On the upper limit of the Oswaldx2019;s efficiency factor for an airplane

摘要

With a view to understand the maximum limit on the airplane Oswald's efficiency factor eo in the quadratic represent on of the Drag Polar, an analytical expression for eon has been derived in terms of the ratio of the horizontal tail lift-coefficient to wing lift coefficient. Maximising eo with respect to this ratio shows that (e o )max is a strong function of the tail span to wing span ratio. It is observed that for reasonably high values of this span ratio (e0 ) max could exceed values of unity.13;