Complex sentence: The Hercules was a considerably larger and more powerful engine, which necessitated the use of larger propellers; to obtain the necessary ground clearance, the engines were mounted centrally upon the wing as opposed to the underslung position used on the Beaufort.
Split into simpler sentences: The Hercules was a considerably larger and more powerful engine, which required larger propellers. To obtain the necessary ground clearance, the engines were mounted centrally on the wing, as opposed to the underslung position on the Beaufort.