07/20/2026. Remarks by
Johan Visschedijk: "Serialed 177 to 192, 218 to 316, and 469, the 53 Model 2 R-4 Observation landplanes ordered for the Aviation Section of the USASC in 1916 were improved versions of the Army R-2s using later 200 hp Curtiss V-2-3 engines. Two more were purchased in 1917, serialed 2157 and 37932. Except for a redesigned tailskid in a more forward position and strut-connected ailerons in both wings, the R-4s were hard to distinguish from the R-2s. Some R-4s also entered Mexico with General Pershing's Punitive Expedition. Additional Army R-4s were ordered after the US entered the war but most were cancelled to allow maximum delivery to the USN."
