Ago C.I

   The AGO copies of the Otto pusher design had limited performance and failed to excite the interest of the Prussian Fliegertruppe who regarded these primitive aircraft as outmoded and were not impressed by the design or workmanship. In fact, the Fliegertruppe expressly prohibited the demonstration of new AGO aircraft because they considered it a waste of effort. In addition to all these negatives, the Prussian authorities strongly preferred the tractor aircraft configuration to the pusher configuration.
   AGO therefore had strong headwinds to overcome to sell aircraft to the military and had to focus on selling aircraft to the Navy. AGO had built some early seaplanes for the Navy that were overweight, fragile, and not successful. Now the Navy excluded AGO from further consideration, although the Navy did buy the few AGO landplanes available when war broke out and they were desperate for trainers.
   Introduction of the C.I in early 1915 briefly transformed Ago's fortunes. The C.I was a pusher design that was much improved compared to the Ago-Otto pusher trainer design. The engine was a 150 hp Benz Bz.III that was more reliable than the engines fitted to the pusher trainer design and more powerful than most of them. Later production C.I aircraft also used the 160 hp Mercedes D.III and a few used the 160 hp Maybach Mb.III depending on engine availability.
   The C.I had a robust airframe with sturdy four-wheel undercarriage. Later the front wheels of the undercarriage were often eliminated for improved speed and climb performance.
   The tail was carried by two streamlined booms that were constructed of wood strips wrapped around a wood frame. Compared to the typical 'lattice tail' pusher designs the Ago C.I was stronger and more streamlined. Movable rudders without fixed fins were fitted to the prototype, but production aircraft had fixed fins for improved stability.
   Two crew were carried in the central nacelle with the engine behind them. The observer occupied the front cockpit for the best field of view for reconnaissance and the best field of fire for the single flexible machine gun fitted for his use.
   The prototype and early production aircraft had side radiators for cooling. Later, airfoil radiators were fitted to reduce drag and vulnerability to enemy fire when they became available.
   The C.I had the typical pusher drawbacks and for that reason few were purchased by the Fliegertruppe. However, it was used by the Bavarian air service, which liked pushers, and the Navy, always short of aircraft, bought some as well. In addition the Navy bought one floatplane version of the C.I, the C.Iw. A few were used by the Fliegertruppe.
   The Otto C.I pusher was briefly used, but the comparatively refined Ago C.I was the only German single-engine pusher used in quantity in combat over the Western Front. It was never numerous but was noticed by the Allies because it was a pusher, an configuration unique to the Ago (and preceding Otto) C.I. It is known to have served with Bavarian Feld-Flieger Abteilung 5b, 8b, 9b, and other units of the Bavarian air service.


Ago C.II

   The Ago C.II was a slightly refined, somewhat more powerful development of the Ago C.I with enlarged wing. The 150 hp Benz Bz.III was replaced by a 160 hp Mercedes D.III and the 2-bay wing of the C.I was replaced by a 3-bay wing. An airfoil radiator was fitted as used by later-production Ago C.I aircraft and the airframe was slightly refined.
   The modest power increase and airframe refinement provided a small speed increase.
   The future did not belong to pusher aircraft and few examples of the C.II were built and used. According to the Frontbestand a maximum of two were at the front at the end of 1915 and a few were used by the Navy.


Ago C.I Aircraft Production
   Order Serials Qty Notes
   Feb. 1915 C.1-8/15 8 Side radiators
   Feb. 22, 1915 S 158-162 5 For the Navy
   Apr. 1915 C.94-105/15 12 Airfoil radiator
   1915 C.191-192/15 2 Airfoil radiator
   May 1915 C.349-373/15 25 Airfoil radiator
   Oct. 1915 C.1903-1914/15 12 Airfoil radiator, two-wheel undercarriage.


Ago C-Type Specifications
Ago C.I Ago C.Iw Ago C.II Ago C.IIw
   Engine 150 hp Benz Bz.III 150 hp Benz Bz.III 160 hp Mercedes D.III 220 hp Benz Bz.EV
   160 hp Mercedes D.III
   160 hp Maybach Mb.III
   Span, Upper 15.1 m 15.1 14.50 m (or 18.30 m) 18.3 m
   Span, Lower 14.34 m 14.34 m - -
   Chord, Upper 1.70 m 1.70 m - -
   Chord, Lower 1.70 m 1.70 m - -
   Gap 1.74 m 1.74 m - -
   Wing Area 47.6 m2 47.6 m2 - -
   Length 9.30 m 9.30 m 9.84 m 11.24 m
   Height 3.10 m - - -
   Empty Weight 960 kg 845 kg 1360 kg -
   Loaded Weight 1,495 kg 1,405 kg 1,946 kg -
   Maximum Speed 130 km/h 130 km/h 137 km/h -
   Climb to 1,000 m 9.5 min. - - -
   Climb to 2,000 m 24 min. - - -
   Climb to 3,000 m 45 min. - - -

Ago C.IV

   Ago had exhausted the potential of the pusher configuration with its C.I, C.II, and C.III designs. To achieve better performance and to create a design that could be sold to the Prussian-dominated Fliegertruppe, Ago turned to the tractor configuration.
   The result was the Ago C.IV, an innovative design of conventional construction that offered much better speed and climb than the pushers that preceded it.
   The Ago C.IV was most easily distinguished from other two-seaters in having a sharply-tapered wing planform. Most WWI aircraft had untapered wings of rectangular planform for ease of manufacturer. However, the induced drag (drag induced by lift) depends on the wing planform, and theoretical calculations indicate that an elliptical wing planform minimizes induced drag. (See the Spitfire for an example of an actual design using this principle.) An elliptical planform wing is difficult to manufacture. However, it can be approximated by the tapered wing planform, which is a compromise.
   The tapered wing has less drag than a rectangular wing but is harder to build. It has more drag than an elliptical wing but is easier to build.
   The resulting C.IV with 220 hp Benz Bz.IV engine was faster than most two-seat reconnaissance airplanes. It was carefully designed to have clean lines and be relatively streamlined for the time. The combination of good power, uncluttered lines, and tapered wing planform gave it good speed and climb for its time. It was much faster than the C.I that Ago had been building, and had the tractor configuration preferred by the Fliegertruppe. Ago appeared to have found the formula, and the C.IV was ordered in quantity starting in June 1916.
   Actual design of the Ago C.IV had started in late 1915. Another innovative feature of the C.IV was the lack of a forward, inboard bracing strut to provide a better field of fire forward between the wings for the observer. Ago was given Patent No. 299,149 for this innovation on Oct. 7, 1915, as they were designing the C.IV.
   The Ago C.IV prototype flew in early 1916 and immediately demonstrated good performance. In trials flown on May 21 the prototype reached 4,000 m altitude in 32 minutes, fast for the time. This encouraged Idflieg to order 24 aircraft in June 1916. Contemporary Idflieg files referred to the Ago C.IV as the so-called light C-type. It was thus a precursor of the later CL-class.
   Type-testing was completed in mid-June. The testing revealed the need to wing strengthening, and after two reinforcements of the metal wing fittings the required strength was achieved.
   An order for 10 aircraft was given to the Munich-based Waggonfabrik Josef Rathgeber AG to bring that company into much-needed aircraft production. Initially the order was for the Rathgeber C.I but was later re-designated the Ago C.IV(Rat) when Idflieg rationalized aircraft designations. However, these aircraft were never delivered and the parts were reduced to spares.
   Spare production capacity was available at Schutte-Lanz, best known for its airship manufacture as a competitor to Zeppelin. By this time airships were losing favor and the superior Zeppelins could fill requirements. None of Schutte-Lanz's own aircraft designs were selected for production and Idflieg ordered 250 Ago C.IV(Schul) aircraft from them to utilize their space production capacity. The size of the order indicated Idflieg’s interest in the C.IV.
   In December 1916 the Ago C.IV arrived at the front. The pilots, who had been used to the stable and reliable Ago C.I were anticipating the C.IV to combine these qualities with significantly improved performance. However, they were soon disappointed. As soon as the C.IV went into service, a rash of fuselage failures occurred during landing. However, this problem was quickly corrected in January and deliveries continued.
   As the crews logged increasing flight time on the C.IV, fatalities due to side-slipping increased alarmingly. The Ago C.IV was grounded at the end of April pending investigation and solution of the flight-control problem.
   The original C.IV prototype and production aircraft had ailerons on the upper wing only and did not have a fixed fin. As a result of the accidents the flight controls of the C.IV were extensively redesigned to improve its flight characteristics. Ailerons were fitted to all wings and a fixed vertical fin was added to the tail. In addition, most all the aircraft delivered by Ago after serial 8950/16 and all built by Schutte-Lanz had an additional bracing strut between the outer wing struts. Idflieg also tested Ago C.IV 1521/17 fitted with conventional two-bay bracing. The first Schutte-Lanz built C.IV was type-tested May 7-8, 1917, during which the metal wing fittings failed again and had to be reinforced. Cleared for combat, few Schutte-Lanz built C.IVs reached the front.
   The tapered wing planform gave good performance but contributed to the flight-control problem and the technology of the time was not adequate to 'tune' the wing's aerodynamics for good stability. With most rectangular planform wings, the designers 'washed out' the angle of incidence at the wingtips to ensure the wing stalled first at the wing root, countering its tendency to stall first at the tips where the ailerons were located, ensuring the pilot retained aileron control during stall recovery.
   After the modified C.IV was returned to the front in the May-June timeframe, the C.IV was moderately successful but was unpopular with aircrews. Continuing pilots' resistance and flight-control problems caused Idflieg to ground the C.IV again on September 7, 1917 and cancel production.
   The Ago C.IV was the last Ago design to be placed in production.


Ago C.IV Aircraft Production
   Order Serials Qty Notes
   June 1916 2740-2763/16 24 Ago
   Sept. 1916 3714-3723/16 10 Rathgeber (not completed; reduced to spares)
   Oct. 1916 5500-5749/16 250 Schutte-Lanz*
   Nov. 1916 3600-3623/16 24 Ago
   Nov. 1916 8950-8999/16 50 Ago
   Feb.1917 1521-1570/17 50 Ago
   May 1917 5575-5674/17 100 Ago. Few if any delivered. Order transferred to LVG C.II(Ago) trainers in Sept. 1917.
* Order reduced to 150 in July 1917 St cancelled in Oct. 1917 after 66 aircraft were delivered.


Ago C-Type Specifications
Ago C.III Ago C.IV
   Engine 160 hp Mercedes D.III 200 hp Benz Bz.IV
   Span, Upper 11.0m 11.90 m
   Wing Area - 37.5 m2
   Length 7.0 m 8.25 m
   Height - 3.50 m
   Empty Weight - 900 kg
   Loaded Weight - 1,350 kg
   Maximum Speed - 190 km/h
   Climb to 3,000 m - 22 min.
   Ceiling - 5,500 m.

Ago S.I

   The growing number of Allied tanks was an ever-increasing problem for the German Army as the war continued. Germany was unable to implement the obvious solution, building a large number of their own tanks, due to lack of industrial capacity. So it addition to new infantry weapons and tactics to counter tanks, Idflieg created a new category of aircraft, the S-type, for anti-tank warfare.
   The S-type was an armored tank destroyer armed with a 2 cm Becker cannon. The Allied tanks were armored against rifle-caliber fire from machine guns and rifles and could be easily penetrated by the heavier shells from the 2 cm Becker, especially as the fire would be against the thin armor on the top of the tanks.
   The final Ago design was the Ago S.I. It was extrapolated from the armored J-type in that the engine and cockpit were similarly armored against enemy rifle and machine gun fire. However, it had an innovative design to enable the gunner to attack tanks with a downward-firing 2 cm Becker cannon. To allow this the undercarriage was designed so there was no axle between the wheels.
   The configuration of the armor and cannon are shown in the adjacent sketch. Two machine guns were intended to be fitted,- one was for the gunner to use to protect the S.I from fighter attack. The other machine gun was likely intended as a fixed gun for the pilot.
   References differ on the engine used. One mentions a 300 hp Basse St Selve BuS.IVa engine and the other mentions a 500 hp Benz, - this would need to be the Bz.VI or Bz.VIv, both of which were 500 hp V-12 engines with a 60° angle between cylinder banks. In any case two prototypes were built in late 1918.
   The Ago S.I was the only S-type completed by war's end and development was too late for production. However, with its armored airframe and downward-firing anti-tank cannon it could be considered the great-grandfather of the contemporary anti-tank helicopter.

BFW CL.I

   Although BFW was in the business of repairing airplanes and building others, mostly intended as trainers, under license, they did build several original designs. The purpose for this has been lost to time. Were the BFW designs intended to let engineers burn off their creative energy or did they seriously want to create a new design team? BFW had the advantage of building the Halberstadt CL.II to learn from. The CL.I was a small biplane with interesting circular frontal radiator. The interplane struts were I-struts. The sole prototype built in 1916/1917 achieved a speed of 175 km/h.


BFW CL.II

   The BFW CL.II was powered by a 185 hp Mana III engine and flew in July 1918. The aircraft appeared to have essentially the same airframe as the earlier CL.I.
   No documentation remains to say why the BFW company decided to design original aircraft in the first place or why the designs were of the CL type. It makes sense BFW would avoid multi-engine types due to low demand, and for the same reason avoid floatplanes. Fighters were especially competitive, so perhaps C-types, CL-types, and N-types would come up as candidates, and BFW built C-types and the Halberstadt CL.II under license so had some familiarity with them. CL-types required robust, maneuverable aircraft of good performance. In contrast, the BFW CL designs all seemed somewhat delicate with only one interplane strut. Furthermore, the incumbent producers, Hannover and Halberstadt, were already working on their next-generation designs. BFW did not have a realistic chance of success as a new, untried design team building CL-type aircraft in competition with Hannover and Halberstadt who were already building very successful CL-types in quantity.


BFW CL.III

   The BFW CL.III, powered by a 200 hp Benz Bz.IV engine, appeared to use the same basic airframe as the BFW CL.I and CL.II. Like them, it remained a sole prototype. Use of a 200 hp engine normally put an aircraft in the C-class, not CL-class, although references to it call it the CL.III. Certainly its airframe was CL-class.
   During flight testing it proved to be faster than the Albatros D.V. The BFW CL.IV was similar to the CL.III but remained a project.

BFW N.I

   In August 1917, Idflieg contracted with the Bayerische Flugzeug Werke (BFW) of Munich to design and build three prototype N.I night bombers. These were to be powered by a 260 hp Mercedes D.IVa engine and be capable of lifting a 500 kg bomb load. A flight duration of four hours was specified.
   The dates of the prototype's completion and first flight are not known. In the fall of 1918, the triplane was fitted with test probes (venturi tubes) to explore the airflow around the airframe and determine the specific glide ratio. During these test flights two crewmen were carried to read and record the data. After the war, one BFW N.I "in repairable condition with engine" was stored at a government depot.
   The fuselage was well-streamlined with good nose entry from a spinner, but the large, flat-plate radiator beneath the top wing doubtless contributed a lot of drag. The BFW N.I appears to have been an attempt to carry a bombload nearly as large as the twin-engine night bombers being used but using only one engine. The bomb load was heavy for a single-engine airplane, and the gunner had a flexible machine gun for defense. The triplane layout was likely chosen to give the required large wing area with moderate span for better maneuverability.
   The ungainly BFW N.I could carry a heavy bomb-load for a single-engine aircraft and seems to have been a reasonable candidate for production. Certainly it was closer to meeting its design requirements than BFW's CL-prototypes. However, it was very slow, which would have presented problems in operational service.
   The existing N-types in service, the AEG N.I and Sablatnig N.I, were not stellar designs and the BFW N.I appeared to be a reasonable alternative. However, German night bomber pilots preferred the twin-engine aircraft, the Gothas, AEGs, and Friedrichshafen G-types they were already flying, and Idflieg decided not to purchase any more N-types.
   Few details of its performance or flying qualities have survived.


BFW N.I Specifications
   Engine 260 hp Mercedes D.IVa
   Wing Span (Upper) 15.006 m (49.2 ft.)
   Length 9.38 m (30.78 ft.)
   Empty Weight 1,500 kg (3,307 lb.)
   Loaded Weight 2,500 kg (5,512 lb.)
   Maximum Speed 110 kmh (66 mph)
   Armament 1 flexible machine gun, 744 kg bombs

Otto Pusher Biplane

   Inspired by the Farman configuration, Flugmaschinen Werke Gustav Otto in Munich designed a pusher biplane that proved popular for its unrestricted field of view forward and downward and for its stability and good handling. The Otto pusher gained a reputation for reliability and won a number of pre-war prizes.
   By early 1914 the Otto company claimed to have built 165 aircraft, most of which were the Otto pusher. When the Bavarian army decided to establish an aviation section, the Bavarian-built Otto pushers came immediately to its attention.
   Starting in 1911, the Bavarian army had purchased 9 aircraft (one Wild monoplane, one Albatros biplane, one Bleriot monoplane, five Euler pusher biplanes, and another Euler biplane obtained from a private owner). On 1 Jan. 1912 the Bavarian airship and motor section spun off a Fliegerkommando (flying command) dedicated to evaluating heavier-than-air craft as weapons. This started the Bavarian air service that remained semi-independent from the much larger Prussian air service.
   With establishment of the Fliegerkommando, the Bavarian army soon developed a preference for pusher aircraft. In contrast, the Prussian army had found the LVG B-type tractor biplane to be superior. In alignment with its pusher preference, the Bavarian army obtained 17 Otto and six Euler pusher biplanes to train its airmen. Otto prevailed in army maneuvers and in 1913 the Bavarian army ordered an additional 46 Otto pushers, together with 12 LVG B-types.
   Initially the Otto pushers were made of wood, but by the time the large Bavarian army orders were placed, most of the pushers had a steel-tube airframe. The aircraft retained the characteristic bathtub-shaped crew nacelle. The Bavarians viewed the pusher configuration to have the advantage of unobstructed field of view facilitating observation, bombing, and weapons handing. In addition, takeoff and landing were easier and the crew were not subject to engine oil spray, propeller blast, or exhaust gases. However, pusher disadvantages were items falling overboard could fly into the propeller and positioning of the wings behind the pilot made attitude orientation difficult.
   Otto work numbers 201-206 were the modernized so-called Series 200 airplanes; a new numbering system started at number 201.
Upon outbreak of war the Otto pusher equipped the Bavarian training units and two Bavarian combat units, Feldflieger-Abteihing 1b and later 4b (renamed from Festungs-Flieger-Abteilung Germersheim and taken out of the fortress to the front), both attached to the 6th Army. It is believed these were equipped with both the triple-rudder 1913 model and the single-rudder 1914 model. FFA 1b flew its first combat flight on 10 August, 1914.
   These Otto pushers were powered by the old Argus four-cylinder engines. With these engines the pilots could barely climb above 1200 m (about 4000 feet); this inhibited spotting French troops as the Otto pushers were subject to ground fire from rifles and machine guns. With ground fighting in the Vosges mountains occurred at 800 to 1000 meters, the Ottos were especially vulnerable at only 200 to 400 meters above the ground. Even worse, the planes were fired on by the soldiers from both sides.
   By August 23, 1914, the Bavarian air service had 19 Otto pushers (with 100 hp Mercedes or Argus engines), 24 LVG B-types, and two unknown types. The Otto pushers were already obsolete, yet FFA 1b had to wait until December before the Ottos were replaced by Albatros and LVG B-types. The LVGs were built by both LVG and Otto under license.
   On April 16, 1915 the Otto pusher inventory was five at FFA 4b, four at Schleissheim, and one at Flugpark 6b. The first armed C-type replacements started to arrive at 6th Army in May 1915.
   Having early developed a preference for tractor aircraft, the Prussian air service, with one exception, did not use the Otto pusher. (During the beginning of BAO (Brieftaubenabteilung Ostende) one Bavarian crew seconded to it flew their Otto pusher biplane.) However, the German Navy, chronically short of aircraft, ordered a number of Otto pusher seaplanes. The Johannisthal naval volunteer pilot school also operated a number of Otto (Ago) pusher landplanes. The naval aircraft were supplied by the AGO Flugzeug Werke, Otto's license company in Berlin.
   Note: From 1914 to end of 1916 there were no Flieger-Abteilungs, despite the term being sometimes used.There were only Feldflieger-Abteilungen (FFA's) and Artiellerieflieger-Abteilungen (AFA's).


Otto 1914 Pusher Specifications
   Source Flight, 14 August 1914. P.862 Flugsport, 1914
   Span, top 14.8 m 14.800 m
   Span, bottom 9.5 m 9.500 m
   Length 10.5 m 10.500 m
   Height - 3.600 m
   Chord 1.8 m 1.800 m
   Gap - 1.500 m
   Track - 2.100 m
   Wing Area, m2 40 -
   Speed in kph 110 -


Ago School Biplane

   As a subsidiary of the Otto company, it is not surprising that AGO's first production aircraft type was a copy of the first successful Otto type, the biplane pusher trainer powered by a 100 hp Argus engine.
   As did Otto, AGO started producing the early version of the Otto pusher trainer with three rudders and later changed to producing the pusher trainer with the simplified tail with one rudder and monoplane tailplane.

Otto C.I

   Whereas many operational Allied aircraft were pushers, the Otto C.I was one of the very few German aircraft to use that configuration. A partial explanation for this is because the Otto company was located in Munich, Bavaria, and the Bavarian air service, which purchased Otto aircraft, was independent of the Prussian-controlled German air service up until about 1915. The German air service strongly preferred tractor aircraft and most production German two-seaters were of that configuration, but, like France and Britain, the Bavarian air service initially favored pusher aircraft. To the Bavarians, the chief benefit of pusher two-seaters was the unobstructed forward visibility for the crew for observation, photography, and bombing.
   Consequently, when in 1912 the Bavarian air service started purchasing aircraft in earnest, 17 Otto pushers (unarmed two-seater biplanes) and six Euler pushers were obtained. The primitive and underpowered Otto B-types with which the Bavarians started combat operations in August 1914 were replaced with LVG and Albatros B-type biplanes starting in December 1914. Thus, in early 1915 the aircraft destined to become the Otto C.I was begun as a private venture to replace the obsolete Otto B-types.
   The prototype of the new aircraft, known as the Otto KD 15, performed its first flight in late May or early June 1915 powered by a 165 hp Austro-Daimler six-cylinder engine. It had twin booms to reduce drag compared to the Otto B and its wing planform and cranked ailerons were based on that of the LVG B-type biplanes then being produced by Otto under license. The prototype KD 15, later to become known as the Otto C.I, was totally constructed of Duralumin, quite an innovation for the time, which saved 200 kg or more of weight compared to steel tubing. However, since Duralumin could not be welded or soldered, the joints had to be connected with bolted sleeve clamps. A four-wheeled undercarriage was mounted to help prevent nose-overs on rough fields and, unlike most aircraft of the time, the rear wheels had brakes.
   The second Otto KD 15 was initially flown with a larger wing than the first prototype, but after being damaged in a hard landing on 7 July 1915, it was rebuilt with wings of reduced span in August. The second prototype also featured a 200 hp Rapp engine and wooden fairings on its metal struts to reduce drag.
   Because the Otto firm was financially distressed, Gustav Otto, the owner, requested and received a production order for six Otto C.I aircraft in August. These six aircraft, designated Otto C.I 544/15 to 549/15, were followed by an order for an additional six aircraft, designated C.I 1115/15 to 1120/15, in November. In addition, the first prototype was purchased after the initial production order had been placed and was given number C.I 3633/15, and the second prototype may also have been purchased for use.
   Production Otto C.I aircraft were powered by a variety of engines, including the 200 hp Rapp, the 160 hp Mercedes, and the 150 hp Benz. Despite its higher power rating, the Rapp was unpopular because it was not nearly as reliable as the Mercedes or Benz, which were strongly preferred for service use. Rapp, located in Bavaria, was later purchased by new owners and reorganized as the Bavarian Motor Works, which then produced the excellent 185 hp BMW.III engine of 1918.
   Easy to fly but with a limited operational ceiling of only about 3,000 metres (9,800 feet) when fully equipped, in German service the Otto C.I served only with Bavarian units such as Flieger-Abteilung 4b, 8b, and 9b, and was soon relegated to training units, where the remaining aircraft were converted to dual controls for pilot training.

Bulgarian Service

   The Otto C.I first batch served with Bavarian Flieger-Abteilungs and one with Prussian FFA58 before it was converted to training service. In 1915 a Bulgarian purchasing commission visited Munich and were taken to see the Otto Werke, where about a dozen Otto C.I aircraft were in storage. The aircraft were available immediately and the Bulgarians bought them all.
   In Bulgarian service the Otto C.I aircraft seemed to be used in action only by the 2nd Aeroplane Otdelenie based at Udovo and others were at the Aeroplane School at Bojurishte.
   Thirteen Otto C.I two-seat twin-boomed biplanes (powered by the 150 hp Benz Bz.III) were delivered to Bojurishte in the spring of 1916. They were used by 2 Aeroplane Otdelenie at Udovo airfield in the bombing and reconnaissance roles. These were still used at the start of 1917 for reconnaissance but soon withdrawn in favor of the Albatros C.III. The known serial numbers appear in the nearby table.

Otto C.I Aircraft Production
   Production Serials Qty Notes
   Prototype C.3633/15 1 At Schleifiheim school (2nd prototype serial unknown)
   1st batch C.544/15-549/15 6 Primarily used by Bavaria (mostly FFA 2b, FFA 4b, FFA 9b, Si FFA 58)
   2nd batch C.1115/15-1120/15 6 Bulgaria
   3rd batch C.3575/15-3580/15 6 Bulgaria

Bulgarian Otto C.I Aircraft
   Serial Delivered Notes:
   C.1115/15 1916 Shown at 2 Otdelenie. Suffered minor crash but appears to have been repaired.
   C.3575/15 1916
   C.3579/15 1916
   C.3580/15 1916
   Probably all Bulgarian Otto C.I aircraft were from production series 2 & 3.