The R-680 was Lycoming's first aircraft engine. Introduced in 1929, the R-680 was very reliable and stayed in production until after World War II. Over 26,000 were built.

models

• R-680-9: 295 hp (220 kW)
• R-680-13: 280 hp (209 kW)
• R-680-17: 220 hp (164 kW)

specifications

• Radial piston engine
• Nine cylinders
• Displacement: 681 cubic inches (11.15 liters)

used by

• Cessna AT-8 Bobcat
• Curtiss-Wright AT-9 Fledgling
• Stearman PT-13 Kaydet
• Stinson Reliant