| Design
            on the Liberty 12 began on 30 May 1917 and testing on 3 July
            of the same year!  By November 1918 over 20,000 had been
            built.  A reliable engine, thousands remained in use into the
            mid 1930s.
             Allison developed an inverted, air-cooled version. 
            This inverted vee had a smaller displacement and was designated the V-1410.  | 
           | 
          
            
                | 12-cylinder, vee water-cooled piston engine |  
                | Displacement: 1,649 cubic inches (27 liters) |  
             
           |