Complex sentence: The fighter's nine cylinder Gnome-Rhône 9Kbrs radial engine was neatly enclosed within a short cowling and drove a variable pitch propeller, a novelty at the time.
Split into simpler sentences: The fighter's nine cylinder Gnome-Rhône 9Kbrs radial engine was neatly enclosed within a short cowling. The Gnome-Rhône drove a variable pitch propeller, a novelty at the time.