The Ago C.IV was an armed reconnaissance aircraft with unusual tapered wings that entered production in 1916 but that was unpopular with its crews and was only produced in small numbers.
Before the C.IV Ago had produced a series of two-boom pusher aircraft, starting with the moderately successful Ago C.I. This was followed by a small number of C.IIs and a single C.III with a smaller wingspan.
The Ago C.IV was a totally new design. It was a two bay tractor biplane, by then the standard layout for observation aircraft, but with unusual tapered wings.
The C.IV had straight edged wings that tapered all the way from the centre to the tips, both in chord and in width. They were built around two Danzig pine box-spars, which also tapered together. The spars were lined by 'I' shaped poplar ribs, each of which had to be a different size because of the tapering wing. This made the wings difficult to produce.
The wings were linked by two outer struts mounted close together and one inner strut towards the back of the wing. This allowed the observer to fire forwards through the wings on two arcs between the fuselage and the outer struts. The prototype and early aircraft had cable bracing between the struts, but this was later replaced with streamlined steel tubes. There were ailerons on both the upper and lower wings. The radiators were carried within the starboard root section of the upper wing and the gravity fuel tank in the port root section.
The prototype had an all moving rudder, but production aircraft gained a fixed vertical fin as well, which made the aircraft easier to fly.
The fuselage had a conventional shape, but an unusual internal structure, with wooden longerons of spruce and ash, and horizontal and vertical spacers made from steel tubes. Behind the cockpits there was a removable curved top deck.
The aircraft was powered by a 220hp Benz engine, surrounded by streamlined metal panels. The airscrew carried a large spinner.
The C.IV was armed with two machine guns - one fixed forward firing Spandau machine gun and one flexibly mounted Parabellum machine gun at the rear.
A total of 260 Ago C.IVs were ordered, mainly from subcontractors, but only about 70 of them were delivered.
The C.IV entered front line service early in 1917, and was immediately unpopular with its crew. The novel wings meant that the aircraft was unstable in flight, and the bulk of the orders appear to have been cancelled.
Engine: Benz Bz.IV inline engine
Span: 39ft 0 1/2in
Length: 27ft 0 3/4in
Height: 11ft 5 3/4in
Empty weight: 1,984lb
Maximum take-off weight: 2,976lb
Max speed: 118mph
Climb Rate: 22min to 9,840ft
Service ceiling: 18,045ft
Range: 466 miles
Duration: 4 hours
Armament: One fixed forward firing 7.92mm LMG 08/15 machine gun and one flexibly mounted 7.92mm Parabellum machine gun.