HDjetp 0 #1 August 17, 2004 What is the performance difference between a 21 cell elliptical and a 27 cell elliptical canopy? Quote Share this post Link to post Share on other sites
piisfish 140 #2 August 17, 2004 what is the difference between a 7 cell and a 9 cell ??scissors beat paper, paper beat rock, rock beat wingsuit - KarlM Quote Share this post Link to post Share on other sites
cvfd1399 0 #3 August 17, 2004 That helped alot Quote Share this post Link to post Share on other sites
Kris 0 #4 August 18, 2004 QuoteThat helped alot That was actually a pretty good answer he gave.Sky, Muff Bro, Rodriguez Bro, and Bastion of Purity and Innocence!™ Quote Share this post Link to post Share on other sites
teason 0 #6 August 18, 2004 QuoteThat was actually a pretty good answer he gave. It was a perfect analogy unless of course the person asking the question doesn't understand the difference between a 7 cell and a 9 cell! Anyone have an aerodynamic answer? Full of words such as parasitic drag and such mumbo jumbo? I'm too much of a layman. Learned that on a previous thread!I would rather be a superb meteor, every atom of me in magnificent glow, than a sleepy and permanent planet. Quote Share this post Link to post Share on other sites
Kris 0 #7 August 18, 2004 QuoteQuoteThat was actually a pretty good answer he gave. It was a perfect analogy unless of course the person asking the question doesn't understand the difference between a 7 cell and a 9 cell! True, definitely true....but most of those asking about 21 vs. 27 cells should already know about those things before getting interested in a canopy like that.Sky, Muff Bro, Rodriguez Bro, and Bastion of Purity and Innocence!™ Quote Share this post Link to post Share on other sites
mjosparky 4 #8 August 18, 2004 QuoteQuoteQuoteThat was actually a pretty good answer he gave. It was a perfect analogy unless of course the person asking the question doesn't understand the difference between a 7 cell and a 9 cell! True, definitely true....but most of those asking about 21 vs. 27 cells should already know about those things before getting interested in a canopy like that. And how are they going to know about such things if they don't ask questions. Did you come into skydiving knowing all the things you know now? If you don't know the answer to his question just say so. HDjetp If you want better answers to you questions, fill out your profile. People don't like responding to a zero. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
grega 0 #9 August 18, 2004 QuoteAnyone have an aerodynamic answer? Full of words such as parasitic drag and such mumbo jumbo? you mean like: Wingtips of the canopy produce a lot of induced drag. Lower pressure at the top of the canopy and the higher pressure at the bottom want to mix because of difference in pressure of course. At the middle cells of the canopy, the canopy is between these two pressures for the most part (except at the trailing edge and behind). but at the wingtips where the canopy ends, those two pressure mix. and the vortices are made (those vortices can be seen behind any airplane that has some smoke trailing). And these vortices are part of the induced drag of the canopy. And the higher the aspect ratio of the wing is the less that induced drag from wingtips is noticed comparing to the lift the canopy produces. 9 cells are wings with higher aspect ratio than 7 cells that why it's better performing wing. With eliptical canopies Aspect ratio is calculated a little different but just to get the point, for square canopies aspect ratio = Span / Chord. Same applies to 21 vs 27 cell canopies. why not making even higher aspect ratio canopies you ask? Because the higher the aspect ratio the funkier the openings will get. that's why reserves are all 7 cell canopies (or 5). HUH, i hope i explained that corectly..."George just lucky i guess!" Quote Share this post Link to post Share on other sites
HDjetp 0 #10 August 18, 2004 Thank you for the answer. I appreciate the detailed answer. As the previous reply stated; I can't learn anything if I don't ask questions. Quote Share this post Link to post Share on other sites
kaerock 1 #11 August 18, 2004 Gold star for you! Also, higher aspect ratio wings generally have a flatter glide, resulting in shallower landings and better ground-travel on long spots. This is why paraglider wings have upwards of a 4 to 1 aspect as opposed to a skydiving canopy's 2.something aspect ratio, they're made more for distance flight, not for terminal speed deceleration and landing. People often prefer 27/9 cell canopies to 21/7 cell for their better glide. -R QuoteQuoteAnyone have an aerodynamic answer? Full of words such as parasitic drag and such mumbo jumbo? you mean like: Wingtips of the canopy produce a lot of induced drag. Lower pressure at the top of the canopy and the higher pressure at the bottom want to mix because of difference in pressure of course. At the middle cells of the canopy, the canopy is between these two pressures for the most part (except at the trailing edge and behind). but at the wingtips where the canopy ends, those two pressure mix. and the vortices are made (those vortices can be seen behind any airplane that has some smoke trailing). And these vortices are part of the induced drag of the canopy. And the higher the aspect ratio of the wing is the less that induced drag from wingtips is noticed comparing to the lift the canopy produces. 9 cells are wings with higher aspect ratio than 7 cells that why it's better performing wing. With eliptical canopies Aspect ratio is calculated a little different but just to get the point, for square canopies aspect ratio = Span / Chord. Same applies to 21 vs 27 cell canopies. why not making even higher aspect ratio canopies you ask? Because the higher the aspect ratio the funkier the openings will get. that's why reserves are all 7 cell canopies (or 5). HUH, i hope i explained that corectly... You be the king and I'll overthrow your government. --KRS-ONE Quote Share this post Link to post Share on other sites
