|  | CH-200 Pacemaker: 220 hp Wright J-5
                (1928) | 
              |  | CH-300 Pacemaker: 330 hp  Wright J-6
                (1929) | 
              |  | 300-W Pacemaker: 300 hp P&W Wasp
                (1930) | 
              |  | CH-400 Skyrocket: 420 hp P&W Wasp C
                (1930) | 
              |  | Model D Skyrocket: 450 hp P&W Wasp
                (1932) | 
              |  | Model E Pacemaker: 420 hp Wright J-6
                (1932) | 
              |  | Model F Skyrocket: 550 hp P&W Wasp
                (1934) | 
              |  | 31-40 Pacemaker Senior: 400 hp  Wright
                R-975 Whirlwind (1935) | 
              |  | 31-42 Pacemaker Senior: 13-40 with more
                powerful engine (1935) | 
              |  | 31-50 Skyrocket Senior: 550 hp P&W
                Wasp Hornet (1935) | 
              |  | JE: U.S. Navy utility version of the
                Pacemaker | 
              |  | RE: U.S. Navy transport version of the
                Skyrocket |