Complex sentence: The chines of the Lockheed Blackbird series extend about 40% of the aircraft's length and contribute useful additional lift at supersonic speeds, and may be understood as enhancing the fuselage lift or as acting as a canard surface.
Split into simpler sentences: The chines of the Lockheed Blackbird series extend about 40% of the aircraft's length and contribute useful additional lift at supersonic speeds. They may be understood as enhancing the lift generated by the fuselage or as acting as a canard surface.