cruzlite 0 #1 December 21, 2003 I was recently told that PD measures its canopies accross the bottom skin rather than accross the top. (Top being industry standard ?) This would make their canopies (10sq. ft. ?) Larger than quoted ? Would anyone care to comment on this? (ie; why?) Thanks D Quote Share this post Link to post Share on other sites
Hooknswoop 19 #2 December 22, 2003 Unfortunately, there is no real industry standard. You could say PD’s canopies are larger, or say some other manufacturer’s are smaller. PIA has measured some canopies (using their method of measuring) and a comparison chart is in the back of Para Gear’s catalog. A lot of the newer canopies have not been independently measured. Derek Quote Share this post Link to post Share on other sites
rigging65 0 #3 December 22, 2003 QuoteWould anyone care to comment on this? (ie; why?) Read my lips..."marketing".... QuoteThis would make their canopies (10sq. ft. ?) Larger than quoted ? Ever flown a PD 176R and a Raven -M181 in the same day? The PD flys much "bigger". It also packs much "bigger". Coincidence or Marketing? There was/is a standard set out by PIA for canopy measuring...but PD opts not to use it. "...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
Ron 10 #4 December 22, 2003 QuoteThere was/is a standard set out by PIA for canopy measuring...but PD opts not to use it. When did it come out? was PD already using another method?"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334 Quote Share this post Link to post Share on other sites
Kolla 0 #5 December 22, 2003 I'm not really qualified to answer this one - as I don't know very much about designing canopies. However, measuring the size of a canopy isn't as simple as one might think it would be - hence the different methods used out there. John LeBlanc once tried to explain to me how and why PD sizes up their canopy that way, but I have to admit that most of it went a right over my head! I did manage to understand that it wasn't a simple task. PIA's method was an attempt to standardize sizing, but there are flaws to that one as well. I am going to see if I can get our Engineering Dept to write up something in very plain English that would help shed some light. Be patient with me though - those guys are a bit swamped right now with a other few fun projects Edit: In the meantime, check out our "Pack Volume Mystery" article - it does help shed some light on the subject: http://www.performancedesigns.com/docs/packvol.pdf Blue ones, Kolla Kolbeinsdottir, Performance Designs, Inc.Blue Skies Magazine Quote Share this post Link to post Share on other sites
skymedic 0 #6 December 22, 2003 Quotethose guys are a bit swamped right now with a other few fun projects Kolla...the never ending tease you are.... Marc otherwise known as Mr.Fallinwoman.... Quote Share this post Link to post Share on other sites
rmsmith 1 #7 December 22, 2003 Easy, dust off your old Calculus textbook from school, and look up "projection". The CAD programs can do this easily too. Quote Share this post Link to post Share on other sites
rigging65 0 #8 December 22, 2003 Quote -------------------------------------------------------------------------------- In Reply To -------------------------------------------------------------------------------- There was/is a standard set out by PIA for canopy measuring...but PD opts not to use it. -------------------------------------------------------------------------------- When did it come out? was PD already using another method? It's been out for some time...I'm not sure when it was released. Yes, PD was already using their own method. As I understand it though, and I could be totally off base here, the PIA standard was "closer" to what most other Mfgs. were using...and further than from what PD was using. I think the thing to remember here, is that it doesn't matter a damn bit what 135 sq.ft. is. What matters is how each mfg's 135 sq.ft. canopy compares in size to one another. Square footage is almost an arbitrary thing. If a "150" is too big, you go to a "135". It doesn't matter if a 150 is actually 140 sq.ft. or 160 sq.ft....as long as everyone's "150" is the same, and that there is a measurable difference between other sizes (ie- a "240" is pretty close to twice as big as a "120"). IMO, sizing is about marketing. If it weren't, companies would agree on a way to measure. Does it really matter if we know we're jumping a 135 or a 138 and they fly the same?? Probably not. Does it matter that you jump a 126 and a 120 and they are nothing alike? Yes. But the mighty dollar rules, and safety takes a back seat to "marketability", thus there isn't standardization...its either that, or its a "we're bigger than you, so do it our way" issue.... sad, really. "...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
Ron 10 #9 December 23, 2003 QuoteIMO, sizing is about marketing. If it weren't, companies would agree on a way to measure. Does it really matter if we know we're jumping a 135 or a 138 and they fly the same?? Probably not. Does it matter that you jump a 126 and a 120 and they are nothing alike? Yes. But the mighty dollar rules, and safety takes a back seat to "marketability", thus there isn't standardization...its either that, or its a "we're bigger than you, so do it our way" issue.... sad, really. I don't know. It might be a combination of: 1. This is the way we have always done it. Why change a Stiletto 120 to a Stiletto 133? Now you have to know year it was made. It just confuses things. 2. Marketing like you said. Most don't know squat about canopy sizes.... 3. We are the big kids on the block...you want to all measure the same way...let it be our way."No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334 Quote Share this post Link to post Share on other sites
riggerrob 643 #10 December 23, 2003 1. This is the way we have always done it. Why change a Stiletto 120 to a Stiletto 133? Now you have to know year it was made. It just confuses things. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Yup! Icarus did that back in 2001. They adopted PD's measuring method to simplify the decision-making process for consumers. Now you have to know what year an Icarus canopy was sewn to know how it was measured. As an aside, the PIA standard measuring method was written by Manley Butler when he he worked at Para-Flite circa 1981, in an effort to get everyone to read off the same sheet of music. A few older manufacturers (PISA and Django) changed to the PIA standard. Unfortunately, several new companies (P.D., Icarus, Atair, etc.) - invented new measuring methods and they have never explained in terms that the average consumer can understand. My pet peeve is marketeers who speak "marketese," politicians who speak "double-speak," etc. Quote Share this post Link to post Share on other sites
johnny1488 1 #11 December 23, 2003 QuoteYup! Icarus did that back in 2001. They adopted PD's measuring method to simplify the decision-making process for consumers. Now you have to know what year an Icarus canopy was sewn to know how it was measured. Not exactly. Icarus has always used PD's method. Precision didnt when they launched the first safires and omegas in the US. Icarus decided not to change the sizing to try to minimize an already cunfusing situation. They waited to launch the safire2 and omni to change them back to PD's method. The xfire, fx, vx, tandem and student XP have always been measured in the same manner as PD's, so if you have a safire or omega, no matter what year, it is smaller (in PD terms) than is stated on the label. Johnny --"This ain't no book club, we're all gonna die!" Mike Rome Quote Share this post Link to post Share on other sites
divnswoop 0 #12 December 24, 2003 PD can call it whatever they want in my book. I'll find the size I like and buy it!!! Quote Share this post Link to post Share on other sites
Ron 10 #13 December 24, 2003 QuotePD can call it whatever they want in my book. I'll find the size I like and buy it!!! It can cause problems..I know a guy that had a Sabre 170 and he wanted to downsize. So he went and got a Safire 149. The problem is the Safire 149 is really about a 135. He had no idea that canopies were measured differently, in fact most jumpers at the DZ didn't know till after this guy broke his leg. See how it can be an issue"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334 Quote Share this post Link to post Share on other sites
sdctlc 0 #14 December 24, 2003 Quotea comparison chart is in the back of Para Gear’s catalog. Here is that chart!"He who Hesitates Shall Inherit the Earth!" Quote Share this post Link to post Share on other sites
Hooknswoop 19 #15 December 24, 2003 QuoteHere is that chart! Thanks. I guess the best way to go would be to measure all canopies the same way aircraft manufacturers measure their wings. I would guess that there is only one way to measure an aircraft wing and all manufacturers use the same method. Derek Quote Share this post Link to post Share on other sites
pilotdave 0 #16 December 24, 2003 Well, probably not. For coefficient of lift calculations, the area of the wing blocked by the fuselage is included in the calculations. But for other calculations (like the wetted area for drag calculations), that area is not included. And I'd be willing to bet different manufacturers estimate that "fake" area of the wing differently. Wouldn't surprise me if dihedral factored in differently too. There's probably a lot of standardization in the big airplane world, but I bet there's very little in the general aviation world. But I could be wrong. Dave Quote Share this post Link to post Share on other sites
divnswoop 0 #17 December 24, 2003 QuoteIt can cause problems..I know a guy that had a Sabre 170 and he wanted to downsize. So he went and got a Safire 149. The problem is the Safire 149 is really about a 135. He had no idea that canopies were measured differently, in fact most jumpers at the DZ didn't know till after this guy broke his leg. So did the canopy break his leg? Or was it the poor decision/guidance of both downsizing the canopy AND going to a elliptical/higher performance canopy. Everybody downsizing should proceed in small single steps. If you switch to a different wing w/ different flight responses, you should maybe think about keeping the same size or even go up. I do agree with you that there should be a standard. However with all the different canopies(square,ellip,crossbraced,airlocks) actual square footage should just a piece of your decision. Shawn Quote Share this post Link to post Share on other sites
johnny1488 1 #18 December 24, 2003 I would wonder about any accuracy of that chart. It list a safire,omega and a vx all as the same size as they are listed. We all know the safire and omega are smaller than they are labeled. I wonder if they actually measured anything or just took info from some other source. Not saying anything is right or wrong, just stirring the pot, I guess. Johnny --"This ain't no book club, we're all gonna die!" Mike Rome Quote Share this post Link to post Share on other sites
Hooknswoop 19 #19 December 24, 2003 QuoteI would wonder about any accuracy of that chart. It list a safire,omega and a vx all as the same size as they are listed Some of the numbers come from the manufacturer and some from canopies PIA has measured. I think the sq. ft. #'s in bold are from the manufacturer. Derek Quote Share this post Link to post Share on other sites
Ron 10 #20 December 26, 2003 QuoteSo did the canopy break his leg? Or was it the poor decision/guidance of both downsizing the canopy AND going to a elliptical/higher performance canopy. Well it is clear it was lack of flying the canopy... However, he might have been fine under a 150 sized elliptical. Several people thought he would be fine under a elliptical 150. However a Safire 149 is not 150. So he went from a square 170 to an elliptical 135. The large jump in size I think was the major factor. No one would have told him he should go from a 170 to an elliptical 135. But due to the sizing differences...Thats what happened."No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334 Quote Share this post Link to post Share on other sites
Supergeil 0 #21 December 26, 2003 QuoteQuotea comparison chart is in the back of Para Gear’s catalog. Here is that chart! Did I miss something here.... two from the same company Sabre135 = 143sqft Stilleto150 = 150sqft Daaah whats the meaning of that??? Quote Share this post Link to post Share on other sites
penniless 0 #22 December 26, 2003 QuoteQuotePD can call it whatever they want in my book. I'll find the size I like and buy it!!! It can cause problems..I know a guy that had a Sabre 170 and he wanted to downsize. So he went and got a Safire 149. The problem is the Safire 149 is really about a 135. He had no idea that canopies were measured differently, in fact most jumpers at the DZ didn't know till after this guy broke his leg. See how it can be an issue I discovered the same thing when I borrowed a Safire129. No injuries, but it took me by surprise! Quote Share this post Link to post Share on other sites
cruzlite 0 #23 December 29, 2003 sdctlc, Thanks for the link. Johnny 1488... I agree, it doesn't appear to be 100% accurate... but I believe it has been updated & is better than the last one I downloaded. Thanks to all for input... D Quote Share this post Link to post Share on other sites
rigging65 0 #24 December 29, 2003 Quote3. We are the big kids on the block...you want to all measure the same way...let it be our way. Great...way to be an "industry leader".... PD is the biggest...which should also give them the responsibility to 'do what's right'. If PD is too stubborn to change to a standard developed by others, fine. Then post, in writing, the method that is used for measurement...and stick to using it. Here's a news flash...PD won't do that! It would be bad for business...even if it would be safer for the jumpers. It's been asked of them several times before to reveal their methods for measuring, and you all you get is double talk and smoke and mirrors. Marketing...way to help maintain safety guys.... BTW, the PIA standard was written by Cliff Schmucker, Sandy Reid, George Galloway and others, not by one person. I have heard (but cannot confirm) that there was in-fact a PD representative there as well. I won't reveal whom I have heard it was, as I can't confirm it. PD wouldn't agree with the system put in place, but they helped design it?? I've also been told, by a very reliable source, that PD "wouldn't even touch" the area of standardizing pack volume. That's the way to be an industry leader, all right. You don't want to play by someone elses rules, fine. But at least make the rules available for others so that they can play by them...and make the industry a safer place. Consider it a direct challenge. I want things to be safer for my customers...what do you want? "...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
Ron 10 #25 December 29, 2003 QuoteGreat...way to be an "industry leader".... PD is the biggest...which should also give them the responsibility to 'do what's right'. If PD is too stubborn to change to a standard developed by others, fine. Then post, in writing, the method that is used for measurement...and stick to using it. Here's a news flash...PD won't do that! It would be bad for business...even if it would be safer for the jumpers. It's been asked of them several times before to reveal their methods for measuring, and you all you get is double talk and smoke and mirrors. Marketing...way to help maintain safety guys.... BTW, the PIA standard was written by Cliff Schmucker, Sandy Reid, George Galloway and others, not by one person. I have heard (but cannot confirm) that there was in-fact a PD representative there as well. I won't reveal whom I have heard it was, as I can't confirm it. PD wouldn't agree with the system put in place, but they helped design it?? I've also been told, by a very reliable source, that PD "wouldn't even touch" the area of standardizing pack volume. That's the way to be an industry leader, all right. You don't want to play by someone elses rules, fine. But at least make the rules available for others so that they can play by them...and make the industry a safer place. Never said it was right...Just fact. QuoteConsider it a direct challenge. I want things to be safer for my customers...what do you want? I would think that you know me well enough by now to know I am all about saftey."No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334 Quote Share this post Link to post Share on other sites
