The A.E.G. G.IV was the most successful in a series of A.E.G. twin engined bombers and was used by the German air service from late in 1916 until the end of the First World War.
The G.I of early 1915 was similar to the B series unarmed reconnaissance aircraft, with the same welded steel fuselage, wooden wing ribs and fabric covering construction. It was powered by two 100hp engines, mounted on struts between the wings close to the fuselage. It was underpowered and only one was built.
It was followed in mid 1915 by the A.E.G. G.II, which was slightly larger, and was powered by two 150hp engines. It could carry 441lb of bombs and around sixteen were built.
Next came the A.E.G. G.III, which introduced balanced control surfaces, 220hp engines and had a 661lb payload. Again a small amount were produced.
The G.IV appeared late in 1916, with the prototype completed in September 1916 and the first production aircraft ready in January 1917. It used the same welded steel tube fuselage and wooden wing ribs as the earlier aircraft, and was mainly fabric covered, but had a plywood skin over the nose. The wings had a fixed centre section and swept-back outer panels that could be detached. They had two 50mm diameter steep tube spars, with a 3ft 8.5in gap between them, and solid wood ribs.
It had two 260hp Mercedes D.IVa engines, giving it another 80hp compared to the G.III. These engines were both more powerful and more reliable than the D.IV engines used on the G.III. The engines were carried on a network of steel struts that were attached to the steel wing spars of the lower wing and were braced to the upper longerons of the fuselage.
It could carry four crew members, and all of the cockpits were connected so the crew could swap places. It was armed with two Parabellum machine guns, both on flexibly mountings - one in the aft cockpit and one in a nose cockpit. It could carry 882lb of bombs, twice the payload of the G.II and a third higher than the G.III, but only with a crew of three. Its main limitation was its poor range with a full bomb load, so it was normally used on short range missions.
The number of aircraft produced is unclear. A.E.G. records show 324 aircraft between January 1917 and October 1918 and known orders reach 320. However many sources give a figure of 500 aircraft, from a total production run for the G series of 550. This may include aircraft produced under licence by Siemens-Schuckert.
The G.IV used the same engines as rival bombers from Gotha and Friedrichshafen, but wasn't as obviously effective as those aircraft, with a lower payload and shorter range. However its increased reliability compensated for this.
The G.IV had two racks for 25lb bombs on the port side of the rear cockpit and one under the floor between the main and rear cockpits. One 50kg bomb could be carried under each of the lower wing and up to three under the fuselage.
The G.IV remained in service from its introduction until the end of the First World War. It was more robust than the Gotha or Friedrichshafen bombers, and was also easier to fly. It entered service in April 1917, quickly replacing the G.III. At first it was used in daylight raids, but these soon had to be abandoned and it was largely used at night. There were never that many in use at any one time - by the end of 1917 there were only 35 in service, and the highest recorded number in service, on 30 June 1918, was only 74. It was used by Kampfgeschwader 1 (based at Etreaux, and supporting the 18th Army). Kampfgeschwader 3 (Ghent, 4th Army), Kampfgeschwader 4 (Guise, 18th Army), Kampfgeschwader 5 (Mouchin, 17th Army) and Kampfgeschwader 7 (La Briquette, 2nd Army), as well as by a number of independent Staffeln.
Late in 1917 the G.IV units moved south and were used for night attacks on Venice, Padua, Verona and Treviso. During this period some aircraft in Kampfgeschwader 4 flew as many as five or six sorties per night, a demonstration of the reliability of the aircraft.
They returned to the Western Front in 1918, and were used as night bombers on that front for the rest of the war. Fifty were still in use in August 1918.
The G.IV was also used as a reconnaissance aircraft, with its range increased by replacing the bomb load with extra fuel.
A number of variants of the G.IV were produced in small numbers.
The G.IVb had an increased span three-bay wing, with another 18ft added to the wing span. It was marginally slower than the standard G.IV but could carry a 2,200lb bomb.
This was followed by the G.IVb-lang, which combined the three-bay wing and a longer fuselage and was powered by two 300hp Basse & Selve BuS.IVa engines. This became the basis of the A.E.G. G.V.
The G.IVk carried a 2cm/ 0.79in Becker cannon in an armoured nose. It was produced in 1918 for use with ground attack forces, especially against tanks, and probably didn't see service although the prototype was sent to the front in December 1917 for service trials. The prototype was followed by an order for five armoured G.IVks, placed in March 1918. The type passed its flight trials in February 1918, and its cannon trials in April, but wasn't used in combat. Four survived to the end of the war and were handed over to the British.
The G.IV was also used for engine experiments, and was tested with 245hp Maybach Mb.IVa engines and 300hp Basse & Selve BuS.IVa engines between September 1917 and March 1918. Neither engine was available in sufficient numbers to be used on production aircraft. Early in 1918 turbo-charged Mercedes engines were tried, but the first prototype was lost in March 1918. An A.E.G. designed turbo-compressor was tested in the summer of 1918, and just before the end of the war an order was placed for twenty more units for combat tests.
Engine: Two Mercedes D.IVa engines
Power: 260hp each
Crew: 3 or 4
Span: 60ft 4.5in
Length: 31ft 9.75in
Height: 12ft 9.5in
Empty weight: 5,291lb
Maximum take-off weight: 8,003lb
Max speed: 103 mph
Climb Rate: 5min to 3,280ft
Service ceiling: 14,765ft
Endurance: 5 hours
Armament: Two 0.31in Parabellum machine guns
Bomb load: 881lb