## Re: [Flightgear-devel] B-47 airfoil

 Re: [Flightgear-devel] B-47 airfoil From: Josh Babcock - 2006-06-29 00:30:40 ```Josh Babcock wrote: > OK, so I got a copy of "Theory", and it has 64(sub1)A-012 in the > coordinate data index. The airfoil I am interested in for the B-47 is > 64A(.225)12, which I think is another way of saying 64(sub?)A-(.225)12, > but I'm not sure. Anyway, I might be able to use that coordinate data in > xfoil to get polar data. If the missing subscript is different than the > 1 in the former, no problem, that just denotes the size of the laminar > drag bucket which I can fudge. The 0/.225 refers to the design lift > coefficient, and I have no idea what effect that would have, or how I > can adjust for it in xfoil. > > There are also polar graphs for 64(sub1)-012, but the 6 and 6A series > have a different camber line IIRC, and I'm afraid that would make a lot > of difference, but I'm not sure. > > So basically I am trying to figure out which of these will be closer in > performance to the real airfoil. Anyone out there got any ideas what > direction I should go? > > Josh > OK, I had a chance to do more reading, and it turns out that these are not the same, A is a substitute for - that denotes a modified mean line and camber resulting in flat surfaces from 0.8 chord to the TE. The lack of a subscript means that it is less than one and can pretty much be ignored. I still don't really know what I can do with the data I have ... Josh ```

 [Flightgear-devel] B-47 airfoil From: Josh Babcock - 2006-06-28 23:42:00 ```OK, so I got a copy of "Theory", and it has 64(sub1)A-012 in the coordinate data index. The airfoil I am interested in for the B-47 is 64A(.225)12, which I think is another way of saying 64(sub?)A-(.225)12, but I'm not sure. Anyway, I might be able to use that coordinate data in xfoil to get polar data. If the missing subscript is different than the 1 in the former, no problem, that just denotes the size of the laminar drag bucket which I can fudge. The 0/.225 refers to the design lift coefficient, and I have no idea what effect that would have, or how I can adjust for it in xfoil. There are also polar graphs for 64(sub1)-012, but the 6 and 6A series have a different camber line IIRC, and I'm afraid that would make a lot of difference, but I'm not sure. So basically I am trying to figure out which of these will be closer in performance to the real airfoil. Anyone out there got any ideas what direction I should go? Josh ```
 Re: [Flightgear-devel] B-47 airfoil From: Josh Babcock - 2006-06-29 00:30:40 ```Josh Babcock wrote: > OK, so I got a copy of "Theory", and it has 64(sub1)A-012 in the > coordinate data index. The airfoil I am interested in for the B-47 is > 64A(.225)12, which I think is another way of saying 64(sub?)A-(.225)12, > but I'm not sure. Anyway, I might be able to use that coordinate data in > xfoil to get polar data. If the missing subscript is different than the > 1 in the former, no problem, that just denotes the size of the laminar > drag bucket which I can fudge. The 0/.225 refers to the design lift > coefficient, and I have no idea what effect that would have, or how I > can adjust for it in xfoil. > > There are also polar graphs for 64(sub1)-012, but the 6 and 6A series > have a different camber line IIRC, and I'm afraid that would make a lot > of difference, but I'm not sure. > > So basically I am trying to figure out which of these will be closer in > performance to the real airfoil. Anyone out there got any ideas what > direction I should go? > > Josh > OK, I had a chance to do more reading, and it turns out that these are not the same, A is a substitute for - that denotes a modified mean line and camber resulting in flat surfaces from 0.8 chord to the TE. The lack of a subscript means that it is less than one and can pretty much be ignored. I still don't really know what I can do with the data I have ... Josh ```