Before revision: Assuming that the profile drag itself has a constant+quadratic dependence on , an alternative drag coefficient breakdown can be given by where {| border="0" |- | || is the constant part of the profile drag coefficient, |- | || is the quadratic part of the profile drag coefficient, |- | || is the span efficiency factor from Lifting-line theory |} Equating the two expressions gives the relation between the Oswald efficiency number e and the lifting-line span efficiency ell .
After revision: Assuming that the0 profile drag itself has a constant+quadratic dependence on , an alternative drag coefficient breakdown can be given by where {| border="0" |- | || is the constant part of the profile drag coefficient, |- | || is the quadratic part of the profile drag coefficient, |- | || is the span efficiency factor from Lifting-line theory |} Equating the two expressions gives the relation between the Oswald efficiency number e and the lifting-line span efficiency ewinginviscid theory, such as .