Complex sentence: The rudder, which extends to the bottom of the fuselage and operates in a cut out between the two elevators, was straight edged in early versions, later replaced by a fuller, curved edged surface.
Split into simpler sentences: The rudder, which extends to the bottom of the fuselage and operates in a cut out between the two elevators, was straight edged in early versions. This was later replaced by a fuller, curved edged surface.