Lift, Drag and Wing SmoothnessThe wings of an airplane (and even the blades of a helicopter) have the task of moving through the fluid creating the greatest lift and the minimum drag.
The smoothness of a profile is defined by Lift / Drag = Cz / Cx
The shapes of wings and choice of profiles are very numerous, but for light and economical aviation, it is necessary to choose wings of high glide ratio.
Note that the data below are indicative as they depend on the
Reynolds number
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Source: The Little Budding AerodynamicistNote an American site:
Airfoil Tools provides you with all the profiles and technical characteristics of this table.
The glide ratio of a wing does not only depend on the chosen profile. The drag induced by
wingtip vortices degrade the theoretical smoothness of a profile (which would be an "infinite" wing).
Also do we tend to lengthen the wing, to reduce the chord at the end of the wing, but also to install devices there to reduce these parasitic vortices such as
fins / winglets.
However, extending the wings too much also leads to difficulties: bulk and structural mechanical weakness, vibrations.
We then end up with strange things like these...
- helios_avion_solaire_aile_souple.png (232.27 KiB) Consulted 772 times
Helios Solar Airplane