W.Green, G.Swanborough The Complete Book of Fighters

AVIATIK (BERG) D I Austria-Hungary

   Designed by Dipl Ing Julius von Berg and frequently referred to as the Berg Scout, the DI was the first single-seat fighter of indigenous design to be manufactured in quantity by the Osterreichisch-Ungarische Flugzeugfabrik Aviatik of Vienna. The prototypes of the DI were the Av 30.19, 30.20 and 30.21, and the first of these was flown on 24 January 1917, differing from the subsequent production model primarily in lacking armament. Of wooden construction with ply fuselage skinning and fabric wing skinning, the DI entered service with the Austro-Hungarian Luftfahrttruppe in the autumn of 1917, by which time armament had standardised on two synchronised 8-mm Schwarzlose machine guns. Initial D Is had the 185 hp Austro-Daimler six-cylinder inline engine, some 140 were built with the 160 hp Austro-Daimler, and 200 and 225 hp Austro-Daimlers were progressively introduced. Some 700 fighters of this Berg type were manufactured by the parent concern and under licence by Lohner, Lloyd, Thone und Fiala, MAG and WKF. The following specification relates to the model powered by the 200 hp Austro-Daimler engine.

Max speed, 115mph (185km/h).
Time to 3,280 ft (1000 m), 2.23 min, to 6,560 ft (2 000 m), 7.63 min.
Endurance, 2.5 hrs.
Empty weight, 1,345 lb (610 kg).
Loaded weight, 1,878 lb (852 kg).
Span, 26 ft 3 in (8,00 m).
Length, 22 ft 6 in (6,86 m).
Height, 8 ft 2 in (2,48 m).
Wing area, 234.66 sq ft (21,80 m2).

P.Grosz, G.Haddow, P.Shiemer Austro-Hungarian Army Aircraft of World War One (Flying Machines)

Aviatik D.I (Lo) Series 115 and 315

  Preparations were underway at Lohner in mid-1917 to replace Aviatik C.I production with the Aviatik D.I fighter, of which 93 had been ordered: 21 from the open 27 January 1917 contract and 72 as part of the 17 July 1917 contract. On 18 May 1918, a further 96 D.I were ordered for a total of 189 aircraft, reduced to 165 in September 1918. Production was divided into 89 series 115 fighters (115.01 to 115.89) powered by the 200 hp Daimler engine and 76 series 315 (315.01 to 315.76) by the 225 hp Daimler engine. The first two series 115 fighters were accepted in December 1917, but owing to subzero winter weather the 17 fighters delivered between 10-31 December 1917 were not accepted until March 1918. Forty series 115 fighters and all those over 115.62 had twin machine gun armament installed at the Front. By 31 October 1918, a total of 88 machines had been accepted.
  In May 1918, shortly after the series 115 fighters had reached the Front, five Flik 60/J aircraft experienced wing trailing edge failure: among them Stabsfeldwebel Albin Heidi (115.30 on 11 May 1918), Oberleutnant Fritz Pisko (115.05 on 16 May 1918 and 115.26 on 18 May 1918) and Leutnant von Szabo (115.24 on 19 May 1918). Other squadrons reported similar incidents. Oberleutnant Frank Linke-Crawford, commander of Flik 60/J and a 27-victory ace, complained in mid-May 1918 that "At present I have seven Berg single-seaters (series 115) whose wings tear apart at high speed at great risk to life. Therefore I cannot permit them to be flown against the enemy." To fix the problem, a Lohner production engineer accompanied a repair team to the Front to fix the wings. Investigation showed that Lohner had substituted a lighter rib section and had attached the fabric in a manner different than specified by Aviatik. How this fact escaped the resident Flars inspector is inexplicable. Uzelac ordered the series 115 returned to the factory for wing replacement. Aircraft beginning with 115.66 left the factory in strict compliance with specifications.
  Unfortunately, Uzelac's order came too late. It is indicative of the sense of duty Austro-Hungarian flying personnel showed throughout the war that they continued to fly the dangerous Lohner-built fighters at "great risk to their lives." Ironically, Linke-Crawford was flying aircraft 115.32 during his last combat on 31 July 1918. Eye-witnesses reported that Linke-Crawford, pursued by British fighters, had just levelled out after a high-speed dive and spin when he was seen "throwing papers overboard." This impression is believed to have been given by shreds of fabric tearing from the wing as a result of the violent maneuvers. As he throttled back to nurse his badly-damaged machine home, Linke-Crawford was attacked and shot down.
  Similar reports of failure led to swift if belated action. The Lohner-built machines were grounded or restricted to noncombat duties. On 4 August 1918, the Army High Command ordered the 200 hp Daimler engines removed from aircraft 115.01 to 115.48 and installed in Aviatik D.I series 238 and 284 fighters to replace their 160 hp engines. Fifteen series 115 fighters, fitted with used 185 hp Daimler engines, were assigned to training duties. A handful of newer production machines remained operational with Fliks 14/J, 56/J, 60/J, and 72/J and singly with Fliks 63/J, 73/J, and 74/J. At least eight, modified for photo-reconnaissance work in September 1918, were assigned to Flik 40/P and 70/P, but saw limited employment. Because the Lohner-built fighters engendered universal mistrust and were considered "unsympathetic aircraft," pilots preferred to operate more robustly-built machines whenever possible. No wonder then that only one pilot, (Linke-Crawford) can be found who was credited with a victory while flying a Lohner-built series 115 fighter (115.32)! The series 115, no matter how well constructed, could not outlive its destructive reputation. In 1920, fifteen series 115 fighters (most with numbers below 115.48) were offered for sale to the Czechoslovakian government.

Aviatik D.I(Lo) Series 115 Specifications
Engine: 200 hp Daimler
Wing: Span Upper 8.00 m (26.25 ft)
Span Lower 7.89 m (25.89 ft)
Chord Upper 1.45 m (4.76. ft)
Chord Lower 1.45 m (4.76 ft)
Total Wing Area 21.7 sq m (233 sq ft)
General: Height 2.50 m (8.20 ft)
Empty Weight 668 kg (1473 lb)
Loaded Weight 798 kg (1760 lb)
Maximum Speed: 185 km/hr (115 mph)
Climb: 1000m (3,281 ft) in 2 min 38 sec
3000m (9,843 ft) in 9 min 52 sec


Aviatik D.I (Lo) Series 315

  By September 1918, series 315 production was in full swing. Records show that only three or four fighters were dispatched from Vienna and it is doubtful if these reached any frontline unit. By 31 October 1918, a total of 22 series 315 fighters had been accepted. Of the remaining 54, half were ready for acceptance and the other half about 50 percent complete. Production had been scheduled to end in December 1918.

Aviatik D.I(Lo) Series 315 Specifications
Engine: 225 hp Daimler
Wing: Span Upper 8.00 m (26.25 ft)
Span Lower 7.89 m (25.89 ft)
Chord Upper 1.45 m (4.76 ft)
Chord Lower 1.45 m (4.76 ft)
Total Wing Area 21.7 sq m (233 sq ft)
General: Length 6.80 m (22.31 ft)
Height 2.50 m (8.20 ft)
Empty Weight 638 kg (1407 lb)
Loaded Weight 912 kg (2011 lb)
Climb: 1000m (3,281 ft) in 2 min 47 sec
2000m (6,562 ft) in 6 min 47 sec
3000m (9,843 ft) in 12 min 45 sec
4000m [13,124 ft) in 22 min


Aviatik D.I Series 38

  The Aviatik D.I was the first fighter designed in Austria-Hungary to enter LFT service. It had evolved from the ill-fated 30.14 prototype, followed by the definitive D.I prototypes (30.19-30.21) that made their successful debut in early 1917. Thus began a broad D.I manufacturing program involving six manufacturers that would account for 43 percent of the total fighter acceptances through October 1918. Eager to replace the dangerous Brandenburg D.I, Uzelac urged Aviatik to begin production at once. The first production machine, 38.01, arrived at Aspern for flight tests in April 1917. That month Flars ordered 48, later increased to 72, D.I fighters, numbered 38.01 to 38.72 and powered by the 185 hp Daimler engine. At the time the formal contract was signed on 17 July 1917, two D.I fighters were at the Front and production was entering high gear.
  The first Aviatik D.I fighter, 38.01, was accepted on 3 May 1917. After being inspected and approved by a Flars engineering commission on 12 May, it was sent to Fluggeschwader I (later Flik 101/G) on 15 May 1917 for service evaluation along with the 30.19 prototype. Aircraft 38.02 went to Flik 12 where it was flown by Hauptmann Godwin Brumowski (17 & 26 June). The first Aviatik D.I victory, an Italian Nieuport, was credited to the CO of Fluggeschwader I, Hauptmann Karl Sabeditsch (flying 38.01) on 20 August 1917. In June 1917, D.I assembly (24 aircraft nearing completion) was slowed in order to analyze the airframe to determine potential weak spots such as had appeared during the Aviatik C.I's service introduction. Taking no chances, Flars directed that the D.I be strengthened in a manner similar to the C.I. In August-September 1917, small numbers of the new Aviatik D.I began to reach Fliks 4, 23, 28, 35, 41/J, and 42/J. Unlike the C.I, initial squadron reaction was generally positive. Pilots praised the performance and regarded the D.I as having "the best climb rate of any fighter without sacrificing maneuverability. The flight characteristics exceed those of all contemporary fighters." In fact, test pilot Antal Feher, flying 38.03 on 12 June 1917, reached a speed of 197 km/h (122 mph), some 10 km/h (6 mph) faster than the new 200 hp Albatros D.III(Oef) series 153 fighter.
  But these fine attributes were negated by the lack of a satisfactory machine gun synchronization mechanism. The wing-mounted machine gun, fixed at a 15 degree angle to fire over the propeller, was reported to be "utterly ineffective." Pilots discovered that it was almost impossible to attack an opponent unless the aircraft was in a dive, thereby losing altitude and leaving the pilot at a disadvantage. Even so, a few victories were recorded by skillful pilots. In addition to Sabeditsch, known are Offizierstellvertreter Friedrich Hefty of Flik 42/J and Feldwebel Karl Benko of Flik 28, who were credited with a victory each on 27 and 29 October 1917, respectively. The D.I series 38 also was operational with Fliks 32, 47, 53/D, and 58/D, and went on to serve as a fighter-trainer with Fliks 63/J, 68/J, and 74/J.
  When Uzelac learned in November 1917 that the D.I was being delivered without gun synchronization some six months after entering service, he ordered Aviatik, who had been working on the problem, to demonstrate progress to date. As of December, twin synchronized machine guns were installed, but at the expense of accessibility, for the guns were mounted alongside the engine out of the pilot's reach in event of a stoppage. Work was under way to modify the airframe for placing the guns in front of the pilot. Tests in mid-January 1918 were successful and beginning in June-July 1918, all D.I fighters were delivered with accessible guns. The problems of cartridge lubrication spray and restricted frontal visibility made it necessary to install the aiming sight alongside the engine. The pilot was required to lean to one side to aim the guns. Consequently, much attention was given to improving visibility, especially reducing the size of the large nose radiator. Many radiator shapes were tested but none proved entirely successful. Nor did the thin wing section permit installation of an airfoil radiator. Throughout the production cycle, and in seeming random fashion, D.I fighters left the factory with either the original nose radiator, a twin side-mounted type, or a block radiator mounted on the upper-wing leading edge.
  It is difficult to understand why Berg, himself a pilot, designed the D.I with such an awkward steering-wheel control. Flik 42/J reported the control as "unsympathetic for fighter pilots, especially difficult to fly in gusty weather." When the more-powerful D.I series 138 appeared still fitted with a control wheel, the outspoken commander of Flik 61/J, Oberleutnant Ernst Strohschneider, vented his displeasure in January 1918 by writing that the fighter "was obviously designed by someone who had never flown." In truth, the wheel control was not all that bad since the light and nimble D.I responded easily to small control movements, but in deference to popular demand it was soon replaced by a stick control.
  Produced in four series, the Aviatik D.I remained in production until the war's end. Being structurally identical, one series did not follow another as might be expected; rather all four were produced in parallel according to engine availability, which had difficulty keeping pace with aircraft output. The D.I was ideally suited for license manufacture because of its relatively simple design. Using wood and plywood with a minimum of complex metalwork, the airframe was ideal for semi-skilled woodworkers to build. In April 1917, Lohner, MAG, and Thone & Fiala received large license orders, followed by Lloyd and WKF in early 1918. As of 31 October 1918 (the last month for which acceptance figures are available), a total of 677 D.I fighters had been accepted. Had production ended as scheduled in December 1918, a grand total of 983 D.I fighters would have been delivered, as shown in the nearby chart. Information regarding the various license-built D.I fighters can be found in the appropriate chapters.

Aviatik D.I Series 38 Specifications
Engine: 185 hp Daimler
Wing: Span Upper 8.00 m (26.25 ft)
Span Lower 7.89 m (25.89 ft)
Chord Upper 1.45 m (4.76 ft)
Chord Lower 1.45 m (4.76 ft)
Sweepback Upper 0 deg
Sweepback Lower 0 deg
Gap 1.35 m (4.43 ft)
Stagger 0.26 m (0.85 ft)
Total Wing Area 20.3 sq m (219 sq ft)
General: Length 6.86 m (22.51 ft)
Height 2.92 m (9.58 ft)
Track 1.80 m (5.91 ft)
Empty Weight 580 kg (1279 lb)
Loaded Weight 850 kg (1874 lb)
Maximum Speed: 187 km/hr (116 mph|
Climb: 1000m (3,281 ft) in 2 min 18 sec
3000m (9,843 ft) in 8 min 4 sec
5000m (16,405 ft) in 20 min 18 sec


Aviatik D.I Series 138

  The most popular Aviatik D.I version was the series 138 powered by the 200 hp Daimler engine. Pressed by the LFT to increase the engine power, Austro-Daimler brought out the 200 hp Daimler engine in early 1917. The power rating was increased by raising the compression ratio and the use of four valves per cylinder. British engineers who tested a captured Daimler engine (taken from aircraft 138.27) reported that it "possessed more originality in design than the majority of enemy engines up to the present time" (July 1918). As part of the 17 July 1917 open contract, 88 D.I series 138 fighters were ordered. These were numbered 138.01 to 138.64 and 138.97 to 138.120 (the numbers 138.65 to 138.96 remained unused). The first aircraft was accepted in September 1917 and the last in November 1918 at the factory by the resident inspecting officer.
  When the 200 hp Aviatik D.I fighters arrived at frontline units beginning in October 1917, they were met with the same mix of enthusiasm and criticism as had greeted the D.I series 38. Flik 42/J reported in January 1918 that the Aviatik was faster, possessed a superior rate of climb, and was more maneuverable than the Albatros D.III(Oef), but that the visibility and armament were unsatisfactory. With respect to climb and speed, Flik 52/D assessed the series 138 as equal to the Sopwith Camel. In February 1918, aircraft 138.98 and 138.114 were dispatched to the German test center at Adlershof for comparison with German fighters. Idflieg (Inspectorate of Aviation Troops) reported that the D.I demonstrated better climb and speed than the Albatros D.V but was less maneuverable.
  A British technical evaluation of a captured D.I (138.27, enemy aircraft number AG 6, flown by Korporal Andreas Kulscar of Flik 4) provides some insight into the Aviatik design practice. The inspection appraisal stated that "everything had been designed to meet the requirements of easy production; everything being kept simple as possible to this end. This does not mean workmanship is inferior. As a matter of fact, the workmanship is very good generally speaking, although the finish may be here and there of a slightly less polished order than is found on some machines." The wings and airframe were of simple construction, but of a "simplicity which does not result in scamped workmanship and hurried finish but which bears evidence of careful design, with ease of production always kept in mind." The timber employed for the wings was of excellent quality, better than that found in the average German machine. The simple fittings combined high strength with light weight. Welding was used to a much smaller extent as compared to German practice. The tailplanes were constructed of large diameter steel tubing, but were single, whereas many German machines used two small-diameter tubes to form a rib.
  The wing was unusual in that the rib section had a pronounced reflex curvature towards the trailing edge and the rear third was remarkably narrow. This feature, introduced by Professor Knoller, was said to reduce the center of pressure travel and result in improved longitudinal stability. But the aerodynamic advantages gained were, to some extent, negated by the danger of fatigue failure caused by the constant inflight flexing of the narrow trailing section. In fact, such failures were a common and sometimes fatal occurrence. In July 1918, Flik 72/J reported that "the wing strength is insufficient. Rib failures have occurred in both wings, causing relatively many accidents including two fatalities." Similar sentiments were voiced by Flik 74/J, noting that the upper wing on the exhaust side was especially vulnerable. The squadron had lost three Aviatik D.I fighters due to wing failure. In response, Berg designed a wing with a smaller chord and additional ribs that reduced the rib spacing by half. Although series 38, 138 and 238 fighters with the new wings were leaving the Aviatik factory in July 1918, it appears that the original wings continued in production, possibly to use up existing stocks. In June 1918, fifteen D.I fighters (38.61, 138.61-63 and 238.56-66) were fitted with a shortened and specially reinforced lower wing that was favorably received by field formations. It is not known if this modification was adopted by the license manufacturers. Notwithstanding the wing reinforcement, the Aviatik D.I continued to have a reputation for being fragile, leading most pilots to prefer the Albatros D.III(Oef) in spite of the D.I's better performance.
  As shown in the accompanying photographs, three types of radiators (nose, side, and leading edge) were employed on Aviatik D.I production aircraft. Apparently these were randomly installed as they became available. The radiators were manufactured by Erenyi, Weich, Windhoff, and Hirschfelder. A number of experimental radiator designs were tested in hopes of improving forward visibility.
  D.I series 138 fighter production spanned a fifteen-month period during which output was geared to the availability of the 200 hp engine. It was supplied to fighter squadrons such as Fliks 14/J, 42/J, 51/J, 56/J, 60/J, 63/J, 68/J, 72/J, and 74/J and in single examples to Fliks 4/D, 15/F, 19/F, 23/D, 28/D, 34/D, 46/F, 53/D, 54/D, 57/F, 58/F, 73/D, and 101/G. As of July 1918, a few served with Flik 37/P as photo-reconnaissance fighters and as trainers with Fleks 6, 19, and the two field flying schools. On 1 August 1918, forty-eight series 138 fighters were serving with frontline squadrons.

Aviatik D.I Series 138 Specifications
Engine: 200 hp Daimler
Wing: Span Upper 8.00 m (26.25 ft)
Span Lower 7.89 m (25.89 ft)
Chord Upper 1.45 m (4.76 ft)
Chord Lower 1.45 m (4.76 ft)
Sweepback Upper 0 deg
Sweepback Lower 0 deg
Gap 1.35 m (4.43 ft)
Stagger 0.26 m (0.85 ft)
Total Wing Area 20.3 sq m (219 sq ft)
General: Length 6.86 m (22.51 ft)
Height 2.92 m (9.58 ft)
Track 1.80 m (5.91 ft)
Maximum Speed: 195 km/hr (121 mph)
Climb: 1000m (3,281 ft) in 1 min 42 sec
2000m (6,562 ft) in 4 min 30 sec
3000m (9,843 ft) in 7 min 36 sec
4000m (13,124 ft) in 12 min 10 sec
5000m (16,405 ft) in 16 min 26 sec
6000m (19,686 ft) in 26 min


Aviatik D.I Series 238

  The chronic shortage of high-powered engines set the stage for the next version of the Aviatik D.I fighter. Because ample stocks of new and reconditioned 160 hp Daimler engines were on hand, Flars tested an Aviatik D.I powered by that engine in December 1917. It was concluded that the combination was capable of attaining acceptable performance for operational service and was approved for production accordingly. The 160 hp Aviatik D.I series 238 acceptances began in January 1918 and ended in August 1918 when the last of 120 fighters was accepted. The serial numbers assigned were 238.01 to 238.90 and 238.105 to 238.134 (the numbers 238.91 to 238.104 remained unused). At least 20 series 238 fighters were accepted without engines. Armament consisted of twin synchronized machine guns but some 50 fighters were delivered unarmed due to the gun shortage. A few series 238 fighters were fitted with redesigned, all-plywood tail surfaces and ailerons, but the number built is unknown. In August 1918, Flik 1 reported that the wooden parts tended to warp out of shape and, being heavier, impeded maneuverability.
  The introduction of the retrograde D.I series 238 fighter in April-May 1918 triggered universal condemnation by Flik pilots. Flik 6/F complained in May 1918 that the underpowered fighter was too slow to intercept Allied observation machines. The series 238 was regarded as adequate for close-escort missions by Flik 23/D but useless in an offensive role and inferior to Allied fighters. Because pilots were unwilling to fly the underpowered D.I, a few resourceful Fliks installed more powerful engines. For instance, Flik 6/F reported no trouble installing 185 hp Daimler engines taken from wrecked aircraft or scrounged from rear-area depots. On 12 July 1918, the LFT ordered the replacement of all 160 hp engines in the series 238 by new or used 200 hp engines but only a few conversions were made. Those aircraft not used as trainers languished for months in storage until engines could be found.
  The D.I series 238 (some powered by 185 or 200 hp engines) was flown as a fighter by Fliks 1/J, 6/F, 13/J, 23/D, 28/D, and 64/F. The type served as an advanced trainer in Fliks 14/J, 43/J, 55/], 56/J, 72/J, 74/J, and with Flek 6 and the two field flying schools. Several series 238 were used as photoreconnaissance fighters by Fliks 37/P, 40/P, and 46/P. On 1 August 1918, eighty-nine Aviatik D.I series 238 fighters were carried in the frontline inventory.

Aviatik D.I Series 238 Specifications
Engine: 160 hp Daimler
Wing: Span Upper 8.00 m |26.25 ft)
Span Lower 7.89 m (25.89 ft)
Chord Upper 1.45 m (4.76 ft)
Chord Lower 1.45 m (4.76 ft|
Sweepback Upper 0 deg
Sweepback Lower 0 deg
Gap 1.35 m (4.43 ft)
Stagger 0.26 m (0.85 ft)
Total Wing Area 20.3 sq m (219 sq ft)
General: Length 6.86 m (22.51 ft)
Height 2.92 m (9.58 ft)
Track 1.80 m (5.91 ft)
Maximum Speed: 192 km/hr (119 mph)
Climb: 1000m (3,281 ft) in 2 min 6 sec
2000m (6,562 ft) in 5 min 50 sec
3000m (9,843 ft) in 10 min 12 sec
4000m (13,124 ft) in 15 min 24 sec
5000m (16,405 ft) in 21 min 34 sec


Aviatik D.I Series 338

  By the middle of 1918, output of the new 225 hp Daimler engine had reached a level sufficient to supply two production fighters, the Albatros D.III(Oef) series 253 and the Aviatik D.I series 338. Contracts for a total of 294 Aviatik D.I fighters powered by the 225 hp engine were awarded to Aviatik, Lohner, Lloyd and WKF. These aircraft had strengthened wings and engine bearers, and were armed with twin guns mounted at eye level.
  As part of the contract dated 18 May 1918, Aviatik built a pre-production batch of eight D.I series 338 fighters for evaluation. These were numbered 338.01 to 338.08. Shortly thereafter, Flars ordered 100 production fighters numbered 338.21 to 338.120 (numbers 338.09 to 338.20 remained unused). The pre-production machines arrived at Aspern in June-July 1918 for flight trials. Engine cooling posed a vexing problem. The nose radiator originally fitted to aircraft 338.01 was replaced by twin Hefa side radiators to improve cooling efficiency and forward visibility. Various other side radiators and an Oefam airfoil radiator (tested in aircraft 338.07) were rejected in favor of a block radiator mounted on the upper wing leading edge which became the production standard.
  Two fighters, 338.03 and 338.04, participated in the Fighter Evaluation held on 9-13 July at Aspern. The climb trials performed with aircraft 338.03 were interrupted when the side radiators began to boil over at altitude, but enough data was obtained to demonstrate a remarkable climb rate, second to none. Tested against a captured Sopwith Camel, aircraft 338.06 was faster and showed equal maneuverability with ability to perform sharp turns without altitude loss. In August 1918, aircraft 338.01 and 338.02 were dispatched to Flik 1/J at Igalo for service trials. Here take-off for interception occurred only after enemy aircraft were positively reported or visually sighted. Since it was a task suitable "only for the most rapid climbing and fastest fighter," the fast-climbing D.I series 338 was the ideal aircraft. Flik 1/J commander Oberleutnant Bela Macourek and Offizierstellvertreter Julius Arigi were both credited with two victories while flying a series 338 fighter. Production fighters began to reach the Front in September 1918, but only very few saw combat service in the waning days of the war.
  After the crash of aircraft 338.89 which killed Aviatik test pilot Feldwebel Franz Tordik on 16 October 1918, investigation discovered a faulty aileron-pulley support. On 29 October appropriate modifications were ordered on the 34 completed fighters: 338.01 to 338.08, 338.21 to 338.35 and 338.86 to 338.96 and those in production. The reasons for the non-consecutive production run is not known. At the war's end, the resident inspection officer accepted 27 completed series 338 fighters at the factory; the remaining 23 were almost complete. Series 338 production was scheduled to end in December 1918.
  Postwar plans calling for the Aviatik D.I series 338 to equip the Austrian air arm were forbidden by the treaty stipulations. Acceding to Czechoslovakian demands, 24 series 338 fighters and ancillary equipment were loaded on freight cars for shipment in December 1918. But the Austrian demobilization office did not grant an export permit until mid-January 1919. By then the fighters, damaged by weather exposure and theft, had only scrap value.

Aviatik D.I Series 338 Specifications
Engine: 225 hp Daimler
Wing: Span Upper 8.00 m (26.25 ft)
Span Lower 7.89 m (25.89 ft)
Chord Upper 1.45 m (4.76 ft)
Chord Lower 1.45 m (4.76 ft)
Sweepback Upper 0 deg
Sweepback Lower 0 deg
Gap 1.35 m (4.43 ft)
Stagger 0.26 m (0.85 ft)
Total Wing Area 20.3 sq m [219 sq ft)
General: Length 6.86 m (22.51 ft)
Height 2.92 m (9.58 ft)
Track 1.80 m (5.91 ft)
Climb: 1000m (3,281 ft) in 1 min 59 sec
2000m (6,562 ft) in 4 min 12 sec
3000m (9,843 ft) in 7 min 30 sec
4000m (13,124 ft) in 12 min
5000m (16,405 ft) in 16 min 24 sec
6000m (19,686 ft) in 27 min 30 sec


Aviatik D.I(Ll) Series 48, 248 and 348

  License production of the Aviatik D.I(Ll), under way at Lloyd before the formal contract was signed on 18 May 1918, comprised 100 fighters in the following series:
Quantity Series Number Engine
10 48.01-10 185 hp Daimler(MAG)
20 248.01-20 160 hp Daimler(MAG)
70 348.01-70 225 hp Daimler(MAG)
  All Aviatik D.I(Ll) series 48 and 248 fighters left the factory modified to receive cameras, etc., for photoreconnaissance work. None had machine guns installed. Although scheduled to receive re-built engines - some taken from retired Aviatik C.I(Ll) machines - aircraft 248.04-248.18 and 248.20 were delivered without engines. The series 48 and 248 fighters were dispatched to Flek 6 in Wiener-Neustadt and placed in storage. Subsequently, a few were flown as trainers or assigned to home defense duties in August 1918. Twenty eight were offered for sale to Czechoslovakia in 1920.
  The first Aviatik D.I(Ll) series 348 fighter was accepted in September 1918. On 31 October 1918, the remaining 69 series 348 fighters were reported completed and awaiting acceptance at Aszod but never delivered to the LFT. A handful were taken over and flown by the Hungarian air service. Aircraft 348.45, 348.46 and 348.49 were attached to the 4th Squadron of the Hungarian Red Airborne Corps at Gyor in April 1919. Hungarian pilot J. Kretz, flying 349.49, shot down a Czech Lebed XII two-seater over Gyor during the postwar fighting. According to Hungarian sources, some D.I(Ll) series 348 fighters were deployed for coastal defense and a few were captured by Italian or Yugoslav troops. As late as 1942, the fuselage of 348.61 was on display in the Hungarian War Museum in Budapest.


WKF 80.08

  This prototype has been identified as an Aviatik D.I built by WKF. As was customary at the time, a production airframe (possibly 84.01) was assigned a prototype number for purposes of engineering inspection and flight evaluation before being given a standard series number. The 80.08 prototype, powered by a 185 hp Daimler engine, was recorded at Aspern on 27 May 1918.


Aviatik D.I(WKF) Series 84, 184, 284, and 384

  WKF became one of the five companies to build the Aviatik D.I under license in July 1917, when Flars placed an order for 48 Aviatik D.I(WKF) fighters, followed by a contract for 50 more on 10 May 1918. In mid-1918, when the original production batches were re-numbered according to engine availability, the production break-down was as follows:
Qty Serial No. Engine Order Date First Acceptance
10 84.01-10 185 Dm 10 May 1918 September 1918
24 184.01-24 200 Dm July 1917 May 1918
24 284.01-24 160 Dm July 1917 May 1918
40 384.01-40 225 Dm 10 May 1918 August 1918
  As was the case with the Aviatik C.I(WKF), the acceptances commenced almost a year after the order was placed. About half the fighters were accepted without engines and the remainder left the factory fitted with reconditioned engines. Records show of the total (45) accepted through October 1918, only six left the factory with machine guns installed.


Aviatik D.I(WKF) Series 84

  The Aviatik D.I(WKF) series 84.01 to 84.10 were intended (and possibly specially equipped) as advanced, single-seat trainers. It is possible that a few served in that capacity with Flek 6 in September-October 1918. All ten survived the war and were in storage awaiting disposal in March 1919. Eight were offered for sale to the Czechoslovakian government in 1920.


Aviatik D.I(WKF) Series 184

  Of the 24 ordered, only a single D.I(WKF) fighter (184.01) was accepted prior to 31 October 1918. It joined Flik 72/J in June 1918. At the war's end, 23 series 184 airframes (numbered 184.02 to 184.24), virtually completed and scheduled for delivery in November, were provisionally accepted by the resident Flars representative. The airframes appear to have been scrapped since they do not figure in the postwar disposal records.


Aviatik D.I(WKF) Series 284

  All D.I(WKF) series 284.01 to 284.24 were accepted prior to September 1918. Confusion exists because WKF completed 24 additional series 284 airframes, originally numbered 284.25 to 284.48. Prior to delivery, Flars decreed that these were to receive the 225 hp Daimler engine and be re-designated series 384. However, before implementation at least 35 series 284 fighters entered the records when they were assigned to rear-area distribution centers, but only a handful actually reached operational units before the war ended. Known are Flik 14/J in the South Tirol and the two field flying schools. One series 284 fighter saw service with Flik 6 in Albania. On 28 August 1918, six Aviatik D.I(WKF) series 284 were released by the LFT to the Navy, but it is doubtful if the transfer occurred. In 1920, aircraft 284.07, 20, 28, and 31 were offered to the Czechoslovakian government.


Aviatik D.I(WKF) Series 384

  Ten Aviatik fighters powered by 225 hp Daimler engines were accepted as series 384 while still carrying their old numbers (284.25, 27, 28, 29, 31, 32, 37, 39, 42, and 48). However, it appears they never left the factory, for after the war 40 series 384 airframes were counted at the WKF factory in good condition - the last 30 airframes, scheduled for delivery in November and December 1918, having been accepted by the resident Flars officer.


Aviatik D.I(MAG) Series 92

  On 9 October 1917, the total of 46 Aviatik D.I(MAG) fighters, ordered on 17 July 1917, was increased to 72 at the expense of the Aviatik C.I(MAG). In addition another 100 fighters were ordered on 10 May 1918. Acceptances of the fighters, numbered 92.01 to 92.172 and powered by the 200 hp Daimler(MAG) engine, began in April 1918. By 31 October, 121 had been accepted, almost all without armament and some without engines.
  When Flik 72/J on the Piave Front received the first Aviatik D.I(MAG) in August 1918, evaluation flights produced such dismal results that the squadron rejected the type because "...it is impossible to fly this aircraft over the enemy...the wing cellule is even weaker than that of the early Aviatik D.I series 38, 138 and 238 fighters" which had been grounded in July 1918 by the Army Command. The 6th Army Command ordered Flik 72/J pilots to inspect and test the series 92 machines stored at Pordenone. It was found that aircraft below 92.50 had been manufactured according to the old Aviatik D.I drawings. The wing cut-out was missing. When tested in a spin, the lower wing (not the short-span version as in late model Aviatik-built fighters) "always showed breakage." Furthermore, the quality of MAG workmanship was defective and slipshod. Nevertheless, in the summer of 1918 the Aviatik D.I(MAG) became operational in small numbers with Fliks 1/J, 6/F, and 13/J on the Balkan Front and in south Tirol with Fliks 7/J, 20/J, and 23/D. Flik 7/J was unique in that it was the only unit totally composed of MAG-built Aviatik fighters. In September-October at least 42 aircraft were rejected by three Army commands and withdrawn from the Front. On 10 October 1918, Flik 74/J tested aircraft 92.18 fitted with reinforced wing ribs and found that at 150 km/h (93 mph - well below its top speed of 187 km/h - 116 mph) the upper-wing trailing edge and the lower wing vibrated so severely that "...one cannot develop trust in the aircraft."
  Twenty-five Aviatik D.I(MAG) fighters were offered to the Czechoslovakian government in 1920. The Hungarian Red Airborne Corps had in service aircraft 92.83 (later civil register HJ 83), 92.85 (HJ 85), 92.80 (armed with a Gebauer motor machine-gun), 92.106 (HJ 106), 92.107 (HJ 107) and 92.115 (HJ 115). Aircraft 92.148 of the 3rd Squadron that landed in Austria in 1919 was confiscated and returned to Hungary on 28 March 1920. The highest serial number identified in Hungarian postwar records is 92.170.
Aviatik D.I(MAG) Series 92 Specifications
Engine: 200 hp Daimler (MAG)
Wing: Span Upper 8.00 m (26.25 ft)
Span Lower 8.00 m (26.25 ft)
Chord Upper 1.45 m (4.76 ft)
Chord Lower 1.45 m (4.76 ft)
Gap 1.47 m (4.82 ft)
Stagger 0.18 m (0.59 ft)
Total Wing Area 22.0 sq m (237 sq ft)
General: Length 6.86 m (22.51 ft)
Height 2.55 m (8.37 ft)
Loaded Weight 888 kg (1958 lb)
Maximum Speed: 200 km/hr (124 mph)
Climb: 1000m (3,281ft) in 2 min 15 sec
2000m (6,562 ft) in 5 mm 30 sec
3000m (9,843 ft) in 10 min
4000m (13,124 ft) in 17 mm
5000m (16,405 ft) in 27 min


Aviatik D.I(Th) Series 101 and 201

  At the time when the formal production contract was signed on 21 June 1917, the first Thone & Fiala-built Aviatik D.I airframe was reported two weeks away from structural tests. A total of 60 Aviatik D.I fighters were ordered as follows:
Qty Series Number Engine Order Date
21 101.01-21 200 Dm 21 June 1917
9 201.01-09 185 Dm 21 June 1917
30 101.31-60 200 Dm May 1918
(Aircraft 201.01-03 were renumbered 101.22-24.)
  Initially all Aviatik D.I(Th) fighters were intended for training purposes and consequently had rebuilt engines installed. Flars reported minor quality-control problems in July 1917, but these were quickly overcome and aircraft of superior workmanship were delivered thereafter. The first production machine, 101.01, arrived at Fischamend on 9 November 1917 for machine-gun installation and was returned to Thone & Fiala on 19 December 1917 to serve as a pattern aircraft. Production acceptances began in March 1918. Owing to the machine-gun shortage, only the first 15 aircraft were delivered armed. Through 31 October 1918, a total of 34 Aviatik D.I(Th) fighters was accepted; ten were provisionally accepted after the war and 16 partially-completed airframes were scrapped.
  Twenty series 101 and two series 201 fighters were listed in the 11th Army frontline inventory of 20 August 1918. Records show that the series primarily saw combat service with Flik 31/P as a photo-reconnaissance fighter. The downing of an Italian Hanriot fighter by Leutnant Vjekoslav Tomasic of Flik 31/P on 4 October 1918, flying aircraft 101.05, is the only known victory achieved with this series. Aircraft 101.32 and 101.33, assigned to Flek 6, were later taken over by the Austrian air service.
  The airframe of aircraft 101.37, presently exhibited in the Technical Museum in Vienna, is noteworthy for its excellent craftsmanship. A few years ago, a rotary-engined biplane (Austrian civil registration A 9) was discovered in a barn and identified as the original Aviatik D.I(Th) 101.40 airframe. Now beautifully restored by the Champlin Fighter Museum in Arizona, it is exhibited in its original 1918 appearance.

E.Hauke, W.Schroeder, B.Totschinger Die Flugzeuge der k.u.k. Luftfahrtruppe und Seeflieger 1914-1918

30. Flugzeuge der Österreichischen Aviatik-Werke Wien, Stadlau
38.01 — 38.72 Aviatik D.I Berg Dm 185
138.01 —138.120 Aviatik D.I Berg Dm 200
238.01 —238.134 Aviatik D.I Berg Dm 160
338.01 — 338.61 Aviatik D.I Berg Dm 225

10. Flugzeuge der Fabrik Jacob Löhner & Co. Wien, Floridsdorf
115.01 — 115.89 Aviatik D.I (Lo) Dm 200
315.01 — 315.29 Aviatik D.I (Lo) Dm 225

40. Flugzeuge der Ungarischen Lloyd-Flugzeugfabrik Budapest
48.01 — 48.10 Aviatik D.I (LI) Berg Dm 185
248.01 — 248.28 Aviatik D.I (LI) Berg Dm 160
348.01 — 348.16 Aviatik D.I (LI) Berg Dm 225

80. Flugzeuge der Wiener Karosserie-Fabrik (W.K.F.) Wien und Hennersdorf
80.02 W.K.F. Aviatik Berg D.I Musterflugzeug Dm 185
84.01 — 84.14 Aviatik D.I (W.K.F.) Berg Dm 185
184.01 — 184.24 Aviatik D.I (W.K.F.) Berg Dm 200
284.01 — 284.48 Aviatik D.I (W.K.F.) Berg Dm 160
384.01 — 384.14 Aviatik D.I (W.K.F.) Berg Dm 225

90. Flugzeuge der Ungarischen Allgemeinen Maschinenfabrik, M.A.G.
92.01 — 92.106 Aviatik D.I (M.A.G.) Berg Dm 200

100. Flugzeuge der Flugzeugfabrik Thöne & Fiala Wien, Alsergrund
101.01 — 101.41 Aviatik D.I (Th) Berg Dm 200
201.01 — 201.09 Aviatik D.I (Th) Berg Dm 160. Dm 185

Журнал Flight

Flight, May 23, 1918.

THE AUSTRIAN BERG SINGLE-SEATER FIGHTER.
200 H.P. AUSTRO-DAIMLER ENGINE.

[While the different types of aeroplanes produced in Germany are fairly well known in this country, owing chiefly to the number of them that have been captured from time to time, our knowledge of the Austrian aircraft industry is more limited. This is partly due to the fact that fewer of them are seen on the western front, Austrian activities in the air being more particularly confined to the Italian theatre of war, where the various types of Austrian machines are probably as well known as are the German on the battle front in France. Also it should be remembered that to a large extent, so far as our knowledge goes, the Austrian industry has been conducted more along the lines of constructing German-designed machines under licence, thus tending to increase output, rather than with an aim to encouraging original design. That home designing has not been altogether stopped in Austria is evident, however, since from time to time one hears of Austrian machines, of makes known not to be German licence productions, being seen by Allied pilots. Among these is the Austrian Berg single-seater fighter. Reports have been received occasionally of this machine, but up to the present nothing definite has been generally known concerning it. Now, however, one of these has been added to the collection in the Enemy Aircraft View Rooms, and by the courtesy of the authorities we are able this week to publish a brief description and an illustration of the Austrian Berg. To the best of our knowledge this is the first description to be published in this country.-ED.]

   SIMPLICITY would appear to be the keynote of design in the Austrian Berg single-seater fighter, both as regards mass, or aerodynamic, design and structural design. The machine has every appearance of being designed chiefly with a view to rapidity of production, yet this object has been attained by a studied simplicity of detail rather than by any scamping in workmanship. In fact, although the finish is not, perhaps, as good as on some machines, the workmanship appears everywhere to be really quite good, and the materials employed in the construction are, if anything, better than found on a good many German machines. Whether this is due to a more plentiful supply of the right materials in Austria than in Germany, or whether Austrian inspection is stricter than that obtaining in Germany, is difficult to say; and one can only call attention to the fact without venturing an explanation.
   Fundamentally the Austrian Berg is of the single-seater fighter type in which the pilot and top plane are so placed in relation to each other that the wing obstructs the view to a very small extent only. This has been accomplished, not so much by reducing the gap to a smaller proportion of the chord than usual, as by making the body very deep and placing the pilot fairly high inside the body. On closer examination it is found that the extra depth of the body is provided by deepening the turtle back, which forms a much greater proportion of the overall depth than is the case in most machines.
   The body proper, which is of the flat-sided variety, is constructed on similar lines to those of the older models of Albatros biplanes, i.e., of longerons and struts of fairly small section, the whole being covered with three-ply wood. As distinct from the Albatros, however, there are only four longerons, the auxiliary rails halfway up the sides of the latter having evidently been deemed unnecessary by the designer of the Berg. The turtle back, which is different from the majority in that it does not, except in front, cover the whole width of the flat top of the body, but comes to a point just in front of the vertical fin, is of a peculiar section. This may, in the absence of a sketch, best be described by saying that it consists of three curvatures, a convex at the top, a concave halfway down, and again a convex at the bottom. The object, evidently, is to provide stream lining of the pilot's head by having the turtle back deep without, however, obstructing the view to too great an extent by having it very wide. Roughly the configuration is that of a man's head and shoulders.
   The pilot's cockpit is very comfortable, the deep top efficiently screening his face while at the same time, owing to the peculiar outline, not obstructing the view to as great an extent as one would imagine. By leaning his head slightly the pilot can easily look past the nose of the machine, so that there is really no "blind" spot beyond a few yards ahead of the machine. The fact that the chord line of the upper wing if projected passes through the pilot's line of vision renders the view forward and upward particularly good. Small circular windows are inserted in the turtle back in front of the pilot, but it appears that the view obtainable through these is of very little practical utility, and the inference is that they are placed there to admit light on to the instrument board rather than to provide direct vision.
   The pilot's seat is extremely comfortable, and is provided with arm rests, thus enabling the pilot to rest one arm while working the control lever with the other. For a long flight this makes for comfort. It is only a minor point, it is true, but one nevertheless which is worthy of consideration. On the whole the machine gives the impression that it would be a very comfortable machine to fly, regarded purely from the flying point of view, and without knowing anything about its capabilities as used for fighting.
   The controls are more or less of the usual type. There is a longitudinal rocking shaft, mounted rather higher above the floor boards than is generally the case. The control lever is forked around this shaft, and is free to oscillate forward and backward for operating the elevator. A short length of cable passes from the lower end of the "joystick" to a point on the floor boards. This limits the extent to which the lower end of the lever can move back, and has the effect of preventing, when on the ground, the elevators from touching and getting damaged. In connection with the lateral controls, the wing flaps are fitted with cranks resting in slots in the planes, and there is a somewhat unusual arrangement whereby the positive cable is taken to the front arm of the crank, so that it is the return cable which pulls the wing flap down. The reason for this may be found in the warped wing flap, which may conceivably have its outer tip tilted upwards to such an extent that the effect of moving the flaps is to put a force acting downward on the flap moved upwards before the flap on the opposite side, which has, of course, been moved down simultaneously, receives an upward force. To bring this peculiar action about the crank on the rocking shaft points downwards instead of, as is more usually the case, pointing upwards.
   The foot bar operating the rudder is of the T type. That is to say, the rudder control cables are attached to a crank arm projecting forward at right angles to the foot bar. The cables are then taken around pulleys near the side of the body, and hence to the rudder cranks. The guards on the rudder bar, which prevent the accidental slipping off of the pilot's feet, are in the form of spiral springs, each composed of two layers, an inner spiral of fairly thin wire, and an outer spiral of heavier wire.
   The engine, which, we are informed, was a 200 h.p. Austro-Daimler, is not shown in place on the machine, but it would appear to have been totally covered in by a deep engine housing. It is mounted on two spruce bearers, each made up of three laminations, mounted on four transverse partitions. These are made up of a spruce centre with facings of three-ply. The armament appears to have been made up of two machine guns, one on each side of the engine, and fitted with the usual interrupter gear.
   The wings, which are both of equal span, present nothing out of the ordinary as regards their construction, except that some of the fittings for the internal wire bracing and compression tubes are exceptionally neat in conception and well carried out. Aerodynamically, however, the wings present an interesting feature. The upper surface of the wing section has a most decided return sweep, beginning behind the rear spar and being of such a magnitude as to present a considerable area of concave surface.
   The undercarriage of the Berg is not in place on the machine as exhibited, but from fragments it is judged to have been of the Vee type, and in the accompanying illustration we have endeavoured to reconstruct it approximately as various considerations indicate that it must have been.
   The tail planes are built of steel tubing throughout, and the fixed tail plane is chiefly remarkable on account of the fact that, although it is built up of single steel tubes, the section is made cambered by bending the single tubes forming the ribs. Both upper and lower surfaces, therefore, have the same camber. The incidence of the tail plane is adjustable, but not during flight.
   Later, as opportunity occurs, we hope to be able to publish some illustrations of the more important constructional details of the Austrian Berg fighter.

  
  
Flight, October 24, 1918.

THE AUSTRIAN BERG SINGLE-SEATER
200 H.P. AUSTRO-DAIMLER ENGINE

[In our issue of May 23rd, 1918, we published a brief description and an illustration of the Austrian Berg Single-Seater. We have since been able to carefully examine this machine in detail, and to prepare drawings and sketches of its main constructional features.-ED.]

   As a type the Austrian Berg belongs to the single-seater fighter class with high-power engine. It follows what has now become almost standard practice for single-seaters in its strut arrangement, which comprises only one pair of interplane struts on each side. As a single-seater it is desirable that the view forward and upward shall be as good as possible, and this has been aimed at, and attained to quite a fair extent, in the Berg by placing the top plane low over the body, where, owing to the angle of incidence, the pilot from where he is placed sees it practically edge on. When we say that the top plane has been placed low over the body we do not mean to infer that the gap between the planes has been reduced beyond normal. Rather has the relative position of top plane and top of body been attained by making the body very deep at this point, and by so seating the pilot - fairly high in the body - that he obtains the view desired. This is accomplished, not so much by making the main body very deep, but by surmounting it with a fairing of turtleback of much greater depth than those usually found on machines of this size. With the object always in view of obstructing the pilot's vision to as small extent as possible, this turtle-back, also that portion of it lying in front of the pilot, has been kept narrow at the top. In section it forms what is roughly the shape of a man's head and shoulders, as will be seen from the front elevation in the general arrangement drawings. In this manner, by leaning his head slightly to one side or other, the pilot can easily see past his engine, the cowling of which, although not in place on the machine examined, has probably conformed to the same contour as the rest of the fuselage top. To the rear of the pilot's seat this turtle-back tapers off until it ends in a point some little distance ahead of the tail planes. The lateral taper of it is somewhat more abrupt than is that of the body rails, so that as the rear portion of the body is approached there is a widening strip of flat horizontal surface on each side of the turtle-back. This will be seen in the plan view of the general arrangement drawings and also in the plan of the body in Fig. 1.

Fuselage.
   Constructionally the fuselage of the Berg biplane is of the same type as that of the earlier models of Albatros biplanes, i.e., there is a light internal framework of wood, covered on sides as well as top and bottom with three-ply. There are no internal wires for bracing the body, the three-ply covering being relied upon to perform this function. Although not possessing such refinements as rounded sides, the body of the Berg is of fairly good stream-line form, as will be seen from the illustrations. The machine exhibited is in a somewhat incomplete state as regards its front portion, especially the top covering of it and the engine-housing and radiator, which is absent. We have endeavoured, however, to reconstruct it to a certain extent, as shown by the dotted lines in the side elevation of the general arrangement drawings. The top plane shows clearly that no radiator has been mounted in its centre section, and as there are no indications that the radiator has been fitted on the sides of the body, the inference is that it must have been placed in the extreme nose. As to the exact shape the radiator may have had, this is a matter for conjecture, but in view of the shape of the fuselage top it appears probable that the radiator was of somewhat similar shape, as otherwise undesirable lines must have developed where the shape of the radiator was carried into that of the engine-housing.
   The general shape of the body, and many of the details will be clear from Fig. 1. It will be seen that there are only four main longerons, whereas the early-type Albatros had six, two of which were placed approximately halfway up between upper and lower corner rails. In the front portion of the body the bulkheads are of special form to provide supports for the two engine-bearers. The shape of these bulkheads or engine cradles is shown in the half-sections I to V inset in Fig 1. As none of these cradles had been sectioned up on the machine examined, it has not been possible to do more than give their outward shape. Judging from such external evidence, however, as rows of tacks, it appears that these cradles or bulkheads are built up of an internal framework of spruce, leaving plenty of open spaces, the whole being covered on both sides by thin layers of three-ply wood. This applies to bulkhead V as well as to the others, although in the drawing it gives the impression of a solid piece of wood.
   From behind the pilot's cockpit to the stern the main members of the body are of simpler form, simple frames of vertical and horizontal struts alternating with bays in which the rectangular strut frame-is reinforced by diagonal struts crossing from corner to corner of the fuselage. These have not been shown in the drawing as they present no features of special interest.
   The manner of joining the struts and cross-members to the main longerons of the Berg is of the simplest, there being no wire bracing to provide for with consequent complexity. The struts simply rest, as shown in Fig. 2, on the longerons, and are secured in place by wood blocks. For the quite plain frames the wood blocks are the only supports for the struts, while where the frame is reinforced by diagonal struts - in the manner referred to above - the joint is slightly more complicated as shown in Fig. 2. Here the angles between the vertical and diagonal struts are filled with wood blocks, while a small triangle of three-ply is tacked to the sides, binding the three struts together. In the neighbourhood of the tail skid some slight variations dictated by local considerations are to be found, but the joint shown in Fig. 2 is typical of the fundamental principle
   The three-ply covering is in the form of fairly large sheets, the use of these being rendered possible by keeping the sides of the body quite flat. Adjoining sheets are butt-jointed, the joint being covered on the inside with a narrow strip of three-ply, which is riveted to the two sheets, thus holding them together. The whole appears to be done in the simplest possible manner so as to facilitate construction, yet it would appear to work quite well in practice. Altogether the impression an inspection of the Berg leaves is to the effect that everything has been designed to meet the requirements of easy production, everything being kept as simple as possible to this end. This does not mean that the workmanship is inferior. As a matter of fact, the workmanship is very good generally speaking, although the finish may be here and there of a slightly less polished order than is found in some machines. The flat top of the fuselage is covered underneath the turtleback by a thin layer of three-ply wood, extensively fretted, as shown in the plan view, Fig. 1. The turtle-back, itself is also of thin three-ply, mounted on light frames built up of several laminations bent to the curvature of the turtle-back at any point, and glued together. The front faces of these frames are covered with thin sheets of three-ply to prevent bending. Where it joins the flat top of the fuselage the turtle-back is tacked to thin strips of spruce, which are in turn tacked and glued to the flat top of the body. With this brief description of the fundamental construction of the Berg body we will leave this subject, the equipment and accessories that, although being placed in it do not form part of the main structure, being reserved for a further instalment.

(To be continued.)


Flight, October 31, 1918.

THE AUSTRIAN BERG SINGLE-SEATER
200 H.P. AUSTRO-DAIMLER ENGINE
(Continued from page 1198.)

   REFERENCE was made, in our last issue to the front bulkheads of the body, which serve the double purpose of body struts and cradles for the engine bearers. In Fig. 1 were shown half-sections of the five front bulkheads showing their general shape and proportions. Fig. 3 shows the general arrangement of the engine bearers and the cradles supporting them. The two engine bearers are built up of three laminations each, all of spruce. As the cradles are not so arranged as to form a series of triangles when seen in side elevation, as is not infrequently done on German machines, the diagonal bracing formed by the 3-ply covering has been reinforced, in the Berg, by two steel tubes on each side. These will be seen in Fig. 3. The front one runs from the point where the engine bearer rests on the front bulkhead to the 3-ply side where this joins former No. 2, the tube being horizontal in side view but sloping out in plan. This was also indicated in Fig. 1 published last week. The second tube, bolted at its front end to the second former, runs through an opening in the third and to the outer edge of the fourth former.

Engine.
   The engine with which the Berg was fitted is a 200 h.p. Austro-Daimler [particulars of which are published elsewhere in this issue, ED.], but as it was not in place on the machine when our representatives examined it we have not been able to obtain any details.

Tanks.
   The main petrol tank is placed in the bottom of the fuselage, and has, according to a stamp on it, a capacity of 82 litres (about 18 gallons). A small service tank is mounted inside the top cowling of the body, supported on four small steel tubes from the top longerons. This tank has a capacity of 16 litres (about 3.5 gallons). As the various connections are not intact on the machine it has been difficult to follow in detail the petrol feed system, but it appears probable that the main petrol tank is under pressure, the fuel being forced from it up into the small service tank by a hand pump mounted on the port side in the pilot's cockpit.

Instruments.
   Fig. 4 shows, in perspective, the whole front portion of the Berg. Underneath the turtle-back, which has been shown broken, will be seen, in front of the wind screen, the instrument board. Few of the instruments were in place when we examined the machine, and there were no indications that the set of instruments fitted contained any of unusual interest. The sides of the turtle-back are fitted at this point with circular windows in order to provide better lighting of the instrument board.
   The pilot's cockpit is of fairly roomy proportions, and the seat itself is of the "bucket" type, fitted with comfortable arm rests, which would appear to be a considerable advantage on a long flight. The seat is mounted, as indicated in Fig 4, partly on the built-up transverse framework at this point and partly on a tubular structure which supports the front of the seat. A safety belt is provided, the springs of which are in the form of rings made up of two sets of coil springs, one inside the other.

Controls.
   The controls of the Berg are shown in Fig. 5. The control lever itself is somewhat incomplete on the machine, the handle in which it terminates at the top being absent so that it has not been possible to ascertain the shape of the grip, otherwise the controls are intact. The control column, it will be seen, is a steel tube, forked at its lower end, the arms of the fork passing on each side of the longitudinal tubular rocking shaft. From upper and lower ends respectively of this fork pass the top and bottom cables of the elevator controls. A transverse bolt forms the pivot around which the control lever oscillates in a fore-and-aft direction. The longitudinal rocking shaft is carried in two bearings, the front one mounted on the bulkhead in front of the pilot, and the rear one carried on two short tubes sloping up from the floor of the cockpit. The aileron control cables, are attached to a crank passing down from the fore end of the rocking shaft. The effect of this arrangement is that the positive cable - that is to say, the cable that passes from the controls to the aileron - raises an aileron, while the return cable lowers an aileron. Why this arrangement has been adopted is not clear, unless it is assumed that the upturned tip of the ailerons has the effect of putting one aileron under a negative load before the corresponding aileron on the other side begins to exert a positive lift.
   The rudder bar of the Berg is welded up of sheet steel. It is of T shape, as shown in the sketch, the control cables passing from the base of the T instead of from the ends of the main cross bar. The foot bar is mounted on a cone of sheet steel, and is prevented from oscillating by a guide on each side, mounted on two short lengths of steel tubing. The base plate of the rudder bar cone has at its rear a lug, to which is attached a short length of cable that is bolted at its other end to the lower end of the control column. This cable has the effect of limiting the amount the control lever can be pushed forward, and has probably been incorporated in order to prevent the elevators from hanging down too low when the machine is on the ground. The rudder cables, after leaving the foot bar, pass over pulleys near the floor, on the sides of the body. These pulleys are indicated in Fig. 5, and one of them is shown in detail in Fig. 6. The pulleys are carried on simple sheet steel brackets bolted to a wood base. The pulley is surrounded with a guard to prevent the cable getting wedged between the pulley and the brackets.
   Where the elevator and rudder cables pass through the 3-ply sides of the body, they are provided with guides of the form shown in Fig. 7. On the inside of the body the guides are in the form of wood blocks shaped to the angle of the cable as shown in the bottom sketch, while on the outside the guides are made of thin sheet steel, screwed at each end to the 3-ply. The top sketch of Fig. 7 shows one of these.

Undercarriage.
   Although in the machine on view at the Enemy Aircraft View Rooms the undercarriage is not in place, there are sufficient of its component parts available to show that it is of the Vee type with struts of stream-line steel tubes. These tubes have been welded at their upper ends to base plates on the lower longerons, and in all four struts this welded joint has given way in the rough landing. The manner in which the struts were joined at the lower end is not apparent from the fragments available, and all it has been possible to do by way of reconstruction is to indicate, as was done in dotted lines in the general arrangement drawings and in the side elevation of Fig. 1, published last week, approximately the proportions and position of the undercarriage. The track, as nearly as it has been possible to judge, has been about 6 ft., and the tyres are marked 760 by 100.
   The tail skid is of the simplest possible form, and does not in itself present any unusual features. The manner of mounting it is, however, rather different from the majority of machines. As shown in Fig. 8, the swivelling skid is pivoted on a short forked member, which is in turn carried at the truncated end of a structure of light wooden strips covered with 3-ply. This structure is of good stream-line form, and although appearing very light, seems to stand up to its work quite satisfactorily. The details of the arrangement will be obvious from the illustration. Springing of the tail skid is provided by coil springs of similar type to those employed for the pilot's safety belt and for the foot guards on the rudder bar, i.e., a smaller spring is placed inside a larger one, and the whole is made up into the form of a ring, one loop of which passes over the free end of the tail skid, while the other is resting on a stub having a bell mouth, and which is mounted on the lower corner of the fuselage.

Tail Planes.
   The tail planes of the Berg are built up throughout of steel tubes. As distinct from the majority of German machines in which steel tubing is employed for tail planes, those of the Berg are of fairly large diameter, but are everywhere single, whereas in many German machines .the diameter of the tubes is very much smaller, but two, used to form a rib. The Berg tail plane is slightly cambered, but owing to its construction of single tubes the upper and lower cambers are parallel. Provision has been made for varying the angle of incidence of the tail plane to a small extent, but not during flight. The divided elevator is similarly built up, but is, of course, perfectly fiat. The tail plane is brazed to the vertical tube forming the stern post and to the bottom longerons of the fuselage. On top there is a stream-line strut joining the rear tube of the tail plane to the vertical stern post, and a cable bracing the tubular leading edge to the vertical fin, as shown in Fig. 9, while underneath the strut is in front and a cable at the rear. Thus on the tail plane a strut on top is balanced by a cable underneath, and vice versa. The lower bracing members of the tail plane come to a point on the fuselage. This was indicated in the general arrangement drawings and also in Fig. 1, published last week.
   The vertical fin is formed by a light structure of steel tubes, and to its rear edge is hinged the rudder, which is constructed on lines similar to those of the tail plane and elevator. Wood blocks spanning the hinges are provided for the attachment of the fabric covering.

(To be continued.)


Flight, November 14, 1918.

THE AUSTRIAN BERG SINGLE-SEATER
200 H.P. AUSTRO-DAIMLER ENGINE
(Concluded from page 1227.)

   THE wings of the Berg single-seater are characterised by the same simplicity - as regards their construction - as that found in the other parts of this machine, a simplicity, be it said, which does not result in scamped workmanship and hurried finish, but which bears evidence of careful design, with ease of production always kept in mind. The timber employed for the wings is of excellent quality, better than that found in the average German machine. The fittings, while apparently combining good strength with light weight, are as simple as possible, and welding is resorted to to a much smaller extent than is the case with the majority of fittings in German aeroplanes. Of the merits of the Berg as a fighting machine we have no information, but from a constructional point of view it shows many features that might with advantage be studied for cheap and rapid production of commercial aeroplanes after the war.
   The wing section of the Berg is somewhat unusual in that it has a pronounced reflex curvature of its trailing edge (upper camber), while the maximum camber of both upper and lower surface is much farther back than is usually the case in modern wing sections. This is clearly shown in Fig. 10. One result of the reflex curvature of the top camber is to provide a very flexible trailing edge, as the ribs become very thin towards the rear. It is probable that in this way a fair amount of lateral stability is provided, since a gust striking a wing will deflect the trailing portion, thus virtually reducing the lift, and the equilibrium of the whole machine may not, as a consequence, be disturbed to the same extent as would be the case in a machine having a rigid section. It is also possible that the reflex curvature may reduce to some extent the travel of the centre of pressure, and so improve the longitudinal stability. As regards the efficiency of this section we have no data available.
   Constructionally, the wings are built up of spruce spars of the box type, with ribs having spruce flanges and poplar webs. The webs are fret-sawed for lightness, and the solid portions between lightening holes are reinforced by vertical pieces of wood, riveted through the webs. The leading edge is also of spruce, hollowed out to a U section. The trailing edge is in the form of a wire. Between the spars there is a zig-zag formation of tape, passing over one rib and under the next and so on.
   The top plane, which is in one piece and has no dihedral angle, is supported from the body by N struts sloping outward slightly, as shown in the scale drawings published in our issue of October 24th. These struts are stream-line steel tubes, and are pin jointed so as to allow of adjustment when rigging. The fore-and-aft adjustment - which also serves to bring the wings at right angles to the centre line of the body - is carried out by having portions of the diagonal struts provided with a thread-and-locknut arrangement. The lateral adjustment is carried out in a, similar manner. The centre section struts form a letter W, as seen in front view, and the inner legs are provided with the same form of adjustment as are the diagonal side struts. In the rear bay the lateral bracing is in the form of cables, crossing above the body, since these are out of the way of the engine. By using struts in the front bay and placing them in a W formation the difficulty of clearing the engine is overcome, and adjustment still rendered possible. Fig. 11 shows the attachment of the front and diagonal side-struts to the top longeron. The struts have forked ends, which fit over the vertical lugs of the base plate that rests on and is bolted to the longeron. Directly bolted to the inner part of this base plate is the foot of the strut that provides lateral bracing for the front bay. This strut is rigidly attached to the longeron, but has the thread-and-locknut adjustment at its upper end. The attachment of the rear side-strut is shown in Fig. 12. This is similar to the attachment of the front struts, but there is the difference caused by the fact that in this bay the lateral bracing is in the form of cables. The manner in which this cable is attached to the base plate is shown in the sketch.
   The attachment of the lower planes to the fuselage is shown in the sketches, Figs. 13 and 14. The rear spar attachment is shown in Fig. 13. To the outer base plate is welded the lug to which the spar is attached by a forked spar box and a quick-release bolt. The rear strut of the undercarriage is also welded to this base plate, but to the lower horizontal part of it.
   Fig. 14 shows the attachment of the lower front spar and of the lift cables. The spar attachment is, it will be seen, very similar to that of the rear spar. There is, however, a horizontal tube running across the fuselage, thus resisting any tension there may be on the spars, while the lift cable attachment is also extended some distance in the manner shown, so as to spread the load to other of the members of which the bulkhead is composed.
   The fittings for the internal bracing of the planes are of a very neat and simple type. The compression struts are in the form of steel tubes, and the drift bracing is stranded cables, while the anti-drift wires are of the solid type. The inter-plane struts are streamline steel tubes, forked at their ends and fitting over eyebolts passing vertically through the spars. The general arrangement of these attachments and of the internal bracing system are indicated in Fig. 15. An analytical sketch of the fitting is given in Fig. 16. It consists of two forgings, one placed on top of the spar and one on the lower side of the spar, the two being held together by vertical bolts passing on the outside of the spar. In addition there is an eyebolt going through the-spar, and to this is anchored the forked end of the inter-plane strut. The lift cable is attached by means of a shackle to a lug formed on the top forging. The incidence cable is attached to the horizontal bolt passing through the fork end of the strut and through the eyebolt, by two very long chain links as shown. The compression tube between the wing spars also occurs at this point, and is attached to one of the vertical bolts on the side of the spars. This is done by welding to the end of the compression tube a strip of sheet steel forming the lugs of the internal bracing, and through the solid part of metal thus formed bore a hole for the vertical bolt. The whole joint is very neat when in place, and is shown from the outside in Fig. 17. This sketch also shows the mounting, on the lower spar, of the aileron cable pulleys.
   In last week s issue we referred to the aileron control system, in which the direct cable from the controls passes to the forward arm of the aileron crank lever, thus pulling the aileron up, while the pulling down of the opposite aileron is left to the return cable. It was pointed out that this system, which is rather the reverse of what is usual practice, has probably been adopted because of the warped ailerons, which may possibly owing to their upward turned tips come under a negative load before the opposite aileron begins to give a positive lift. The aileron and a portion of the upper plane are shown in Fig. 18. The aileron, which is of tubular construction, is hinged to a false spar as in nearly all machines of enemy origin. It will be noticed that this portion of the top plane is generously provided with three-ply reinforcement. The horizontal aileron crank lever works in a slot formed by triangles of ply-wood, and the control cables pass from the cranks over pulleys as shown in Fig. 17, and hence to the controls, passing through the bottom plane.

Camouflage.
   The Berg single-seater is somewhat different from German machines in its camouflage, possibly because it has been used on the Italian front, where the ground is of different colouring. The whole of the tail and the under surface of both main planes are painted a pale sandy yellowish brown, while the body and top surfaces of the planes are painted in addition with irregular streaks of a darker brown.