06/30/2008. The GAX (Ground Attack Experimental) was designed by I.M. Laddon and built by the US Army Engineering Division at McCook Field, Ohio, USA, in 1919. The three crew consisted of a pilot, seated in the fuselage, and two gunners, one seated in the front of each pusher engine nacelle with a 420 hp Liberty 12 twelve-cylinder water-cooled V-engine. The aircraft was tested at McCook Field under Project Number P-129.
Twenty production models were to be built by the industry and Boeing was the successful bidder, eventually ten GA-1's were ordered, s/n 64145 to 64154. These were powered by two 435 hp Liberty 12A's and the first flew in May 1921.