A Forgotten Few: Austro-Hungarian Fighters

‘The advent of World War I found the Austro-Hungarian Empire poorly equipped to fight a war of attrition. The industrial base of the Dual Monarchy, barely equal to the insatiable demands of technological warfare, was never able to attain the high level of mobilization of its powerful German ally.’

Austro-Hungarian Army Aircraft of World War One by Peter Grosz, George Haddow and Peter Schiemer.

Adding to these concerns was the faltering start in the field made from the outset by the Austro-Hungarian army, which was characterized by “a posture of watchful neglect on behalf of the War Ministry, abetted by an unimaginative, ultra-conservative officer corps.” Nevertheless, military ballooning had begun in 1890 and by 1911 the service was known as the Luftschifferabteilung, (airship section or LA). However, it was soon realised that the expense of maintaining and operating even a small fleet of airships would swallow up the entire budget of the fledgling service and they were abandoned in favour of aeroplanes that same year. In 1910, a competition was held to choose the air service’s aircraft and the German Etrich Taube monoplane was judged to be the outstanding winner.

Yet, expenditure on the air service remained meagre and it was not until the arrival of the energetic Major Emil Uzelac as the service’s first commander in 1912 that the situation began to improve. With the encouragement of the Army’s Chief of Staff, Conrad von Hötzendorf, the service planned an ambitious programme of expansion to 40 Fliegerkompagnien (Fliks or squadrons), totalling 240 aircraft by 1916.

Unfortunately, the Austrian War Ministry failed to foster competition between the different Austrian and Hungarian aircraft companies in the immediate pre-war years and chose to rely exclusively on products built by Lohner, a company owned by Austrian businessman Camilio Castiglioni. Competing companies, faced by a lack of orders, were forced into bankruptcy and large numbers of talented Austro-Hungarian designers and engineers left to find employment in Germany.

With the beginning of hostilities in July 1914 and the subsequent escalation into a general European war, the War Ministry had no choice but to permit German companies to establish subsidiaries in Austria to address the shortfall in both numbers and quality of aircraft. The German firms of Albatros, (trading in Austria as Phönix) and Aviatik built factories in Vienna, Deutsche Flugzeug Werke, (DFW), established Lloyd in Aszód, near Budapest, while Castiglioni purchased the German Brandenburg company from Etrich. Castiglioni later gained control of Phönix and the Ungarische Flugzeug Werke, (UFAG), adding them to his already sizeable empire. Meanwhile, following Italy’s declaration of war in 1915, the LA’s name was changed to Luftfahrtruppen, (aviation troops or LFT).

During 1915 and early 1916, Austro-Hungarian aircraft found themselves increasingly engaged in air combat with their Italian counterparts over the Alpine territory of northern Italy and the pressing need for an effective fighter aircraft soon became apparent. A small consignment of Fokker E.IIIs was somewhat reluctantly despatched from Germany but these were already nearing obsolescence. The German refusal to provide more modern fighter aircraft, added to the increasing numbers of Italian Nieuport 10s and 11s, made matters worse. Accordingly, the War Ministry had no choice but to turn to the Empire’s domestic aircraft industry for help.

The Brandenburg D.I

By fortunate, (or, perhaps, unfortunate), chance, the Brandenburg company was designing a new fighter aircraft in the spring of 1916. This aircraft employed Professor Knoller’s pyramidal design of interplane bracing, supposed to impart great strength and, owing to the lack of bracing wires, low drag, although this claim appears dubious. This arrangement gave the aircraft its distinctive appearance and the familiar nickname of “star-strutter”.

The first prototype, known as the Kampfdoppeldekker, or KD, flew during the spring of 1916 and a refined second prototype was ordered by the LFT in April the same year. It was while this aircraft was undergoing trials with Flik 26 that Uzelac ordered the production of 122 aircraft, now to be known as the Brandenburg D.I. Fifty would be produced by Brandenburg in Germany and the rest under licence by Phönix, at Stadlau in Vienna.

Brandenburg’s first series of twenty aircraft, (serials 65.50 to 65.69), was fitted with the 160hp Daimler engine, while the second series, (serials 65.70 to 65.99), was fitted with the 150hp Daimler. Aircraft from this second series were structurally lightened but, due to the lower engine power output, demonstrated only marginally improved performance over the first series in manoeuvrability and climb. The engine on all versions of the aircraft was completely enclosed in a bulky cowling which partially impaired the pilot’s view forwards. In consequence, the gun sight was fitted to the fuselage side. The gun itself was housed inside a Type II VK gun canister weighing 82 lb, which further reduced the aircraft’s performance and, with the Brandenburg becoming known as the “Flying Coffin”, was nicknamed the “Baby Coffin”.

The version built by Phönix was lighter and fitted with the 185hp Daimler engine, improving performance slightly. The seat was raised, allowing the pilot to sight the single machine gun without leaning out of the cockpit. Unsurprisingly, the Phönix-built Brandenburgs were “vastly preferred” to their German counterparts and would score the majority of the type’s victories.

The first Brandenburg-built D.Is began to arrive at the Front in November 1916 and the first Phönix-built versions in February 1917. Unfortunately, initial combat experience was universally discouraging. Adolf Heyrowsky, the commander of Flik 19, regarded the D.I as obsolete upon arrival and was particularly critical not only of its low ceiling, (9,840 feet) but also its poor handling. In November 1916, Uzelac, on learning that Flik 19 had grounded the Brandenburg D.I, visited the unit and, in Heyrowsky’s absence, demanded to fly one of the aircraft. When Heyrowsky returned he found that Uzelac had crashed the aircraft and was in hospital with concussion, an incident which can have done little to enhance the fighter’s reputation. A formal report produced in February 1917 further condemned the D.I for its poor climb and reiterated concerns over the aircraft’s dangerous flying characteristics. In desperation, tailfins were manufactured by Brandenburg and sent out to the Fliks to provide a measure of stability but, at best, this was only a stopgap measure.

On 20 May 1917, Flik 23 reported:

In the pilots’ unanimous opinion, they cannot give full attention to the combat at hand if they are so totally occupied with controlling the aircraft. In addition, the climb is so slow that the fighter must take off well before our observation aircraft in order to reach escort altitude. The KD’s ceiling is much inferior to that of enemy Nieuports, which generally operate between 4 and 5000 metres.

While Flik 41/J stated:

The KD is absolutely useless…the best pilots (and only they can fly the type) are shackled, ruin their nerves and perish in crashes over the airfield, without their expert skill achieving anything.

On 26 May, Uzelac wrote a letter to units operating the D.I, in which he acknowledged the aircraft’s faults but stated that, faute de mieux, pilots would have to persevere until better aircraft became available. It is interesting to note, however, that, despite the Hansa-Brandenburg’s poor reputation, it was flown with success by the five highest-scoring Austrian aces, as shown in the table which follows this article.

A few units converted the aircraft to the photo-reconnaissance role but, as new fighters were introduced, so the Brandenburgs were gradually withdrawn. The LFT ordered all Brandenburg D.Is to be removed from the Front in January 1918.

Ironically, a few D.Is found a new lease of life at training units, where the aircraft’s notoriously difficult flying characteristics can scarcely have endeared it to pupils.

The Aviatik D.I

Help was at hand however. On 16 October 1916, Aviatik tested a new fighter, designated the 30.14. This could not have ended more disastrously however, for the aircraft, after making a few hops along the ground, rose into the air, described a “wobbly” flight path and then, during a turn, crashed sufficiently violently to kill its pilot, Ferdinand Konschel. A revised version was built, (the 30.14 “improved”) and this aircraft so impressed the LFT that an order for another prototype was given, incorporating some 40 improvements. Flars, (Fliegerarsenal, Aviation arsenal, the organisation responsible for testing, production and acceptance of LFT equipment), test pilot Oskar Fekete was enthusiastic about 30.19, reporting on its “fabulous climb and enormous manoeuvrability.” The aircraft was despatched to the Italian Front on 15 May 1917 where, eight days later, it scored the type’s first success, when it shot down a Caproni bomber. By now, the Brandenburg D.I’s shortcomings were well-known and the LFT lost no time in ordering the new fighter, christened Aviatik D.I, in quantity. Indeed, so impressive was the Aviatik, and so urgent was the LFT’s need for a new fighter, that large orders were placed for production with the parent company and five other manufacturers. By the end of the war, Aviatik D.Is had been produced by the following companies:

Aviatik: 336
Lohner: 110
Thöne & Fiala: 34
MAG: 121
WKF: 45
Lloyd: 31

Initially, like so many new aircraft, the Aviatik D.I suffered from teething troubles. Early production was slowed as Aviatik had to strengthen the aircraft’s wing. The first examples, (the series 38), which saw service from the late summer of 1917 were not equipped with a gun synchronisation system. The wing-mounted machine gun was instead set at an angle of fifteen degrees to avoid the propeller’s arc and was reported by pilots to be “utterly ineffective.” From December 1917, twin synchronised machine guns were fitted but these were out of reach in the event of a stoppage. It was not until June/July 1918 that D.Is were delivered with accessible machine guns. As with the Brandenburg, the height of the engine cowling restricted forward visibility and the gun sight was fitted to the side of the fuselage. In consequence, much time and effort was devoted to improving visibility for the pilot; a range of different radiator shapes were tested but none was truly satisfactory. In 1918, fresh concerns were raised over fatigue weakness in the upper wing. Flik 74/J, for example, reported three incidents involving the failure of the upper wing. In response, Aviatik produced a strengthened wing which, however, only gradually entered production, probably due to the necessity of using up stocks made to the original design.

Aviatik would eventually produce the D.I in four series, differing in terms of engine power output. Pressure for better performance from the LFT resulted in 200hp (series 138) and then 225hp (series 338) Daimler engines being fitted. However, the parlous state of the engine industry forced the use of reconditioned 160hp engines being used in the series 238. These aircraft were, naturally, considered underpowered and generally disliked by the front-line Fliks. Indeed, many resorted to bartering more powerful engines from depots or even recovering them from other wrecked D.Is.

Lohner began producing the Aviatik D.I in late 1917 in two series, one with the 200hp engine, the other with the 225hp engine. However, the Lohner aircraft are best remembered for a series of catastrophic upper wing failures stemming from a failure to follow Aviatik’s manufacturing specifications. Although the problem was identified and solved, the Lohner-built aircraft acquired an evil reputation, especially following the death of leading ace Frank Linke-Crawford. On 30th July 1918, Linke-Crawford, flying a Lohner-built D.I, entered a dive while in combat with Italian Hanriots, and was seen to be “throwing papers overboard”. In fact, the “papers” were pieces of wing fabric. As Linke-Crawford pulled out of the dive and throttled back in an attempt to nurse his aircraft home, he was attacked and shot down. Ironically, Linke-Crawford is credited with the only confirmed kill for a Lohner-built Aviatik D.I.

Aircraft built by Thöne & Viala, (a small Viennese firm building other company’s products), were produced with reconditioned engines and originally assigned to training units. However, a number of aircraft served with Flik 31/P as photo-reconnaissance aircraft and that unit scored the only known success for a Thöne & Viala-built D.I, destroying an Italian Hanriot on 4 October 1918.

MAG, (Ungarische Allgemeine Maschinenfabrik AG, a company partially owned by Fokker), produced 121 aircraft between April and October 1918, many of which were unarmed and without engines. The wings of these aircraft were manufactured according to the original Aviatik design and suffered from structural weakness. This, in combination with “defective and slipshod” workmanship, doomed the aircraft’s reputation, in spite of remedial work undertaken to cure the problem. A strengthened aircraft was tested in 1918 but both wings vibrated so badly that a subsequent report stated that “one cannot develop trust in the aircraft.” Nevertheless, a few MAG-built examples served in the Balkans and Tyrol.

Orders for 98 Aviatik D.Is were placed with WKF, (Wiener Karosserie und Flugzeugfabrik, a car body and furniture manufacturer), but no more than 45 are known to have been delivered, about half of which were accepted without engines; just six had machine guns fitted. Although ordered in the summer of 1917, it was a year before the first acceptances began and only a tiny number of WKF-built Aviatik D.Is saw service before the war ended.

Lloyd began production of the Aviatik D.I in 1918 but only a few were delivered with engines and all were unarmed, being finished as photo-reconnaissance aircraft. All appear to have been placed in storage before the war’s end.

The Aviatik D.I cannot be regarded as the most successful of the Dual Monarchy’s fighters, due in large part to the structural weakness which plagued the design during its lifetime. Added to this were dire engine shortages, which crippled production of the aircraft.

Of the Empire’s leading aces, Julius Arigi and Frank Linke-Crawford are each known to have scored seven victories on the type.

The Phönix D.I-III

At the time that Phönix began licence production of the Brandenburg D.I, the company started to explore the potential of the so-called “Nieuport wing”, or sesquiplane. Although known to be weaker than a conventional lower wing, the sesquiplane design appeared to offer a number of compensating benefits, not least of which was an excellent field of view downwards for the pilot. Tests were made with a prototype aircraft adapted from a Brandenburg D.I. The forward fuselage was raised to the level of the upper wing, which was increased in area. Although this aircraft was soon crashed, it was rebuilt, as serial 20.14, and incorporated a redesigned fuselage.

A second prototype, (serial 20.15), was constructed in parallel, fitted with a conventional lower wing and a 185hp engine, while a third, (serial 20.16), was fitted with a revised form of sesquiplane wing and a 200hp engine. All three were tested during June 1917 and it was quickly established that, while the second prototype was superior in rate of climb to the first aircraft, the third “did not demonstrate suitable flight characteristics.” There appeared to be concerns regarding the strength of the sesquiplane lower wing on the first and third prototypes, an unsurprising criticism in the light of problems encountered by Nieuport and Albatros.

However, it was not considered that the second aircraft possessed the performance required. More power was the solution and the third prototype was returned to the Phönix works, where the wings were replaced with revised versions of those tested on the second prototype. This aircraft was tested and officially inspected in August 1917, when Flars pronounced it “ripe for production.” It was this aircraft which provided the basis for the Phönix D.I.

The Phönix D.I entered service in October 1917 and immediately found favour thanks to its docile handling characteristics. However, some pilots complained about the aircraft’s lack of speed and poor rate of climb against “Nieuport, SPAD and Sopwith fighters” and felt that the D.I was “almost too stable for quick combat manoeuvres.”

In response to these criticisms, Phönix produced aircraft serial 20.18, which featured high-aspect ailerons, no wing dihedral, a revised tailplane, balanced elevators and a lighter airframe, all of which was designed to improve the aircraft’s manoeuvrability. A comparative trial on 19 December 1917 proved that, while the production D.I took 28 minutes to reach 16,405 feet, the new aircraft took only 19 minutes. Flars immediately ordered the aircraft into production as the Phönix D.II.

In March 1918, Phönix further improved the D.II by fitting the 230hp Hiero engine. Although 48 of this mark, the D.IIa, were ordered, supply shortages forced Phönix to fit 200hp Hiero engines to approximately a fifth of the D.IIa airframes produced.

Further modifications were made to the design and five prototypes were built for the July 1918 Fighter Evaluation held at Aspern, Vienna. The first three, (serials 20.22, 20.23 and 422.23), were revised versions of the D.II/D.IIa. The aim was to improve visibility for the pilot, the accessibility of the machine guns and the aircraft’s performance and poor manoeuvrability, a lack of which was the type’s Achilles heel.

As far as can be ascertained, the changes made were:
Serial 20.22: 230hp Hiero engine, ailerons fitted to both wings, seat raised and machine guns moved to within reach of pilot.
Serial 20.23: 225hp Daimler engine, upper wing “raised slightly” and machine guns moved to within reach of pilot.
Serial 422.23: ailerons fitted to both wings.

Among the test pilots present at Aspern was Frank Linke-Crawford, who wrote approvingly:

For my squadron I desire a Phönix single-seater with the pilot’s view and machine guns located as in the 20.23; ailerons on both wings (20.22 and 422.23) and, if possible, the Gebauer motor machine gun. The bead sight should be replaced by an aiming telescope (English type with large field of view or the new electrical sight.

The final variant, the D.III, was designed with the test results in mind and incorporated ailerons on both lower and upper wings. However, by the time deliveries of the D.III were being made, the war was drawing to a close and none saw service with the Dual Monarchy. Nevertheless, the LFT’s unfulfilled decision, made in mid-1918, to concentrate production on two types of fighter in 1919, one being the famous Fokker D.VII, the other the Phönix D.III, speaks volumes for the latter’s reputation.

Of the leading Austro-Hungarian aces, Frank Linke-Crawford scored seven victories while flying a Phönix D.I, while Kurt Gruber scored six.

The fourth and fifth aircraft at the Competition, serials 20.24 and 20.25, were completely different to the Phönix scouts, as the photograph of the former shows. The streamlined, veneer-covered fuselage recalled Albatros practice, while the narrow lower wing gave the pilot an excellent downward field of view. Neither aircraft was ready when inspected at the Competition, nor were any production contracts placed before the war ended.

Mention must be made of the Oesterreichische Daimler Motoren (Oeffag) Albatros D.III, flown by many Austro-Hungarian fighter pilots. Oeffag, owned by Skoda, was awarded the contract to build the new fighter over Phönix, the obvious candidate. This decision, which at first sight seems anomalous, was motivated by two factors: first, the Phönix works was concentrating on the development of its own fighter and secondly, the War Ministry was eager to foster competition, in particular against the monopoly of Castiglioni’s Brandenburg-Phönix-UFAG empire.

The Oeffag factory corrected the structural deficiencies inherent in the original Albatros design and produced an excellent fighter aircraft. The absence of a spinner, a characteristic of the later Oeffag D.IIIs, improved the efficiency of the propeller and raised the maximum speed by nine miles per hour. Moreover, due to the strength of the design and the quality of the construction, the airframe was able, without serious detriment, to take a series of increasingly powerful engines.

The aircraft was well-received by the Fliks; indeed, all nine of the leading Austro-Hungarian aces scored victories while flying the Oeffag Albatros D.III.

Aircraft flown by the leading Austro-Hungarian Aces:

Godwin Brumowski (35 victories): Hansa-Brandenburg D.I, Albatros D.III
Julius Arigi (32 victories): Hansa-Brandenburg D.I, Albatros D.III, Aviatik D.I
Benno Fiala von Fernbrugg (28 victories): Hansa-Brandenburg D.I, Albatros D.III
Frank Linke-Crawford (27 victories): Hansa-Brandenburg D.I, Albatros D.III, Phönix D.I, Aviatik D.I
Jozsef Kiss (19 victories): Hansa-Brandenburg D.I, Albatros D.III
Ferenc Gräser (18 victories): Albatros D.III
Eugen Bönsch (16 victories): Albatros D.III
István Fejes (16 victories): Albatros D.III
Ernst Strohschneider (15 victories): Albatros D.III
Adolf Heyrowsky (12 victories): Hansa-Brandenburg C.I (two-seat aircraft)
Kurt Gruber (11 victories): Phönix D.I