I'm glad to hear others questioning the validity of aspects of this paper. I was starting to worry that my still very limited understanding of aerodynamics was badly flawed. I skimmed the whole thing and also noticed a number of statements that seem to contradict my understanding of the collective wisdom this group has developed from many years of actual experience.
I've been following this list for a number of years but until I saw Jeff's post I hadn't picked up that the 'new' airfoil is a bit of a religious issue, so I hope I'm not opening a can of worms here. However the statement in the paper about the AS5046 being inferior to the RAF48 at cruise did cause me to raise an eyebrow. I though better cruise performance was the primary reason for the development of the 'new' airfoil? And my reading of the graphs in the paper led me to the opposite conclusion - doesn't higher lift for a given amount of drag equate to better performance? Cheers, Tony On 28 June 2012 00:46, Jeff Scott <[email protected]> wrote: > Sorry if my previous post was so badly formatted. My mail program takes a > nicely formatted email, then screws it up for me after the fact. I'll > repost as what I posted previously came back to me so messed up as to make > it unreadable. My apologies for the repost. > > --------------------------------------- > > ------------------------------------- I read through the bulk of the > paper. While there are numerous typos and errored statements (like stating > to avoid the most forward CG when he clearly means aft CG), for the most > part, the paper is pretty good work and spot on with the testing and > modifications I've done over the years. However, it is in bad need of a > final editing and rewrite. I hope this wasn't his final version to turn in > for his PHD, as his adviser will tear him apart with some of the glaring > errors. Since the concepts in this paper seem to match very closely with my > plane (originally a C-85 with additional wing area and operating out of a > high altitude airport), I can make a 1:1 comparison with his predicted > performance numbers. I have 6 more sq ft of wing area than his proposed > plane and fly at significantly heavier gross weights. My stall speed is a > bit lower than his prediction and my cruise with the C-85 was actually a > bit faster than his prediction. I won't touch his analysis of the AS series > vs the RAF series wings. That would be more like arguing politics and > religions. The analysis of the tail performance appears to be accurate, > although that seems to get some folks on here stirred up as much as arguing > politics and religion. If you are looking for a structural analysis of the > plane, it's not in here and specifically states that it is not the intent > of the paper. This paper is strictly about aerodynamics. I do agree with > Larry in that he took some of the obviously incorrect numbers (200 mph > cruise on 65 hp VW) from the KR advertising and tried to use them as a base > line in some of the analysis. Bad data in makes for in bad data out after > the analysis, so his data based on the sales literature is a bit skewed. > -Jeff Scott Los Alamos, NM _______________________________________ > _______________________________________ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to [email protected] > please see other KRnet info at http://www.krnet.org/info.html >
