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Other sources state that max aero benefit of a superduper airfoil vs a cylinder of the same width is about 1:10...So the above seem a bit generous (1:24)
Both statements can be true, if the Cervelo graph is for an infinitely long tube with its axis at right angles to a homogeneous flow field and the "other source" is for a finite tube raked at bicycle tube angles in the practical bicycle flow field. The actual section of a circular down tube along the flow line is more like the ellipse represented by the second bar on Cervelo's graph.
gbj_tester-
the "other source" is for a finite tube raked at bicycle tube angles in the practical bicycle flow field.
No this was just from places like the one linked above http://airfoiltools.com/search/index?m%5BmaxCamber%5D=0&m%5Bsort%5D=5 which shows 2D infinite airfoils. The drag coefficient of airfoils continue to improve at higher speeds/bigger sizes (than bikes)
umop3pisdn 's example is only true at much higher speeds than 30mph
svenhöek
Cervelo published this at some point:
Other sources state that max aero benefit of a superduper airfoil vs a cylinder of the same width is about 1:10 at bike speeds/bike tubing sizes. (with a headwind or no wind)
So the above seem a bit generous (1:24), but cervelo usually know what they are doing.
edit: Also with sidewind forward propulsion is possible. Maybe that is why the numbers are so good. The ratio could be calculated as a average of different wind angles