The Coventry Victor Motor Company began building motorcycles in 1911. In the 1920s, they began building a family of two- and four-cylinder HOAEs for light aircraft. Other firms and aircraft builders are reported to have converted Coventry Victor motorcycle engines for light aircraft use, as well. The firm was well-known into the 1950s for its horizontally-opposed industrial engines. In the 1950s, the firm re-entered the light aircraft engine business with an updated Neptune 3.
O-42 -- {2.953 / 3.071 / 42.1} / {75 / 78 / 689}
Same stroke as O-46, O-91.
2cyl; O.H.V. IV; N/A hp@N/A rpm; 1924-1926; Wt = N/A.
Single-ignition engine.
Ae39.
Applications: None found.
O-46 -- {3.071 / 3.071 / 45.5} / {78 / 78 / 745}
Same bore and stroke as O-91, apparently.
Same stroke as O-42.
2cyl; O.H.V. IV; 20hp@4500rpm; 1924-1926; Wt = 70#.
Single-ignition engine; as O-42 with an increase in bore.
Ae39.
Applications: None found.
O-91 -- {3.071 / 3.071 / 91.0} / {78 / 78 / 1491}
This is a guess at bore and stroke since the displacement has been reported as 1.5 liters, which is consistent with the O-46 dimensions.
Same stroke as O-42.
4cyl; Neptune 1; 40-45hp@N/A rpm; 1925-1927; Wt = 120#.
Single-ignition engine.
Ae39.
Applications: None found.
O-98 -- {3.150 / 3.150 / 98.2} / {80 / 80 / 1608}
Same stroke as O-111.
4cyl; Neptune 2; 32hp@2500rpm, 40@N/A (TO); 1925-1927; Wt = 130#.
Single-ignition engine.
Ae39.
Applications: None found.
O-111 -- {3.346 / 3.150 / 110.8} / {85 / 80 / 1816}
Same stroke as O-98.
4cyl; Neptune 3; 30hp@2000rpm, 55@N/A (TO); 1925-1940; Wt = 130#.
Single-ignition engine.
Ae39toAe41; J41toJ42.
Applications: None found.
4cyl; Flying Neptune; 55hp@3200rpm, 65@N/A (TO); 1955-1958; Wt = 200-210#.
Dual-ignition engine.
AJJ2; J56-57toJ58-59.
Applications: (UK) French Druine (built by Britten-Norman) D.54 Turbulent [G-APFA]. (US) Piper L-4H (re-engined for flight testing) [G-AIYX].