KR> Double shear WAFs
The analysis of the failure mode of the KR WAFs done by Don Reid starts on page 46 of the set of newsletters located at http://www.krnet.org/newsletter/nl5.pdf . He practically wrote the whole newsletter that month. In another analysis he sent to the list in 1998, Don made the following comment in answering a similar question about the roll of clamping force in holding the WAFs in contact with the spars: "The frictional load can not be used in the structural analysis. The wood will expand and contract due to weather, the metal in the fittings and bolts will expand and contract with temperature. The ONLY way to calculate the stresses is to assume that they are transferred in the bolts bearing on the wood." This is steel on wood, of course, rather than the steel to steel joint that we were talking about, but shows that neglecting friction is not uncommon. The page before Don's article (page 45) was Jim Hill's KR2. He passed away several years ago now, but this plane was my first KR ride, and Jim turned out to be one of my very best friends. I now own his hangar. A lesson learned was that he hooked up ram air to the front of the carb and went for a test flight. On climbout the more speed he picked up, the leaner it ran, until it finally quit on downwind. Problem was the airport was one-way due to high trees on the end, so he landed very long and ended up in the cotton field off the end of the runway, breaking the tail off the plane. This was about the time I'd done the tail airfoils, so we outfitted his plane with the new horizontal and vertical stabs, rudder, and elevator, and added another bay to it to make it "almost" a KR2S. He reported the difference was amazing. My point though is that even a simple change like ram air can make a huge difference. Our theory was that pressurizing the carb without pressurizing the float bowl reduced the gravity fuel flow to a level the engine could no longer run on. There was a little tube hanging around that should probably have been connected to the ram air source. At least I think that was a float carb...if not, the tube was an overflow or something...that was a long time ago. But the fact remains that even something as simple as adding ram air can be a serious matter with unintended consequences. For those who haven't looked through the newsletters, you don't know what you're missing. Time spent reading these things will save you more time than it takes to read them, and probably answer a lot of questions that you didn't know you had. The rest are at http://www.krnet.org/newsletter . See y'all in McMinnville...arriving early Thursday afternoon... Mark Langford ML at N56ML.com http://www.n56ml.com
KR> KR Gathering
Doesn't matter when you text if your phone is like my wife's. Her phone's auto correct has Tourettes syndrome. What it spits out shouldn't be heard in public. John Melvin In a message dated 8/31/2015 8:46:25 A.M. Mountain Daylight Time, krnet at list.krnet.org writes: Thats why you shouldn't text and drive even on blue tooth. You never know what your phone will say. On Aug 31, 2015 9:32 AM, "Mike Arnold" wrote: > Then could you possibly give me a phone call sometime when you have a few > minutes I'd really like to ask you a few questions I'm new to the KR to > thing and new decay Arnett so I sure would appreciate a call if you can let > me know and I'll send you my phone number > On Aug 31, 2015 9:29 AM, "Mike Arnold" wrote: > >> My wife and I are going to take the motorhome out for a few days this >> weekend how can I find some kartoos within driving distance of Springfield >> Missouri >> On Aug 31, 2015 8:42 AM, "Dan Prichard via KRnet" >> wrote: >> >>> Looks like the weather forecast for the event will be great. Sunny, >>> winds out of the NW and temps in the 70's. Smoke from the wild fires should >>> stay to the East of Mt Hood. >>> >>> Dan Prichard >>> >>> Sent from my iPhone >>> ___ >>> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >>> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org >>> please see other KRnet info at http://www.krnet.org/info.html >>> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to >>> change options >>> >> ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
KR> bolt torque?
Larry is correct in that a tightened fastener stretches. We use torque because it is easier to measure. Based on the physical characteristics of the metal, the amount of torque applied vs. thread configuration can be used to calculate the approximate stretch of the fastener which, based on the tensile strength and elongation characteristics of the material, can be used to determine the 'clamp force' being applied to the joint. That's an oversimplification, but as others have said, is probably close enough for KR work. This is why for some applications new fasteners are recommended due to the fatigue factor involved in repeated stretching in high force applications. As usual, your mileage may vary. Mark W N952MW --- Larry Flesner said -Original Message- bolt torque? When a bolt is tightened (torqued) the bolt will stretch. Measuring the "stretch" will indicate the amount of torque. Probably more accurate than measuring with the wrench as other factors can cause a false reading. Larry Flesner --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
KR> KR Gathering
Good idea, Paul! There's a farm supply store just across from the airport. I am almost certain they sell aircraft grade rope ;) > On Aug 31, 2015, at 4:19 PM, Paul VISK via KRnet > wrote: > > I think a piece of rope in a good square knot should surfice. : ) > > > Paul ViskBelleville Il618-406-4705 > > Original message From: Mike Arnold via KRnet list.krnet.org> Date: 8/31/2015 3:42 PM (GMT-06:00) To: KRnet list.krnet.org> Cc: Mike Arnold Subject: Re: KR> KR > Gathering > Well that sounds like fun we should talk I'll see if my wife is interested > in going south lol > On Aug 31, 2015 12:37 PM, "James Babcock via KRnet" > wrote: > >> Mike, I have a flying, plans-built KR2 in Mt Home, AR if you come down >> this way. I can taxi you around in it but no flight because it doesn't have >> a seat belt for passenger. >> >> James Babcock > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options
KR> KR Gathering
I think a piece of rope in a good square knot should surfice. : ) Paul ViskBelleville Il618-406-4705 Original message From: Mike Arnold via KRnet Date: 8/31/2015 3:42 PM (GMT-06:00) To: KRnet Cc: Mike Arnold Subject: Re: KR> KR Gathering Well that sounds like fun we should talk I'll see if my wife is interested in going south lol On Aug 31, 2015 12:37 PM, "James Babcock via KRnet" wrote: > Mike, I have a flying, plans-built KR2 in Mt Home, AR if you come down > this way. I can taxi you around in it but no flight because it doesn't have > a seat belt for passenger. > > James Babcock >
KR> Torque
Sorry, I meant for the bolts holding the inboard and outboard spars together, Virg On 8/31/2015 3:23 PM, Nerobro via KRnet wrote: > I thought the limit on the WAF was the crush strength of the wood as > opposed to the strength of the bolts? > > On Mon, Aug 31, 2015 at 2:22 PM, Virgil N.Salisbury via KRnet < > krnet at list.krnet.org> wrote: > >> There is information some where as to the torque for each size >> bolt and thread pitch. A good reference, Virg >> >> >>
KR> KR Gathering
Well that sounds like fun we should talk I'll see if my wife is interested in going south lol On Aug 31, 2015 12:37 PM, "James Babcock via KRnet" wrote: > Mike, I have a flying, plans-built KR2 in Mt Home, AR if you come down > this way. I can taxi you around in it but no flight because it doesn't have > a seat belt for passenger. > > James Babcock > > Sent from my iPhone > > > On Aug 31, 2015, at 9:29 AM, Mike Arnold via KRnet > wrote: > > > > My wife and I are going to take the motorhome out for a few days this > > weekend how can I find some kartoos within driving distance of > Springfield > > Missouri > > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options >
KR> Reaming WAFs
There is information some where as to the torque for each size bolt and thread pitch. A good reference, Virg On 8/31/2015 2:15 PM, brian.kraut--- via KRnet wrote: > And that is almost how they are done on the Mustang 2. Those without > folding wings use a bolt and nut, but when using folding wings you use a > bolt ground to a bullet shaped end instead of threads and just bang it > in the hole. The wing gap seal has a piece on it that keeps them from > being able to back out. > > However, on the KR I do recommend a nut and if you are putting it on > might as well torque it correctly. Since you have two relatively thin > WAFs that can be bent a bit it is best to have them clamped together so > the bolt is really loaded only in shear as designed. >
KR> Reaming WAFs
Just to add my 2 cents of limited knowledge - I remember during my time as an airforce tech, torqueing a critical bolt so that the Length of the torqued bolt was *increased* by a set figure...what was all that about ?! Mac On Mon, Aug 31, 2015 at 1:31 PM, Robert7721 via KRnet wrote: > Concur with Mark. No need to get concerned about this one folks. I > actually did a bad thing and forgot to tighten one, I found it during > another maintenance check later. Probably flew with the nut loose for a > couple hundred hours but it didn't make any difference. > > > Rob Schmitt > > > > > -Original Message- > From: Mark Langford via KRnet > To: KRnet > Cc: Mark Langford > Sent: Sun, Aug 30, 2015 6:00 pm > Subject: Re: KR> Reaming WAFs > > > Nobody's shown me a torque for KR wing attach fittings. It's not in the > > plans. Why is that? Because friction was not even considered in the > > analysis of the wing attach joint. It was a pure shear calculation. > It's > simply a pinned joint, and safe enough on that basis alone. > > Although I'm > certainly not advocating anybody do this, you could likely > fly around with > cottered pins in place of the bolts to keep them from > sliding out of place, > and you'd be fine. I'm pretty sure there are > airplanes and ultralights that > use simple pinned joints. > > Sure, torquing the bolts to some reasonable number > is the common-sense > thing to do, and as Larry pointed out, people do exactly > that. > Calculating optimal torque for a lubricated fastener and nut is > > commendable, but not necessary. > > I'm a mechanical engineer, and recognizing > that it's simply a pinned > joint, I just torqued them by feel and got on with > my business. > Sure...considering friction would be nice, but the designer > simply can't > count on these connections being done perfectly, so he designs > them to > be foolproof, and then add a factor of safety on top of that. That's > > what we're dealing with on these WAFs. After all, this plane was touted > as > being buildable with only simple tools... > > > Mark > Langford > ML at N56ML.com > http://www.n56ml.com > > > > ___ > Search > the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe > from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet > info at http://www.krnet.org/info.html > see > http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options >
KR> Reaming WAFs
I thought the limit on the WAF was the crush strength of the wood as opposed to the strength of the bolts? On Mon, Aug 31, 2015 at 2:22 PM, Virgil N.Salisbury via KRnet < krnet at list.krnet.org> wrote: > > There is information some where as to the torque for each size > bolt and thread pitch. A good reference, Virg > > > On 8/31/2015 2:15 PM, brian.kraut--- via KRnet wrote: > >> And that is almost how they are done on the Mustang 2. Those without >> folding wings use a bolt and nut, but when using folding wings you use a >> bolt ground to a bullet shaped end instead of threads and just bang it >> in the hole. The wing gap seal has a piece on it that keeps them from >> being able to back out. >> >> However, on the KR I do recommend a nut and if you are putting it on >> might as well torque it correctly. Since you have two relatively thin >> WAFs that can be bent a bit it is best to have them clamped together so >> the bolt is really loaded only in shear as designed. >> >> > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options >
KR> KR Gathering
Mike, I have a flying, plans-built KR2 in Mt Home, AR if you come down this way. I can taxi you around in it but no flight because it doesn't have a seat belt for passenger. James Babcock Sent from my iPhone > On Aug 31, 2015, at 9:29 AM, Mike Arnold via KRnet > wrote: > > My wife and I are going to take the motorhome out for a few days this > weekend how can I find some kartoos within driving distance of Springfield > Missouri >
KR> KR Gathering
O K, Lighten up. Chuckle, chuckle, Virg On 8/31/2015 10:30 AM, Mike Arnold via KRnet wrote: > That supposed to be the letter K and the letter R and two not cartoons > On Aug 31, 2015 9:29 AM, "Mike Arnold" wrote: > >> My wife and I are going to take the motorhome out for a few days this >> weekend how can I find some kartoos within driving distance of Springfield >> Missouri >> On Aug 31, 2015 8:42 AM, "Dan Prichard via KRnet" >> wrote: >> >>> Looks like the weather forecast for the event will be great. Sunny, winds >>> out of the NW and temps in the 70's. Smoke from the wild fires should stay >>> to the East of Mt Hood. >>> >>> Dan Prichard >>> >>> Sent from my iPhone >>> ___ >>> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >>> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org >>> please see other KRnet info at http://www.krnet.org/info.html >>> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to >>> change options >>> > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options >
KR> Reaming WAFs
And that is almost how they are done on the Mustang 2. Those without folding wings use a bolt and nut, but when using folding wings you use a bolt ground to a bullet shaped end instead of threads and just bang it in the hole. The wing gap seal has a piece on it that keeps them from being able to back out. However, on the KR I do recommend a nut and if you are putting it on might as well torque it correctly. Since you have two relatively thin WAFs that can be bent a bit it is best to have them clamped together so the bolt is really loaded only in shear as designed. Original Message Subject: Re: KR> Reaming WAFs From: Mark Langford via KRnet List-Post: krnet@list.krnet.org Date: Sun, August 30, 2015 3:59 pm To: KRnet Cc: Mark Langford Although I'm certainly not advocating anybody do this, you could likely fly around with cottered pins in place of the bolts to keep them from sliding out of place, and you'd be fine. I'm pretty sure there are airplanes and ultralights that use simple pinned joints.
KR> KR Gathering
Thats why you shouldn't text and drive even on blue tooth. You never know what your phone will say. On Aug 31, 2015 9:32 AM, "Mike Arnold" wrote: > Then could you possibly give me a phone call sometime when you have a few > minutes I'd really like to ask you a few questions I'm new to the KR to > thing and new decay Arnett so I sure would appreciate a call if you can let > me know and I'll send you my phone number > On Aug 31, 2015 9:29 AM, "Mike Arnold" wrote: > >> My wife and I are going to take the motorhome out for a few days this >> weekend how can I find some kartoos within driving distance of Springfield >> Missouri >> On Aug 31, 2015 8:42 AM, "Dan Prichard via KRnet" >> wrote: >> >>> Looks like the weather forecast for the event will be great. Sunny, >>> winds out of the NW and temps in the 70's. Smoke from the wild fires should >>> stay to the East of Mt Hood. >>> >>> Dan Prichard >>> >>> Sent from my iPhone >>> ___ >>> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >>> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org >>> please see other KRnet info at http://www.krnet.org/info.html >>> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to >>> change options >>> >>
KR> KR Gathering
Then could you possibly give me a phone call sometime when you have a few minutes I'd really like to ask you a few questions I'm new to the KR to thing and new decay Arnett so I sure would appreciate a call if you can let me know and I'll send you my phone number On Aug 31, 2015 9:29 AM, "Mike Arnold" wrote: > My wife and I are going to take the motorhome out for a few days this > weekend how can I find some kartoos within driving distance of Springfield > Missouri > On Aug 31, 2015 8:42 AM, "Dan Prichard via KRnet" > wrote: > >> Looks like the weather forecast for the event will be great. Sunny, winds >> out of the NW and temps in the 70's. Smoke from the wild fires should stay >> to the East of Mt Hood. >> >> Dan Prichard >> >> Sent from my iPhone >> ___ >> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org >> please see other KRnet info at http://www.krnet.org/info.html >> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to >> change options >> >
KR> KR Gathering
That supposed to be the letter K and the letter R and two not cartoons On Aug 31, 2015 9:29 AM, "Mike Arnold" wrote: > My wife and I are going to take the motorhome out for a few days this > weekend how can I find some kartoos within driving distance of Springfield > Missouri > On Aug 31, 2015 8:42 AM, "Dan Prichard via KRnet" > wrote: > >> Looks like the weather forecast for the event will be great. Sunny, winds >> out of the NW and temps in the 70's. Smoke from the wild fires should stay >> to the East of Mt Hood. >> >> Dan Prichard >> >> Sent from my iPhone >> ___ >> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org >> please see other KRnet info at http://www.krnet.org/info.html >> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to >> change options >> >
KR> KR Gathering
My wife and I are going to take the motorhome out for a few days this weekend how can I find some kartoos within driving distance of Springfield Missouri On Aug 31, 2015 8:42 AM, "Dan Prichard via KRnet" wrote: > Looks like the weather forecast for the event will be great. Sunny, winds > out of the NW and temps in the 70's. Smoke from the wild fires should stay > to the East of Mt Hood. > > Dan Prichard > > Sent from my iPhone > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options >
KR> bolt torque?
At 08:30 AM 8/31/2015, you wrote: >Just to add my 2 cents of limited knowledge - I remember during my time as >an airforce tech, torqueing a critical bolt so that the Length of the >torqued bolt was *increased* by a set figure...what was all that about >Mac >+++ When a bolt is tightened (torqued) the bolt will stretch. Measuring the "stretch" will indicate the amount of torque. Probably more accurate than measuring with the wrench as other factors can cause a false reading. Larry Flesner
KR> Reaming WAFs
Concur with Mark. No need to get concerned about this one folks. I actually did a bad thing and forgot to tighten one, I found it during another maintenance check later. Probably flew with the nut loose for a couple hundred hours but it didn't make any difference. Rob Schmitt -Original Message- From: Mark Langford via KRnet To: KRnet Cc: Mark Langford Sent: Sun, Aug 30, 2015 6:00 pm Subject: Re: KR> Reaming WAFs Nobody's shown me a torque for KR wing attach fittings. It's not in the plans. Why is that? Because friction was not even considered in the analysis of the wing attach joint. It was a pure shear calculation. It's simply a pinned joint, and safe enough on that basis alone. Although I'm certainly not advocating anybody do this, you could likely fly around with cottered pins in place of the bolts to keep them from sliding out of place, and you'd be fine. I'm pretty sure there are airplanes and ultralights that use simple pinned joints. Sure, torquing the bolts to some reasonable number is the common-sense thing to do, and as Larry pointed out, people do exactly that. Calculating optimal torque for a lubricated fastener and nut is commendable, but not necessary. I'm a mechanical engineer, and recognizing that it's simply a pinned joint, I just torqued them by feel and got on with my business. Sure...considering friction would be nice, but the designer simply can't count on these connections being done perfectly, so he designs them to be foolproof, and then add a factor of safety on top of that. That's what we're dealing with on these WAFs. After all, this plane was touted as being buildable with only simple tools... Mark Langford ML at N56ML.com http://www.n56ml.com ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
KR> KR Gathering
Looks like the weather forecast for the event will be great. Sunny, winds out of the NW and temps in the 70's. Smoke from the wild fires should stay to the East of Mt Hood. Dan Prichard Sent from my iPhone
KR> Double shear WAFs
That's a great solution, similar to a lot of older sailplanes. On 8/31/2015 5:49 AM, Mark Langford via KRnet wrote: > I went single shear as well. As you can see by the nut plates holding > the bolts in place, this arrangement isn't far from a "pinned joint". > It's shown at http://www.n56ml.com/900hour/
KR> Double shear WAFs
Let me try that again...this time as plain text rather than "rich text"... John Bouyea wrote: >>Don Reid wrote back in 2007 that the WAF bolts function better as a single bolt in double shear top & bottom (2 total) than 2 on each fitting, forward and aft, top & bottom (4 total).<< I think most folks realized that a single bolt would be better than one, but the implementation is slightly challenging. I originally just went with two single shear bolts...because it was clearly working fine for the hundreds of KRs built before mine, and still had a lot of airplane left to build at the time! But later, my incentive was to make the wings easier to get off and on after I closed up the gaps between the inner and outer stub wings. So while I had the wings off to build another wing tank, I went single shear as well. As you can see by the nut plates holding the bolts in place, this arrangement isn't far from a "pinned joint". It's shown at http://www.n56ml.com/900hour/, as well as how to build a vinyl ester fuel tank in a matter of hours, and "after-the-fact" Hoerner wing tips. Don Reid also did an article in the August 1995 KR Newsletter regarding the specific WAF design...the value of the "lightning" holes in load sharing. The Newsletters are posted at http://www.krnet.org/newsletter/ . I'll try to identify exactly which batch that one is in and post it tonight. Mark Langford, Harvest, AL ML "at" N56ML.com www.N56ML.com
