billvon 2,406 #26 January 21, 2003 >better is to simply view a chart of a canopy's perfromance vs wing loading. Such a chart would be great, but trying to characterize a wing's performance by a one-dimensional chart (or even two or three dimensions) may still be a bit misleading. A newer jumper may want a canopy that doesn't "twitch" a lot during final, and glide speed (for example) is not a good predictor of that. >exactly my point in that it (squares vs ellipticals) is not a pretty good guide. I'd say it might be better than a single chart trying to completely characterize a canopy's performance. >when it comes to modern canopies you are no longer a parachutist, > you are a pilot. i would like to see jumpers be far more educated > about the wings they pilot . . . Agreed, but nonetheless a simpler guide to canopies will help newer jumpers unfamiliar with high performance canopies to make safer decisions. I would recommend a triathalon 150 over a stiletto 150 for someone who is moving down from a 170 or 190 sq ft Sabre because on my performance 'chart' a triathalon is more forgiving than a stiletto, no matter what their performance charts say. In addition, not to single you out, but manufacturers lie. (To put it more nicely, they do not agree on a standard of truth.) One look at the pack volume and areas of a given canopy compared to the PIA measurements will show this. Some even change the measurement system based on how they want the canopy perceived, and then change back such that a canopy of the same size has two different measurements. This casts doubt on any sort of manufacturer's performance chart; you can't even compare two canopies of the same size because they might not be the same size! I don't know what form an ideal performance chart would take, nor am I sure what characteristics I would put in such a chart. The only way I've ever been able to rate canopies for other people is to jump them and then base recommendations on my experiences. I'd be interested to see what sort of objective 'forgiveness' or 'performance' chart one could generate for a variety of canopies. Quote Share this post Link to post Share on other sites
rigging65 0 #27 January 21, 2003 QuoteI have read a lot of ads proclaiming a canopy to have the "highest perfomance" of any canopy. Jumpers are interested in facts, manufacturers give us marketing. ...and might that be because no one wants to stay on the same page as everyone else and use a STANDARD?? God forbid anyone actually produce numbers based on the standards PIA set up to use so we have something to compare items against. It's all arbitrary anyway, at least we could all stay on the same arbitrary scale! There are standards in place for sizing, pack volume, etc...but few companies will follow them. It's all smoke and mirrors...advertising... Makes it awful tough to educate new folks on technical issues of their gear.... "...and once you had tasted flight, you will walk the earth with your eyes turned skyward. For there you have been, and there you long to return..." Quote Share this post Link to post Share on other sites
Hooknswoop 19 #28 January 21, 2003 PIA has a standard for canopy performance? Hook Quote Share this post Link to post Share on other sites
cobaltdan 0 #29 January 22, 2003 been a very long day. just finished up. spent the second shift setting up a new factory space for expansion. i am quite dizzy from oiling the floors. you do not realize the degree of fumes until your out of it.... anyway, a quicky on characterizing canopy performance. most manufacturers recommended loading charts are bs. they are so skewed towards conservative that everyone ignores them. from day one we have tried to provide real world charts. additionaly we provide actual data. i.e other companies publish ad after ad stating stuff like " softest opening canopy ever period!" with nothing to substantiate. we provide dataloged force vs. time graphs and live demonstrate 180mph deployments at boogies. any perceived hype you hear coming from my mouth is simply passion or excitement, i always have hard data to back it up. im an engineer not a salesman. with or without dataloggers a manufacturer can provide a realistic chart of canopy performance at different wing loadings. without a datalogger it will be pretty basic but still more useful that the simple tapered, semi, elliptical canopy labeling, which is just meaningless as it does not take into consideration wingloading or the actual planform. with dataloggers 1 jump per wingloading (although more is better) is all that is needed to gather the data required for a super performance chart. the pilot must fly a general routine. we have invested an insane amount of money developing out dataloggers, and they are available to other companies. numbers dont lie. every canopy company should have one. our newest model is revolutionizing military applications containing our new inertial nav. unit. data is recorded to flash cards 360' yaw, pitch, roll, acceleration and velocity in all axis, angular rates up to 1200' / sec, plus 3dimensional gps accurate to 2m, barometric altitude, 4 riser links, + desired aditional sensors. this new dataloger goes beyond just testing canopy openings and allows complete classification of a canopy's flight envelope. this was done so as to allow us to create a software simulator. canopies are recorded and then the data is imported in to our software. the software then can 'fly' generating a virtual gps fix. this false signal is received by an autopilot computer. the simulator receives the output steering controls from the autopilot and reacts accordingly in its generation of its gps signal. this allows autonomous parachute systems and uav's to be tested and perfected quickly. anyway, i am babbling. hope to see everyone at the pia. sincerely, dan<><>Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
Hooknswoop 19 #30 January 22, 2003 Dan- A few questions: At what wing loading is a Cobalt "ideal" for beginners, and how many skydives (range) do you define "beginner" as? Your student canopy, do you mean the Cobalt? How do you define performance? Max speed? Max turn rate? Glide ratio? Altitude lost in a 360-degree turn? Do you dis-agree that an elliptical (tapered) [even Atair uses the term elliptical, even though we all know canopies are really tapered, it is a term that is recognized by everyone and understood, like Zerox], canopy will have better performance than a square (rectangular) [another skydiving term, square canopies are really rectangular], all other things being equal? Does Atair have a chart showing performance vs. wing loading for the Cobalt? Hook Quote Share this post Link to post Share on other sites
rigging65 0 #31 January 22, 2003 QuotePIA has a standard for canopy performance? I guess I need to spell it out, for those having trouble taking the next step: PIA has standards for measurements. If mfgs. followed those standards (or ANY universal standard) then jumpers would be able to compare one canopy against another for performance. Right now, it's pretty tough to take any two 135 sq. ft-ish canopies and compare them against each other because they're different sizes...so obviously they will perform differently, but is that due to size and loading or cut and trim??? Does my post make more sense to you now Hook? Like I said before, it's a lot of smoke and mirrors... "...and once you had tasted flight, you will walk the earth with your eyes turned skyward. For there you have been, and there you long to return..." Quote Share this post Link to post Share on other sites
Hooknswoop 19 #32 January 22, 2003 Sorry, didn't mean to come off that way. That was my fault. PIA has a set method of measuring the size of canopies. They measure a lot of canopies and publish those numbers. For example to compare the performance of a Sabre 170 (PIA 179 sq. ft.) and a Monarch 175 (PIA 183 sq. ft.) the Monarch is 4, not 5 sq. ft. larger. Not a big difference from the manufacturer's numbers. Tom compare my Safire 189 to a Sabre 170, the manufacturer said that Safire1's are actually printed 7% larger than the way PD measures their canopies, which makes my Safire 189 a Safire 174 for comparing to a PD. Before the 7& rule came out, I let a few people jump the canopy and they all agree that it had more peromance than a Sabre 170. That makes sense, a Semi-elliptical 174 out-performed a square 170. So not knowing that it was a 174 didn't matter for performance comparison. It was faster, regardless of the numbers printed on the label. So, I think it would be nice if every manufacture used the same method to measure canopies, it isn't absolutely necessary for determining canopy performance. Without a series of charts showing turn rate vs. wing loading, glide speed vs. wing loading, max speed vs. wing loading, etc, for each canopy size, all we have is plan form catagory and size. Not excellent standards by any means, but unil something better comes out it is all we have. For someone to say you are doing it all wrong, you should be referencing a non-existant chart to determine performance is silly. I eagerly await Dna's reply to my (and others) questions. Again, my apologies Rigging65, Hook Quote Share this post Link to post Share on other sites
rigging65 0 #33 January 22, 2003 No offense taken Hook, really. I must admit that this is a sensitive subject with me, so I'm sorry if I came off as an ass. I'm really not, just ask meAs a gear mfg. AND a dealer, it's difficult when not everyone is playing by the same rules...especially with the way a lot of new jumpers have become so "Internet Educated" about what they "need", gear wise. We sell canopies every week to people that come in insisting that they know what they want. Our staff is very good about gently asking "why" and, especially with new jumpers, MOST of the time it comes out that they saw an ad, read a website somewhere and heard about it in the yard, and that's their entire reason (ironic that this discussion is going on on-line, no?)! Our feeling is that, as a gear shop, we have the responsibility to educate our customers, then let them decide what they want. This cuts squarely into our profits, as it takes time to educate, but I feel it's our duty to offer the best service we can, and that includes education. And we have had a lot of repeat business in the past because of it. What really burns me, of course, is now when you take the time to educate someone then they bring you an online quote for gear and say "beat it or I'll go there"...what do you do? Jumpers have changed over the years, so you just roll with it, I guess, and hope the Mfgs. support their dealer network. The way this gets back around to measurements is that a lot of yard-gossip about which canopy is better or worse is based on how a given wing feels in the air as compared to another...which, of course, is an unfair comparison if you don't know the sizing issues. So, the yard-gossip becomes cannon law and all the sudden you're fighting ignorance...which is no easy taskI just think that some basic level of standardization would help with that, that's all. I would, personally, love to have a complete set of comparison charts, as you discussed, as the Engineer in me loves that sort of thing, but I don't honestly think they'd be of much use to your average weekender. Again, sorry if I was curt in my initial reply! "...and once you had tasted flight, you will walk the earth with your eyes turned skyward. For there you have been, and there you long to return..." Quote Share this post Link to post Share on other sites
rgoper 0 #34 January 22, 2003 i'm currently flying a Heatwave 170^2 @ 1.58:1--Richard-- "We Will Not Be Shaken By Thugs, And Terroist" Quote Share this post Link to post Share on other sites
cobaltdan 0 #35 January 22, 2003 hook, imo a cobalt is a superior choice to a sabre/2, safire/2, or hornet. loading tends to be slightly higher on a cobalt for identical foward speed. i.e. 1.0 sabre = 1.2 cobalt. anyone who is safe flying a sabre, safire or hornet class canopy will be equally safe or safer flying a cobalt at similar to slightly higher wing loading. chart: we have a real world wingloading chart posted on our web site. what i mean by real world is a list of where most of our customers fall into. i.e. begineer 1.2-1.4, intermediate 1.4-1.6 etc... and btw we have always used pia standards of measure. the reason some companies do not is simply marketing. i.e. another company uses a computer program as we do to scale canopies. they can measure their canopies to any standard easily. but it is simply a marketing strategy to measure so as to skew results to create a perceived lighter wing loading. i.e take a safire it is easier to use a different standard of measure so as to be able to market a 1.0 loading recomendation for a begineer than to simply state the truth as we do. i.e. a particular canopy is suitable for a begineer at 1.2, etc... if a canopy is more efficient there can be less of it for the same effect. you do not care about footage you care about efficiency. extra sail area that does not generate lift does you little good. most jumpers do not realize that the extra area of a square canopy superimposed over an elliptical is simply drag and does little for lift. even though the canopy is larger it can not be more efficient. there are equally significant gains in efficiency by reducing canopy distortions. sincerely, dan<><>Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
skygod7777 0 #36 January 22, 2003 Quotei'm currently flying a Heatwave 170^2 @ 1.58:1 um, your profile says a cobalt 170. do you have 2 canopies?? later Quote Share this post Link to post Share on other sites
Hooknswoop 19 #37 January 22, 2003 Quoteimo a cobalt is a superior choice to a sabre/2, safire/2, or hornet. loading tends to be slightly higher on a cobalt for identical foward speed. i.e. 1.0 sabre = 1.2 cobalt. Quotemost jumpers do not realize that the extra area of a square canopy superimposed over an elliptical is simply drag and does little for lift. even though the canopy is larger it can not be more efficient. there are equally significant gains in efficiency by reducing canopy distortions. I am a little confused, a square canopy (Sabre) has more foward speed at the same wing loading, but the Cobalt has less drag and is more efficent? Quoteanyone who is safe flying a sabre, safire or hornet class canopy will be equally safe or safer flying a cobalt at similar to slightly higher wing loading. Just so I understand, you recommend putting students under Cobalts at a 1.2 wing loading? Has this been done? I have taught students (with 3 tandem jumps) using Sabre mains at a 1:1 wingloading. PD, Icarus, and I'm sure other manufacturers have wing loading charts as you descrivbe, beginner to expert. They don't seem to be very useful, or at least skydivers seem to ignore them. Quoteif a canopy is more efficient there can be less of it for the same effect. you do not care about footage you care about efficiency. extra sail area that does not generate lift does you little good. most jumpers do not realize that the extra area of a square canopy superimposed over an elliptical is simply drag and does little for lift. even though the canopy is larger it can not be more efficient. there are equally significant gains in efficiency by reducing canopy distortions. So you agree that planform makes a large difference in a canopy's performance, along with wingloading. So what is so wrong about classifing canopies by their plan-form, then factoring in size and wing loading? If someone is jumping a Sabre and is considering going to a Stiletto of the same size, they will notice different flight characteristics, mainly due to the different plan form. Turn rate, max speed, altitude lost in a turn and recovery arc will all be different without a change in wing loading. Thanks for taking the time, I know you are busy. Hook Quote Share this post Link to post Share on other sites
cobaltdan 0 #38 January 23, 2003 "If someone is jumping a Sabre and is considering going to a Stiletto of the same size, they will notice different flight characteristics, mainly due to the different plan form." wrong, not mainly because of the planform, mainly because of the sum of many design variables. this is why canopies with more 'agressive' planforms can be more docile and canopies with less 'agressive' planforms can be pocket rockets. this is getting beat to death. i hope to see you at pia and we can discuss further. sincerely, dan<><>Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
rigging65 0 #39 January 23, 2003 Quotewrong, not mainly because of the planform, mainly because of the sum of many design variables With the exception of line trim, wouldn't most all of these variables be encompassed by the planform? "...and once you had tasted flight, you will walk the earth with your eyes turned skyward. For there you have been, and there you long to return..." Quote Share this post Link to post Share on other sites
Hooknswoop 19 #40 January 23, 2003 I won't be at PIA this year. Do you consider the Cobalt to be a good student canopy? Loaded at 1.2:1? Why does a Cobalt loaded higher than a Sabre of the same size have a slower speed if it is more efficent? Hook Quote Share this post Link to post Share on other sites
AggieDave 6 #41 January 23, 2003 Heatwave 170 loaded at just a hair under 1.7:1. It opens like a dream and swoops like a banshee midget on crack... Oh, and I spent only $900 on it brand new with custom colors, it appeared at my door in 4-weeks...well, lets just say I love everything about this canopy. --"When I die, may I be surrounded by scattered chrome and burning gasoline." Quote Share this post Link to post Share on other sites
bbarnhouse 0 #42 January 23, 2003 I fly a Sabre2 and a Stiletto. I prefer the Stiletto. Cheers! BB Quote Share this post Link to post Share on other sites
relyon 0 #43 January 23, 2003 PD Lightning 143 (1.35) or 126 (1.5), depending on the dive. Bob Quote Share this post Link to post Share on other sites
rgoper 0 #44 January 23, 2003 Quoteum, your profile says a cobalt 170. do you have 2 canopies?? yep.--Richard-- "We Will Not Be Shaken By Thugs, And Terroist" Quote Share this post Link to post Share on other sites
skygod7777 0 #45 January 23, 2003 QuoteQuote -------------------------------------------------------------------------------- um, your profile says a cobalt 170. do you have 2 canopies?? -------------------------------------------------------------------------------- yep. ok, that makes sense. just wondering, which one do you like better?? later Quote Share this post Link to post Share on other sites
rgoper 0 #46 January 23, 2003 QuoteDo you consider the Cobalt to be a good student canopy? Loaded at 1.2:1? Hook: while i can't speak for Atair, or Dan, i can speak from my experience from flying my Cobalt 170^2. i wouldn't reccomend this canopy at ANY wingloading for a "novice" sky diver. the openings are too unpredictable. hell i'm just under 500 jumps and three years in the sport and i've flown a lot of different canopies, but the Cobalt has been by far the most challenging and difficult, (my first chop on jump # 475) i've shipped it back to Atair for inspection, and if they give it a "clean bill of health" i'll have the H-Mod done and see what happens, until then i'll fly my HeatWave. don't get me wrong, Atair has great service, and the canopy, when it behaves correctly is a dream to fly, and the flare power on the bottom end is way kewel, but the "two stage openings" has some issues from my experience. take away the "two stage opening", then i think i might consider putting a student under it at 1:1 a lot of dz's are putting students under sabre2's and stilettos now, teach em now i guess?--Richard-- "We Will Not Be Shaken By Thugs, And Terroist" Quote Share this post Link to post Share on other sites
Hooknswoop 19 #47 February 2, 2003 OK, we never got to finish this discussion, so now that you are back form PIA: Your student canopy, do you mean the Cobalt? Do you recommend putting students under Cobalts at a 1.2 wing loading? Has this been done? At what wing loading is a Cobalt "ideal" for beginners, and how many skydives (range) do you define "beginner" as? Does Atair have a chart showing performance vs. wing loading for the Cobalt?, not a recommended wing loading chart, most manufactures have those, PD has it right on the label. How do you define performance? Max speed? Max turn rate? Glide ratio? Altitude lost in a 360-degree turn? Why do you say a square canopy (Sabre) will have more forward speed at the same wing loading as the Cobalt, but the Cobalt has less drag and is more efficient? Isn't this contradictory? Would you agree that a common characteristic of elliptical canopies is a higher max turn rate and faster turn response than an equally sized, material, and wing-loaded square canopy? Hook Quote Share this post Link to post Share on other sites
webracer 0 #48 February 3, 2003 I have: Samurai 136 (1, 1 more ordered) Samurai 120 (ordered) Jedei 120 (1) I love Brian's canopies. Looks like he's designing a new one to bridge the gap between eliptical and tri-cell xbrace. That'll probably be the only thing to get me off these Samurais.Troy I am now free to exercise my downward mobility. Quote Share this post Link to post Share on other sites
cobaltdan 0 #49 February 3, 2003 OK, we never got to finish this discussion, so now that you are back form PIA: Your student canopy, do you mean the Cobalt? yes i mean the cobalt and previously the space/alpha. we are also offering our 'indigo' canopy for this season in sizes 170, 190 & 210. it is slightly less tapered than a cobalt, and the openings are tuned for lighter wingloadings. Do you recommend putting students under Cobalts at a 1.2 wing loading? yes, anyone you would consider safe under a sabre, safire or hornet is equally safe on a cobalt. Has this been done? yes At what wing loading is a Cobalt "ideal" for beginners, and how many skydives (range) do you define "beginner" as? around 1.2 off student status. again anyone you would consider safe on a sabre, safire or hornet. Does Atair have a chart showing performance vs. wing loading for the Cobalt?, not a recommended wing loading chart, most manufactures have those, PD has it right on the label. check out our web site faq page. How do you define performance? Max speed? Max turn rate? Glide ratio? Altitude lost in a 360-degree turn? all of the above, depends on context. Why do you say a square canopy (Sabre) will have more forward speed at the same wing loading as the Cobalt, but the Cobalt has less drag and is more efficient? Isn't this contradictory? no it isn't. Would you agree that a common characteristic of elliptical canopies is a higher max turn rate and faster turn response than an equally sized, material, and wing-loaded square canopy? reducing drag from the ends of a canopy will translate to a faster turning speed all things being equal. but they are not, there are more variables to consider. a designer can make an elliptical canopy that does not turn as fast as a less elliptical canopy. sincerely, dan<><>Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
jerm 0 #50 February 3, 2003 Samurai 150 love it love it love it... Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time Quote Share this post Link to post Share on other sites
