A split winglet configured for attachment to a wing tip of a wing. The split winglet may include an upper winglet extending from the wing tip above a chord plane of the wing and a ventral fin projecting below the chord plane. The upper winglet and the ventral fin may include tip configurations. At least one of the upper winglet tip configuration and the ventral fin tip configuration may be provided by a curved blade cap attached thereto. The curved blade cap may include a leading edge having a first curve with a first radius, and a trailing edge having a second curve with a second radius different from the first radius. The curved blade cap may also include a distal segment oblique to the first curve and the second curve.