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

L.V.G. C III
   This machine was virtually a standard L.V.G. C II with the observer transferred to the front cockpit, although in dimensions it did differ marginally. It remained only an experimental aircraft, and probably only the one machine was built. Engine, 160 h p . Mercedes D III. Span, 12.7 m. (41 ft. 8 in.). Length, 8.0 m. (26 ft. 3 in.). Height. 3.2 m. (10 ft. 6 in.). Area, 36 sq.m. (389 sq.ft.). Weights: Empty, 845 kg. (1,859 lb.). Loaded, 1,405 kg. (3,091 lb.). Armament, one Parabellum machine-gun in front cockpit.

J.Herris LVG Aircraft of WWI. Vol.1: B-Types & C.I (A Centennial Perspective on Great War Airplanes 34)

LVG C-Types
  
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  The LVG C.III was a simple conversion of the C.II with its observer in front. Although seating the observer/gunner in the rear cockpit seemed to offer the best defensive field of fire, Idflieg was not ready to have all C-types built with the gunner in the rear cockpit until operational experience validated that. The C.III was limited to prototype status as, by the time it appeared, operational experience had indeed confirmed the superior defense provided by seating the gunner in the rear cockpit.
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LVG C-Type Specifications
LVG C.I LVG C.II LVG C.III LVG C.IV
Engine 150 hp Benz Bz.III 150 hp Benz Bz.III 160 hp Mercedes D.III 160 hp Mercedes D.III 220 hp Mercedes D.IV
Span, Upper 14.5 m 12.68 m/12.85 m/&13.80 m (C.IIN) 12.7 m 13.6 m
Span, Lower - - - 10.9 m
Chord, Upper - - - 1.98-1.72 m
Chord, Lower - - - 1.77-1.58 m
Gap - - - 1.85 m
Wing Area 41.5 m2 37.6 m2 36 m2 38.2 m2
Length 8.61 m 8.1 m 8.0 m 8.51 m
Height 3.27 m 2.93 m 3.2 m -
Empty Weight 835 kg 845 kg 845 kg 1,050 kg
Loaded Weight 1,373 kg 1,405 kg 1,405 kg 1,600 kg
Maximum Speed 100 km/h 130 km/h - 172 km/h
Climb to 1,000 m - - - 6 minutes
Climb to 2,000 m - - - 13 minutes
Climb to 3,000 m - - - 24.5 minutes
Climb to 4,000 m - - - 43.5 minutes

J.Herris LVG Aircraft of WWI. Vol.2: Types C.II - C.V (A Centennial Perspective on Great War Airplanes 35)

LVG C.III

  The first German armed two-seaters were field conversions of unarmed B-types. The B-types were designed with the observers seated in the front cockpit to give them the best field of view forward and downward. Consequently, when machine guns were added to these aircraft, the guns were mounted on rails alongside the forward observers' cockpits.
  When the first armed C-types were designed, most were designed with the observer in the rear cockpit to give him the best field of fire rearward to most effectively defend the aircraft from fighter attack. While this was the intuitive solution, Idflieg wanted to preserve the option of locating the observer/ gunner in the front seat pending operational experience that showed conclusively that the gunner in the rear was the preferred solution.
  As a result, the LVG C.III was one of a number of C-types ordered with the observer/gunner in the front cockpit. The most well-known C-types of this configuration were the Aviatik C.I, C.II, and C.III, all of which had the observer in the front cockpit and all of which were produced in some numbers and used in combat. Less well-known was the DFW C.I which was also used in combat and seated the observer in front.
  Unlike those aircraft, the Albatros C.IV, a C.III modified to seat the observer in front, and the LVG C.III, an LVG C.II modified to have the observer in front, did not serve in combat as far as is known. Only 12 Albatros C.IV aircraft were built and these were used for flying testbeds, mail delivery, and other non-combat purposes. The LVG C.III was unique among the C-types with observer in front that the observer had a gun turret instead of the gun being mounted on rails attached to the fuselage.
  Only three LVG C.III prototypes are thought to have been ordered as, by the time it was built, it was clear from operational experience that locating the gunner in the rear cockpit offered a more effective defense against fighter attack. However, Polish sources report acquiring two LVG C.III aircraft after the war with serials thought to be 3300/15 and 3309/15, so perhaps a small batch was built similar to the batch of 12 Albatros C.IV aircraft.