7 cell or 9 cell...that is the question?

[traker 0]

I was told that 9 cells give good performance ( 7 cells as well). I was also told that 7 cell mains can give harder landings?

Basically what I'm after is the pros and cons of the two types.....

I know a hefty amount of you can answer this with your eyes closed so giver.....please!


Traker

"we can either clmib down...or take the 15 second express shuttle" ---- during a snow storm on a 1000 foot antenna

[dan_iv 0]

try a search
clicky here

[airborne82nd 0]

i am a 7 cellchump and i land very soft. i have jumped some small 7 cells too.

i have flown a few 9 cells and only a couple of times. i landed them ok.

if i didnt do aff on a 7 cell and 99 % of my jumps on a 7 cell i might say the 9 cell seemed easier to land.

I dont know much about 9 cells i am not sure how to pack one either

do a search her for the 9 cell vs 7 cell there are some great threads on it.

the 9 cell seem to glide more and the 7 seemed to be trimed down a bit.

our dz has 5 7 cell tandems and 1 9 cell tandem and that 9 cell thing keeps going and going.

also no one swooops 7 cells they do that stuff with the 9 cell high speed canopys. 7 cells recover to quick.

i let a buddy of mine jump my tri and ill be darned if he didnt do a 180 and swoop it in but it ran out of gas for him it was funny. i would never try it. he is an awesome swooper and has competed

but do a search 9cell vs 7 cell and happy reading

and happy landings

[DrewEckhardt 0]

Quote

I was told that 9 cells give good performance ( 7 cells as well). I was also told that 7 cell mains can give harder landings?

There's no truth to that. I haven't jumped a ZP canopy that wouldn't land with zero vertical speed. Larger F111 canopies of any cell count don't seem to reach zero vertical speed on straight-in landings but land fine if they're not jumped out. Smaller PD reserves land fine too.

[councilman24 37]

The question is not this simple.

Some history. (okay, nap time)

One of the most popular early ram airs, after most of the bugs worked out, was a 5 cell Stato Star. (see ebay, one was on there yesterday) The other most popular canopy was the 7 cell Strato Cloud (in it's many iterations). In those days the width of the cell was dictated by the width of the fabric available. So 5 cells were closer to square, 7 cells essentially 5 cells with two more added. The first 9 cells were 7 cells with two more. Other newer models came on the market and 5 cells because of their low aspect ratio fell out of favor. Then came 5 cells with the same aspect ratio of 7 cells. The top and bottom skins had the fabric running side to side rather than front to back. So the cells width was no longer dicated by the width of the fabric. Paraflite pioneered this with the swift reserve and the cirrus cloud and other canopies. I had a cirus cloud and like it. The landing stunk by todays standards and even then, early 80's, it had a reputation as hard to land. Because of this is wasnn't very popular. But I stood up all or my landings. (then that was a feat, still is for some people) With the advent of zp smaller canopies could perform with higher loads so the cells no longer needed to be the width of the fabric. Let's see, 8, 10, and 11 traditional cell canopies were also made. The Cirrus cloud described above looked like the michelin man because the width of the cells allowed them to "puff" out. This gave poor wing performance. I still like the way mine flew and still have it. The only reason I stopped jumping it in 1987 was I busted up my ankle (not due to the canopy) and I needed something much bigger.

Then the multi cells, cross brased, designs came out, first in non zp, to give smother airfoils and better performance, along with elliptical or tapered canopies.

In general zp 9 cell canopies became the standard if you didn't go to a multi cell canopy. 7 cell and 9 cell non zp canopies were still popular for students (still are) and for lower performance landings, like sinking a tight demo jump.

Then came the Triathlon. This 7 cell zp canopy performed (disputedly by some) like a nine cell but gave less pack volume due to less material.

I had a Sabre 9 cell non tapered zp 190 sq. ft canopy and a Triathlon 190 7 cell non tapered canopy. (still have the tri) To my mind they flew almost identical. I measured air speed with an anemometer and got identical air speeds, about 30 mph. Now some may realize the Sabre may actually have been a little bigger due to the measuring differences. The flares were a little different but not necessarily one better than the other. (this is up for debate also)

PD then came out with the Spectre 7 cell to compete (in my opinion) with the popular Triathlon. It was softer (read longer) opening, and maybe flew a little better. Both are still popular.

I have purposfully left off most of the multi cell and elliptical stuff for simplicity.

Soooooooooo, a 7 cells can perform similar or better than a nine cells. The individual canopies must be compared one to one, not 7 cells to 9 cells. It might be safe to say IN GENERAL 9 cell canopies of the same design and type MAY have better performance than 7 cell canopies, depending on your criteria for "better" performance. There is a reason that all (I think all) purpose built BASE canopies are 7 cells. Stability, on heading openings, and other characteristics make larger 7 cells better than 9 cells for BASE.

Long answer to a short question.

Here's the short answer. 7 cells pack smaller for a given size. But 9 cells may perform better in terms of landings than the 7 cell. Design (particular model) needs to be considered for comparison. With ALL of the above as exceptions and explination.

Hmmm, enough time wasted.

Hmmm, only 3 replies while I was writing this.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[airborne82nd 0]

wow now thats an answer!!!!!!!!!!!!!

[phoenixlpr 0]

Simple: Try them! You can decide too.
It`s quite a personal preference.

[airborne82nd 0]

councilman24

I am 192 on a 175tri with new lines and about 250 jumps

it flys great

whats my forward spped????

[Kris 0]

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also no one swooops 7 cells they do that stuff with the 9 cell high speed canopys. 7 cells recover to quick.

Don't tell Brigette Liss that, as she used to compete in the Pro class in the PST on a Spectre.

Also, PD's Velocity is a tri-chambered, crossbraced 7-cell, as is the FX and the Xaos 21.

Sky, Muff Bro, Rodriguez Bro, and
Bastion of Purity and Innocence!™

[justinb138 0]

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Don't tell Brigette Liss that, as she used to compete in the Pro class in the PST on a Spectre.

I've seen some people out at the DZ get a nice surf with PD Lightnings too.

[Kris 0]

Quote

I've seen some people out at the DZ get a nice surf with PD Lightnings too.

Lightnings frighten me with their landings, but I have seen some pretty amazing things done with them, and even with an Aerodyne Smart reserve that easily went almost 180' on a swoop.

Sky, Muff Bro, Rodriguez Bro, and
Bastion of Purity and Innocence!™

[white_falcon 0]

Hey airborne,

Its my guess that most of your jumps are on a 0 (zero) cell. LOL

( i dont think you could say a -10 has any cells.) lol

Scott

[airborne82nd 0]

oh i get it the round chute ha ha

i lost many skin cells landing on with the rounds but i have a bunch of square jumps also

i hate rounds i hope i never have to jump a round again

[white_falcon 0]

you and me both brother, I got the knees to prove it, how bout you? lol

Scott

[airborne82nd 0]

my knees are ok for some reason. i did military freefall halo jumps so i got it easy i did a bunch of those.

i never was injured, i know one guy who had a cigerette roll and total malfunction from 800 ft burned in.

i was one of the spec op medics on the scene. he never lost concsiousness and only broke his pelvis, well not only but nothing else and he jumped 5-6 months later.

how about that???

[white_falcon 0]

jeez, "only broke his pelvis" lol, lucky guy.

right after i got to bragg, we had a spec 4 double mal from 1200. WALKED OFF THE DZ!!!!!

slight nerve damage to his feet. He terminated (cant blame him) and got reassigned armor.

(are we playin one up?? if so i am done. lol)

scott

[airborne82nd 0]

wow were you there???
i was

huh ha ha kidding

walked off???? whats a double malfuntion? both canopys out?? do you think they provided enough lift to save him ?? or did he land on a bible.?? man GOD saved him amazing was it sicily??? and not on the FLS thats hard.

was it holland the sandbox??

you know that guy will die in the bathtub or something huh. i think i would have kept jumping chances of that hapneing again would be slim

well you won that one that is unreal

[white_falcon 0]

I dont remember what dz, that was 14 yrs ago. Yes a double mal, both reserve and main failed, both out tho, so he had SOMETHING slowing him down.

As far as jumping again, our CO manifested him the next day to jump w/ B Co. and he (the CO) said the same thing you did, "whats the chances of that happening again?" "freefall" Brown said to the CO, "Sir, do you know what the chances of my living again are?".

LOL

Scot

[airborne82nd 0]

ssg brown black guy 3/73rd armour?????tall

not a jumpmaster?????

[white_falcon 0]

Nope,

Spec 4 Brown (Dennis, I think but not sure) A Co 2/325 in '89

Scott

[traker 0]

thanks for all the help guys.... greatly appreciated! councilman24, that reply was insane....I love that shit!

Godspeed!

"we can either clmib down...or take the 15 second express shuttle" ---- during a snow storm on a 1000 foot antenna