08/14/2005. Remarks by Philo Lund: "Early 1922 Brigadier General William "Billy" Mitchell, Assistant Chief of the US Army Air Service, made a trip to Europe and visited Holland and the Fokker works. The prototype of the Fokker C.IV two-seat fighter-reconnaissance aircraft was shown to the general and he immediately bought the prototype and two developed series aircraft, powered by a 420 hp Liberty 12A, they became the Corps Observation type XCO-4 (s/n 68557) and CO-4 (s/n 68565 to 68566).

Before delivery of the three aircraft in 1922, the Netherlands Aircraft Manufacturing Company (Fokker's sales organization in the US lead by R.B.C. Noorduyn) received an order for an additional five aircraft for delivery in 1923. Known by the company as Model 3, these were designated CO-4A by the USAAS and received the s/n 23-1205 to 23-1209. Differences were the lengthened fuselage, redesigned nose, a 435 hp Liberty 12A engine and side radiators and the lacking of the gas tank between the wheels.

In 1924 the Netherlands Aircraft Manufacturing Company became Atlantic Aircraft Manufacturing Company, it was this (Fokker) company that modified one of the two CO-4s (s/n 68565) into a AO-1 (Artillery Observation) as a private venture, after rejection by the USAAS it was modified to become a CO-4A.

All aircraft were used for experimental flying, they remained in service until 1926. The following McCook Field Project Numbers were allocated:

68557 "P-250"
68565 "P-284"
68556 "P-285", later "P-365"
23-1209 "P-325"."




Span: Length: Height: Weight empty: Weight loaded: Max speed:

XCO-4/CO-4 41 ft 6 in (12.65 m) 29 ft 8 in (9.04 m) 10 ft 10 in (3.30 m) 3.020 lb (1,370 kg) 4,494 lb (2,038 kg) 134 mph (216 kmh)

CO-4A 41 ft 6 in (12.65 m) 30 ft 4 in (9.25 m) 10 ft 10 in (3.30 m) 3.020 lb (1,370 kg) 4,525 lb (2,053 kg) 135 mph (217 kmh)