it was old.

Edit, I also knew about the 5 cell reserve and saw one landed.

I have no idea how they would fly.

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

[riggerrob 558]

I have seen and jumped an 8-cell canopy once.
It was a Laser 8-cell (about 250 square feet), built by FTS.
The opening was reasonable and concluded with a dead center.
It flew a bit slower than my (slightly smaller) 7-cell Cruislite 220 and a bit faster than a 9-cell Manta 288.

[smooth 0]

What canopies have 6 or 8 cells?

I've flown a 5-cell (Strato-Star). Does a 7or 9-cell with an end cell closed count?

[billvon 2,400]

I've flown:

5 cell canopies (DC-5)
7 cell (lots)
8 cell (Corvette paraglider)
9 cell (lots)
11 cell (Strong 520)
21 cell (Xaos21 98)
33 cell (Edel paraglider)

[ryoder 1,387]

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What canopies have 6 or 8 cells?

I've flown a 5-cell (Strato-Star). Does a 7or 9-cell with an end cell closed count?

Well in that case, I landed a 4-cell, (5-cell Safety-Flyer with an end cell closed). Glide ratio about 1:1, and the "landing" wasn't pretty, but I got up and walked away, (spitting grass & dirt out of my mouth).

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[Liemberg 0]

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What canopies have 6 or 8 cells?

My guess would be "not many"

If you want an even number of line(groups) you tend to end up with an od number of cells...

"Whoever in discussion adduces authority uses not intellect but memory." - Leonardo da Vinci
A thousand words...

[mjosparky 3]

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What canopies have 6 or 8 cells?

My guess would be "not many"

If you want an even number of line(groups) you tend to end up with an od number of cells...

Line groups, A, B, C, and so on are counted front to back or cord not side to side or span.

Sparky

My idea of a fair fight is clubbing baby seals

[darkwing 4]

I have built and jumped canopies with 5, 6, 7 and 8 cells. There is nothing special about 6 & 8. They open and fly just fine.

Here is a photo of me jumping my 6-cell at the 1978 Nationals.

-- Jeff
My Skydiving History

[Liemberg 0]

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Line groups, A, B, C, and so on are counted front to back or cord not side to side or span

True , however:
line-attachment is between the cells and I was 'rearanging the groups', sort of...

(Ah, if you people only spoke dutch! Then I could explain!
My point was that you would want an even distribution of the lines between left and right risers...
Come to think of it: How did they solve that one on the 'Laser'? Billvon?

Edit (hadn't seen the 'Darkwing' photo when I posted this, the solution seems to be that lines from left and right share attachment points in the middle...Next question: can you propack this without a centre cell that goes around your packjob?)

"Whoever in discussion adduces authority uses not intellect but memory." - Leonardo da Vinci
A thousand words...

[3ringheathen 0]

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My point was that you would want an even distribution of the lines between left and right risers...
Come to think of it: How did they solve that one on the 'Laser'?

Interesting:
In the photo of a 6 cell that Darkwing provided it appears that one line from both the right and left riser share a single attachment point on the rib between the two center cells.

That would be an increasingly significant disadvantage as wingloading increases.

I can't think of any particular advantage of the design. Maybe that's why they aren't made that way anymore?
-Josh

If you have time to panic, you have time to do something more productive. -Me*
*Ron has accused me of plagiarizing this quote. He attributes it to Douglas Adams.

[katzurki 0]

How's this for a canopy? 13 cells! (not an actual canopy of course...)

[phoenixlpr 0]

So what?

I had some rides on triangular reserve.

http://www.kfki-isys.hu/pg/prof/pzp/a.htm
This is Hungarian....but you may check pictures of PZ-81 reserve.

http://www.zavod3.ru/catalogue.html?level=position§ion=1&subsection=7&position=10&nls=2

Edit: new link has been added

[darkwing 4]

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Interesting:
In the photo of a 6 cell that Darkwing provided it appears that one line from both the right and left riser share a single attachment point on the rib between the two center cells.

That would be an increasingly significant disadvantage as wingloading increases.

I can't think of any particular advantage of the design. Maybe that's why they aren't made that way anymore?
-Josh

I don't understand your comment about "significant disadvantage as wingloading increases." I don't see any connection to wingloading for this.

When engineering a canopy at some point you have to decide on the number of cells. The most obvious trade offs are aerodynamic advantages of a smoother airfoil with more cells, but with more cells you have more seam bulk, construction time, expense, and drag from more suspension lines.

Regarding propacking, there is no problem with even-number of cells. The canopy tail still has a center, and if you didn't look closely, you would notice no difference regardless of your packing method.

I have about 250 jumps on 6 & 8 cell canopies, and there really is no issue I ever noticed that is inherently problematic for them.

-- Jeff
My Skydiving History

[mjosparky 3]

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So what?

I had some rides on triangular reserve.

http://www.kfki-isys.hu/pg/prof/pzp/a.htm
This is Hungarian....but you may check pictures of PZ-81 reserve.

http://www.zavod3.ru/catalogue.html?level=position§ion=1&subsection=7&position=10&nls=2

Edit: new link has been added

That looks like a single keel Paradactly. (sp) Designed by Jim Handbury in the 70's.

Sparky

My idea of a fair fight is clubbing baby seals

[FineHavanas 0]

How's that for a Reserve Repack Cycle (12 years) And notice the descent rate: 5,62 m/s - ouch

[3ringheathen 0]

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I don't understand your comment about "significant disadvantage as wingloading increases." I don't see any connection to wingloading for this.

On the canopy you showed us, it probably didn't matter at all.

You touched upon my line of thinking when you wrote:

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...but with more cells you have more seam bulk, construction time, expense, and drag from more suspension lines.

It seems to me that your 6 cell canopy ends up with an extra set of 4 lines. That is, since a line from each riser goes to the center rib, you end up with a pair of A,B,C,and D lines, where on an odd # design, you'd only have one set.
Near as I can tell, the average bulk and drag from extra lines is increased with an even number of cell design.
Like I said, it probably didn't matter too much on that particular design.
I bet it'd be a far more noticable disadvantage on a 95ft2 swoop machine.

Come to think of it, the convergence of lines at the center could also increase the probability of slider hangups and malfunctions. Just a theory, though.

Don't get me wrong, I think it's cool. I'd love to play with canopy design if I had the chance. I'd love to jump your 6 cell, or a triangle reserve.

I jump at the chance to try novel canopies. So far It's just been T10s, Paracomanders, Thunderbows, and one reverse engineered Russian rig with a paradactyl as a reserve. Lucky me, the main worked.
-Josh

If you have time to panic, you have time to do something more productive. -Me*
*Ron has accused me of plagiarizing this quote. He attributes it to Douglas Adams.