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My point really was that if the front half of your shape has fucked the airflow, you can't get much back with the back half, and a semicircular front half has already fucked your flow. If you imagine modifying this aerofoil into two competing shapes, one with the original nose followed by a semicircular tail and one with a semicircular nose followed by the original long tail, you should find that the one with the original nose has the lower drag.
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gbj_tester
Brommers
I'm not sure that's correct. My understanding, admittedly based on motorsports wind tunnel testing and CFD work rather than for bicycles, is that it's the trailing edge which is most important, hence why a teardrop shape has a much lower Cd figure than a reverse teardrop shape:
Also, if you had the pointed end at the front then the drag profile would be very susceptible to yaw. It might be aerodynamic if the airflow was from directly ahead at all times, but as soon as the airflow started coming at it from an angle you'd get horrible vortices off the sharp leading edge.
I think the Cervelo RCA white paper shows it most clearly at Figure 16. If the leading edge was most important, then the oval shape would be superior to the teardrop aerofoil shape.
Edit: Found figure 16 as a .gif, it's here:
P.S. It also shows that a Kamm tail (the third profile) is better than a circle, but still nowhere near as good as a teardrop shape with the same front area.