Thank you Don, very nice post. --- Donald Reid <[email protected]> wrote:
> At 01:27 PM 11/7/2005, you wrote: > >I would like to see that reference, I would be > >surprised if the center of lift didn't move some > with > >changes in AoA. > > These last few posts have mixed a number of > different aero terms. > > The 1/4 chord location is located 0.25 times the > chord back from the > leading edge and on the chord line. In x/c , y/c > coordinates that > means 0.25, 0.0 > > The aerodynamic center is the point at which the > pitch moment is > constant. It is near the 1/4 chord location but > generally a little > behind it. It can be above or below the chord line > but it is > generally near the chord line. This is the point > where all most all > modern aero design is based. It does not move to > any significant > degree over any angle of attack below stall. On a > symmetrical > airfoil, the 1/4 chord is the aerodynamic center. > > Based on my calculations, the aerodynamic center of > the AS series in > x/c , y/c coordinates is: > AS5045 0.2533, -0.0006 > AS5046 0.2539, -0.0007 > AS5048 0.2566, -0.0012 > and for comparison, the RAF48 is 0.2528, -0.0005 > > The center of lift and center of pressure are older > terms that mean a > point at which the pitch moment is equal to zero. > These move with > the angle of attack. They are difficult to use in > any real > aeronautical calculation but they still show up in > older reference books. > > > > > Don Reid - donreid "at" peoplepc.com > Bumpass, Va > > Visit my web sites at: > > AeroFoil, a 2-D Airfoil Design And Analysis Computer > Program: > http://aerofoilengineering.com > > KR2XL construction: > http://aerofoilengineering.com/KR/KR2XL.htm > Aviation Surplus: > http://aerofoilengineering.com/PartsListing/Airparts.htm > EAA Chapter 231: http://eaa231.org > Ultralights: http://usua250.org > VA EAA Regional Fly-in: http://vaeaa.org > > > > _______________________________________ > Search the KRnet Archives at > http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to > [email protected] > please see other KRnet info at > http://www.krnet.org/info.html > __________________________________ Yahoo! Mail - PC Magazine Editors' Choice 2005 http://mail.yahoo.com
