From: "Romulo Augusto" Subject: COZY: Lightlings damage Date: Fri, 16 Oct 1998 21:58:34 -0300 Dear Colleagues, a friend told me about the (low) damages caused by lightnings in composite planes. He said, the damages are not big, but the damages are present. And so, he suggest me glassed along the fuselage and wings strips of copper ( Cu) inside it. he said me, there no necessity to put wires, just stripes, because the intensity of the discharge is big, but short. What you think about? This worry is proceeded? I ask this, because my state has a high incidence of ligthnings and we now about the discharge what appears in the stormscope and our eyes can't see it. Thank you in advance for your inputs! Romulo Augusto da Cruz, Jr., Lt, MD, Cozy Plans SN #730 Office: Rua da Bahia 1345/1103 Lourdes, Status: Pre-building Belo Horizonte, MG , Brasil Phones: 55-31-274-5667, 55-31-497-2080 , 55-31-954-9478 Romulojr@brhs.com.br , Cozybuilder@yahoo.com Date: Sat, 17 Oct 1998 10:31:35 -0400 From: "Marc J. Zeitlin" Subject: Fwd: COZY: Lightlings damage Romulo Augusto writes; >a friend told me about the (low) damages caused by lightnings in composite >planes. He said, the damages are not big, but the damages are present. Actually, the damage can be tremendous, because the energy does not get dissapated, but concentrates in the area of the strike. In composites, lighning strikes tend to lead to explosive deconstruction of the strike area. Not good. >And so, he suggest me glassed along the fuselage and wings strips of copper >( Cu) inside it. he said me, there no necessity to put wires, just stripes, >because the intensity of the discharge is big, but short. Glasair did a bunch of testing, and it involved a lot more than this - the whole skin needs to be saturated with conductive material, which in fact does have to be connected together. AFAIK, it also didn't make a whole lot of difference - I don't think they're offering it as an option to their kits, and it was extremely expensive, as well as heavy. Remember, even metal planes get damaged by lightning strikes. >What you think about? This worry is proceeded? >I ask this, because my state has a high incidence of ligthnings and we now >about the discharge what appears in the stormscope and our eyes can't see >it. We've had discussions about this in the past (I'm sure the archives have something) and to me, the right answer is just to stay away from thunderstorms and lightning altogether. If you fly in T-storm areas a lot, get a strikefinder and/or a stormscope. Even if you HAD some lightning protection that worked somewhat, this would still be the right answer. -- Marc J. Zeitlin               marcz@ultranet.com 3 Sweetbriar Way              http://www.ultranet.com/~marcz/ Acton, MA  01720              http://cozy.canard.com/ From: cdenk@ix.netcom.com Date: Sun, 18 Oct 1998 20:59:45 -0500 (CDT) Subject: Re: COZY: Lightlings damage A bigger issue is turbulence, wind shear, and microbursts. These are all excellent reasons to give Thunder storms plenty of clearance. I have one (among others) rule that I never break. On departure, if I can't get to clear air with execellent (40 miles or better) visibility at 10,000' or more, and then maintain that if there is any slightest hint of thunder along the route, ITS A NO GO!!! Just prior to departure, its either checking the radar and surface observations my self, or an extensive discussion with an official briefer, and and pilots that have just landed. It took several less than ideal happenings to back off my own limits, including a microburst Norheast of Atlanta in the area of 2000' MSL towers where we were taken from 3000' to 2000', and a 90 degree turn at 200 mph. The controllers comment was "Some ride eh" That was on a vector supposedly around some level 2 and 3 storms that took us over Athens, Ga. instead of from Chattanooga, Tenn. to Rome, Ga., probably 80 miles out of our way. The COzy is a fine long haul machine, but its not a jet or turbo with all the neat things to penatrate all weather. The strike finders and stormscopes are not cheap and not light weight either. From: "Romulo Augusto" Subject: Re: COZY: Lightning damage Date: Mon, 19 Oct 1998 13:24:19 -0200 Dear Marc, Wayne, Nat and all, I ask my friend again about the lightnings damage explanation and he said me, when the plane is a condutor (good or bad), the sector where the ligthining uses like a ground pole will explodes really. He explains me, when (in the time ago) he told me about the low damages, he was talking about the effects of lightinings in flight, concerned to "rats, mice ways" in the surface of the composite. But, if the discharge reach a point with right eletrical resistence, this local will be carbonized, what will reduces the eletrical resistance at this point. Ok, this was what my friend said. I ask so, if this is true, the composite is all high eletric resistent, and this is the point of my question, would have more or less risk of damage, when in comparision with the full metal airplanes? When I was in the Air Force, once time in the FL190, the canopy of the jet what I was a passenger turns green and flashing, like a neon light. We on board didn't feel nothing. Is necessary a high voltage to cause that effect. Almost a lightning. This could affect the composite stuff? Ok, I just want my plane ( and me) safe. I hate explosive delaminations, firstly if I would be on board... :-) Best Regards. Romulo Augusto. -----Mensagem original----- De: L. Wayne Hicks Para: Cozy Builders Mailing List Data: Segunda-feira, 19 de Outubro de 1998 11:05 Assunto: RE: COZY: Lightning damage > > >-----Original Message----- >From: Marc J. Zeitlin [SMTP:marcz@ultranet.com] >Sent: Saturday, October 17, 1998 10:32 AM >To: Cozy Builders Mailing List >Subject: Fwd: COZY: Lightlings damage > >Romulo Augusto writes; > >>a friend told me about the (low) damages caused by lightnings in composite >>planes. He said, the damages are not big, but the damages are present. > > > >We've had discussions about this in the past, the right answer is just to >stay away from >thunderstorms and lightning altogether. > >Marc J. > >[L. Wayne Hicks] Any of you who've read Dick Kriedel's account of his >lightning strike will shudder at the mere thought of this subject. He is >indeed lucky to be alive. If you've seen any of NASA's lightning strike >tests conducted on composite structures in a laboratory environment, you'd >stay as far away from CB as possible. The composite literally exploded. > Besides, it won't be the lightning that'll kill you first... it'll be the >severe updrafts/downdrafts followed by hail going through your windscreen. > Oh, don't forget about the ice, too. Shall I go on? > Date: Fri, 23 Oct 1998 19:07:26 -0500 From: Bulent Aliev Subject: COZY: Lightning and Carbon Fiber I would like to share few actual cases of carbon fiber composites, struck by lightening. The last one was tonight on the evening TV news. Middle aged lady was golfing in FL during approaching thunder storm and got hit by lightening. She survived with about 70% permanent loss of hearing, burns etc. The golf club made of carbon fiber exploded and looks like she was holding horse tail in her hand, with the rubber handle intact. Two years ago a large racing fiberglass sailboat was built with carbon fiber stringers for stiffness. Year late was hit by lightning and the hull survived, except the stringers also exploded and looked like the golf club I saw on the news. I know few more cases identical to the ones above. So when I read about builders that are tempted all the time to sneak few carbon fiber lay ups here and there in their airplanes, I wander if it is worth the risk? Waiting for the flame throwers : ) Regards Bulent