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