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HydroGuy

Canopy questions - 7 cell and 9 cell

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Before I say anything, my instructors were not present @ the DZ yesterday...so I COULDN'T ask them :P

Since AFF, I have been jumping 7 cells...yesterday downsizing to a Spectre 190...giving me basically a 1:1 ratio. What are the differences between a 7 cell Spectre and a lower performance 9 cell like a Sabre 2? (Other than two cells for the smart asses out there!) Is one more accurate or easier to land? Or are these really personal preferences? Does one design handle different wing loadings differently?

Some one please edumacate me...
Get in - Get off - Get away....repeat as neccessary

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http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=search_results&search_forum=all&search_string=spectre%20vs.%20sabre&sb=score&mh=25

Try these search results. :)
"There is only one basic human right, the right to do as you damn well please. And with it comes the only basic human duty, the duty to take the consequences." -P.J. O'Rourke

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Hi Hydro,
The short answer is that generally for the same sq. ft. a 9 cell has a highre aspect ratio than a 7 cell. That is to say take the wing span and divide it by the average chord. Thus for a given sq ft. canopy, the higher aspect ratio canopy will yield better performance. Since on a highrer aspect ratio canopy there is less distance for the air to pass accross from nose to tail, there is less induced drag produced. Sound complicated? Once you figure it out, it's a cinch. Stay tuned, there's more!!
SCR-2034, SCS-680

III%,
Deli-out

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I ran a search and read for at least two hours 7 cell vs 9 cell...but not sabre vs spectre. Guess I'll check back in another couple of hours....

I never saw a mention of performance differences vs different wing loadings though.
Get in - Get off - Get away....repeat as neccessary

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9-cells tend to have a higher aspect ratio than 7-cells. This makes the wing more efficient. You should get flatter, longer glides and better flares for softer landings. Lower aspect ratios handle turbulence better and fly in deep brakes better, making them more suitable for steep accuracy approaches.
That's a gross simplification, but gives you a place to start. Remember that more cells means more lines, though, which means more drag, less glide, so more cells is not always the answer. There's a bunch of other factors, too.

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I know of an experienced jumper (6000+ jumps) who jumps a Spectre. Among other things, he loves the constant on-heading openings. According to him...

"For once you have tasted Absinthe you will walk the earth with your eyes turned towards the gutter, for there you have been and there you will long to return."

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Gotta love it. Every person has posted that Spectres have a steeper glide...yet the PD website states
Quote

Many jumpers do not expect a seven-cell canopy to glide as far as a
comparable nine-cell, but at full glide the Spectre actually has a slightly flatter glide angle than some nine-cell
canopies, including both the original Sabre and the Sabre2.



But, after reading PD's PDF on the Spectre, I did learn that I am probably only flaring about 3/4's of the way...probably why I keep beating the snot out of myself during landings.
Get in - Get off - Get away....repeat as neccessary

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Gotta love it. Every person has posted that Spectres have a steeper glide...yet the PD website states



No one posted anything about a Spectre having a steeper glide....If you re-read what was posted, people offered general advise about the difference between 7 cells and 9 cells.

Take it anyway you wish, but remember, you asked.

Sparky
My idea of a fair fight is clubbing baby seals

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No one posted anything about a Spectre having a steeper glide....If you re-read what was posted, people offered general advise about the difference between 7 cells and 9 cells.

Take it anyway you wish, but remember, you asked.

Sparky



I should have been more specific. In my search spectre vs Sabre2, I found this was a statement reiterated time and time again. My own instructor, Jim Wallace, has told me that a Spectre will have a steeper angle of descent...hence my confusion upon reading the PD website.

I asked to learn...and if I get confused, I'll ask more.
Get in - Get off - Get away....repeat as neccessary

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