Mercedes in-line 6
2 – 7.9 mm
The AGO C 4, First World War observation biplane aircraft, had wings which were wider at their roots, gradually narrowing to their tips. Instead of two struts on the inner portion of the wing, a single strut was placed in its center to give the machine gunner a wider field of fire.
To help better control the aircraft, later models had ailerons fitted to both lower and upper wings. Additional bracing was added to the wings to prevent flexing during high-g maneuvers, and the vertical stabilizer was made larger. Although these modifications offered a slight improvement, they did not cure the control issues of the AGO C 4.
The AGO C 4 could better the climb rate and speed of many other aircraft flying at the time it was introduced. However, it exhibited wing tip stall at lower speeds in tight turns, and particularly while landing. That and a sensitivity to over control were problems which led to the aircraft being produced in limited quantities.
A total of some 62 AGO C 4 aircraft were produced.