From: krnet-bounces@mylist.net on behalf of krnet-request@mylist.net Sent: Saturday, December 20, 2003 9:04 AM To: krnet@mylist.net Subject: KRnet Digest, Vol 255, Issue 1 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. switches and electrics (Oscar Zuniga) 2. Re: switches and electrics (Mark Langford) 3. Re: Switch Ratings (Martindale Family) 4. Re: switches and electrics (Dana Overall) 5. Bose Headsets (Mark Youkey) 6. Re: spruce list posted! (Joseph H Horton) 7. flying inverted (Steve and Lori McGee) 8. Re: Switch Ratings (larry severson) 9. Calendar (Steve and Lori McGee) 10. Re: Bose Headsets 11. Re: spruce list posted! (B. Wunder) 12. Re: Calendar (Ray Fuenzalida) 13. Re: Switch Ratings (Martindale Family) 14. RE: Switch Ratings (Philip Maley) 15. KR Information 16. Switch Ratings (larry flesner) 17. Switches--again (JIM VANCE) 18. Aircraft Parts (Orma Robbins) 19. Re: airfoil design (Mark Langford) 20. Builder in UK needs help. (Mark Jones) 21. Re: KR Information (Thomas Brock) 22. Recommendation from Rick Wilson 23. Re: airfoil design (lloyd schultz) 24. Recommendation from Rick Wilson ---------------------------------------------------------------------- Date: Fri, 19 Dec 2003 14:27:12 -0600 From: "Oscar Zuniga" To: krnet@mylist.net Subject: KR>switches and electrics Message-ID: Content-Type: text/plain; format=flowed MIME-Version: 1.0 Precedence: list Message: 1 Netters; One of the best resources for information on electrical systems in aircraft is AeroElectric Connection, at http://www.aeroelectric.com/ . Bob Nuckolls has lots of good reference info and explanations to answer your questions on this stuff (DC vs. AC switch ratings, etc.). They also offer parts and pieces for sale, through B&C Aero, here: http://www.bandc.biz/parts.html and everything is aircraft grade. If you study nothing else, Bob's info on grounding systems and theory are worth the reading... particularly in composite construction. It helps to get a grasp of how electrical noise originates and propagates, and how to properly ground your avionics and wiring to ensure that overcurrent protective devices function properly and noise does not hash up your avionics. Educate yourself while you sit by the fire waiting for Santa... download and print some of Bob's notes (or order "The Aeroelectric Connection", a manual for the homebuilder). Oscar Zuniga San Antonio, TX mailto: taildrags@hotmail.com website at http://www.flysquirrel.net _________________________________________________________________ Enjoy the holiday season with great tips from MSN. http://special.msn.com/network/happyholidays.armx ------------------------------ Date: Fri, 19 Dec 2003 14:42:55 -0600 From: "Mark Langford" To: "KRnet" Subject: Re: KR>switches and electrics Message-ID: <002b01c3c670$ae7e3790$5e0ca58c@tbe.com> References: Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 2 OZ wrote: > One of the best resources for information on electrical systems in aircraft > is AeroElectric Connection, at http://www.aeroelectric.com/ . I resisted the urge to buy this book for a long time, convinced that I knew everything I needed to know about aircraft electrical systems. Boy, was I wrong! I finally broke down and bought this book a few months back, and there's not a page in it where I don't learn something fairly profound. I wish I'd read it BEFORE I wired my plane, rather than AFTER. This is one of those rare books that you can read and become an "instant expert", as far as I'm concerned. I'm not quite as crazy about redundancy as Bob is, but like Oscar says, it's an incredible resource... Mark Langford, Huntsville, AL N56ML at hiwaay.net see KR2S project N56ML at http://home.hiwaay.net/~langford ------------------------------ Date: Sat, 20 Dec 2003 09:13:34 +1100 From: "Martindale Family" To: "KRnet" Subject: Re: KR>Switch Ratings Message-ID: <003f01c3c67e$9374f340$75a0fea9@johnjane> References: <003e01c3c631$17668e00$0600a8c0@oemcomputer> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 3 Yikes Thanks Jim But does the 1/8 rule apply to unequal voltages? Would 125 VAC 3 amps really equate to 12VDC 0.375amp!! Is this really correct? If so, my ignition switches are about 8 times under rated for my Bosch 3 amp coils and most of my other swirches are suspect as well! Off to Aeroelectric I go. The Martindale Family 29 Jane Circuit TOORMINA NSW 2452 AUSTRALIA phone: 61 2 66584767 email: johnjane@chc.net.au > The exact number varies with the construction of the switch, but a > rule of thumb is that the D C current rating is about 1/8 that for A C..... (note appropriate use of snip and subject heading) ------------------------------ Date: Fri, 19 Dec 2003 17:59:29 -0500 From: "Dana Overall" To: krnet@mylist.net Subject: Re: KR>switches and electrics Message-ID: Content-Type: text/plain; format=flowed MIME-Version: 1.0 Precedence: list Message: 4 As I've said before, to add a "me too", aeroelectric.com is the place to go for your answers. In planning my glass panel, the use of Bob's switchable ebuss with a diode between my main buss and the ebuss provides direct current to what I put on my ebuss while switching all other circuits out of the loop. In my case, redundancy is an issue and The Book is an absolute required book for you aviation construction library. This is a case where you get your monies worth in the aviation world. Dana Overall 1999 & 2000 National KR Gathering host Richmond, KY RV-7 slider, Imron black, "Black Magic" Finish kit Buying Instruments. Hangar flying my Dynon. http://rvflying.tripod.com do not archive >From: "Mark Langford" >Reply-To: KRnet >To: "KRnet" >Subject: Re: KR>switches and electrics >Date: Fri, 19 Dec 2003 14:42:55 -0600 > >OZ wrote: > > > One of the best resources for information on electrical systems in >aircraft > > is AeroElectric Connection, at http://www.aeroelectric.com/ . > >I resisted the urge to buy this book for a long time, convinced that I >knew everything I needed to know about aircraft electrical systems. >Boy, was I wrong! I finally broke down and bought this book a few >months back, and there's not a page in it where I don't learn something >fairly profound. I wish I'd read it BEFORE I wired my plane, rather >than AFTER. This is one of those rare books that you can read and >become an "instant expert", as far as >I'm concerned. I'm not quite as crazy about redundancy as Bob is, but like >Oscar says, it's an incredible resource... > >Mark Langford, Huntsville, AL >N56ML at hiwaay.net >see KR2S project N56ML at http://home.hiwaay.net/~langford > > >_______________________________________________ >see KRnet list details at http://www.krnet.org/instructions.html _________________________________________________________________ Grab our best dial-up Internet access offer: 6 months @$9.95/month. http://join.msn.com/?page=dept/dialup ------------------------------ Date: Fri, 19 Dec 2003 17:52:38 -0600 From: "Mark Youkey" To: "KR builders and pilots" Subject: KR>Bose Headsets Message-ID: <010201c3c68b$2f234420$6400a8c0@blah> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 5 It's Friday, so an aviation post... I got to fly with a Bose Headset X the other day... Amazing! I have about 800 hours under my Dave Clark H10-76, and was completely = flabbergasted at how much more comfortable and quieter the Bose was. = I've flown with active noise cancellation before, and it felt like there = was almost a pressure on my eardrums when the ANR was turned on. Not so = with the Bose. In addition to that, the Bose was about 1/4 the weight = of my current headset, and didn't squeeze my head at all. =20 The neat thing was that I could hear the guy sitting next to me mumble = things under his breath, not just the things he was saying to me. I know the headsets are friggin expensive, but they are incredible when = it comes to comfort and noise reduction.=20 With that all being said, I was on a jet rather than a prop, but thought = you may be interested. I'd reccommend that you do your best to at least = demo a Bose Headset X. Wow! I saw them about $100 cheaper than the page below, but I haven't tried = shopping around. Just got the webpage for a reference. http://www.bose.com/controller?event=3DVIEW_PRODUCT_PAGE_EVENT&product=3D= headsetx_headset_index&src=3DCC201&alias=3Danrheadset.bose.com Mark Youkey myoukey@cox.net Oklahoma City ------------------------------ Date: Fri, 19 Dec 2003 18:54:25 -0500 From: Joseph H Horton To: krnet@mylist.net Subject: Re: KR>spruce list posted! Message-ID: <20031219.185425.-468873.0.joe.kr2s.builder@juno.com> Content-Type: text/plain MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 6 Several places different off the top of my head for the S model -longerons were longer -shelf and engine mount cross members -more 5/8" material for the extra bay and cross bracing under turtle deck area I'm not sure that the spar material was the sme but ply list will be different too Joe Horton list of Spruce for the > KR2 that > he got from Wicks. You might need to check against differences in > the S if > you're going to build an S, but the only place I can think would be > different would be the length of the vertical stabilizer and rudder > (maybe), > although there may be others. Anyway, it's at > http://www.krnet.org/kr2woodkit.jpg . ------------------------------ Date: Fri, 19 Dec 2003 18:25:21 -0600 From: "Steve and Lori McGee" To: Subject: KR>flying inverted Message-ID: <003401c3c68f$c1161a20$0202a8c0@lori8v5h2xi9m3> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 7 Or at least roll overs and half loops. Is the corvair capable and with = what carb setup? Steve McGee Endeavor Wi. USA Building a KR2S widened. lmcgee@maqs.net=20 ------------------------------ Date: Fri, 19 Dec 2003 16:35:13 -0800 From: larry severson To: KRnet Subject: Re: KR>Switch Ratings Message-ID: <5.2.1.1.0.20031219163232.024ba0f8@pop-server.socal.rr.com> In-Reply-To: <003f01c3c67e$9374f340$75a0fea9@johnjane> References: <003e01c3c631$17668e00$0600a8c0@oemcomputer> Content-Type: text/plain; charset="us-ascii"; format=flowed MIME-Version: 1.0 Precedence: list Message: 8 But does the 1/8 rule apply to unequal voltages? >Would 125 VAC 3 amps really equate to 12VDC 0.375amp!! Watts are volts X amps. You are talking 375 watts (AC) vs 4+ watts (DC). You went the wrong way way with the 1/8. Larry Severson Fountain Valley, CA 92708 (714) 968-9852 larry2@socal.rr.com ------------------------------ Date: Fri, 19 Dec 2003 18:36:18 -0600 From: "Steve and Lori McGee" To: Subject: KR>Calendar Message-ID: <008c01c3c691$486daa50$0202a8c0@lori8v5h2xi9m3> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 9 For those that have sent pics - thank you! BUT WE NEED MORE! Also there has not been a huge response, so if you are inclined to get = one let me know if you haven't already. Steve McGee Endeavor Wi. USA Building a KR2S widened. lmcgee@maqs.net=20 ------------------------------ Date: Fri, 19 Dec 2003 20:35:36 EST From: JSMONDAY@aol.com To: krnet@mylist.net Subject: Re: KR>Bose Headsets Message-ID: <1d8.17063a3b.2d150168@aol.com> Content-Type: text/plain; charset="US-ASCII" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 10 Try the Seinnheiser 400 headset (ANR)... much better for the money... The link below seems to have the cheapest price.. and definitely execellent service. at www.aviation-headset.com John S. Monday KR2S Laguna Beach, CA ------------------------------ Date: Fri, 19 Dec 2003 20:59:02 -0600 From: "B. Wunder" To: "KRnet" Subject: Re: KR>spruce list posted! Message-ID: <006101c3c6a5$3c37cfe0$6400a8c0@computer> References: <001701c3c5e0$65838490$2402a8c0@800Athlon> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 11 Mark wrote: > > sent me a list of Spruce for the KR2 that > he got from Wicks..... . Anyway, it's at > http://www.krnet.org/kr2woodkit.jpg . Just a little amplification....I ordered the KR2S Spruce wood kit from Wicks. When I went thru the Wicks invoice and tried to inventory what I had received, I had a difficult time determining what I had(all those pieces in a 14ft long box don't look like airplane structure). The Wicks invoice under "Item Number" listed many "KR200-xxx" numbers for the wood pieces. When I called Wicks, they sent me the list Mark posted. With that as a cross reference I could quickly identify what wood pieces went with what part of the airplane and label it appropriately. I think they should include this list as part of their kit makeup....maybe it was left out. Yes, there are differences between the KR2 and KR2S wood kits... the firewall and vertical stab/rudder pieces are two areas that were not given KR200 numbers along with the plywood kit because they are different from the KR2. r/Bernie KR2S Builder Lexington Park, MD http://mywebpage.netscape.com/n2w6 . ------------------------------ Date: Fri, 19 Dec 2003 19:27:10 -0800 (PST) From: Ray Fuenzalida To: KRnet Subject: Re: KR>Calendar Message-ID: <20031220032710.9999.qmail@web42004.mail.yahoo.com> In-Reply-To: <008c01c3c691$486daa50$0202a8c0@lori8v5h2xi9m3> Content-Type: text/plain; charset=us-ascii MIME-Version: 1.0 Precedence: list Message: 12 I will also like a calendar. Maybe one day my plane will be included. Ray - Steve and Lori McGee wrote: > For those that have sent pics - thank you! > BUT WE NEED MORE! > Also there has not been a huge response, so if you > are inclined to get one let me know if you haven't > already. > > Steve McGee > Endeavor Wi. USA > Building a KR2S widened. > lmcgee@maqs.net > > > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html __________________________________ Do you Yahoo!? New Yahoo! Photos - easier uploading and sharing. http://photos.yahoo.com/ ------------------------------ Date: Sat, 20 Dec 2003 18:57:38 +1100 From: "Martindale Family" To: "KRnet" Subject: Re: KR>Switch Ratings Message-ID: <004101c3c6cf$0e73b5e0$75a0fea9@johnjane> References: <003e01c3c631$17668e00$0600a8c0@oemcomputer> <5.2.1.1.0.20031219163232.024ba0f8@pop-server.socal.rr.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 13 Hi Larry Yeh that's what I thought but something still niggles. 125VAC at 3 amps should be roughly equilvalent to 14VDC at 27 amps. I ought be OK but somehow the latter seems excessive? 125VAC at 3 amps relates to 125VDC at only 0.375 amps by Jim's rule of thumb, that is, voltage being equal, DC current rating is about 1/8 of AC but it can vary depending on switch quality according to Aeroelectrics. Aeroelectrics also says "in a nutshell, 125VAC ratings equate favourably and conservatively to 14VDC ratings -as long as the switch has a healthy snap action"....the latter to minimise arcing time. ...and so I am relieved in some ways but still curious about what is causing my 1/2 volt drop across the switches... maybe they are arcing internally and building up a resistance or maybe they're just dirty...either way as Jim suggests, they're headed for the bin. See Ya The Martindale Family 29 Jane Circuit TOORMINA NSW 2452 AUSTRALIA phone: 61 2 66584767 email: johnjane@chc.net.au ----- Original Message ----- From: "larry severson" To: "KRnet" Sent: Saturday, December 20, 2003 11:35 AM Subject: Re: KR>Switch Ratings > > But does the 1/8 rule apply to unequal voltages? > >Would 125 VAC 3 amps really equate to 12VDC 0.375amp!! > > Watts are volts X amps. You are talking 375 watts (AC) vs 4+ watts (DC). > You went the wrong way way with the 1/8. > > > Larry Severson > Fountain Valley, CA 92708 > (714) 968-9852 > larry2@socal.rr.com > > > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html > ------------------------------ Date: Sat, 20 Dec 2003 17:27:31 +0800 From: "Philip Maley" To: "'KRnet'" Subject: RE: KR>Switch Ratings Message-ID: <012401c3c6db$819c56b0$0301a8c0@wotech.net> In-Reply-To: <004101c3c6cf$0e73b5e0$75a0fea9@johnjane> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 14 One thing to remember is that an amp is an amp regardless of the overall circuit voltage. If a switch is going to get hot at 1 amp in a 125V AC circuit it will also get hot at 1 amp in a 12V DC circuit. So it's probably safest to look at current capacity and voltage as separate parameters when selecting a switch. Phil Maley Perth Australia ------------------------------ Date: Sat, 20 Dec 2003 04:30:58 EST From: LJHusky1@wmconnect.com To: krnet@mylist.net Subject: KR>KR Information Message-ID: <37.423bc220.2d1570d2@wmconnect.com> Content-Type: text/plain; charset="US-ASCII" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 15 I am new to this group and would love to have some information about the KR. I am wondering if there is any way to up the gross weight. Bigger engine, extra spars. I am wanting to use a direct drive EA81 engine for my power plant. I really like the KR but need a little more gross weight. Any information would be great. Larry Husky ------------------------------ Date: Sat, 20 Dec 2003 05:53:12 -0600 From: larry flesner To: KRnet Subject: KR>Switch Ratings Message-ID: <3.0.6.32.20031220055312.00877c50@pop.midwest.net> In-Reply-To: <012401c3c6db$819c56b0$0301a8c0@wotech.net> References: <004101c3c6cf$0e73b5e0$75a0fea9@johnjane> Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Precedence: list Message: 16 >One thing to remember is that an amp is an amp regardless of the overall >circuit voltage. If a switch is going to get hot at 1 amp in a 125V AC >circuit it will also get hot at 1 amp in a 12V DC circuit. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ It would appear that several posters missed the point on why a switch will handle less DCV than ACV. When a switch contact closes the current will start flowing before the contact closes. It will arc across the gap when conditions are right. The same happens when the contact opens. The current continues to flow in the form of an arc as the contacts open until it can no longer jump the gap. The DCV will sustain the arc longer than ACV and thus "burn", "pit" and otherwise destroy the contact much faster. Some better quality switches will use gold plated contacts and such things as the contacts making a swipping action on open and close to help clean the contacts. I randomly opened switch bodies to check the contacts of a failed switch in my 33 years with Xerox and it is amazing what you will see and the switch only failing intermittently. One suggestion for those high current circuits where you are concerned with switch failure is to use a high amp rated relay to carry the circuit current and the switch to energize the relay where it only carries a very low coil current. You can get a good quality Bosch 30 amp (small body), multi-contact relay for under $5 with a little searching. I wouldn't trust the "made in Mexico" relays from Auto Zone or similar suppliers. This is not a dig at our neighbors south of the border but applies to poor quality components regardless of where they are made. Many will say that you double the number of components that could fail but I'm convinced you will be reducing the odds that they will do so. Just my non scientific gut feel. I've not seen the book several poster have mentioned but I've heard from other sources that it is very good. I should have put it on my Christmas list. Larry Flesner Carterville, Illinois ------------------------------ Date: Sat, 20 Dec 2003 07:00:18 -0600 From: "JIM VANCE" To: "krnet" Subject: KR>Switches--again Message-ID: <005501c3c6f9$ddd53640$0800a8c0@oemcomputer> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 17 The voltage passing through a switch is significant only when designing = the insulation. The power that a switch dissipates is the current passing through the = switch times the voltage DROP across the switch. For example, if a = switch has a voltage drop of 0.01 volts and is passing ten amperes, it = will be dissipating 0.1 watts. If the contacts get bad and the voltage = drop is two volts with a current of ten amperes, the switch is = dissipating 20 watts. That's why a bad switch will get worse very = quickly. Every time a switch opens or closes, an arc results. If the current is = more than an ampere, that arc will "clean" the contacts. However, with = the new solid state technology, we sometimes have switches that are = passing microamperes. There is no arc, so dust and oxidation can build = up and cause the switch to perform intermittently. That is why good = quality electronics equipment will use gold plated contacts to eliminate = the oxidation. A C switch ratings versus D C is a whole different ballgame. It is a = function of how quickly the arc is quenched when the switch is opened. = As the alternating current goes from positive to negative, it passes = through zero. If the switch has just begun to open and it is arcing, as = the voltage goes through zero, the arc goes out. Once the arc has shut = off, it probably won't reignite. When you open the switch on a D C circuit, the arc starts and keeps on = going until the switch contacts are far enough away to cause the arc to = quench. Switches designed for high D C current usually have a snap = action so that the contact is broken quickly. They also usually have = more metal in the contacts to dissipate the heat and to compensate for = the metal lost to arcing. When you see volt-ampere ratings on a switch, that switch is probably = designed to control a motor. A motor will draw several times as many = amperes as it starts than it will when running. Obviously, that takes a = very strong switch. If anyone has further questions or comments, please contact me off-line. Jim Vance = Vance@ClaflinWildcats.com ------------------------------ Date: Sat, 20 Dec 2003 08:31:54 -0500 From: "Orma Robbins" To: "KRnet" Subject: KR>Aircraft Parts Message-ID: <010d01c3c6fd$a33d3970$5dcb4944@ROBBINS1> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 18 Seasons Greatings to all Netters, and may your favorite Santa be kind to = each of us and leave a GPS or other Aircraft goodie under our trees. =20 With all the discussion of switches and ratings and such, I offer this = reminder. We have the right to install what ever we choose in our home = builts, but we must constantly tell ourselves that we are building = aircraft and having an operational failures usually occures when we are = in the air, which is unacceptable. I have found that it is easier to = buy the correct type of part if we stick with aviation supply houses. = Even then you must investigate to make sure that the part you want to = use is designed for that purpose. I have seen KR with all sorts of non = aviation items. In building my KR 19 years ago, even I violated good = practice. And today occasionally I find that I must upgrade a part or = component in the name of safety and reliability. Orma aka AviationMech 19 Years flying the KR-2 36 Years in Aviation AP/IA From robertjtallini@earthlink.net Sat Dec 20 06:37:28 2003 Received: from pintail.mail.pas.earthlink.net ([207.217.120.122]) by lizard.esosoft.net with esmtp (Exim 3.36 #1) id 1AXiES-0003Sl-00 for krnet@mylist.net; Sat, 20 Dec 2003 06:37:28 -0800 Received: from bigbird.psp.pas.earthlink.net ([207.217.78.244]) by pintail.mail.pas.earthlink.net with esmtp (Exim 3.33 #1) id 1AXi3T-0005M1-00 for krnet@mylist.net; Sat, 20 Dec 2003 06:26:07 -0800 Message-ID: <8539000.1071930367305.JavaMail.root@bigbird.psp.pas.earthlink.net> Date: Sat, 20 Dec 2003 08:26:06 -0600 (GMT-06:00) From: robert tallini To: krnet@mylist.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Earthlink Zoo Mail 1.0 Subject: KR>airfoil design X-BeenThere: krnet@mylist.net X-Mailman-Version: 2.1b3 Precedence: list Reply-To: robert tallini , KRnet List-Id: KRnet List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Help: Please bear with me as this is a new computer and I'm having a little trouble getting used to it. The question I have for anyone who would care te express an opinion concerns the airfoil for a KR2S. The design I would like to use is the one Roy Marsh developed for the KR2S prototype. It is a modified NACA 230012. Roy won the Sun & Fun 'under 100 hp' race at a speed of 190 mph. He cruised at 160 and stalled at 45-50 depending on load. He was usiung a RevMaster VW 80 hp turboed engine. The question I have concerns the depth of the main spar. It would be limited to 5 1/2" at the root and 4" at the tip. Roy used 3/32" ply web on both faces of both spars and in addition he attached a 5/8" spruce strip at the top and bottom of both spars to form an I beam effect. I would prefer to use 3/16" webs and omit the spruce strips. I have no idea whether I would be cutting a safety corner. I would appreciate any comments. Thanks, Bob Tallini. ------------------------------ Date: Sat, 20 Dec 2003 09:04:31 -0600 From: "Mark Langford" To: "KRnet" Subject: Re: KR>airfoil design Message-ID: <004701c3c70a$92d8d4b0$1202a8c0@basement> References: <8539000.1071930367305.JavaMail.root@bigbird.psp.pas.earthlink.net> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 19 Bob Tallini wrote: >>The design I would like to use is the one Roy Marsh developed for the KR2S prototype. It is a modified NACA 230012. << Bob, I just plain wouldn't use a 23012, no matter how modified it was. Although it was used on everything from Cherokees to Bonanzas, the stall characteristic is not something you want to intentionally build into any new aircraft. Visit http://home.hiwaay.net/~langford/23012.gif and notice how the wing stalls very abruptly. It goes from flying to stalled almost instantly (the "cliff-like" plot on the left). I believe Roy once told me he had to land at about 80 mph, and that doesn't surprise me. Why not use an airfoil that was designed specifically for the KR2S by modern methods with one of the design goals being a reasonable stall speed and gentle stall characteristic (gradual). If you haven't seen it, visit http://www.krnet.org/as504x/ for the details, and check the same curves. You'll see something a lot more gentle. Making the spar thinner will give you problems with gear mounting, wing tank capacity will be significantly reduced, and you have the strength problem (weight will go up) that you're now faced with. Yes, Roy did it, but Roy also sold his plane after a few short years. Ron Lee bought it, flew a few times, and sold it quickly. Not sure if anybody's flying it now, but I'm not convinced you really want to replicate that wing. Funny thing about that plane is that it's the "poster child" for RR's KR2S advertisements, although the wing is a completely different animal than the plans call for. If you really want to do this, I've temporarily posted some "shareware" software that will do that analysis for you at http://home.hiwaay.net/~langford/spar.zip . Plug in the dimensions and characteristics for a stock wing, then plug in the dimensions for yours, and then tweak caps and plywood dimensions until you get strength numbers the same or better than stock. This is just an approximation, as there are fine points of plywood layers and such that probably enter into it, but it's a good "ballpark" method of making sure you don't do anything stupid. Still, I wouldn't touch that airfoil with a ten foot pole. You mention this airfoil to an aerodynamicist, and he'll start shaking his head. Yes, I know Roy's son is an aero engineer, and he specified this airfoil, but he didn't have the AS504x airfoil at his disposal, and he didn't have to fly it... Mark Langford, Huntsville, AL N56ML "at" hiwaay.net see KR2S project at http://home.hiwaay.net/~langford ------------------------------ Date: Sat, 20 Dec 2003 09:13:03 -0600 From: "Mark Jones" To: "KR Net" Subject: KR>Builder in UK needs help. Message-ID: <004c01c3c70b$c3ed91c0$6401a8c0@wi.rr.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Message: 20 There is a gentleman in the UK who is having trouble getting a rpm drop = when he applied carb heat. His inspector wants this resolved before = signing off his plane. If anyone can help him please e-mail him direct = with your responses. As far as I know he is not on the Net. Thanks >original message >,- the engine is a Revmaster 2100D fitted to my KR2. It seems to run as = well with carb heat as without. Prop is 52" by 46" and >runs at 2950 rpm = static. Merry Christmas to = you and yours.. Mac UK > = macwood@tinyworld.co.uk Mark Jones (N886MJ) Wales, WI USA=20 E-mail me at flykr2s@wi.rr.com Visit my KR-2S CorvAIRCRAFT web site at =20 http://mywebpage.netscape.com/n886mj/homepage.html ------------------------------ Date: Sat, 20 Dec 2003 07:26:17 -0900 From: Thomas Brock To: KRnet Subject: Re: KR>KR Information Message-ID: <3FE477D2.CD437A84@arctic.net> References: <37.423bc220.2d1570d2@wmconnect.com> Content-Type: text/plain; charset=us-ascii; x-mac-type="54455854"; x-mac-creator="4D4F5353" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 21 Hi Larry, I am new to the group also. I've been a netter for only about a week, but the folks here has been fabulously helpful. I'm not a builder, but a person who wants to buy a completed KR to learn how to fly in. I also want a plane that will carry two "average size middle aged adults." Today's pilots are heavier than they were 50 years ago. My instructor and I would weigh in about 250 pounds each. Therefore, I would definitely need to have a KR that would fly with a heavier gross weight. Please let me know what you find out. Also, if you are a builder or have a plane that would carry 2 good sized adults for sale, let me know. Best wishes, Thomas Brock LJHusky1@wmconnect.com wrote: > I am new to this group and would love to have some information about the KR. > I am wondering if there is any way to up the gross weight. Bigger engine, > extra spars. I am wanting to use a direct drive EA81 engine for my power plant. > I really like the KR but need a little more gross weight. Any information > would be great. > > Larry Husky > _______________________________________________ > see KRnet list details at http://www.krnet.org/instructions.html ------------------------------ Date: Sat, 20 Dec 2003 08:46:15 -0800 From: rwdw2002@yahoo.com To: krnet@mylist.net Subject: KR>Recommendation from Rick Wilson Message-ID: <200312201646.hBKGkFiF032083@redbaron.barnstormers.com> Precedence: list Message: 22 Rick Wilson recommends the following Barnstormers classified ad (click on link) http://www.barnstormers.com/listing.php?id=22835 68x60 wood prop AOL users, use this link: http://www.barnstormers.com/listing.php?id=22835 ------------------------------ Date: Sat, 20 Dec 2003 09:40:21 -0700 From: lloyd schultz To: KRnet Subject: Re: KR>airfoil design Message-ID: <3FE47B75.E1D730BA@earthlink.net> References: <8539000.1071930367305.JavaMail.root@bigbird.psp.pas.earthlink.net> <004701c3c70a$92d8d4b0$1202a8c0@basement> Content-Type: text/plain; charset=us-ascii MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: list Message: 23 Mark- Which Cherokee used the 23012? I've flown several airplanes that use 23012, none of which were threatening. Aren't the flight characteristics of a wing nearly as dependent on aspect ratio, geometric twist, wing loading, high-lift devices, stall strips and planform...to name a few...as the section used? I believe you're correct that the Bonanza used 23012 (for most of the outer portion of the wing)...but I always found them one of the most docile airplanes out there. I can't help thinking that making a "sweet"-flying wing is like baking a really good pastry...it's as much a result of the chef's ability as the vitals used. No? -Lloyd Schultz Mark Langford wrote: > Bob Tallini wrote: > > >>The design I would like to use is the one Roy Marsh developed for the KR2S > prototype. It is a modified NACA 230012. << > > Bob, I just plain wouldn't use a 23012, no matter how modified it was. > Although it was used on everything from Cherokees to Bonanzas, the stall > characteristic is not something you want to intentionally build into any new > aircraft. Visit http://home.hiwaay.net/~langford/23012.gif and notice how > the wing stalls very abruptly. It goes from flying to stalled almost > instantly (the "cliff-like" plot on the left). I believe Roy once told me > he had to land at about 80 mph, and that doesn't surprise me. Why not use > an airfoil that was designed specifically for the KR2S by modern methods > with one of the design goals being a reasonable stall speed and gentle stall > characteristic (gradual). If you haven't seen it, visit > http://www.krnet.org/as504x/ for the details, and check the same curves. > You'll see something a lot more gentle. > > Making the spar thinner will give you problems with gear mounting, wing tank > capacity will be significantly reduced, and you have the strength problem > (weight will go up) that you're now faced with. Yes, Roy did it, but Roy > also sold his plane after a few short years. Ron Lee bought it, flew a few > times, and sold it quickly. Not sure if anybody's flying it now, but I'm > not convinced you really want to replicate that wing. > > Funny thing about that plane is that it's the "poster child" for RR's KR2S > advertisements, although the wing is a completely different animal than the > plans call for. > > If you really want to do this, I've temporarily posted some "shareware" > software that will do that analysis for you at > http://home.hiwaay.net/~langford/spar.zip . Plug in the dimensions and > characteristics for a stock wing, then plug in the dimensions for yours, and > then tweak caps and plywood dimensions until you get strength numbers the > same or better than stock. This is just an approximation, as there are fine > points of plywood layers and such that probably enter into it, but it's a > good "ballpark" method of making sure you don't do anything stupid. > > Still, I wouldn't touch that airfoil with a ten foot pole. You mention this > airfoil to an aerodynamicist, and he'll start shaking his head. Yes, I know > Roy's son is an aero engineer, and he specified this airfoil, but he didn't > have the AS504x airfoil at his disposal, and he didn't have to fly it... > > 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: Sat, 20 Dec 2003 08:48:06 -0800 From: rwdw2002@yahoo.com To: krnet@mylist.net Subject: KR>Recommendation from Rick Wilson Message-ID: <200312201648.hBKGm6ti000365@redbaron.barnstormers.com> Precedence: list Message: 24 Rick Wilson recommends the following Barnstormers classified ad (click on link) http://www.barnstormers.com/listing.php?id=22836 68x60 prop AOL users, use this link: http://www.barnstormers.com/listing.php?id=22836 ------------------------------ _______________________________________________ See KRnet list details at http://www.krnet.org/instructions.html End of KRnet Digest, Vol 255, Issue 1 *************************************