Differance between 7 and 9 cells?

[fallingchip 0]

Anyone got the time to explain...

I am seeing pretty good deals on new complete rigs, but have 7 cells.

______________________________________________
"A radical man is a man with both feet firmly planted in the air."
-Franklin Delano Roosevelt

[katzurki 0]

Here, I'll search it for you:

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?t=search_engine&do=search_results&search_forum=forum_6&search_type=AND&search_string=7+9+cell

[ps5601 0]

2 - sorry couldn't resist.

7 cell canopies are generally more "solid", smoother openings, more predictable (note I did say generally). They have a greater aspect ratio (depth to width).

9 cell canopies are generally more responsive to inputs - the down side of this is that they are often more prone to not quite so nice openings, on the other hand the turn faster etc if that's what you want. 9-cells generally flare better for landing.

Of course all of the above is highly dependant on your wing loading and canopy size!

Best bet, talk to instructors and experienced canopy pilots at your DZ

Blue skies

Paul

[darkwing 5]

let me correct the above definition of "aspect ratio". It us conventionally given as span to chord, so a canopy that is 22 feet wide and 10 feet from nose to tail would have an apsect ratio of 2.2. Generally speaking, 9-cell canopies have higher aspect ratio, but it is certainly not a universal requirement. Also, be aware, that single measure, such as square footage, or aspect ratio, only tell part of the story on a canopy. there are other factors, such as leading and trailing edge taper, airfoil, trim...

-- Jeff
My Skydiving History

[pilotdave 0]

Don't worry too much about the number of cells. Read up on the particular type of canopy you're looking at. Find one that seems to have flight characteristics that you like. Then see if you can try some different types of canopies out.

Dave

[rendezvous 0]

In general 9 cells give you more glide while 7 cells come down steeper. If you are at a long spot and need the extra glide you would be better off under a 9 cell. On the other hand if you are landing off and have limited space the 7 cell will do you good service. That said, the ZP 7 Cells made these days have extremly competitive flight characteristics at the level at which you will be flying atleast to begin with (I'm not talking about high performance flying e.g swooping etc). A lot really comes down to learning good canopy piloting skills before the 7 cell vs 9 cell difference kicks in. Good canopy skills can be learn't equally well on either.

[fallingchip 0]

Thanks to all for your input. I am not looking for a high performance canopy at all, swooping does look like fun but has never impressed me (no offense to the swoopers), I just like coming down nice and soft.

______________________________________________
"A radical man is a man with both feet firmly planted in the air."
-Franklin Delano Roosevelt

[bob.dino 1]

If you've any questions on the characteristics of a particular canopy, just click on the 'Search Posts' link near the top of the page and enter the name of the canopy.

The two most popular moden 7-cell designs are probably the Aerodyne Triathlon and PD Spectre. I really enjoy my Spectre.