The newsletters are great, but they also show many excited reports of big modifications that (sometimes years later) turn out to be disasters. So you have to be a detective and look ahead to see how something turned out.
Mike Taglieri On Mon, Aug 31, 2015 at 10:28 PM, Mark Langford via KRnet < krnet at list.krnet.org> wrote: > 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 > > > > _______________________________________________ > 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 >
