The Ago C.I was a twin-boomed pusher observation aircraft that was the first C-type aircraft to enter service, and that was a moderate success.
Before the First World War the Ago Company had struggled to gain military orders. A contract to provide aircraft for the German Navy was a failure after the aircraft were judged to be unsatisfactory. After the outbreak of the First World War every source of aircraft became important, and late in 1914 Ago was asked to develop an armed observation aircraft with a good field of fire. Ago responded with a twin-boom pusher design, which allowed the gun to be carried in the nose.
Twin boom pushers were a common sight during the First World War, but the French Farman pushers and British F.E. types were flimsy looking models, with open lattice works on their booms.
In contrast the Ago C.I was a more robust looking aircraft. The crew of two sat in a short central nacelle, with the pilot in the rear cockpit (mounted in the middle of the nacelle) and the observer in the nose. The engine was mounted at the rear of the nacelle, with a large part of it exposed above the structure. The nacelle was mounted on the lower wing, and was connected to the upper wing by vertical struts. The prototype had a rounded front on the nacelle, production aircraft had a pointed tip with four sides. A hot water heating system was installed, feeding hot water from the engine to the front of the nacelle.
The two tail booms were long and thin, with a streamlined shape. They were made of two moulded plywood halves joined at the centre line. They were carried between the wings, close to the bottom wing than the top, and connected to the wings by four long spars above and four shorter spars below.
The C.I. was a two-bay biplane. The wings had a wooden framework and fabric covering.
The C.I was the first German aircraft to carry a Parabellum LMG 14 machine gun. The gun was mounted in the observer's cockpit. A small windscreen was attached to the gun ring, and moved with the gun. The observer had a good field of fire, although to fire downwards he had to stand up in his cockpit. The aircraft could also carry a small number of bombs.
The prototype had tapered ailerons and a large cut-out section in the rear of the wings to make room for the propeller. Production aircraft had a smaller cut out, and equal chord ailerons.
The main wheels were attached to the bottom corners of the central nacelle and were just behind the leading edge of the wings. A second set of wings was placed just below the nose to protect against rough landings, but these were often removed in service. Tail skids were mounted below each of the tail booms.
The prototype was originally built with all-moving rudders with a curved shape. It was later modified to have small triangular fixed tail fins and redesigned rudder with straight sides, the entire unit forming a triangular shape.
The two rudders were linked by fixed tail plane, with a normal elevator at its rear.
The prototype was probably ready by January 1915. A first order for eight aircraft was placed by the Army before 22 February 1915, when the Navy ordered five aircraft. At least 64 were built.
The type underwent its type test in April 1915, and later in the same month went to the front for service tests.
The first army aircraft entered service in June 1915 and it remained in use at the front for two years. The highest number recorded in service was 23 on 30 June 1916. Late in 1916 the remaining aircraft were moved to training establishments, but there were still five at the front at the end of February 1917 and one left on 30 April.
The C.I was a popular aircraft, with good flight controls, no problems during taking or landing and a robust construction. By the autumn of 1915 its climb rate and speed were both considered to be somewhat slow. The Navy also reported the same problems with poor construction as in their pre-war Ago aircraft. The good field of fire was popular, but the engine location caused some concern, as it could crush the crew in a crash. On the other hand it did act as armour for the crew.
A seaplane version of the design was produced, as the Ago C.Iw. This used a 150hp Benz Bz.II engine and was delivered to the seaplane testing command on 7 May 1915. It made its maiden flight on 25 May 1915 and was accepted on 27 July 1915. It then went to a training unit, where it crashed on 11 June 1916, killing both members of the crew.
Engine: Benz Bz.III or Mercedes D.III
Power: 150hp or 160hp
Span: 47ft 6 3/4in
Length: 32ft 3 1/2in
Empty weight: 1,764lb
Maximum take-off weight: 2,910lb
Max speed: 90mph
Climb Rate: 10 minutes to 3,280ft
Armament: One LMG 14 machine gun in nose