Complex sentence: The Westland Wessex was a British-built turbine-powered development of the Sikorsky H-34, was developed and produced under license by Westland Aircraft (later Westland Helicopters).
Split into simpler sentences: The Westland Wessex was a British-built turbine-powered development of the Sikorsky H-34. It was developed and produced under license by Westland Aircraft (later Westland Helicopters).