From: To: Subject: KRnet Digest, Vol 96, Issue 1 Date: Monday, July 14, 2003 11:08 AM Send KRnet mailing list submissions to krnet@mylist.net To subscribe or unsubscribe via the World Wide Web, visit http://mylist.net/listinfo/krnet or, via email, send a message with subject or body 'help' to krnet-request@mylist.net You can reach the person managing the list at krnet-owner@mylist.net When replying, please edit your Subject line so it is more specific than "Re: Contents of KRnet digest..." Today's Topics: 1. Plywood vs composite skins (Larry A Capps) 2. Re: Plywood vs composite skins 3. Re: KR2 / s Photo request (Phil Matheson) 4. Appoligies (ROBERT COOPER) 5. Re: Timing 6. Re: Appoligies (Dana Overall) 7. plywood vs. composite 8. Re: My KR2S (Brian Kraut) 9. Re: Pin holes (Brian Kraut) 10. Re: My KR2S (Justin) 11. RE: Timing (Norman Stapelberg) 12. My KR2S 13. Re: My KR2S (Dan Heath) 14. Re: Pin holes 15. RE: ballistic chute (SPRAGUE, DONALD E. (JSC-SD) (KS)) 16. Boat fiberglass or plywood skins (Robert Stone) ---------------------------------------------------------------------- Date: Sun, 13 Jul 2003 15:22:54 -0500 From: "Larry A Capps" To: "'KR builders and pilots'" Subject: KR>Plywood vs composite skins Message-ID: <000701c3497c$8ae93ee0$0400a8c0@schpankme> In-Reply-To: <000901c349b8$24126020$61d91818@computer> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 1 There is absolutely no reason for building a "Composite Fuselage" version of the KR and including the 5/8" square spruce used to constructed the KR fuselage sides/top/bottom. In a composite fuselage, except for a top longeron (running from firewall to TE of wing), the 5/8" square spruce would be nothing more than weight and additional work. Beam me up Scotty, Larry A Capps KR Newsletter Naperville, IL -----Original Message----- You are incorrect by you saying it is hanging on by the foam. I am making it to where the wood and fiberglass having full contact the entire fuselage which it will be doing the same work as the plywood. ------------------------------ Date: Sun, 13 Jul 2003 17:19:06 EDT From: Ronevogt@aol.com To: krnet@mylist.net Subject: Re: KR>Plywood vs composite skins Message-ID: Content-Type: text/plain; charset="ISO-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 2 Netters; I would like to respond to the statement made regarding plywood. =A0 "I= f=20 you think about it, when you hang 150+ lbs on the firewall, the fuselage sid= es=20 between the engine and the landing gear take a lot of stress.=A0 The top=20 longerons are being stretched (tension), and the bottom ones are trying to b= uckle..." A few years ago, I flew out to Victorville, Ca., to check out a KR-2=20 that was being parted out. I thought that maybe I could get a deal on some=20 parts. The airplane had about 50 hours on it, and was flying behind a Revma= ster. =20 After buying the airplane from the original builder, the new owner took it u= p=20 for his first flight. On landing, the gear collapsed and the airplane broke= =20 in half...right in front of the main spar. Imagine if that would have happe= ned=20 if he was still in the air. (The part about it breaking in half, not the=20 gear collapse). There would be one more black eye for homebuilders and KRs.= =20 Indeed, the area between the front spar and the firewall undergoes a tremend= ous=20 amount of stress, as indicated by where the airplane broke when the gear=20 collapsed. After seeing that, I went home and installed birch plywood on th= e=20 interior of my airplane between the front spar and the firewall. In additio= n to the=20 added strength, I plan to avoid bad landings. =20 RV=20 ------------------------------ Date: Mon, 14 Jul 2003 08:01:29 +1000 From: "Phil Matheson" To: "KR builders and pilots" Subject: Re: KR> KR2 / s Photo request Message-ID: <003601c3498a$50f1e350$3597dccb@Office> References: <3F0F3EF3.95B59753@ns.sympatico.ca><00bf01c347fb$f17c1470$91d598c8@OSWALDO> <003001c34881$b0dd9ac0$ba21f218@hot.rr.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 3 Thanks to Daniel R Heath, I'm looking for a nice photo of a KR2 or KRs to go onto the VW Engine Centre and homebuilt-aviation web page in Australia. If you have a photo of a KR that you would allow to be used on a web page ( Check out the sites listed below ) could you send them to me with you approval to use them and I will sent them to Ron Slender, Or if you have any more comments about the webs sites, contact Ron Slender directly. Many thanks. Phil Matheson matheson@dodo.com.au VH-PKR ( reserved) 61 3 58833588 See our VW Engines and Home built web page at http://www.vw-engines.com/ www.homebuilt-aviation.com/ ------------------------------ Date: Sun, 13 Jul 2003 18:13:11 -0400 From: "ROBERT COOPER" To: "krnet" Subject: KR>Appoligies Message-ID: Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 4 If I offended anyone, especially Mark or Dana with my remark about Dana = finishing his airplane before Mark, I sincerely apologize. I have = nothing but the highest regard for Dana and Mark both as gentlemen and = craftsmen. My comment was made in jest and was not meant to offend. Jack Cooper mailto:kr2cooper@msn.com http://www.jackandsandycooper.com/kr2 Fayetteville, NC. From n56ml@hiwaay.net Sun Jul 13 15:27:51 2003 Received: from ant.hiwaay.net ([216.180.54.10] helo=mail.hiwaay.net) by lizard.esosoft.net with esmtp (Exim 3.36 #1) id 19bpJu-0003nz-00 for krnet@mylist.net; Sun, 13 Jul 2003 15:27:50 -0700 Received: from basement (user-24-214-88-148.knology.net [24.214.88.148]) by mail.hiwaay.net (8.12.9/8.12.9) with SMTP id h6DMRMYG914165 for ; Sun, 13 Jul 2003 17:27:23 -0500 (CDT) Message-ID: <005601c3498e$09810560$1202a8c0@basement> From: "Mark Langford" To: "KR builders and pilots" References: Subject: Re: KR>Appoligies Date: Sun, 13 Jul 2003 17:28:08 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-BeenThere: krnet@mylist.net X-Mailman-Version: 2.1b3 Precedence: list Reply-To: KR builders and pilots List-Id: KR builders and pilots List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Help: No problem at all, Jack. I've got pretty thick skin, and besides, I missed it completely if that could have been taken in some negative way. I've decided I'm going to finish when I finish, and nothing anybody can do or say will make it happen any faster! Doing body work, running the oil system plumbing, and hooking up some wires... Mark Langford, Huntsville, AL N56ML "at" hiwaay.net see KR2S project at http://home.hiwaay.net/~langford ----- Original Message ----- From: "ROBERT COOPER" To: "krnet" Sent: Sunday, July 13, 2003 5:13 PM Subject: KR>Appoligies > If I offended anyone, especially Mark or Dana with my remark about Dana finishing his airplane before Mark, I sincerely apologize. I have nothing but the highest regard for Dana and Mark both as gentlemen and craftsmen. My comment was made in jest and was not meant to offend. > > Jack Cooper > mailto:kr2cooper@msn.com > http://www.jackandsandycooper.com/kr2 > Fayetteville, NC. _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html > ------------------------------ Date: Sun, 13 Jul 2003 19:23:03 EDT From: AviationMech@aol.com To: krnet@mylist.net Subject: Re: KR>Timing Message-ID: <29.44465eab.2c4343d7@aol.com> Content-Type: text/plain; charset="US-ASCII" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 5 In a message dated 7/12/2003 6:26:28 AM Eastern Daylight Time, bonzabay@netactive.co.za writes: > What static revs should I try for using I have both a 2000 and a 2300 type IV and have operated them both behind the same 52X52 prop. They both turned the same static RPM of 3000. The difference seems to have to do with deck height and resultant compression ratio. My 2000 has more balls pre CC. I concur with Mark on the timing question and would add that RPM is "You'll get whatever the engine can pull" with that prop. The smaller the pitch, the more RPM. I would guess you may hit your target. I'm interested to hear your results, I would like to get more RPM out of mine. ------------------------------ Date: Sun, 13 Jul 2003 19:23:44 -0400 From: "Dana Overall" To: krnet@mylist.net Subject: Re: KR>Appoligies Message-ID: Content-Type: text/plain; format=flowed MIME-Version: 1.0 Precedence: list Message: 6 Hey Jack, I knew you were kidding also. Not a problem here and I was sure, as Mark said in his post, there wasn't a problem on his end. The one good thing is I'm betting you will see both of these planes at next years KR Gathering............course you might make me park in the grass with the other metal "rattle cans". Dana Overall 1999 & 2000 National KR Gathering host Richmond, KY RV-7 slider/fuselage Finish kit ordered!! Buying Instruments http://rvflying.tripod.com do not archive _________________________________________________________________ MSN 8 with e-mail virus protection service: 2 months FREE* http://join.msn.com/?page=features/virus ------------------------------ Date: Sun, 13 Jul 2003 20:44:58 -0400 From: To: krnet@mylist.net Subject: KR>plywood vs. composite Message-ID: Content-Type: text/plain; charset="ISO-8859-1"; format="flowed" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: list Message: 7 Sent once I'll try again. The decision to build a KR was long in the making. Followed Mark Langfords work since he put in on the net. The KR is proven, strong, fast, and affordable. The KR does lend itself for mods but lets be smart. I am building to plans execpt a corvair with the new wings (which have flown) Making Major structural changes brings danger to the pilot and THOSE ON THE GROUND. When a KR registered as a KR goes down, the crash is listed as a KR. Those making mojor changes should seek registering the plane as a totally new design. I am proud to be building a KR. One that will fly. Steven Phillabaum Auburn, AL ------------------------------ Date: Sun, 13 Jul 2003 21:12:11 -0400 From: Brian Kraut To: KR builders and pilots Subject: Re: KR>My KR2S Message-ID: <3F12036B.1050702@earthlink.net> References: <002901c347ba$91bc9410$61d91818@computer><3F0F131A.000001.01936@Computer> <001d01c34807$0c67b540$61d91818@computer> <003c01c34887$0e29c870$1202a8c0@basement> Content-Type: text/plain; charset=us-ascii; format=flowed MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 8 I agree and add the following. 1/8" plywood is 12 pounds for a 4 X 8 ft sheet.. I haven't measured, but I don't think there is more than 18 pounds of plywood in the whole KR. There really isn't any weight to save here The biggest problem with glass is that it will need to be so thick to get the buckling resistance you need that it will weigh at least as much as the wood. Glass does have good tensile strength, but very low buckling and torsional strength for an equivalent weight. Quoting some excerpts from Low Power Laminar Aircraft Structures by Alex Strojnik, "Plywood is the single most efficient aircraft material we know. It combines the highest shearing/buckling resistance with the lowest density. ... In an extensive study, directed at analysing the suitability of material for structural stressed skins several years ago, A. Puck (Some Examples of the Design and Construction of Highly Loaded Sailplane Parts in FRP, OSTIV Publication 1960) came to the conclusion that while theoretically the bidirectional fiberglass fabric + epoxy offer the highest shearing strength for the weight -today this honor would go to carbon fiber- it is the plywood that possesses the highest resistance (shearing and torsion) against wrinkling. By far." Now if you did a sandwich construction with foam between the stringers and glass on both sides you would increase the buckling and bending strength a lot, but you would need something other than urethane foam because the glass will tend to tear off of the foam under bending , torsion, and buckling loads. You would need to use a higher density, and heavier, core. You will probably have a finished weight more than with the plywood by the time you are done, and by the time you load it up with fillers to get it as smooth and flat as the plywood it will certainly be a lot heavier and take you three times as long. Sorry to disagree with you Justin, these are just my two cents. Good luck with your project and keep us posted. Mark Langford wrote: >Justin wrote: > >>I dont feel that plywood is a good choice. I know it is proven for many >>years but why not make it stronger and most likley lighter using >> >fiberglass > >>to get a perfect smooth finsh? It's not as if im changing the airframe to >>accept the fiberglass, it is still a stock KR2S airframe unlike the other >>fiberglass boats which make complex shapes. >> > >So, there have been something like 1500 of these built, and not ONE of them >has ever had the plywood mysteriously sheer off and create a crash, but you >don't think it's good enough? The plywood isn't there just to keep the wind >out. It's an integral part of the structure. If nothing else, it acts as a >gusset. > >> It's actually not much work to use this fiberglass skinning. I draw on >>the foam and cut it out, it will take me about an hour to do the whole >>fuselage and then applying the glass (2 people) will be about another >> >hour > >>X 2 (inside and out). Sanding the foam will take a few hours. >> > >I think you're seriously mistaken here. It can't get any easier to finish >something than plywood is. You start with a smooth, flat surface, that >really only requires a little sealer and fine sanding and it's ready for >primer and paint. You must not have had much experience with fiberglass, >but the surface will be far from straight, and the pinholes will eat your >lunch trying to fill them all. My guess is it'd take at least three times >more effort to skin it with fiberglass then with plywood., and the strength >is still in serious doubt... > >Mark Langford, Huntsville, AL >N56ML "at" hiwaay.net >see KR2S project at http://home.hiwaay.net/~langford > > > >_______________________________________________ >see KRnet list details at http://www.krnet.org/instructions.html > ------------------------------ Date: Sun, 13 Jul 2003 21:21:52 -0400 From: Brian Kraut To: KR builders and pilots Subject: Re: KR>Pin holes Message-ID: <3F1205B0.1040403@earthlink.net> References: <001501c34958$82910e40$ba21f218@hot.rr.com> Content-Type: text/plain; charset=windows-1252; format=flowed MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 9 I have done a few repairs and I usually put vacuum bagging film over=20 them or sometimes just tape right over a small repair with plastic=20 packing tape. There is almost no sanding to do when you do that. The=20 only disadvantage I can see is that you wind up with resin filling the=20 weave on the top instead of squeeging out the excess and later filling=20 with micro or something lighter than pure resin. Robert Stone wrote: >Netters, > I don't understand all the talk about pin holes being such a proble= m. When I built the KR-1 and KR-2 years ago (l977) after laying up fibe= rglass and resin we covered the entire surface with a piece of cordite sp= rayed with mold release. This is kind of like cling wrap only thicker. W= hen it was dry and the cling wrap removed the surface was so smooth that = very little sanding was required. After minimal sanding a coat of feathe= r fill was applied and sanded. Feather fill sands out very easy to a sur= face smooth as a shirt button. There were a few pin holes of course but = there was also a product like bondo that came in a tube like tooth paste.= each pin hole got a finger dab of this paste and then final sanding rea= dy for sealer and paint. The finish was so good on our KR-2, we won the = best composite prize at the Chino Airport EAA Fly-in in 1977. One of the= judges told me that their final decision was biased on the beautiful fin= ish. There are much better products on the market today than Feather fil= l and bondo so I just don't see pin holes being that big a problem. > >Bob Stone, Harker Heights, TX >rstone4@hot.rr.com_______________________________________________ >see KRnet list details at http://www.krnet.org/instructions.html > ------------------------------ Date: Mon, 14 Jul 2003 09:07:56 -0500 From: "Justin" To: , "KR builders and pilots" Subject: Re: KR>My KR2S Message-ID: <001d01c34a11$5363ba50$61d91818@computer> References: <002901c347ba$91bc9410$61d91818@computer> <3F0F131A.000001.01936@Computer> <001d01c34807$0c67b540$61d91818@computer> <003c01c34887$0e29c870$1202a8c0@basement> <3F12036B.1050702@earthlink.net> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 10 Sounds like im conviced on using the plywood just putting a layer of deck cloth over it for a nice smooth finsh. The reason I posted that I was to use fiberglass skins after doing the correct tests was in fact to get people to give their opinions. Obvously I was incorrect or maybe I wasn't but I dont want to fly this bird with any question of it going to fail. Not worth the risk or extra work to use fiberglass skins. Anyone who put all the skins on after the boat was built know any secrets? It seems like it is going to be a job. Justin Vist My KR2S www.geocities.com/attngrabber14/kr2s ----- Original Message ----- From: "Brian Kraut" To: "KR builders and pilots" Sent: Sunday, July 13, 2003 8:12 PM Subject: Re: KR>My KR2S > I agree and add the following. > > 1/8" plywood is 12 pounds for a 4 X 8 ft sheet.. I haven't measured, > but I don't think there is more than 18 pounds of plywood in the whole > KR. There really isn't any weight to save here > > The biggest problem with glass is that it will need to be so thick to > get the buckling resistance you need that it will weigh at least as much > as the wood. Glass does have good tensile strength, but very low > buckling and torsional strength for an equivalent weight. > > Quoting some excerpts from Low Power Laminar Aircraft Structures by Alex > Strojnik, > > "Plywood is the single most efficient aircraft material we know. It > combines the highest shearing/buckling resistance with the lowest > density. ... > In an extensive study, directed at analysing the suitability of material > for structural stressed skins several years ago, A. Puck (Some Examples > of the Design and Construction of Highly Loaded Sailplane Parts in FRP, > OSTIV Publication 1960) came to the conclusion that while theoretically > the bidirectional fiberglass fabric + epoxy offer the highest shearing > strength for the weight -today this honor would go to carbon fiber- it > is the plywood that possesses the highest resistance (shearing and > torsion) against wrinkling. By far." > > Now if you did a sandwich construction with foam between the stringers > and glass on both sides you would increase the buckling and bending > strength a lot, but you would need something other than urethane foam > because the glass will tend to tear off of the foam under bending , > torsion, and buckling loads. You would need to use a higher density, > and heavier, core. You will probably have a finished weight more than > with the plywood by the time you are done, and by the time you load it > up with fillers to get it as smooth and flat as the plywood it will > certainly be a lot heavier and take you three times as long. > > Sorry to disagree with you Justin, these are just my two cents. Good > luck with your project and keep us posted. > > Mark Langford wrote: > > >Justin wrote: > > > >>I dont feel that plywood is a good choice. I know it is proven for many > >>years but why not make it stronger and most likley lighter using > >> > >fiberglass > > > >>to get a perfect smooth finsh? It's not as if im changing the airframe to > >>accept the fiberglass, it is still a stock KR2S airframe unlike the other > >>fiberglass boats which make complex shapes. > >> > > > >So, there have been something like 1500 of these built, and not ONE of them > >has ever had the plywood mysteriously sheer off and create a crash, but you > >don't think it's good enough? The plywood isn't there just to keep the wind > >out. It's an integral part of the structure. If nothing else, it acts as a > >gusset. > > > >> It's actually not much work to use this fiberglass skinning. I draw on > >>the foam and cut it out, it will take me about an hour to do the whole > >>fuselage and then applying the glass (2 people) will be about another > >> > >hour > > > >>X 2 (inside and out). Sanding the foam will take a few hours. > >> > > > >I think you're seriously mistaken here. It can't get any easier to finish > >something than plywood is. You start with a smooth, flat surface, that > >really only requires a little sealer and fine sanding and it's ready for > >primer and paint. You must not have had much experience with fiberglass, > >but the surface will be far from straight, and the pinholes will eat your > >lunch trying to fill them all. My guess is it'd take at least three times > >more effort to skin it with fiberglass then with plywood., and the strength > >is still in serious doubt... > > > >Mark Langford, Huntsville, AL > >N56ML "at" hiwaay.net > >see KR2S project at http://home.hiwaay.net/~langford > > > > > > > >_______________________________________________ > >see KRnet list details at http://www.krnet.org/instructions.html > > > > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html > ------------------------------ Date: Mon, 14 Jul 2003 07:33:09 +0200 From: "Norman Stapelberg" To: "'KR builders and pilots'" Subject: RE: KR>Timing Message-ID: <000001c349c9$6a9dda90$efea1ec4@norman> In-Reply-To: <001801c34860$20b1f660$c0cc07c4@user> Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 11 Good day Eric I have a 2.4 Lt type 4 and am currently running at the following settings, timing 25 deg B.T.D.C (airfield elevation 5340 Ft) Static R.P.M 2900 (Prop 52 x 47 ) Hope the info helps Regards Norshel Control Instrumentation cc Norman Stapelberg Cell: 027 83 277 9725 Home: 027 11 818 1345 Fax: 027 11 818 3547 South Africa ZS-UKR (90%) -----Original Message----- From: krnet-bounces@mylist.net [mailto:krnet-bounces@mylist.net] On Behalf Of Evezard Sent: 12 July 2003 12:26 PM To: KR NEWS Subject: KR>Timing Hi Netters, I have a type 4 long block 2l VW engine.What are the figures for the best timing setting using a Bosch distributor.?What static revs should I try for using a 52 dia x 48 ins. prop.? Many thanks for excellent help in the past. Best Regards, Eric Evezard South Africa. _______________________________________________ see KRnet list details at http://www.krnet.org/instructions.html ------------------------------ Date: Mon, 14 Jul 2003 01:37:06 EDT From: WA7YXF@aol.com To: krnet@mylist.net Subject: KR>My KR2S Message-ID: <189.1c43156e.2c439b82@aol.com> Content-Type: text/plain; charset="US-ASCII" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 12 Anyone who put all the skins on after the boat was built know any secrets? It seems like it is going to be a job. Justin..... Compared to the application of fiberglass skins you'll find using Plywood to be a piece of cake. I felt putting on the bottom skin first might keep things straight while putting the side skins on. Can't think of any secrets I might pass along as it wasn't difficult at all. Lynn N37LH ------------------------------ Date: Mon, 14 Jul 2003 06:05:50 -0400 (Eastern Standard Time) From: "Dan Heath" To: Subject: Re: KR>My KR2S Message-ID: <3F12807E.000001.03004@Computer> References: <001d01c34a11$5363ba50$61d91818@computer> Content-Type: Text/Plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 13 Justin,=0D =0D I think the most difficult job you are going to have, is getting all that varnish off. Our boat was finished, and varnished. When I went to insta= ll the other things that go on top of the boat, I sanded off all the varnish= =2E=20 I then installed my first item. The next day, all I had was a gooey mess= =2E=20 T-88 would not stick, VinylEster would not stick, and Poly Fiber resin wo= uld not stick. Someone suggested that I sand and then wash with acetone or lacquer thinner. That worked, but it was a very time consuming and laborious job. As you sand the varnish off, it gets into the pours of th= e wood. If you could get it stripped with a varnish stripper that would no= t affect the glue, that might be the best way to start.=0D =0D Since you are good at running tests, I suggest that you come up with a method and apply it to a stick and some plywood. Be sure that you get a complete bond. =0D =0D N64KR=0D =0D Daniel R. Heath - Columbia, SC=0D =0D DanRH@KR-Builder.org=0D =0D See you in Red Oak - 2003=0D =0D See our KR at http://KR-Builder.org - Click on the pic=0D See our EAA Chapter 242 at http://EAA242.org=0D =0D -------Original Message-------=0D =0D From: KR builders and pilots=0D Date: Monday, July 14, 2003 12:08:22 AM=0D To: engalt@earthlink.net; KR builders and pilots=0D Subject: Re: KR>My KR2S=0D =0D Sounds like im conviced on using the plywood just putting a layer of deck= =0D cloth over it for a nice smooth finsh. The reason I posted that I was to = use=0D fiberglass skins after doing the correct tests was in fact to get people = to=0D give their opinions. Obvously I was incorrect or maybe I wasn't but I don= t=0D want to fly this bird with any question of it going to fail. Not worth th= e=0D risk or extra work to use fiberglass skins.=0D =0D Anyone who put all the skins on after the boat was built know any=0D secrets? It seems like it is going to be a job.=0D =0D Justin=0D Vist My KR2S=0D www.geocities.com/attngrabber14/kr2s=0D =0D =0D ----- Original Message -----=0D From: "Brian Kraut" =0D To: "KR builders and pilots" =0D Sent: Sunday, July 13, 2003 8:12 PM=0D Subject: Re: KR>My KR2S=0D =0D =0D > I agree and add the following.=0D >=0D > 1/8" plywood is 12 pounds for a 4 X 8 ft sheet.. I haven't measured,=0D > but I don't think there is more than 18 pounds of plywood in the whole=0D > KR. There really isn't any weight to save here=0D >=0D > The biggest problem with glass is that it will need to be so thick to=0D > get the buckling resistance you need that it will weigh at least as muc= h=0D > as the wood. Glass does have good tensile strength, but very low=0D > buckling and torsional strength for an equivalent weight.=0D >=0D > Quoting some excerpts from Low Power Laminar Aircraft Structures by Ale= x=0D > Strojnik,=0D >=0D > "Plywood is the single most efficient aircraft material we know. It=0D > combines the highest shearing/buckling resistance with the lowest=0D > density. ...=0D > In an extensive study, directed at analysing the suitability of materia= l=0D > for structural stressed skins several years ago, A. Puck (Some Examples= =0D > of the Design and Construction of Highly Loaded Sailplane Parts in FRP,= =0D > OSTIV Publication 1960) came to the conclusion that while theoretically= =0D > the bidirectional fiberglass fabric + epoxy offer the highest shearing=0D > strength for the weight -today this honor would go to carbon fiber- it=0D > is the plywood that possesses the highest resistance (shearing and=0D > torsion) against wrinkling. By far."=0D >=0D > Now if you did a sandwich construction with foam between the stringers=0D > and glass on both sides you would increase the buckling and bending=0D > strength a lot, but you would need something other than urethane foam=0D > because the glass will tend to tear off of the foam under bending ,=0D > torsion, and buckling loads. You would need to use a higher density,=0D > and heavier, core. You will probably have a finished weight more than=0D > with the plywood by the time you are done, and by the time you load it=0D > up with fillers to get it as smooth and flat as the plywood it will=0D > certainly be a lot heavier and take you three times as long.=0D >=0D > Sorry to disagree with you Justin, these are just my two cents. Good=0D > luck with your project and keep us posted.=0D >=0D > Mark Langford wrote:=0D >=0D > >Justin wrote:=0D > >=0D > >>I dont feel that plywood is a good choice. I know it is proven for ma= ny=0D > >>years but why not make it stronger and most likley lighter using=0D > >>=0D > >fiberglass=0D > >=0D > >>to get a perfect smooth finsh? It's not as if im changing the airfram= e=0D to=0D > >>accept the fiberglass, it is still a stock KR2S airframe unlike the=0D other=0D > >>fiberglass boats which make complex shapes.=0D > >>=0D > >=0D > >So, there have been something like 1500 of these built, and not ONE of= =0D them=0D > >has ever had the plywood mysteriously sheer off and create a crash, bu= t=0D you=0D > >don't think it's good enough? The plywood isn't there just to keep the= =0D wind=0D > >out. It's an integral part of the structure. If nothing else, it acts=0D as a=0D > >gusset.=0D > >=0D > >> It's actually not much work to use this fiberglass skinning. I draw=0D on=0D > >>the foam and cut it out, it will take me about an hour to do the whol= e=0D > >>fuselage and then applying the glass (2 people) will be about another= =0D > >>=0D > >hour=0D > >=0D > >>X 2 (inside and out). Sanding the foam will take a few hours.=0D > >>=0D > >=0D > >I think you're seriously mistaken here. It can't get any easier to=0D finish=0D > >something than plywood is. You start with a smooth, flat surface, that= =0D > >really only requires a little sealer and fine sanding and it's ready f= or=0D > >primer and paint. You must not have had much experience with=0D fiberglass,=0D > >but the surface will be far from straight, and the pinholes will eat y= our=0D > >lunch trying to fill them all. My guess is it'd take at least three=0D times=0D > >more effort to skin it with fiberglass then with plywood., and the=0D strength=0D > >is still in serious doubt...=0D > >=0D > >Mark Langford, Huntsville, AL=0D > >N56ML "at" hiwaay.net=0D > >see KR2S project at http://home.hiwaay.net/~langford=0D > >=0D > >=0D > >=0D > >_______________________________________________=0D > >see KRnet list details at http://www.krnet.org/instructions.html=0D > >=0D >=0D > _______________________________________________=0D > see KRnet list details at http://www.krnet.org/instructions.html=0D >=0D =0D =0D _______________________________________________=0D see KRnet list details at http://www.krnet.org/instructions.html=0D =2EFrom clgard@attcanada.ca Mon Jul 14 05:53:43 2003 Received: from outbox.allstream.net ([207.245.244.41]) by lizard.esosoft.net with esmtp (Exim 3.36 #1) id 19c2pU-0008ih-00 for krnet@mylist.net; Mon, 14 Jul 2003 05:53:22 -0700 Received: from attcanada.ca (osh-on50-135.dial.allstream.net [142.154.117.7]) by outbox.allstream.net (Postfix) with ESMTP id E39F81EF88B; Mon, 14 Jul 2003 08:52:12 -0400 (EDT) Message-ID: <3F12A77C.2050601@attcanada.ca> Date: Mon, 14 Jul 2003 08:52:12 -0400 From: chris gardiner User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:0.9.4) Gecko/20011128 Netscape6/6.2.1 X-Accept-Language: en-us MIME-Version: 1.0 To: KR builders and pilots Cc: Owen Macpherson Subject: Re: KR>Oshkosh plans References: <00d501c3482c$720b2600$6401a8c0@wi.rr.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1b3 X-BeenThere: krnet@mylist.net X-Mailman-Version: 2.1b3 Precedence: list Reply-To: clgard@attcanada.ca, KR builders and pilots List-Id: KR builders and pilots List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Help: Well, Owen MacPherson and I are still planning to fly our KR's to KOSH ( weather permitting). We should be arriving early ( Sat urday or Sunday , before) to beat the crowd on approach ( we hope). Since we are planning to camp next to the planes , they will probably park us in the boonies. Let us know where/when the "Brats and Beer " meeting is planned before departure so we can find the KR Heads on the field . The forum on Wednesday should work for us attending it as well ( ass promised to Jim) . Cheers Guys and see you at KOSH. Chris Gardiner KR2S PS > Received my Red Oak Gathering video while I was in Mexico . Looks great . Who do I send a check to and for how many pesos ? ( I mean $) Mark Jones wrote: >So far, including myself, Dana and Mark L., three other KR builders have >said they will attend the beer and brats cook out. As far as I know you can >grill just about anywhere....we could even do a tailgate party in the >parking lot. I will stop by the convention headquarters next week and ask >them for suggestions. The KR forum being presented by Jim Faughn and Mark >Langford is on Wednesday July 30th at 2:30 pm in forum pavilion 10 (US >Tools). As Dana asked...PLEASE let us know if you plan on attending the beer >and brats cookout. > >Mark Jones (N886MJ) >Wales, WI USA >E-mail me at flykr2s@wi.rr.com >Visit my KR-2S CorvAIRCRAFT web site at >http://mywebpage.netscape.com/n886mj/homepage.html > > >----- Original Message ----- >From: "Dana Overall" >To: >Sent: Friday, July 11, 2003 10:58 PM >Subject: KR>Oshkosh plans > > >>OK, time to start putting the Oshkosh plans together on a serious note. >>What time is the KR forum on Weds.? Mark Jones and I really would like to >>know how many KRNet members are planning on attending Oshkosh on Weds. >> >I'm > >>thinking, but open to discussion, a beer and brats open air dinner for the >>KRNet gang along with any KR pilots who make it to Oshkosh. If some of >> >the > >>people who simply attend the forum catch wind, well so be it. How does >>everyone feel about this line of thinking? I'm just thinking there are a >>lot of "squatters" at all these forums, as I spoke at one KR forum at SNF. >>Is the KR forum going to be held in the same area the one on the new wing >>was a couple years ago? >> >>Next line of questions. I am not as familiar with Oshkosh as Sun & Fun in >>that I worked a couple years in the ground advisor tower there. Are there >>any good spots to cook out that we can get close to with vehicles? Beer >> >and > >>brats, along with coolers and grills are a load to carry. Don't ask me >> >how > >>I know. I have a great Coleman, Thermos........whoever it is, Grill as >> >you > >>go that will handle all the cooking. I'm either going to be camping in >>homebuilt camping or the big ol parking lot known as Camp Scheeler (sp), >>probably homebuilt camping. >> >>Seriously now, we would like some comments and a rough hand count on who >> >is > >>going to be at Oshkosh on Weds. Once again, so many people on these lists >>make comments they would like to put faces to names off a forum. Here is >> >a > >>great chance to do just that. >> >>Myself and Mark Langford and now Mark Jones have been involved in putting >>together basement KR gatherings, an east coast gathering, SNF group rates >> >at > >>motels, a couple national gatherings, along with a couple SNF very >> >informal > >>get togethers. I rank these well up on my flying experiences. If at all >>possible be there, you will find we all have something in common and >>conversation flows as if friends for years and, I hate this word but, >>fellowship in common and that is this love in building these flying >> >machines > >>that the uninformed think we are nuts to do. >> >>Chime it, let's talk about this. >> >>I am keeping my fingers crossed my Dynon unit will be in before I leave. >> >If > >>it is, we will do some great glass cockpit flying as it is all electric >> >with > >>an internal battery. Check out dynondevelopment.com or >>http://rvproject.com/20030709.html?updated >> >> >>Three cases is enough for me............just don't know about the rest of >>you (yeah, right maybe my college days but now three in one night is >> >enough > >>to do me in, Oshkosh is a different story though:-) >> >>Anybody who sees Melody Mountains, please let her know about the plans >> >(you > >>really have to be an old timer on the KRNet to know this joke......OH, >> >sorry > >>Melody, I mean KR groupee...........sorry, I mean KR enthusiast) >> >> >> >>Dana Overall >>1999 & 2000 National KR Gathering >>Richmond, KY >>RV-7 slider/fuselage >>Finish kit ordered!! Buying Instruments >>http://rvflying.tripod.com >>do not archive >> >>_________________________________________________________________ >>Help STOP SPAM with the new MSN 8 and get 2 months FREE* >>http://join.msn.com/?page=features/junkmail >> >> >>_______________________________________________ >>see KRnet list details at http://www.krnet.org/instructions.html >> > > > >_______________________________________________ >see KRnet list details at http://www.krnet.org/instructions.html > > ------------------------------ Date: Mon, 14 Jul 2003 08:02:49 -0500 From: asavant@notes.state.ne.us To: KR builders and pilots Subject: Re: KR>Pin holes Message-ID: In-Reply-To: <3F1205B0.1040403@earthlink.net> Content-Type: text/plain; charset=US-ASCII MIME-Version: 1.0 Precedence: list Message: 14 Brian Kraut wrote: >I have done a few repairs and I usually put vacuum bagging film over >them or sometimes just tape right over a small repair with plastic >packing tape. There is almost no sanding to do when you do that. The >only disadvantage I can see is that you wind up with resin filling the >weave on the top instead of squeeging out the excess and later filling >with micro or something lighter than pure resin. Wouldn't peel ply work better at minimizing pin holes and absorbing extra resin at the same time? Ameet Savant asavant@notes.state.ne.us ------------------------------ Date: Mon, 14 Jul 2003 11:11:57 -0500 From: "SPRAGUE, DONALD E. (JSC-SD) (KS)" To: 'KR builders and pilots' Subject: RE: KR>ballistic chute Message-ID: <7C3C0FB750552747873452E91E6D06F9EEE722@jsc-mail08.jsc.nasa.gov> Content-Type: text/plain; charset="ISO-8859-1" MIME-Version: 1.0 Precedence: list Message: 15 Bill, I'm interested in the BRS chute if you still have it. You can call me here or on my cell phone 281 989 5110. The $3000 chute is the one rated at 1050 lbs isn't it? I have the smaller one and will have to upgrade before I can safely take the wife along. I should have my airworthiness certificate exam in a week or so. I've done most of the taxiing etc and am fairly happy with the performance. My opinion is that the cost of a ballistic chute is much cheaper than life insurance. Certainly, the idea has allayed a lot of my wife's fears. Take care and have a good day. Don Don Sprague,M.D.,M.P.H. Project Manager/Medical Director Kelsey-Seybold Occupational Medicine Clinic NASA, Johnson Space Center Phone: 281-483-7785 Fax: 281-244-5179 -----Original Message----- From: WILLIAM HUNTLEY [mailto:xzostd1@msn.com] Sent: Thursday, July 10, 2003 10:58 PM To: krnet@mylist.net Subject: KR>ballistic chute I have a BRS chute with KR mounting kit . $3000.00 value for $1300.00. Still in its box. I switched to Glastar Bill Huntley 906-864-0347_______________________________________________ see KRnet list details at http://www.krnet.org/instructions.html ------------------------------ Date: Mon, 14 Jul 2003 12:55:51 -0500 From: "Robert Stone" To: "KR builders and pilots" Subject: KR>Boat fiberglass or plywood skins Message-ID: <001401c34a31$2a292ba0$ba21f218@hot.rr.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 16 Netters, It's been a long time since I built and I do not have a set of = plans any more but I seem to remember the original design was for the = boat frame to be skinned with 1/8" aircraft plywood and then covered = with a thin layer of fiberglass cloth and Ken thought this would make = the strongest structure considering all the compression and tinsel = pressures from the engine. As long as I knew him (from 1970 to his = death) he never had an engine fall off so he must have been right. Bob Stone, Harker Heights, TX rstone4@hot.rr.comFrom gleone@tritel.net Mon Jul 14 11:07:11 2003 Received: from tctisp1.tctwest.net ([216.166.159.7]) by lizard.esosoft.net with esmtp (Exim 3.36 #1) id 19c7jD-000ERe-00 for krnet@mylist.net; Mon, 14 Jul 2003 11:07:11 -0700 Received: from DDMWDD11 (tt1a2m155.tritel.net [216.166.160.155]) by tctisp1.tctwest.net (8.11.6p2/8.11.3) with SMTP id h6EI71d29913 for ; Mon, 14 Jul 2003 12:07:01 -0600 (MDT) MIME-Version: 1.0 Message-Id: <3F12F130.000004.02840@DDMWDD11> Date: Mon, 14 Jul 2003 12:06:40 -0600 (Mountain Standard Time) Content-Type: Text/Plain X-Mailer: IncrediMail 2001 (2001138.2001138) From: "gleone" References: <001401c34a31$2a292ba0$ba21f218@hot.rr.com> X-FID: PLAINTXT-NONE-0000-0000-000000000000 X-FVER: 3.0 X-CNT: ; Content-Transfer-Encoding: quoted-printable X-Priority: 3 To: Subject: Re: KR>Boat fiberglass or plywood skins X-BeenThere: krnet@mylist.net X-Mailman-Version: 2.1b3 Precedence: list Reply-To: KR builders and pilots List-Id: KR builders and pilots List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Help: My question is, why not just build it according to plans rather than try raining body parts and debris all over the countryside? That's why we ha= ve plans: To build from.=0D =0D -------Original Message-------=0D =0D From: KR builders and pilots=0D Date: Monday, July 14, 2003 11:59:22 AM=0D To: KR builders and pilots=0D Subject: KR>Boat fiberglass or plywood skins=0D =0D Netters,=0D It's been a long time since I built and I do not have a set of plans any more but I seem to remember the original design was for the boat frame to= be skinned with 1/8" aircraft plywood and then covered with a thin layer of fiberglass cloth and Ken thought this would make the strongest structure considering all the compression and tinsel pressures from the engine. As long as I knew him (from 1970 to his death) he never had an engine fall o= ff so he must have been right.=0D =0D Bob Stone, Harker Heights, TX=0D rstone4@hot.rr.com_______________________________________________=0D see KRnet list details at http://www.krnet.org/instructions.html=0D =0D =2E ------------------------------ _______________________________________________ See KRnet list details at http://www.krnet.org/instructions.html End of KRnet Digest, Vol 96, Issue 1 ************************************