Complex sentence: The Battle was powered by the same high-performance Rolls-Royce Merlin piston engine that powered various contemporary British fighters, however the Battle was weighed down with a three-man crew and a bomb load.
Split into simpler sentences: The Battle was powered by the same high-performance Rolls-Royce Merlin piston engine that powered various contemporary British fighters. However the Battle was weighed down with a three-man crew and a bomb load.