The Curtiss V-1570 Conqueror was a 12-cylinder vee liquid-cooled aircraft engine. Representing a more powerful version of the Curtiss D-12, the engine entered production in 1926 and flew in numerous aircraft.
Designed in 1924 as a military successor to the Curtiss D-12, initially named the Conqueror, it was later given the military designation of V-1570 based on its displacement of 1,570 cubic inches (26 L). The engine featured open-ended cylinder liners (advanced technology for the period) and pressurized liquid cooling. Developments including the use of a supercharger gradually increased power output until reliability problems due to overheating and coolant leaks became apparent. Military funding for further development of the Conqueror was cut in 1932, efforts by Curtiss to market the engine for civil airliners failed and the line was dropped from production.