From: krnet-bounces+johnbou=speakeasy.net@mylist.net To: John Bouyea Subject: KRnet Digest, Vol 346, Issue 227 Date: 12/2/2004 8:59:33 PM 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. RE: spars (Stephen Jacobs) 2. Spars and extra materials (Colin & Bev Rainey) 3. RE: spars (Donald Reid) 4. Re: canopy construction (Joseph H. Horton) 5. Re: Spars and extra materials (gleone) 6. Redoing the WAFS (Serge VIDAL) 7. Re: Redoing the WAFS (larry severson) 8. Re: Redoing the WAFS (VIRGIL N SALISBURY) 9. Federal Do Not Call List (JIM VANCE) 10. Re: Federal Do Not Call List and a KR question (David Lininger) 11. Bent Spars = Big Flaps? (Tom Boyett) ---------------------------------------------------------------------- Message: 1 Date: Thu, 2 Dec 2004 07:50:40 +0200 From: "Stephen Jacobs" Subject: RE: KR> spars To: "'KRnet'" Message-ID: <000001c4d832$df015f30$6a64a8c0@stephen> Content-Type: text/plain; charset="us-ascii" What's the common thinking about making the main spar one piece? +++++++++++++++++++ I share your discomfort here John, plus a few others. I accept that the KR spar is stronger than a brick outhouse and there have been no reported failures etc. etc. It still worries me. As ever, I express my views in the hopes that the more informed among us will step in and put me straight. It is not so much the strength of the WAF's that concerns me, it is drilling all those holes in the spar (cap). Even the landing gear mounts require holes drilled in the upper and lower spar cap at the very point of highest load (almost). I cannot bring myself to do this - my intention is to add a wider pillar between the caps where the undercarriage mounts, add a 2mm 4130 "back-plate" behind the spar - then drill the mounting holes through the pillar - not the spar caps. This way the legs are sort of clamped to the spar without any holes in the load bearing caps - maybe even one size up on the ply web between the legs (and the necessary precautions against stress risers). I may compromise by having holes in the top cap (no plans for any inverted flight any time soon). The above approach is probably not acceptable for the WAF's, so this is my chosen way to deal with this particular concern and a few other short-comings at the same time. I plan to build a bent, laminated spar with the dihedral starting at the fuselage (as suggested by Mark L on his web site). Riley Collins has already done this and it worked out great. The next trick is to relocate the WAF's outboard to about half span. I.e. the centre section spar is "bent" up just as it passes through the fuselage side - and continues further out. = the load on the WAF's is now substantially reduced (shorter moment) so using the same (or similar) WAF design and material will substantially improve the margin. = doing away with the crank wing may look nicer to some of us - I personally like the way a KR looks anyway. = Fuel tanks (centre section) will drain better. = Flaps of better proportions. Take care Steve J ------------------------------ Message: 2 Date: Thu, 2 Dec 2004 04:10:24 -0500 From: "Colin & Bev Rainey" Subject: KR> Spars and extra materials To: "KRnet" Message-ID: <007f01c4d84e$c253d860$2d432141@RaineyDay> Content-Type: text/plain; charset="iso-8859-1" Netters Search the archives and I am sure you will find a comment from one of the more learned builders cautioning against randomly adding your own "reinforcements" to assemblies with out first testing the results. The WAFS have never failed when properly built, and I fly behind them and trust them fully. The wrappings of carbon fiber I believe is a BAD idea. Many metals gain their strength in their ability to flex with loads, not remain rigid. If you stiffen the WAFs with carbon fiber, the mixing of the two materials may lead to the initial loads being taken by the CF and then when it breaks, abruptly load the WAFs instead of a gradual load causing them to be stressed by a snapping shearing force instead of a tensile gradually applied load. This sudden load may exceed the strength of the WAF when normally it would not due to the sudden application of force. Also future inspection becomes impossible and it is possible to then have what is now a BAD problem with Long Eze and Vari Eze aircraft where the wing attach hardware is being found to have corroded and allow the wing to fall off if not replaced. You would not be able to see the corrosion buildup, until during pre-flight you noticed excessive movement of the wing. What the builder did who built mine is he extended the wood through the front WAFs so that the bolts travel through the WAF AND the wood in order to connect the wings, making for as close to solid wings as you can get with them still removable. Other areas of the aircraft are going to give you problems way before the WAFs do, focus on those areas, and don't try to re-invent the wheel. That part aint broke, so don't try to "fix it". FLY SAFE! Colin & Bev Rainey KR2(td) N96TA Sanford, FL crainey1@cfl.rr.com http://kr-builder.org/Colin/index.html ------------------------------ Message: 3 Date: Thu, 02 Dec 2004 05:24:21 -0500 From: Donald Reid Subject: RE: KR> spars To: KRnet Message-ID: <6.1.0.6.2.20041202051037.01af7fc0@mail.peoplepc.com> Content-Type: text/plain; charset="us-ascii"; format=flowed Every few years, we go through a long thread of discussion about spar re-design. In this recent set, the one thing that is apparent is that the people talking about making major changes in the spar do not have any training in structural design. This is not an area where you design by eye-ball engineering. You can NOT say "well, that looks about right" and expect to have an acceptable product. Ken Rand and Stu Robinson where not experts in airplane structures, but they did not need to be. They copied an existing design and did not screw around with it. The only potential good result that I can see coming from this recent set of discussions is that most of the planes will never be finished. They will languish in a shop or hanger for years, with occasional periods of unfruitful effort by an increasingly discouraged builder. The unfinished project will finally be sold to some unsuspecting potential pilot and so on and so on and so on. If you do not know what you are doing, then DON'T DO IT. Built more-or-less to plans, the KR wing structure is acceptable. It is not (as someone recently implied) perfect but it is good enough. Don Reid - donreid "at" peoplepc.com Bumpass, Va Visit my web sites at: AeroFoil, a 2-D Airfoil Design And Analysis Computer Program: http://aerofoilengineering.com KR2XL construction: http://aerofoilengineering.com/KR/KR2XL.htm Aviation Surplus: http://aerofoilengineering.com/PartsListing/Airparts.htm EAA Chapter 231: http://eaa231.org Ultralights: http://usua250.org VA EAA State Fly-in: http://vaeaa.org ------------------------------ Message: 4 Date: Thu, 2 Dec 2004 05:46:41 -0500 From: "Joseph H. Horton" Subject: Re: KR> canopy construction To: krnet@mylist.net Message-ID: <20041202.054642.1172.0.joe.kr2s.builder@juno.com> Content-Type: text/plain; charset=us-ascii On Wed, 1 Dec 2004 20:01:52 -0500 "Fritz" writes: > Let me try again, I understand a Todd's canopy is fairly thin and > flexible.My original > question was if I could build the canopy surround before I installed > the plexiglas. > It appears that most guys glue it in first,I can't see myself lying > on my back trying > to reinforce the surround. > sin. Fritz Fritz I had made a reverse jig out of wood that fit over the front and rear of the frame and side rails to keep the shape along each edge. This created a box of sorts. Then I turned it over and did all the reinforcing and windscreen installation on the floor. It turned out good enough for KR work. Joe Horton joe.kr2s.builder@juno.com ------------------------------ Message: 5 Date: Thu, 2 Dec 2004 08:15:48 -0700 (Mountain Standard Time) From: "gleone" Subject: Re: KR> Spars and extra materials To: "KRnet" Message-ID: <41AF31A4.000004.03776@YOUR-FD6NVJCER4> Content-Type: Text/Plain; charset="iso-8859-1" I should clarify what I'm doing. The CF will be on the spar and the WAF's will attach as normal. Doing: WAF-CF-SPAR-CF-WAF. NOT doing: CF-WAF-SPAR-WAF-CF. This arrangement will add strength to the spars where the WAF's attach yet the WAF's will still have flex and can still be inspected. Gene Leone, Worland, Wyoming "Michael Moore is a living example to NEVER trust ANYONE who's bigger around than they are tall!" -------Original Message------- From: Colin & Bev Rainey Date: 12/02/04 02:11:15 To: KRnet Subject: KR> Spars and extra materials Netters Search the archives and I am sure you will find a comment from one of the more learned builders cautioning against randomly adding your own reinforcements" to assemblies with out first testing the results. The WAFS have never failed when properly built, and I fly behind them and trust them fully. The wrappings of carbon fiber I believe is a BAD idea. Many metals gain their strength in their ability to flex with loads, not remain rigid. If you stiffen the WAFs with carbon fiber, the mixing of the two materials may lead to the initial loads being taken by the CF and then when it breaks, abruptly load the WAFs instead of a gradual load causing them to be stressed by a snapping shearing force instead of a tensile gradually applied load. This sudden load may exceed the strength of the WAF when normally it would not due to the sudden application of force. Also future inspection becomes impossible and it is possible to then have what is now a BAD problem with Long Eze and Var! i Eze aircraft where the wing attach hardware is being found to have corroded and allow the wing to fall off if not replaced. You would not be able to see the corrosion buildup, until during pre-flight you noticed excessive movement of the wing. What the builder did who built mine is he extended the wood through the front WAFs so that the bolts travel through the WAF AND the wood in order to connect the wings, making for as close to solid wings as you can get with them still removable. Other areas of the aircraft are going to give you problems way before the WAFs do, focus on those areas, and don't try to re-invent the wheel. That part aint broke, so don't try to "fix it". FLY SAFE! Colin & Bev Rainey KR2(td) N96TA Sanford, FL crainey1@cfl.rr.com http://kr-builder.org/Colin/index.html _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net please see other KRnet info at http://www.krnet.org/info.html ------------------------------ Message: 6 Date: Thu, 2 Dec 2004 17:27:20 +0100 From: "Serge VIDAL" Subject: KR> Redoing the WAFS To: KRnet Message-ID: Content-Type: text/plain; charset="us-ascii" OK, thanks to all of you who sent me advice on how to resurface and repaint the WAFs. If I understand well, the best thing would be to cadmium plate the WAFs, but since this is not an easy option, the next best thing seems to be to prime them. For priming, the consensus seems to be to use two parts Epoxy primer, rather than Zinc chromate primer. So, I will see what the local hardware store has to offer on that department. To remove the rust stains on the spars, the best solution is to sand, and recoat with Epoxy. I suppose 5 minutes Epoxy will be good enough for that. Now, considering that my plane has spent most of its life by the sea, including a nasty six months episode in a harbour customs warehouse in Tunis, the WAFS are in surprisingly good shape. The paint has flaked, and there is some surface corrosion, but no trace of pitting or fretting. The holes are pretty clean, and still perfectly round. I did some advanced research on corrosion repair and treatment (meaning that I read the relevant chapter of the AC-43 13 standard ;-)). On the chapter dedicated to highly stressed steel parts, they say one should not use power tools to remove the rust, because this could cause overheating the part, and therefore ruin the original heat treatment. Luckily, for surface cleaning, I have a secret weapon: rotary Nylon brushes. Serge Vidal KR2 ZS-WEC Paris, France ------------------------------ Message: 7 Date: Thu, 02 Dec 2004 08:33:27 -0800 From: larry severson Subject: Re: KR> Redoing the WAFS To: KRnet Message-ID: <5.2.1.1.0.20041202083231.026ce008@pop-server.socal.rr.com> Content-Type: text/plain; charset="us-ascii"; format=flowed > For priming, the consensus seems to be to use >two parts Epoxy primer, rather than Zinc chromate primer. So, I will >see what the local hardware store has to offer on that department. I doubt that your local hardware store will have either. Try the Internet. Larry Severson Fountain Valley, CA 92708 (714) 968-9852 larry2@socal.rr.com ------------------------------ Message: 8 Date: Thu, 2 Dec 2004 17:08:56 -0500 From: VIRGIL N SALISBURY Subject: Re: KR> Redoing the WAFS To: krnet@mylist.net Message-ID: <20041202.172126.3308.2.virgnvs@juno.com> Content-Type: text/plain; charset=us-ascii read the item, re putting epoxy in the bolt holes and assembling. goot n tight fit, Virg On Tue, 30 Nov 2004 10:04:50 -0500 "Orma" writes: > the intention is to clean > > Hello Serge > > Rust will pit the metal as well as flake. I would bead blast the > WAF's to > make sure that all the corrosion was removed. I would also sand and > reseal > the spars, while you have access to them. Also check the bolt holes > for fit > and the remainder of any rust. > > Orma > Southfield, MI > N110LR celebrating 20 years > Flying, flying and more flying http://www.kr-2.aviation-mechanics.com/ > > > > _______________________________________ > Search the KRnet Archives at > http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to KRnet-leave@mylist.net > > please see other KRnet info at http://www.krnet.org/info.html > > Virgil N. Salisbury - AMSOIL www.lubedealer.com/salisbury Miami ,Fl ------------------------------ Message: 9 Date: Thu, 2 Dec 2004 20:26:18 -0600 From: "JIM VANCE" Subject: KR> Federal Do Not Call List To: , "krnet" , "ray weygandt" , , "Rodene Doty" , "Terry Chisek" , "William Olsen" Message-ID: <003101c4d8df$b2d49780$0600a8c0@oemcomputer> Content-Type: text/plain; charset="iso-8859-1" According to a message I have received from the A F Academy Association of Graduates, the FCC has recently authorized the publishing of a directory of cell phone numbers. That means that the tele-marketers will be able to call you with their wonderful offers, unless you have opted out. To do this, go to www.donotcall.gov. It will permit you to verify if your home phone is on the llist. Mine was not, although I had placed it on the Kansas list. It will also allow you to list your cell phone number. You can also get on the list by calling 1.888.382.1222. However, you MUST call from the phone that you want to have on the Do Not Call list. Thought you might want to know. Jim Vance@ClaflinWildcats.com ------------------------------ Message: 10 Date: Thu, 02 Dec 2004 21:25:39 -0600 From: David Lininger Subject: Re: KR> Federal Do Not Call List and a KR question To: KRnet Message-ID: <41AFDCB3.50702@positech.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed JIM VANCE wrote: >According to a message I have received from the A F Academy Association of Graduates, the FCC has recently authorized the publishing of a directory of cell phone numbers. That means that the tele-marketers will be able to call you with their wonderful offers, unless you have opted out. > >To do this, go to www.donotcall.gov. It will permit you to verify if your home phone is on the llist. Mine was not, although I had placed it on the Kansas list. It will also allow you to list your cell phone number. > >You can also get on the list by calling 1.888.382.1222. However, you MUST call from the phone that you want to have on the Do Not Call list. > >Thought you might want to know. > > See http://urbanlegends.about.com/library/bl_cell_phone_directory.htm for more information. Some years ago (>10) I started building my KR2. I managed to get the fuse sides built before other things interferred and I had to stop working. I know that the T88 I bought back then probably should not be used for the plane, but what about the glue joints I made back then? The sides have never been exposed to weather, but they have been flat on the worktable in the shed all this time. Should I start over, or will these be okay to continue? If I can use these sides yet, I want to at least get to the boat stage during the spring and summer building season (no heat or a/c in the shed). -- 73, David, kb0zke Rev. 2:10c ------------------------------ Message: 11 Date: Thu, 2 Dec 2004 22:30:56 -0600 From: "Tom Boyett" Subject: KR> Bent Spars = Big Flaps? To: Message-ID: <008a01c4d8f0$e42b2540$0e02a8c0@TOMSCOMPUTER> Content-Type: text/plain; charset="iso-8859-1" As Mark L has mentioned, the bent spars offer many advantages and one that really interests me is a flap that starts at the fuselage and extends outboard of the stub wing. This creates the potential for some very effective flaps. As I don't yet own a set of plans, I'm uncertain of the rear spar WAF junction and how one would hinge the flap. I assume the rear spar sweeps forward at the WAF, which creates a discontinuity for a hinge line. How would you guys do it? ------------------------------ _______________________________________________ See KRnet list details at http://www.krnet.org/instructions.html End of KRnet Digest, Vol 346, Issue 227 *************************************** ================================== ABC Amber Outlook Converter v4.20 Trial version ==================================