The Centaurus had a cylinder swept volume of 3,272 in³ (53.6 l), close to that of the American Wright Duplex-Cyclone large radial, making the Centaurus one of the largest aircraft piston engines to enter production, while that of the Hercules was 2,363 cubic inches (38.7 l). The nearly 40 percent higher capacity was achieved by increasing the stroke from 6.5 to 7 in (170 to 180 mm) and by changing to two rows of nine cylinders instead of two rows of seven but the diameter of the Centaurus was only just over 6 percent greater.[2]