Hi guys, So with all the knowledge in the group, why do we not do a proper analysis of the KR aircraft, and dispel or the myths and wrong things said or printed. I am sure all the info is already available, clean it up and put all technical items together in a true document, one that could be looked at as the words of Rand. There is so much history and on going improvements that could be added to the document to show the real story of the modern KR aircraft. Make it right for new comers (like me), and older KR owners who do not know all that is to be told about these planes.
Just a thought. Why lose all the knowledge and skills in this group. All to often this information is lost for ever. A lot of you started your journey when Ken started this project. Keep the journey, and the skills alive. Cheers, Brian ----- Original Message ----- From: "Mark Langford" <m...@n56ml.com> To: "KRnet" <kr...@mylist.net> Sent: Sunday, July 01, 2012 1:53 PM Subject: Re: KR> Structural Analysis Larry Flesner wrote: >>Using the performance numbers directly from the Rand sales literature >>indicates to me that very little research was done to verify actual >>performance of the KR before they were used to make his assumptions or >>calculations. That's were I lost total faith in his conclusions. I'm even >>wondering about the qualifications of the three professors signing the >>cover page. But hey, that's just me. Your conclusions may vary. :-) << Regarding the paper at http://www.engr.sjsu.edu/nikos/MSAE/pdf/Bravo.F11.pdf, I agree with everything Larry says. But I managed to read the whole thing (except for the half of the paper that was standard derivations), and I also found a lot of it very "interesting". One thing that really sticks in my mind is the 35 pounds of stick force is required during takeoff, according to the control analysis. I'll bet just about all KRs would perform an instant half-loop to stall and crash if you really did that. When Troy Petteway was coaching me to fly my plane for the first time, he said "set the trim to neutral and when it's ready to fly it'll take off all by itself". My plane is that way as well. 35 pounds of stick force isn't anywhere near reality, and could get somebody killed in a hurry. And I found the following piece of advice to be truly amazing...the only advice given regarding CG of the aircraft: "The recommended CG range for the original KR2 is 15 to 35% of MAC. Acknowledging the pitch sensitivity issue of this airplane, the CG position needs to be chosen very carefully. Therefore the most forward CG position should be avoided." No mention of aft CG at all. This is completely backwards from reality as well...forward CG is very stable, aft CG is UNstable, and not just for the KR! Regarding airfoil selection, selecting a "cruise speed" of 180 mph at 15,000' while powered by an 85 hp engine for comparison purposes is wishful thinking. I suspect (at least hope) this guy knows something about aerodynamics, but his choice of beginning with "published numbers" for KR performance was just his first mistake. I sincerely doubt that he knows more about airfoil design than Dr. Ashok Gopolaranthnam , who specializes in airfoil design and designed the AS504x series specifically for the KR2S, and is now an aerodynamics professor ( see http://www.mae.ncsu.edu/faculty-staff/profile/ashok-gopalarathnam/) at NCU. Do a Google search for Ashok Gopalarathnam and you'll get 4200 aerodynamically leaning hits. With a name like that, they're probably all his. Do a Google search for Boris Bravo and you'll get ONE hit that is probably be him. My money's on Ashok when it comes to airfoil design and comparison. I notice one of the references listed is "Verification of Airworthiness of a Modified KR-2 Aircraft" by his "project partner". It's at http://www.engr.sjsu.edu/nikos/projectsMSAE.htm , along with the current subject report. These two reports are very similar and contain some of the same mistakes and factual errors. If I were Nordin, I'd feel violated! I have to wonder why the Bravo analysis is "secure" and can't be printed, unlike the other reports listed on that page. The document security is also set to make it "invisible" to search engines, and therefore less likely to be found by those interested in such things. I wonder why. And given Larry's comment about not doing much research was done to verify actual KR performance, he's had five years to do a little research on that, and has obviously been to both www.krnet.org and www.n56ml.com but didn't learn much . I could go on, but why bother? This "analysis" is a complete "red herring" from the KR pilot's and builder's standpoint. I should have been doing something constructive tonight rather than wasting my time on this... Mark Langford ML at N56ML.com website at http://www.N56ML.com -------------------------------------------------------- _______________________________________ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
