Hello Kr folks: I've only been lurking here in KRnet world for a couple months, just received my KR plan set less than 2 weeks ago, and my WW corvair conversion manual 3 days ago. So it is safe to say that I know very very very little about KRs, corvairs, and well to be quite honest, engines of any type... And given that I have just under 300 hours in my flight log book, I'm still a very low timer in the air to boot... so I'm hardly qualified to offer much...
but finally a thread that has at least a tiny familiar feel to it... the topic of RESEARCH... (I happen to teach research methods and statistics courses to undergrad, masters and PhD students at Univeristy of Idaho - but please don't hold it against me... gotta make a living somehow ;-)...) I've found this discussion, and Williams related posts very interesting because IMHO, everyone, even those who seemingly disagree with each other, are "right." I admit, there is no way that I would conclude with a high level of confidence, based on Williams sample of engines and research so far, that nitriding will solve the crankshaft issue. As many of you have alluded to, there are simply way too many variables coming in to play to isolate the cause from a pure experimental perspective. I don't even know what all the processes in the discussion involve regarding grinding, nitriding, extensions, bearings etc., but it seems pretty obvious that there are many many factors such as prior condition of the cranks before being used for flight, type of flight hours, installation details etc., all of which might be involved in the problems. Even if all of those variables could be controlled for, a sample of n=5 doesn't provide much in the way of strong evidence. However, that said, given WW's expertise and experience with corvairs, and given the possible ramifications of a broken crank, and given WW's positive reputation and stated business philosophy, I too would rather follow a policy on the conservative side, at least until further research can be designed and carried out to provide more evidence of the cause, and potential solution to the problem. If a larger sample of flying corvairs, both with and without nitriding could be put through the same inspection process, and if a variety of additional variables (time, type of flying, etc) could be associated with each engine, then we'd be on our way to buildling evidence we could be more confident in. But lacking such, to me, the work William has done so far provides reasonable justification for his offered advice. Especially given the legal nature of our society. I love stats, analyses, science, research evidence, and all that. I live for it. But sometimes expert opinion is worth a whole lot, especially when ideally designed research just is not practical or realistic. Like others have said. My thoughts are probably worth what you paid for them... Thanks for the great discussion group. I hope by the end of the summer that I can report a KR2S project under way. I've visited virtually every one of your web-sites and am both envious and impressed. This is a great group and a fabulous learning experience. Tony Moscow, ID > -------Original Message------- > From: Colin Rainey <brokerpilot9...@earthlink.net> > Subject: KR> Crankshafts and testing > Sent: 18 Jan '06 03:02 > > Mark and Mark and netters I agree whole heartedly. > And if I find that the cranksahft that WW sold me is NOT nitrided I will > have it nitrided. > > What I should have said is that it is premature to draw conclusions that > nitriding will do anything > to address the broken crankshafts in OUR CASES. If nitriding is known for > adding durability > to a crank then it is a good thing regardless, I agree. But I believe there > is ALOT more > investigating to be done on this issue, then just treat the cranks and > re-install and fly. > That is all I wanted to make clear. With the volume of knowledge and > numbers of engines > this group has collectively, a collaboration should be able to yield a great > deal of useful > information in this pursuit that all will benefit by, including WW. I would > like to stimulate > all of us to work together to go beyond where WW is now with this and SOLVE > this > issue, not wait on him to discover it. > > By WW's words himself the problem did not begin until after 2004 when his > version engines began > to become widely used. What has been changed from the way they were > previously used > in airplanes prior to 2004? A good starting point for understanding where > the problem is, is to > look at the way the engines were installed and used prior to WW, and compare > to our engines > now. Then we know what needs to be tested like Ron Eason suggested, and we > can save > alot of time and energy, and money. Like Ron said, maybe the way Bill Clapp > and Steve > Makish flew their engines has much more of a factor on the cracks then the > machining. Yes > we all could benefit from better cranks, but we should not stop there. We > need to find out for > sure why these crankshafts are/were cracked. > > That is my main point, take it for what it is worth... > > > Colin Rainey > First National Mortgage Sources > Lending Solutions in All 50 States > 386-673-6814 office > 407-739-0834 cell > brokerpilot9...@earthlink.net > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html >
