Hello Everybody,
Span efficiency factor appears in the lifting-line theory of Prandtl describing Lift and vortex drag of a finite wing. According to this theory, the most efficient wing is an elliptical one and, roughly speaking, the span efficiency factor defines an efficiency of a given wing planform relatively to elliptic wing.
In the framework of the lifting line theory the span efficiency cannot exceed 1.
My question is: can this efficiency factor be more than 1, when going beyound lifting-line approximation ? (sorry for abusing notion of efficiency which supposed to be less <= 1).
In other words: does it exist such a wing whose induced drag is less than that of estimate for elliptic wing in the lifting-line theory (provided aspect ratios and lift coefficients are the same and viscous effects, such as skin friction and boundary layer, are neglected).
Thanks
Truffaldino
Span efficiency factor appears in the lifting-line theory of Prandtl describing Lift and vortex drag of a finite wing. According to this theory, the most efficient wing is an elliptical one and, roughly speaking, the span efficiency factor defines an efficiency of a given wing planform relatively to elliptic wing.
In the framework of the lifting line theory the span efficiency cannot exceed 1.
My question is: can this efficiency factor be more than 1, when going beyound lifting-line approximation ? (sorry for abusing notion of efficiency which supposed to be less <= 1).
In other words: does it exist such a wing whose induced drag is less than that of estimate for elliptic wing in the lifting-line theory (provided aspect ratios and lift coefficients are the same and viscous effects, such as skin friction and boundary layer, are neglected).
Thanks
Truffaldino
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