I'm currently in the process of designing a winglet for my low speed aircraft in xflr.
While researching about winglets I read in a Boeing article that if the baseline outboard wing is relatively lightly loaded, as on the 747-200, the potential benefit of tip devices can be greatly reduced. I don't understand the logic behind this statement.
Also what would be the optimal airfoil selection for the winglet? How would the chord, thickness, camber, etc. affect the weight and drag reduction due to the winglet?
And would the geometric twist affect the performance of the winglet?
Any other tips for winglet design would be greatly appreciated.