You would probably want to align the two profiles based on the main spar position.
Bill Johnson -------------------- It actually works out the same since (at least on the KR1) the fwd main spar is perpendicular to the airfoil section. What I was describing was a more general way to do it (which will yield the same results) because that theory goes to pot when the spar is angled fwd or aft and I wasn't 100% sure about the spar geometry for the 2/2S Matt ------------------------------------------------- Matthew Elder Orangeburg, SC http://www.infinigral.com/melder My Airplane Project: http://www.infinigral.com/melder/flying/KR1/ ----- Original Message ---- From: Bill Johnson To: Matthew Elder ; KRnet Sent: Tuesday, May 9, 2006 12:50:30 PM Subject: RE: KR> Airfoil interpolation was 18% something or other You would probably want to align the two profiles based on the main spar position. Bill Johnson -----Original Message----- From: krnet-bounces+wpj=comcast....@mylist.net [mailto:krnet-bounces+wpj=comcast....@mylist.net] On Behalf Of Matthew Elder Sent: Tuesday, May 09, 2006 11:58 AM To: KRnet Subject: KR> Airfoil interpolation was 18% something or other Personally, I would do it in CAD... If you don't have that ability, the easiest hands on way I can think of is to take your 15% and lay it on top of your 18" with the leading edge for the 15% offset from the leading edge of the 18% the distance that it's supposed to be (as measured in the planform view). You would need to divide up the perimeter of both 'foils into percentage sections (like you do when you are cutting a foam core anyways for calling out positions). Connect the appropriate section marks of each 'foil with lines, and mark a point half way (or whatever station ratio you are looking for, in your case 4'/8' which happens to be 1/2). Connect all the points. The more curvature there is, the more points you will want to develop the new curve obviously. There is a "by the book" way to do it, but I don't recall the details, and don't have the book in front of me at the moment. Matt ------------------------------------------------- Matthew Elder Orangeburg, SC http://www.infinigral.com/melder My Airplane Project: http://www.infinigral.com/melder/flying/KR1/ ----- Original Message ---- From: Jerry Morris To: kr...@mylist.net Sent: Tuesday, May 9, 2006 10:41:05 AM Subject: KR> 18% airfoil? I want to hot wire the 18% tapering to 15% but only four feet at a time. how do i come up with the middle airfoil? if the section was 8' what would the 4' airfoil be, 16.5%? do i take the 15% and 18% airfoil and average the size between them in cord and curves? thanks jerry > >Message: 3 >Date: Mon, 08 May 2006 09:21:42 -0500 >From: Steve Eberhart >Subject: Re: KR> Spar wood >To: KRnet >Message-ID: <445f53f6.80...@newtech.com> >Content-Type: text/plain; charset=ISO-8859-1; format=flowed > >I am not sure, from reading all of the posts in this thread, if a >constant 18% thick wing is what is being discussed here or an 18% >tapering to 15%. The 18% AS5048 was originally designed to be used as >the root airfoil of a wing that tapered to the 15% AS5045 airfoil at >the tip. According to Ashok, the 15% and 16% airfoils are well suited >for use in single airfoil wings. I don't remember any discussions >about using the 18% in any configuration other than as a root airfoil >tapering to a 15% at the tip. > >Steve Eberhart >Building an RV-7A but I still have the original AS504x wind tunnel >models in the attic. > > > _______________________________________ 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 _______________________________________ 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
