Brodhead Pietenpol Association

Original Posted By: "Jim Markle"
Subject: Pietenpol-List: KevlarI'm thinking of putting a couple layers of Kevlar on the fuselage tank I'm building to offer more safety over a simple fiberglass tank. I read in the Wickscatalog that Kevlar is 2.5 times stronger than E glass, and 10 times stronger than aluminum on a specific tensile strength basis.The problem is I don't want to invest in a pair of $60 scissors that will probably be used one time. Does anybody have any experience in cutting Kevlar with a regular pair of scissors or is there an alternative to the $60 version?Roy________________________________________________________________________________

Original Posted By: Rcaprd(at)aol.com
Subject: Pietenpol-List: KevlarI'm thinking of putting a couple layers of Kevlar on the fuselage tank I'm building to offer more safety over a simple fiberglass tank. I read in theWicks catalog that Kevlar is 2.5 times stronger than E glass, and 10 timesstronger than aluminum on a specific tensile strength basis.The problem is I don't want to invest in a pair of $60 scissors that will probably be used one time. Does anybody have any experience in cuttingKevlar with a regular pair of scissors or is there an alternative to the $60version?Roy________________________________________________________________________________

Original Posted By: Pilots4ETW(at)wmconnect.com
I have experience cutting Kevlar and the scissors are an absolute must.But don't buy any. I have a pair sitting here collecting dust and would be gladto loan them to you.Send me an SASE (and promise that you'll return them!) and you're welcome to borrowthem.If you decide to buy some for yourself, don't buy the $60 ones....get the $26 ones from ACP (http://www.acp-composites.com/acp-ta.htm)Jim MarklePlano, TX214.505.6101 ----- Original Message -----

Original Posted By: "walt evans"

Original Posted By: Pilots4ETW(at)wmconnect.com
Subject: RE: Pietenpol-List: KevlarI've worked a fair amount in the composites industry with Kevlar, so here'smy two cents worth. 1) Don't think Kevlar is gonna give you what you'relooking for in terms of accident damage to your tank over glass, especiallyusing only a couple plies over the glass core, 2) if you impact something,that pokes a hole in your gas tank, you're gonna have a leak whether it'scovered with Kevlar or not, the resin system will shatter and leak at thedamage spot, 3) Kevlar is very hard to work with for two reasons, a: itcuts very difficult therefore needing the special cutting tools, so yougotta shell out the $60+ bucks, b: it has a lot more filaments per towbundle than glass so it consumes more resin per square foot to wet thesebundles out. 3) Kevlar has a tendency to separate from the glass plies. The composites shop folks at Lufthansa used to get new 737/747 enginecowlings from their supplier in the US that had a Kevlar inter-ply toprevent jet engine vanes from shooting thru the cowling into the fuselage. I watched them remove the Kevlar ply, just like peel ply, and toss it away,because subsequent repairs to the cowling wouldn't stick. Kevlar has acouple nice advantages, a) stronger than fiberglass or carbon, b) lighterthan either one.Gordon BowenOriginal Message:-----------------

Original Posted By: Pilots4ETW(at)wmconnect.com
Subject: Re: Pietenpol-List: KevlarIn a message dated 3/11/2005 5:15:56 AM Central Standard Time, Pilots4ETW(at)wmconnect.com writes:I'm thinking of putting a couple layers of Kevlar on the fuselage tank I'm building to offer more safety over a simple fiberglass tank. I read in the Wickscatalog that Kevlar is 2.5 times stronger than E glass, and 10 times stronger than aluminum on a specific tensile strength basis. The problem is I don't want to invest in a pair of $60 scissors that will probably be used one time. Does anybody have any experience in cutting Kevlar with a regular pair of scissors or is there an alternative to the $60 version?Roy & Sterling, I agree with Gordon. I don't think the effort to use Kevlar in with the lay-ups of Fiberglass is worth it. Kevlar is the most abrasion resistant material of all the composite materials...that's why it's used in bullet proofvests. It is a LOT more expensive, hard to cut, difficult to wet out. You'retrying to build 'Crashworthyness' into your plane...much better to build 'Airworthyness' into it. There are two types of Fiberglass: E-glass is used whereelectrical resistance is the requirement, and S-glass is used when strength isthe requirement. Of all the composite materials, Carbon Fiber is the strongest in compression, but offers poorest in abrasion resistance, thereforeeach type of material has it's place in a given design, in addition to the type of resin. I used Omni-direction Kevlar on the leading edge (about 1/2" wide), for 'tipping material', on the 3 props that I've built, because of it's abrasion resistance. Then wrapped the entire blade with one layer of the light weight fiberglass, all the way to the root. I used Polyester Resin (auto body stuff)on the props. Epoxy Resin, such as the 'West System', is the preferred type ofresin for fuel, oil, and chemical resistant applications.Chuck G.________________________________________________________________________________

Original Posted By: "tmbrant1(at)netzero.com"
Subject: Re: Pietenpol-List: KevlarSo, 4 layers of Kevlar over two layers of fiberglass in a fuel tank build up(in a Pietenpol having the fuel tank a few feet away from the pilot, in awooden airplane) does not add any safety? In looking at a search of Kevlar=20fueltanks on the internet, many folks riding pocket rockets (fast motorcycles) areswitching to Kevlar gas tanks so they don't cook their nuts over an open fire.Also, the radio control airplane people are using Kevlar gas tanks so theirexpensive RC airplanes don't cook upon hard landings. And, many law enforcementgroups using Ford Crown Victorias are now using Kevlar so their officersdon't burn if rear ended.Here are some links.https://commerce67.datapipe.com/eraavia ... l.stmEra's EnhancedExternal Auxiliary Fuel Systemfor Bell 412/212/205/UH-1H/V/NTwo externally mounted "Kevlar=C2=AE" fuel tanks providing an additional 140gallons of usable fuel, extending endurance by 1.5 hours meets FAR 29.952 NPRMcrashworthiness criteria.http://www.f1technical.net/article19.htmlFuel tank F1 cars use fuel tanks made from puncture-proof Kevlar. Thisdramatically reduces the risk of any fire during an accident. The tank reshapesitself in the area where any pressure is being put.http://www.benlovejoy.com/concorde/crash.htmlThird, the fuel tanks. The bottom of several of the fuel tanks were linedwith rubber-kevlar shielding, both to reduce the risk of debris reaching thefuel, and to dramatically reduce the rate at which fuel would flow out throughaleak.http://www.amerindustrial.com/article.htmAmer Industrial Technologies Inc., has designed a fire-resistant fuel tanksystem for the Long Island Railroad that will allow tank full of fuel withoutrisking the spill of fuel or fumes in an accident. Ahmad Amer=E2=80=99s=20=E2=80=9Cbullet-proof=E2=80=9Drail-road car, lined by a puncture-resistant bladder made of Du Pont Co.=E2=80=99sKevlar, can carry 500 pounds of fuel and withstand a collision with a load of upto 250,000 pounds. Kevlar is the same material used in making bullet-proofvests. http://www.mustang50magazine.com/roadtests/4288/The cars were shipped from the DAP facility to Mascotech for installation ofthe special custom HD cooling system and the special 20-gallon Kevlar fuelcell. Those who raced the 1993 Cobra R complained of too small a fuel tank,forcing extra fuel stops in endurance races that cost them time and position onthetrack compared to the Camaros.http://www.autosafety.org/article.php?scid141&did813 On Friday, with the cooperation of Ford, Florida state troopers beganinstalling Kevlar-reinforced tubs in their trunks, which are designed to organizeequipment so items don't shoot forward in a crash and puncture the gas tank.________________________________________________________________________________