O.Thetford, P.Gray German Aircraft of the First World War (Putnam)

Gotha G II and G III
   The Gotha G II and G III of 1916 were the first of Burkhard's twin-engined designs, and differed only in interior detail. A small number was built and used on the Western Front, one unit to be so equipped being Bogohl III at Ghent. Engines, two 260 h.p. Mercedes D IVa. Span, 23.7 m. (77 ft. 9 1/4 in.). Length, 11.79 m. (38 ft. 8 1/4 in.). Area, 89.5 sq.m. (967 sq.ft.). Weights: Empty, 2,182 kg. (4,800 lb.). Loaded, 3 192 kg. (7,022 lb.). Speed, 148 km.hr. (92.5 m.p.h.). Climb, 3,000 m. (9,840 ft.) in 28 min., 4,000 m. (13,120 ft.) in 41 min. Armament, two Parabellum machine-guns for nose and dorsal/ventral positions.

J.Herris Gotha Aircraft of WWI (A Centennial Perspective on Great War Airplanes 6)

Gotha G.II

   Construction of the Gotha G.I gave Gotha the experience needed to design and build a long-range bomber, something Major Wilhelm Siegert, the commander of Idflieg and a supporter of strategic bombing, had wanted since the beginning of the war. Gotha engineer Hans Burkhardt, who had worked with Oskar Ursinus to build the Gotha G.I, was the natural choice for designer of the new bomber.
   Earlier Burkhardt had modified crashed Gotha G.I G.9/15 by placing the fuselage on the lower wing, which greatly reduced the likelihood of a nose-over on landing. Burkhardt stated he had three main priorities when he designed the Gotha G.II; speed, protection of the observer in the nose, and ease of transportation. The later sounds odd today, but at that time, when airplanes were transported long distances, they were normally dismantled and moved by train rather than flying them. This counter-intuitive procedure was driven by the limited reliability of contemporary aircraft.
   Burkhardt's ideas were accepted by Idflieg, who placed a production order for ten bombers on 18 December 1915. To have a worthwhile range and payload the new bomber needed much more power than the Gotha G.I, and the engines were specified as 220 hp Mercedes D.IV straight-eights mounted as pushers. The Mercedes D.IV was an inline eight-cylinder motor developed from the reliable 160 hp Mercedes D.III six-cylinder by adding two more cylinders. The Mercedes D.IV was powerful and reliable in single-engine airplanes, but sometimes suffered crankshaft failures in twin-engine airplanes due to flexing of the block. A transitional design, the engine was soon replaced in production by the simpler six-cylinder D.IVa.
   The resulting Gotha G.II was a completely new design that established the configuration for all subsequent operational Gotha bombers. The prototype G.II was a two-bay aircraft that entered flight trials in March 1916. The under-carriage had eight wheels, four underneath each nacelle, for safe landings. Both two-bladed and four-bladed propellers were tried with the slow-turning geared engine. Matching a fixed-pitch propeller with engine and airframe to maximize speed and climb was a painstaking task that could only be accomplished by time-consuming flight-testing.
   The prototype G.II was fast for its time but had insufficient climb with a full bomb load. An enlarged, three-bay wing gave the production version the required performance.
   The undercarriage was also revised for the production G.II. Although the original undercarriage prevented nose-overs, it lacked brakes as did all WWI aircraft. An extended landing run could result in a fatal accident by running off the edges of the field. To solve this potential problem Burkhardt simplified the undercarriage by removing the forward wheels and moved the center of gravity aft, allowing a conventional tail skid that provided the necessary braking action. Unfortunately, this aft shift in the center of gravity made the aircraft far less stable in pitch, a situation that was to plague all subsequent Gotha bombers in service. Landing accidents due to pitch instability were responsible for 76% of all Gotha bomber losses, more than three times as many losses as all other reasons combined.
   Finally, the too-small rudder of the G.II prototype was replaced with a fixed fin and larger rudder in the production G.II, improving stability and controllability in flight.
   The G.II had a crew of three,- a bombardier-gunner in the front cockpit, the pilot in the center cockpit, and a gunner in the aft cockpit. The wings and fuselage were of typical wood and fabric construction, although the nose was covered with plywood. The tail surfaces were of steel tubing covered with fabric. The engine nacelles and undercarriage formed a single sub-assembly; for easy handling these could be moved around when fitted with separate, auxiliary wheels, a feature that was pattented. Fuel and oil tanks were in the engine nacelles with a gravity fuel tank mounted above the upper wing. Two bomb racks in the fuselage held fourteen 10-kg bombs. The total useful load was 1,010 kg.
   Production of the G.II began on 25 April 1916 and the type test was completed on 17 July 1916. Serial numbers assigned to the ten production aircraft were G.II 200/16 - 209/16. The G.II wing cellule finally passed the static load test during the week of 11 August 1916 after six failures that had to be rectified.
   Of the 10 G.II bombers built only eight reached Staffel 20 of KG4 in August/September 1916, apparently the only unit to use the G.II operationally. One G.II remained at FEA 3 in Gotha and the other was badly damaged during flight evaluation. Unfortunately, there is no information available regarding the combat use of the G.II, which was limited by the small number of aircraft and the problematical reliability of the engines.


Gotha G.II Specifications
Engines: 2 x 220 hp Mercedes D.IV
Wing: Span Upper 23.70 m
Span Lower 21.90 m
Area 89.5 m2
Chord Upper 2.30 m
Chord Lower 2.30 m
Gap 2.22 m
Sweepback 1.5°
General: Length 12.40 m
Height 4.30 m
Empty Weight 2182 kg
Loaded Weight 3192 kg
Maximum Speed: 148 km/h
Climb: 3000m 28 min
4000m 41 min
Range: 500 km


Gotha G.III

   The G.II was quickly superseded in production by the improved G.III. The main difference between the types was the engine; the G.III was powered by the 260 hp Mercedes D.IVa engine of six cylinders. The new engine did not suffer the occasional crankshaft failures of the straight-eight it replaced, was cheaper to produce, offered slightly more power, and was soon available in quantity. The additional power enabled the useful load to be increased from 1,010 kg to 1,235 kg.
   The other important change for the G.III was an opening for a ventral, downward-firing machine gun. Idflieg ordered 25 G.III bombers on 3 May 1916; deliveries started on 16 October and were completed on 26 March 1917. Serial numbers are thought to be G.375/16 - G.399/16. One G.III, G.398/16, was sent to Halbgeschwader I as a trainer and G.392/16 was sent to the Daimler factory for flight-testing an experimental Mercedes D.IVa. The rest of the G.IIIs were delivered to KG2. KG2 was moved around and flew missions on the Western Front as well as daylight bombing missions on the Balkan Front, stationed at Hudova along with a few G.II bombers. The most significant result in the Balkans was destruction of the railway bridge over the Donau at Cernovoda in late September 1916; this deprived the Romanian army of essential supplies and reinforcements. Interestingly, one squadron commander complained that the G.III easily outdistanced its two-seat escorts. In August-September 1917 the G.III was retired from the front.


Gotha G.III Specifications
Engines: 2 x 260 hp Mercedes D.IVa
Wing: Span Upper 23.70 m
Span Lower 21.90 m
Area 89.5 m2
Chord Upper 2.30 m
Chord Lower 2.30 m
Gap 2.22 m
Sweepback 1.16°
General: Length 12.22 m
Height 3.90 m
Empty Weight 2383 kg
Loaded Weight 3618 kg
Maximum Speed: 140 km/h
Range: 700 km


Gotha G-Type Bomber Production Summary
Order Date Type Qty Serials Notes
Dec. 18, 1915 G.II 10 200-209/16 Delivered Aug.-Sep. 1916
May 3, 1916 G.III 25 376-399/16 Delivered 16 Oct. 1916-26 March 1917

M.Dusing German Aviation Industry in WWI. Volume 1 (A Centennial Perspective on Great War Airplanes 84)

Gothaer Waggonfabrik A.-G., Gotha (Go)

Aircraft Development:

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  Shortly thereafter, the company brought out its own design of a G-airplane, since the Ursinus design could not hold up in the long run due to its heavy armor with a high-mounted fuselage that raised the center of gravity excessively.
  The development of aircraft engines also led to a considerable improvement in the performance of the G-planes. Gotha already installed 2 engines of 260 hp each and gave the planes an armament of 2 MG (one in front, one in the rear) and soon increased this armament to 3 pieces. The bomb load increased from 150 to 300 kg due to the improved design and towards the end of 1916 to 450 kg, bringing a further increase in armament to 4 MG. At the end of 1916, the Gothaer Waggonfabrik delivered 50 aircraft, a squadron specially designed for use against England (4 MG, 450 kg bomb load).
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