Clément-Bayard was an important early French manufacturer of aircraft engines and lighter-than-air vehicles. They built three HOAE. A contemporary reference is the 1920 book by E. Charles Vivian (ECV) in which a chapter covers horizontally-opposed aircraft engines. The Clément-Bayard engines are described as notable engines among several HOAE from various countries. Vivian's book is available on the Internet and can be found here.
O-15 (2-Stroke) -- {2.205 / 1.968 / 15.0} / {56 / 50 / 246}
Same bore and stroke as O-30.
2cyl; N/A; 7hp@3100rpm; 1922; Wt = 18#.
Two-stroke cycle engine.
Ae39.
Applications: None found.
O-30 (2-Stroke) -- {2.205 / 1.968 / 30.1} / {56 / 50 / 493}
Same bore and stroke as O-15.
4cyl; N/A; 14hp@N/A rpm; 1922; Wt = N/A.
Two-stroke cycle engine.
Ae39.
Applications: None found.
OL-180 -- {5.118 / 4.370 / 179.8} / {130 / 111 / 2947}
2cyl; N/A; 30hp@N/A rpm; 1909-1912; Wt = 110#.
Liquid-cooled, dual-ignition engine.
Ae39; ECV; J1912; LEO.
Applications: (France) Blériot XI; Santos-Dumont XX Demoiselle (Bébé, JouJou).