I'm not recreating the wheel...when I bought the partially complete fuselage the original owner had already done the steps to extend the wings...the stub wing spars are slightly longer...the spar caps are thicker and the spars are longer...basically taking advantage of the inherent increase in strength the as5048 provides. My research has been in order to satisfy myself that this is a good idea and to make sure I don't create cg problems...so I started out trying to follow the logic with how the cg was originally derived on the kr2...that's when I found the confusion with mac...it can't be 45.1 as stated in the plans...and that was confirmed with what you sent yesterday. I would be willing to bet the work was done on the kr2 it just wasn't reflected on the specifications page. It looks like the range in the plans for the kr2 is slightly conservative...and that conservatism is just reduced with the kr2s.
I am still assuming that the cg range for an as5048 is still 15 - 35% mac. All my years as the weight and balance focal point for the awacs tell me that is a good assumption. https://sites.google.com/site/mykr2stretch/ https://sites.google.com/site/mykr2stretch/parts-for-sale On Aug 18, 2013 6:50 AM, "Mark Langford" <ml at n56ml.com> wrote: > Jon, > > It occurred to me that although the KR wing planform may not be perfect, > there's certainly nothing badly wrong with it or it's stall characteristics > that should keep anybody from forging ahead and getting a KR built and in > the air. It might be past the point of diminishing returns to try to > improve on it a lot. The "new" KR airfoil (the AS504x series) created by > graduate student PhD Ashok Gopalarathnam was thoroughly evaluated for stall > characteristics during the redesign. This airfoil was specifically > designed for this airplane, and not many homebuilders have this luxury. > His charter was that lift coefficient and pitching moment not be degraded, > and that stall characteristics didn't suffer. Past experience by a LOT of > KR pilots have not revealed a real problem with either the stock airfoil or > the new one. > > That's not to say that the wing planform can't be improved on, just that > it might not be worth the trouble to "fix it". I fully understand if you > enjoy a good challenge and view it as an opportunity to get the cobwebs out > and review some aero knowledge, make another incremental improvement to the > breed, and are not in a hurry to get in the air. But for those builders in > their 60's, 70's, and 80's, they have no reason to slow down and wait for > developments. As William Wynne says, "every day you find something to do > other than building your airplane is another day closer to losing your > medical"! Having said that, I've certainly done my share of that stuff. > > While I'm on my soapbox, anyone building a new KR should go straight to > the AS504x series, rather than using the RAF48 provided with the plans. > This new airfoil has been thoroughly tested with good results, and the > only real difference is the shape of the airfoil, not the wing structure or > anything else. There are no "gotchas" hiding in this airfoil. It's the > elusive free lunch. See http://www.krnet.org/as504x/ for details and > free airfoil template downloads. It's a no-brainer, and I have no personal > monetary gain to make from "selling" this airfoil as opposed to the > RAF48.... > > Mark Langford > ML at N56ML.com > website at http://www.N56ML.com > ------------------------------**-------------------------- > > > ______________________________**_________________ > Search the KRnet Archives at > http://tugantek.com/**archmailv2-kr/search<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<http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org>to > change options >