This aircraft differs from other photos of the C.23 in that it has extended ailerons, aka elephant ear ailerons
Powered by two 600 hp Salmson 18Z. These are two rows of nine cylinders. Water cooled.
Another source, Glenn D. Angle's 1921 Aircraft Engine Encyclopedia, list these as model Z-18, 500 hp at 1600 rpm, 560 hp at 1700 rpm.
