7-cell vs 9-cell

[diveforfun97 0]

I am about to buy a main off of dropzone, but a I have never jumped a 7 cell chute. Is there any differences in performance between jumping a 170 sq 7- cell chute vs a 9 cell chute of the same size. I am a pretty conservative flyer when im under the cloth. What I am mst concerned with is if there is a difference between my rate of decent, and the flair. Thanks .

[amstalder 0]

Meet your new best friend: The search function
http://www.dropzone.com/cgi-bin/forum/gforum.cgi?do=search_results&search_forum=forum_18&search_type=AND&search_string=7+cell+9+cell

Happy reading (this is one of my favorite searches btw, I look at the differences between 7 and 9 cell canopies often)

[pilotdave 0]

Before you buy anything, talk to instructors at your DZ about your choices, if you haven't already. Make sure the seller will let you try the canopy before you agree to buy it. There definitely are differences between 7-cells and 9-cells and more importantly between different models of canopies. You might love one 7-cell and hate another. Or you might hate 7-cell canopies altogether. You won't know what you like or dislike until you try at least a couple.

Make sure you're buying smart... don't get screwed. Read the advice on here about buying used equipment and talk about your choices and prices with someone you trust.

Dave

[councilman24 37]

What they said.

Don't buy ANYTHING without getting at least two EXPERIENCED intructor/rigger opinions.

WAY too general of a question. We could have answered it in 1988. Not now. WHOLE depends on the particular canopies under discussion.

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

[jsreznor 0]

Wasn't this on your A-license test? I'm pretty sure the SIM has important information about the differences between 7 and 9 celled canopies.

[skybill 22]

Hi dive,
Besides the 7 vs 9 cell difference, don't buy "any" equipment without having "your" rigger check it out first. If you don't know the dif. xtwn a 7 and 9 cell of the same ft2 then do some research. If you don't, you may do some more walking than you planned.

SCR-2034, SCS-680

III%,
Deli-out

[npgraphicdesign 3]

Difference between a 7cell and a 9cell: 2 cells.



Sorry I'm just being a wiseass

[skybill 22]

Quote

Difference between a 7cell and a 9cell: 2 cells.



Sorry I'm just being a wiseass

Hi NP,
Yup, 2 cells!!!! And answer this ??, What's the aspect ratio diference between the two and how will it affect flight performance?? Given; same canopy model, ft.sq., weight of jumper, temp., pressure, humidity.

SCR-2034, SCS-680

III%,
Deli-out

[npgraphicdesign 3]

Quote

Quote

Difference between a 7cell and a 9cell: 2 cells.



Sorry I'm just being a wiseass

Hi NP,
Yup, 2 cells!!!! And answer this ??, What's the aspect ratio diference between the two and how will it affect flight performance?? Given; same canopy model, ft.sq., weight of jumper, temp., pressure, humidity.

Can't answer that because I'm still a noob..hence me being a wiseass.

On a side note, would love some ejumacation on what you just mentioned above. I fly a Triathlon 210, and would love to learn more about the differences between 7 and 9 cell canopies, aside from the obvious.

[skybill 22]

Quote

Quote

Quote

Difference between a 7cell and a 9cell: 2 cells.



Sorry I'm just being a wiseass

Hi NP,
Yup, 2 cells!!!! And answer this ??, What's the aspect ratio diference between the two and how will it affect flight performance?? Given; same canopy model, ft.sq., weight of jumper, temp., pressure, humidity.

Can't answer that because I'm still a noob..hence me being a wiseass.

On a side note, would love some ejumacation on what you just mentioned above. I fly a Triathlon 210, and would love to learn more about the differences between 7 and 9 cell canopies, aside from the obvious.

H
Hi np,
OK, here'z a quick project for ya' google up aerodynamics, lift, aspect ratio, induced drag and lift/drag. Knowledge is power....get some!!!! Let us know what you find out.

SCR-2034, SCS-680

III%,
Deli-out

[skybill 22]

Hi np,
Don't know if ya' did much research last night but there's no really short answer. Without a lot of whiz/bang ya gonna get more horizontal distance coverage per unit of sink with the 9 cell. You will walk further with the 7. There's this concept in aerodynamics called induced drag. that's the drag that is produced by the wing creating lift. Look at a side view of your canopy (airfoil) and note that for the same sq.ft. the 7 cell will have more nose to tail(chord) distance and less span than the 9 cell. Since the mass of air traveling over the wing will have to travel farther and be in contact with the canopy surface longer with the 7 cell over the 9 cell ya end up with more drag created. Ya ain't gonna cover as much ground, sorry. Hope my short answer helps you out. Next time you run into Brian Germain or the PD guys, buy em' a couple of beers and ask them.

SCR-2034, SCS-680

III%,
Deli-out

[Chubba 0]

Make sure you demo some modern 9-cell ZP designs when deciding on your first canopy.

I'm very bias but the results I see from new jumpers getting their first set of gear are very positive.

[freeatlast 0]

I would also suggest demoing as much suitable gear as you can before making a decision - it's often tempting to jump right in and grab the first "BARGAIN" that comes along.

I once bought a snowboard whilst i was on holiday - they didn't have a demo available - so i paid my £400 (about $600 at the time) as i had read every review and it sounded perfect ...

Well safe to say that it was sold off within a few weeks as it STANK! - it wasn't the boards fault - 100's of great reviews - I JUST DIDN'T LIKE IT

Unfortunately i couldn't get a refund and ended up selling it second hand and loosing a whole heap of $$$'s.

So nothing replaces trying the gear first ...

If you really can't demo one - then listen to those who know you and the canopy (your rigger or instructor).

But remember everyone's taste is different ...

[Chubba 0]

On that note freeatlast and this is most definitely the wrong advice, I bought my Sabre2 170 (loaded 1.0) purely from reading DZ.com.

I was having very bad canopy control on a Fury 220, bad pattern, bad flare, bad everything... turned up at the DZ without consulting my instructors and told the DZO/CI what I had bought ($6500 rig).

Absolutely kicked my ass... I recieved a grilling that literally put me in tears.

Now I've passed over 100 standups in a row on my first canopy, I love it.

I think DZ.com is a valuable resource for people buying their first canopy, just be sure to have these discussions with your instructors.

[freeatlast 0]

Very true indeed ...

If you buy first and try later then you take your chances with what you get.

I had someone who was currently flying a 220 ask me if it was ok to buy a rig with a 155 reserve in it the other day!

Sometimes you will get away with it (I have) but sometimes it will bite you!

The best decisions are usually the ones that you make with as many of the facts as you can reasonably determine...

[samanthacullen 0]

This is an interesting question... I personally have an Electra 150 (9cell) which I love, but I am frequently jumping my dads Beta 155 (7cell). This is also a great canopy; I get great landings and it is really good for canopy control. I jump this when I do CRW with him and it is perfect.
In his opinion 7cells can do everything except swoop - so if thats what you want to do then don't go there. For general skydiving purposes, especially if you are more into the freefall side of things my experience of both has shown that they are equally enjoyable. BUT... as everyone else has said do your research: it very much depends on what you want to achieve as to what you fly

[uscallesen 0]

Quote

I am about to buy a main off of dropzone, but a I have never jumped a 7 cell chute. Is there any differences in performance between jumping a 170 sq 7- cell chute vs a 9 cell chute of the same size. I am a pretty conservative flyer when im under the cloth. What I am mst concerned with is if there is a difference between my rate of decent, and the flair. Thanks .

I did the same research about a year ago - and ended up replacing my Sabre1-170 (9 cell) with a brand new Storm-170 (7 cell) - would I recommend the Storm to others ? Hell yeah ! - I've got about 50 jumps on the sabre and the same on the Storm so far.

For me the most important requirement for my new 'chute was that I wanted soft sweet openings (something my Sabre always denied me ) and I wanted something that would handle turbulence well. I got both with the Storm - What I lost was the awesome forward speed of the Sabre during landings - all the 7-cells I've seen are much better suited for accurate landings than for swooping. Besides that I cant say there's much difference between the 3-4 different 9-cells I've flown and the Storm - except for the openings - the are SOO smooth

[diveforfun97 0]

Thank you to everyone. All of it was great advice. I did fail to mention that I was not jumping into buying the chute right away, just starting the research process (as I said I am very conservative). I will continue my search and let you all know what I find.

[shah269 0]

So 7 cells are just slower.....you would think this would be perfect for student and beginners?

Life through good thoughts, good words, and good deeds is necessary to ensure happiness and to keep chaos at bay.

The only thing that falls from the sky is birdshit and fools!

[JohanW 0]

They are not just slower.

You are oversimplifying things.

Johan.
I am. I think.

[Baksteen 84]

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Fury 220[..]Sabre2 170

Quote

Well, you have a large F111 canopy versus a small (for our experience level) zepo one - not a very fair comparison.

That said, I always have to laugh at people who self-righteously ask me whether I enjoy walking back from a long spot with that 7-cell of mine.

What is gonna cover more ground, I ask you - my 7-cell 190 loaded at 1.3 or thier 9-cell 120 loaded at 1.7?

@Shah: My Storm has more speed (both forward AND downward) than an equally loaded Pilot.
It also turns a lot snappier and flares better than an equally loaded Sabre.

"That formation-stuff in freefall is just fun and games but with an open parachute it's starting to sound like, you know, an extreme sport."
~mom

[kallend 2,026]

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Hi np,
Don't know if ya' did much research last night but there's no really short answer. Without a lot of whiz/bang ya gonna get more horizontal distance coverage per unit of sink with the 9 cell. You will walk further with the 7.

How far you walk depends on how accurately you land, not on how many cells your canopy has.

...

The only sure way to survive a canopy collision is not to have one.

[kallend 2,026]

When I was hit from behind at 100ft agl and knocked into line twists, I was very glad I was jumping my 7-cell Spectre and not my 9-cell Stiletto.

...

The only sure way to survive a canopy collision is not to have one.

[JohanW 0]

Quote

This is an interesting question... I personally have an Electra 150 (9cell) which I love, but I am frequently jumping my dads Beta 155 (7cell). This is also a great canopy; I get great landings and it is really good for canopy control. I jump this when I do CRW with him and it is perfect.
In his opinion 7cells can do everything except swoop - so if thats what you want to do then don't go there. For general skydiving purposes, especially if you are more into the freefall side of things my experience of both has shown that they are equally enjoyable. BUT... as everyone else has said do your research: it very much depends on what you want to achieve as to what you fly

It's the Indian, not the arrow ..

.. though you have me wondering why I swoop my Triathlon and CRW my Stiletto.
(Yes, I know why I do that. Yes, I do it on purpose. For me, it is the right tool for the job.)

Johan.
I am. I think.

[skybill 22]

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Quote

Hi np,
Don't know if ya' did much research last night but there's no really short answer. Without a lot of whiz/bang ya gonna get more horizontal distance coverage per unit of sink with the 9 cell. You will walk further with the 7.

How far you walk depends on how accurately you land, not on how many cells your canopy has.

Hi kal baby,
Howard cosel once said,"'Ya can't argue with ignorance!" (or something very close to that!!) Now, here's the deal. L/D has nothing to do with accuracy!! The bottom line is this," For a given number of square feet, a canopy with a higher aspect ratio [mean wing span/average chord] {holding all else constant; fabric type, airfoil shape, type of lines, suspended weight} will provide more horizontal distance covered per unit of sink. Got that???" Now, if you took a 7 cell, like an old Mike Furry Django "Pegasus" and expanded it to the same wingspan/chord as the "Dragonfly," without adding the additional ribs to make it a 9 cell the airfoil would baloon out and reduce its efficiency. If you took the 7 cell "Pegasus" and a 9 cell "Dragonfly" and with same suspended weights , opening side by side, the Dragonfly will "outglide" the Pegasus, (You can do this same experiment with countless other canopy designs) "SO," if you used the maximum Pegasus spot for both canopys, both canopys will make it to the target , it's just that the Dragonfly will have some extra altitude to burn off before landing. Sorry about that old man. Conversly if you were in the Pegasus on the max Dragonfly spot, "You'd be walking to the target!!" That's all the whiz/bang I'm gonna' get into for you....."GOT THAT???"

SCR-2034, SCS-680

III%,
Deli-out