CO-1 to CO-8
Gallaudet, Engineering Division, Fokker
Experiments in Corps Observation,
All of these prototypes were Liberty-powered biplanes, except the first, the CO-l. Designed by I. M. Laddon, of the Engineering Division, the CO-l was the Armyís first all-metal, high-wing monoplane. Two prototypes were built at McCook Field, one for static test, and the other first flown on July 26, 1922. Two crewmen were carried along with 287 pounds of observation equipment and 300 pounds of defensive armament; two fixed Browning and two flexible Lewis guns.
On June 22, 1922, Gallaudet received a contract to develop a production version, because of Gallaudetís work on the low-wing, all-metal DB-l bomber. Their CO-l version, improved with balanced ailerons and strengthened landing gear, first flew June 20, 1923, but only one example was built. The wing arrangement was considered bad for the observerís vision, so a projected CO-3 replacing the corrugated dural skin with fabric-covering was dropped.
The Engineering Division also built a conventional biplane in 1922, the CO-2, designed by Jean A. Roche with the usual Liberty, four guns, and fabric covering, but that prototype crashed during tests.
General Mitchell had visited the Fokker factory in the Netherlands and saw the C IV, a two-seat biplane based on the D VII fighter, but powered by a Liberty engine. One was imported and, after tests, purchased May 29, 1922, along with two more. Designated CO-4 by the Air Service, it had the typical Fokker style steel-tube, fabric-covered fuselage, wooden cantilever wing structure with N struts, and square nose radiator. The main gas tank was between the wheels, a feature intended to protect the crew in case of fire.