Date: Thu, 23 Feb 1995 15:35:57 -1000 From: earlyd@flour.ee.byu.edu (David Early) Message-Id: <1995Feb23.183051@flour.ee.byu.edu> Organization: BYU ECEn Dept Subject: Materials was Re: Beginner Kite Making I am about to embark on my first experiment with ripstop nylon and have a couple of questions for the experienced and knowledgeable ones among us. In the local fabric store, they sell a ripstop nylon for about $3.50-$5 a yard in 48" and 60" widths. Now, I am usually one to say "you get what you pay for" but in this case I am wondering if there is anything wrong with using this material. It has no resin coating like sailcloth to stiffen it, but it is strong, thin and light weight. If they only problem with the material is life expectency (i.e. it won't last as long as the "good stuff") then I don't care. Some of my early attempts will be learning experiences and I hate to use $10 a yard material to learn on when the $4 a yard stuff will work just as well. Any insight?? Dave Early earlkyd@newt.ee.byu.edu = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 24 Feb 1995 04:35:39 -1000 From: dickbell@netcom.com (Dick Bell) Message-Id: Organization: NETCOM On-line Communication Services (408 261-4700 guest) Subject: Re: Materials was Re: Beginner Kite Making David Early (earlyd@flour.ee.byu.edu) wrote: : In the local fabric store, they sell a ripstop nylon for about $3.50-$5 a yard Dave, You won't want to build kites with this material. It is very streachy. It does make a good material for making a kite bag though. Thats a bag for a single kite....not a bag for all your kites. :-) -- -------------------------------------------------------------------------------- Dick Bell dickbell@netcom.com Dallas, Texas = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 24 Feb 1995 02:59:41 -1000 From: jburka@Glue.umd.edu (Jeffrey C. Burka) Message-Id: <3ikl7t$pc1@geog20.umd.edu> Organization: Project Glue, University of Maryland, College Park Subject: Re: Materials was Re: Beginner Kite Making In article <1995Feb23.183051@flour.ee.byu.edu>, David Early wrote: >In the local fabric store, they sell a ripstop nylon for about $3.50-$5 a >yard in 48" and 60" widths. Now, I am usually one to say "you get what you >pay for" but in this case I am wondering if there is anything wrong with >using this material. It has no resin coating like sailcloth to stiffen it, >but it is strong, thin and light weight. If they only problem with the >material is life expectency (i.e. it won't last as long as the "good >stuff") then I don't care. Some of my early attempts will be learning >experiences Ripstop nylon is sort of a genre of fabric where the weave is reinforced at regular intervals by extra threads. Most "ripstop" kites are built from a subgenre, spinnaker cloth. Spinnaker cloth, as you've noted, has a coating. This not only stiffens the fabric, but also makes it less porous (I've seen some *ridiculously* porous ripstop). Spinnaker cloth is also a lot less stretchy and is much lighter, weight wise. The fact that the fabric is less stretchy and lighter and less porous means that a spinnaker cloth kite will not only last much better than one made from clothing-grade fabric, but it will also also fly better from the outset. At least, in most cases. I won't deny that there are plenty of kites out there designed to be built from porous fabric or that stetch in fabric can't be taken advantage of. The crispness and lack of stretch tend to make, in my opinion, spinnaker cloth easier to work with and sew than clothing grade ripstop. If you're learning to make kites, why handicap yourself? >I hate to use $10 a yard material to learn on when the $4 a >yard stuff will work just as well. Perhaps you've been paying too much attention to the Into the Wind catalog's prices (cf Marty's recent comments), but there's no need to spend $10/yd on spinnaker cloth. Admittedly, you get less/yd since most fabrics favored by kiters are 41" wide and not 48" or 60", but you can get a good quality spinnaker cloth from Hang 'em High for $5.35 a yd. Icarex polyester, the current 'hot' fabric and the one I find easiest to sew, can be had for $6.99 a yard. And there are other mail order houses with similar prices, such as Kite Studio. Additionally, sometimes you'll find sails where you can get a certain color for a discounted price (particularly at Kite Studio), which would be perfect for learning on. Unfortunately, living in Utah, you're probably nowhere near a sailmaker, but one can often get free scraps from sail makers, and I've made some pretty substantial kites out of nothing but scraps. Good luck with your kite making... Jeff -- |Jeffrey C. Burka | Pithy, insightful quote to be inserted | | | when one occurs to me. *If* one occurs | |jeffy@glue.umd.edu | to me. | = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 24 Feb 1995 16:23:48 -1000 From: cvdunton@pinn.net (Charlie Dunton) Message-Id: <3im40l$t5m@everest.pinn.net> Organization: Pinnacle Online - Internet access for Hampton Roads, Virginia - 498-3889 Subject: Re: Materials was Re: Beginner Kite Making = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 24 Feb 1995 16:23:48 -1000 From: cvdunton@pinn.net (Charlie Dunton) Message-Id: <3im40h$t5m@everest.pinn.net> Organization: Pinnacle Online - Internet access for Hampton Roads, Virginia - 498-3889 Subject: Re: Materials was Re: Beginner Kite Making In article <1995Feb23.183051@flour.ee.byu.edu>, earlyd@flour.ee.byu.edu says... > > >I am about to embark on my first experiment with ripstop nylon >and have a couple of questions for the experienced and knowledgeable >ones among us. > >In the local fabric store, they sell a ripstop nylon for about $3.50-$5 a yard >in 48" and 60" widths. Now, I am usually one to say "you get what you pay for" >but in this case I am wondering if there is anything wrong with using this >material. It has no resin coating like sailcloth to stiffen it, but it is >strong, thin and light weight. If they only problem with the material is life expectency >(i.e. it won't last as long as the "good stuff") then I don't care. Some of my >early attempts will be learning experiences and I hate to use $10 a yard material >to learn on when the $4 a yard stuff will work just as well. > > >Any insight?? > Dave, you are right when you say "you get what you pay for". The coating on sailcloth is important for two main reasons. It reduces the porosity of the fabric which helps most kites fly better, but even more importantly, it locks the weave of the cloth in place, which greatly reduces excessive stretch and distortion when flying. Its also easier to work with when sewing. The nice thing is that in this case you really don't have to pay that much more for the good stuff. Hang-Em High Fabrics is selling a wide variety of colors of sailcloth in both 41" and 54" widths. (Lots of 54" stuff coming in for '95). At $5.35 for the 41" and $6.45 for the 54", it's only a dollar or so more for the good stuff. Hang-Em High can be reached at (804) 233-6155 (Richmond, Va) Disclaimer: I am a good friend of Tom Marvin at H-E H as well as a very satisfied customer, but I feel most everyone on Rec.Kites would agree that Tom runs a first rate business. Charlie --- May you never stand in the shadow of your kite cvdunton@pinn.net = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sun, 26 Feb 1995 19:06:37 -1000 From: lthrall@netcom.com (Jo and Lee) Message-Id: Organization: NETCOM On-line Communication Services (408 261-4700 guest) Subject: Re: Materials was Re: Beginner Kite Making Charlie Dunton (cvdunton@pinn.net) wrote: : In article <1995Feb23.183051@flour.ee.byu.edu>, earlyd@flour.ee.byu.edu says... [snip] : >I am about to embark on my first experiment with ripstop nylon : >and have a couple of questions for the experienced and knowledgeable : >ones among us. : >Any insight?? : [snip again] Hang-Em High Fabrics is selling a : wide variety of colors of sailcloth in both 41" and 54" widths. (Lots of : 54" stuff coming in for '95). At $5.35 for the 41" and $6.45 for the 54", : it's only a dollar or so more for the good stuff. : Hang-Em High can be reached at (804) 233-6155 (Richmond, Va) We agree that Hang-Em High is quite good. You may also want to check with Bill Tyrrell at Kitestuff, phone (215) 348-1744. He sells among other things ripstop "seconds" which have the occasional blemish, imperfection etc but are otherwise high-quality material. The price in the flyer we have is $3.50 per yard for 2-10 yards of 41" wide, a bit more for "hot" colors & wider widths, and the prices go down as you buy more. Check with him for current prices. We have recently purchased some seconds from Bill and the fabric was quite good - some blemishes but small enough to work around easily, and I think suitable for your purposes. Good luck! - Jo. Disclaimer: We personally do not know Tom Marvin at H-E H nor Bill Tyrrell at Kitestuff. Nor would it bother us if either of them posted a message saying "hey I've got ripstop at such-&-such a yard". Nor would it likely bother frank unless it was Dave Gomberg doing the posting :-X -- Joanne Petithory & Lee Thrall lthrall@netcom.com = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Mon, 27 Feb 1995 08:26:30 -1000 From: sasaki@netope.harvard.edu (Marty Sasaki) Message-Id: <3it5gm$phv@netope.harvard.edu> Organization: Harvard University Subject: Re: Materials was Re: Beginner Kite Making In article , lthrall@netcom.com (Jo and Lee) writes: |>Disclaimer: We personally do not know Tom Marvin at H-E H nor Bill Tyrrell |>at Kitestuff. Nor would it bother us if either of them posted a message |>saying "hey I've got ripstop at such-&-such a yard". Nor would it likely |>bother frank unless it was Dave Gomberg doing the posting :-X Is this an advertisement? ;-) I've met both Tom and Bill and they are both terrific people. If you get on the phone and start talking with Bill, he will tell you everything that he knows about a particular subject. Ask him about high flying parafoils some time... ;-) Tom Marvin has one of the best mail order services that I've ever experienced. If he can't put it into the mail to you the next day, he apologizes and will give you realistic delivery times. -- Marty Sasaki Harvard University Sasaki Kite Fabrications sasaki@harvard.edu Network Services Division 90 Melrose Street 617-496-4320 10 Ware Street Arlington, MA 02174 Cambridge, MA 02138-4002 phone/fax: 617-646-1925 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sun, 26 Mar 1995 17:43:46 -1000 From: rmiller@primenet.com (Ray Miller) Message-Id: <3l5c9i$fgo@news.primenet.com> Organization: TEKED of Boise Subject: Re: Materials was Re: Beginner Kite Making In article <1995Feb23.183051@flour.ee.byu.edu>, earlyd@flour.ee.byu.edu (David Early) says: > > >I am about to embark on my first experiment with ripstop nylon >and have a couple of questions for the experienced and knowledgeable >ones among us. > >In the local fabric store, they sell a ripstop nylon for about $3.50-$5 a yard >in 48" and 60" widths. Now, I am usually one to say "you get what you pay for" >but in this case I am wondering if there is anything wrong with using this >material. It has no resin coating like sailcloth to stiffen it, but it is >strong, thin and light weight. If they only problem with the material is life expectency >(i.e. it won't last as long as the "good stuff") then I don't care. Some of my >early attempts will be learning experiences and I hate to use $10 a yard material >to learn on when the $4 a yard stuff will work just as well. > > >Any insight?? > > >Dave Early >earlkyd@newt.ee.byu.edu > > You got that right! You do get what you pay for.... However, to what use are you going to put the fabric? If you are going to build light, durable single-line deltas, or some such, taffeta (sp?) or fabric store 3/4 oz. ripstop nylon will do nicely. But, if you desire to build stunt kites that are resistant to stretch and deformity, you had better stick to the coated ripstop. You see, the resin has two purposes, to aid in preventing the deformity of the weave and stretching, and to lessen the porosity of the cloth. As you probably already know, if you hold a piece of ripstop nylon over your mouth and try to blow through it, you cannot if it is cloth that has been coated on both sides. This is 0-porosity - particu- larly good for stunt kites. The rest is self-explanitory. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Tue, 28 Mar 1995 08:38:20 -1000 From: andrew@tug.com (Andrew Beattie) Message-Id: Organization: /usr/lib/news/organisation Subject: Re: Materials was Re: Beginner Kite Making rmiller@primenet.com (Ray Miller) writes: >As you probably already know, if you hold a piece of ripstop >nylon over your mouth and try to blow through it, you cannot if it is >cloth that has been coated on both sides. Like they say... don't try this at home kids... :-) I agree with Ray, but if you read Buggies, Boats & Peels, you'll learn about an old Peel, which flew fine despite the fact that you could easily breath through the skin! Andrew -- New to rec.kites? START HERE! | To: www@kfs.org send an email message like this->| Subject: service | http://www.kfs.org/kites/welcome/index.html echo '/Frank Kenisky/f:j' >> $HOME/News/rec/kites/KILL # *PLONK* = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Tue, 28 Mar 1995 18:05:13 -1000 From: lord@eskimo.com (David Lord) Message-Id: Organization: Eskimo North (206) For-Ever Subject: Re: Materials was Re: Beginner Kite Making In article andrew@tug.com (Andrew Beattie) writes: >From: andrew@tug.com (Andrew Beattie) >Subject: Re: Materials was Re: Beginner Kite Making >Date: Tue, 28 Mar 1995 18:38:20 GMT >rmiller@primenet.com (Ray Miller) writes: >>As you probably already know, if you hold a piece of ripstop >>nylon over your mouth and try to blow through it, you cannot if it is >>cloth that has been coated on both sides. >Like they say... don't try this at home kids... :-) >I agree with Ray, but if you read Buggies, Boats & Peels, you'll learn >about an old Peel, which flew fine despite the fact that you could easily >breath through the skin! For a peel which relies mostly on Bernoulli lift if you can maintain its aero shape then the porosity should not matter much. However for a stunter or most single line kites this is not the case. They rely more on reaction of the wind impinging on the front surface of the kite. Porosity means loss of some of this reaction force and loss of performance. Everybody always thinks of a kite as an airplane wing in a steady state condition(except Sasaki thankfully) and attempts to analyze as such. The closest we ever come to such a condition is while buggying on a reach with the kite parked with relation to the buggy. Then the kite is pretty much performing as a wing under steady state conditions. Dave Lord lord@eskimo.com http://www.eskimo.com/~lord = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Wed, 29 Mar 1995 10:45:49 -1000 From: sasaki@netopd.harvard.edu (Marty Sasaki) Message-Id: <3lcgtt$jjd@netope.harvard.edu> Organization: Harvard OIT Network Services Subject: Re: Materials was Re: Beginner Kite Making In article , lord@eskimo.com (David Lord) writes: |>For a peel which relies mostly on Bernoulli lift if you can maintain its aero |>shape then the porosity should not matter much. However for a stunter or most |>single line kites this is not the case. They rely more on reaction of the wind |>impinging on the front surface of the kite. Actually, this is incorrect. There are two types of lift, one is Bernoulli, and the other I will call "plate lift". It has another term, but I don't remember what it is. Bernoulli lift is the result of pressure imbalance between the "top" and "bottom" of an airfoil. Plate lift is due to air particles hitting the surface the momentum of the particles is translated into lift. Someone who designs fighter jets told me that plate lift effects are almost zero except at trans- and super-sonic velocities at low pressure/high altitudes. Kites almost always operate at sub-sonic velocities where Bernoulli lift dominates. I'm not sure, technically, why porosity means a loss of lift except that the airflow around/through a foil that is porous is "complex". This reminds me of a discussion that I had with Lee Hetherington. Most of the time, all of this discussion about efficiency and enhanced lift is moot (ignoring traction and lifting applications). Most of the time the forces involved are large enough that we can tolerate very inefficient airfoils and such. High(er) efficiency considerations become important as the wind drops and the materials used result in a fragile kite. Getting back to the issue of materials, ever notice that red fabric is more wind porous than other colors? This is most noticeable in ripstop nylon and not noticeable with Icarex. All red hot air balloons are larger to compensate for this. I don't why this happens but have been testing fabric ever since I heard this and it has been largely true... Porousity is not a bad thing. The best flying single line delta that I've ever made was made from a cotton/polyester bed sheet. It required a little more wind, but in 10 mph it was rock solid and flew at a high angle. I've been tempted to make stunt kites out of bed sheets. This should work well in high wind where you want a kite that flies slower with less pull... -- Marty Sasaki Harvard University Sasaki Kite Fabrications sasaki@noc.harvard.edu Network Services Division 26 Green Street 617-496-4320 10 Ware Street Jamaica Plain, MA 02130 Cambridge, MA 02138-4002 phone/fax: 617-522-8546 = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Thu, 30 Mar 1995 08:50:10 -1000 From: salanne@convex.csc.FI (Simo Salanne) Message-Id: <3leuh2$sim@pobox.csc.fi> Organization: STACK Finland Subject: Re: Materials was Re: Beginner Kite Making In <1995Mar30.150003.27346@ericsson.se> era_pul@ki.ericsson.se (Peter Ulfheden) writes: >Andrew Beattie (andrew@tug.com) wrote: >: In article lord@eskimo.com (David Lord) writes: >: >>about an old Peel, which flew fine despite the fact that you could easily >: >>breath through the skin! >: > >: >For a peel which relies mostly on Bernoulli lift if you can maintain its aero >: >shape then the porosity should not matter much. >: Except that I'd kinda rely on the non-porosity to keep the air-pressure in the >: bag. The Peels are optimised, such that a mere 10reduction of the vent on a >: big Peel will lead to inflation problems, on an zero-porosity Icarex Peel, yet >: we get the experience described above. I don't get it... >Couldn't it be that the leakage of air through the >seams is of greater effect than porosity? As you know, Andrew has a habit to soak his Peel in sea water making the thread swell and fill the needle holes;-) Simo -- Simo.Salanne@csc.fi STACK Finland ==================================================================== Are you familiar with Kite Flyers Web Site? http://www.kfs.org/kites = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Thu, 30 Mar 1995 12:54:50 -1000 From: hayden1009@aol.com (Hayden1009) Message-Id: <3lfcrq$85t@newsbf02.news.aol.com> Organization: America Online, Inc. (1-800-827-6364) Subject: Re: Materials was Re: Beginner Kite Making Marty Sasaki wrote: >Getting back to the issue of materials, ever notice that red fabric is >more wind porous than other colors? I have noticed that with embroidery floss or wools that the same "weight" threads actually have different thicknesses. Some colors are heavier than other, even across fibers. I just assumed that the chemicals used to create some colours were either heavier, or the chemicals for others actually eat the fibers a bit. Alice Hayden 8^) = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 31 Mar 1995 11:45:18 -1000 From: lord@eskimo.com (David Lord) Message-Id: Organization: Eskimo North (206) For-Ever Subject: Re: Materials was Re: Beginner Kite Making In article <3lcgtt$jjd@netope.harvard.edu> sasaki@netopd.harvard.edu (Marty Sasaki) writes: >From: sasaki@netopd.harvard.edu (Marty Sasaki) >Subject: Re: Materials was Re: Beginner Kite Making >Date: 29 Mar 1995 20:45:49 GMT >In article , lord@eskimo.com (David Lord) writes: >|>For a peel which relies mostly on Bernoulli lift if you can maintain its aero >|>shape then the porosity should not matter much. However for a stunter or most >|>single line kites this is not the case. They rely more on reaction of the wind >|>impinging on the front surface of the kite. >Actually, this is incorrect. There are two types of lift, one is >Bernoulli, and the other I will call "plate lift". It has another >term, but I don't remember what it is. Bernoulli lift is the result of >pressure imbalance between the "top" and "bottom" of an airfoil. Plate >lift is due to air particles hitting the surface the momentum of the >particles is translated into lift. >Someone who designs fighter jets told me that plate lift effects are >almost zero except at trans- and super-sonic velocities at low >pressure/high altitudes. >Kites almost always operate at sub-sonic velocities where Bernoulli >lift dominates. >I'm not sure, technically, why porosity means a loss of lift except >that the airflow around/through a foil that is porous is "complex". Marty I seldom have any disagreements with what you post, but there always comes an exception. Consider a stunt kite at the moment of launch with as yet no forward velocity. The angle of the sail to the wind is such that the kite is way into total stall and there is for practical purposes no Bernoulli lift generated. Plate lift is what makes the kite move, and untill its velocity increases to the point the apparent wind vector has rotated to an angle that is below stall there is very little if any Bernoulli lift. Also consider a single line kitesuch as a Rok. Although I have not measured the angle at which they fly they look to have a large angle to the wind and their shape is about as poor an airfoil as you could want. My opinion is that they rely mostly on plate lift. Most single surface kites are the poorest of airfoils. One needs a path differential to generate the higher velocity air that results in lower pressure on the upper surface. I suspect that due to the low renyolds numbers encountered on kites that Bernoulli lift comes from separation bibbles that create a virtual surface. I have built kites with curved battens to shape the sail, with most of the camber very close to the leading edge. This was done to encourage a separation bubble to form just behind the leading edge spar on the lower surface to create a thick virtual airfoil. This kite flew similar to a flexifoil in that it was sluggish to launch, and pull increased at a very high rate as it accelerated. The reason the initial plate lift was not as effective was that the sail was not reflexed so the bridle setting had to be abnormally low to counteract the pitching moment once the kite accelerated. For jets I agree that plate lift does not amount to much, but they are very dense and are not in a stalled condition. This is true for almost any airplane I know about, even the lightest operate at wing loadings several times that of a kite and they are designed with proper airfoil wings. Plate lift can only lift relatively light objects like kites. Of course if you increase the energy in the wind like during a hurricane larger objects can be lifted. For a foil the reason porosity would not be a serious factor, provided it was low enough that inflation was not compromised, is that for lower surface higher pressure air to migrate to the lower pressure upper surface it would have to pass through two layers of pourous cloth with very little pressure differential across the first layer. Granted that leakage from inside to the upper surface should cause some decrease in lift even if it was supplied from the vents. Dave Lord = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 31 Mar 1995 10:59:39 -1000 From: lord@eskimo.com (David Lord) Message-Id: Organization: Eskimo North (206) For-Ever Subject: Re: Materials was Re: Beginner Kite Making In article andrew@tug.com (Andrew Beattie) writes: >From: andrew@tug.com (Andrew Beattie) >Subject: Re: Materials was Re: Beginner Kite Making >Date: Thu, 30 Mar 1995 05:49:23 GMT >In article lord@eskimo.com (David Lord) writes: >>>about an old Peel, which flew fine despite the fact that you could easily >>>breath through the skin! >> >>For a peel which relies mostly on Bernoulli lift if you can maintain its aero >>shape then the porosity should not matter much. >Except that I'd kinda rely on the non-porosity to keep the air-pressure in the >bag. The Peels are optimised, such that a mere 10reduction of the vent on a >big Peel will lead to inflation problems, on an zero-porosity Icarex Peel, yet >we get the experience described above. I don't get it... >Andrew First the leakage due to porosity will be greatest at the highest pressure points, assuming uniform porosity. If porosity is not uniform then it will be greatest where the combination of the two factors are greatest. If porosity is uniform then the leakage air volume would have to exceed 100f the inflation air entering. Further the leakage will constantly decrease as the inflation pressure decreases. One other factor is that the inflation problems caused by too small a vent are likely local problems associated with a tip during a turn and not the total kite envelope. Seems to me there is some room between porosity leakage and inflation problems due to a 10reduction in vent area that allows a leaky kite to perform properly. Dave Lord check out my web page, just added a kite gallery of kites I designed http://www.eskimo.com/~lord = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 31 Mar 1995 19:06:00 -1000 From: johnsen@eskimo.com (Brian Johnsen) Message-Id: Organization: Tethered Airfoil R&D Pty. Ltd.(C)(R)(TM) CD CASS Subject: Re: Materials was Re: Beginner Kite Making In article <3lcgtt$jjd@netope.harvard.edu>, Marty Sasaki wrote: >Getting back to the issue of materials, ever notice that red fabric is >more wind porous than other colors? This is most noticeable in ripstop >nylon and not noticeable with Icarex. All red hot air balloons are >larger to compensate for this. My spin on this would be that red material would have a higher infrared energy transfer. Though that shouldn't affect the size of the balloon. You just have to run more propane through it to keep up with the other colors. Then again, utltraviolet degradation of red plastic materials is a known source of frustration. -- Rollerskate Mechanics Discover Dan Quale Was Married To Benjamin Disrali In Previous Life -- Brian Johnsen johnsen@eskimo.com Seattle, Washington USA = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =