An encyclopediae of 1914-18 aircraft types

Austro-Hungarian flag Knoller

The Knoller story: How to not do it

In 1914, Austro-Hungarian aviation was in sorry state, with many old planes from various manufacturers and origins stacked together, no tactics or proper school and this lack of coherence conducted the Army and its aviation corps branch to urge the adoption of homogeneous from various manufacturers. The first step was to order in 1915 eighty-six Hansa-Brandenburg B I aircraft, manufactured later up to 335 at Fischamend arsenal, but they were soon obsolete. So there were powerful solicitation throughout the Empire for more proposals from many manufacturers and in fact no less than 125 prototypes were tested, but few made it to production runs. One of these upstarts was the "Knoller Program" which until the provided resources for the development and production of trusted two-seater warplanes.

Richard Knoller, the founder, was actually a professor at the Technical University in Vienna, and seen as an aviation expert, already working with the Aviation Arsenal of Fischamend. Due to his backing, the project got credentials quite rapidly. However the program also underwent considerable time pressure, but went through three stages, with the development of the Knoller B I, C I and C II. Thöne & Fiala aircraft works started in January 1915 on the Knoller B I, a biplane plagued by initial delays, so much so the first flight only occurred on 13 November 1915. And this experience revealed numerous issues with the airframe.

Many improvements took plane until new tests were carried out by January-April 1916 helping to identify more agility and structure problems. But the B.II ultimately went through a forty-three production even though it was obviously not ready for it, from July 1916.
Knoller C.II
Meanwhile, starting already in late 1915 work began on a more powerful Knoller C.I was devised at Phönix works with the Aviation Arsenal, solving numerous technical issues delaying the first flight to April 1916, followed by more issues so much that these planes appeared to be a wasted investment, only countered by Knoller’s own reputation. Therefore after another serie, the military maintained their trust and ordered the development of the Knoller C.II, which, again, accumulated problem of its own.

Only by the spring of 1917 the Parliament got wind about what was happening with the "Knoller Program" and the issue was raised by Count Adalbert Sternberg, which publicly revealed the the development mess which had been until then stubbornly pursued, and obtained a vote for killing the program. In this enterprise, the Aviation Corps commissioned 185 Knoller aircrafts of all models between 1915 and 1918 which were all more or less unusable aeroplanes, or at least for training, but even were dangerous in this role.

Between considerable delays in the supply of more effective aircraft of a more sound design and the scarcity of resources, time and money were wasted. This could be a scenario familiar to us since this wastage appeared in time of war when the state's funds are allocated in emergency in such way, large open to any idea or submission.

Aircraft Industrial records

Thee Knoller as seen above were devised and produced, but without much success.
  • Knoller B.I (1916) -50
  • Knoller C.I (1916) -16
  • Knoller C.II (1917) -75
  • Knoller 70 (1918) -2 prototypes

Knoller B.I (1916)

Knoller B.I
Knoller B.I photo, credits flyingmachines.ru

The first plane in this lineage had exceptionally a wireless wing design (warren-truss wing cellule). But this observation biplane later denominated by the Army Knoller B.I proved on first trials structurally disastrous. The fuselage twisted so much that it added stress and deformation to the outer wings to the point of rupture in flight. Therefore many modifications were made to the first and second prototype, not with that much gains in performances although some issues were solved.

After the fifth production machine called 35.85 the Fliegerarsenal Fischamend ordered ten more aircraft (35.86 to 35.95) but only the first was shortly flown showing all its potential for disaster. The army then ordered the whole batch to be placed in storage, although some sources claims they were used some time for training. On december, 31, 1915, Aviatik earned a contract for 32 Knoller B.I more. However the first of this serie, 35.01 yet had again a cortege of structural issues and nearly crashed after a brief flight. The second one had its elevator horns rupturing while the the observator seat of the 35.07 wet through the fuselage and were grounded. In the end only 4 aircrafts ended for training and tests only.

Knoller B.I wings palette
Knoller B.I from wings palette

Knoller C.I (1916)

Knoller C.I - Aviadejavu.ru
The Knoller C.I, credits Aviadejavu.ru

The Knoller C.I was a reconnaissance aircraft defined as a conventional biplane design with staggered wings, while the pilot and observer were seated in tandem in an open cockpit and an upper swept back wing. Production took place at Phönix, but only a small numbers saw the light as the army was already interested by the Knoller C.II. The same problems that had plagued the B.I also grounded the C.I and there were no record of active use, or even proof they actually flown.

Crew: 2, pilot and observer
Dimensions: 8.5 x 12.70 x 3.30m (27 ft 11 in x 41 ft 8 in x 10 ft 10 in) x Wing area: 36 m2 (387 ft2)
Weight: Empty 780 kg (1,720 lb)
Engine: Austro-Daimler 120hp 6-cyl, 120 kW (160 hp)
Armament: 2x Spandau 8mm MGs

Knoller C.II (1917)

Knoller C.II
The Knoller C.II 119.15 at Prague museum

Prof. Richard Knoller designed the two-seat reconnaissance Knoller B.I manufactured by Aviatik (35 with a 100 hp Mercedes engine) and subcontracted by Thöne & Fiala. In the summer of 1916, the KuK Luftschifferabteilung commissioned Albatros from Vienna, Stadlau, to convert this biplane into a fighter, equipped with a 160 hp Austro-Daimler engine, which gave series 25, slightly redesigned in mid-1916. Aviatik and Lohner also entered production with the series designated Knoller C.II. In September 1916, the first arrived at Aspern. Lohner offered in its final letter from October, 10, 1916 to built the Knoller C II with a 160 hp Austro-Daimler and deliver 24 planes ar each 28,000 crowns each, and another 24 at 32,000 crowns each.

According to the performance of the Aviatik 30.10, maximum setup weight was under 700 kg. After inquiry because of the high surcharge, the company Lohner tried to cross the test cell with the type Aviatic 18.5 which represented 1500 hours of work but only 380 hours on the Lohner cell. The offer was approved by the Austro-Hungarian War Department with Decree 5/L3568, of 8 december 1916, registered on January 4, 1917 in the Commission Book No. 80, page 164. According to the final letter, the schedule included the following completions: 1 test plane ready on the 13th October 1916, then 2 on the 21st, then another three on Oct. 28, four on November, four on November 11, four on Dec. 23, four on Dec. 30 and the last four of the series on January 6, 1917.

Knoller C.II
The Knoller C.II 119.15 at Prague museum

The first 24 Lohner-Knoller C.II, Ba.19 were equipped with a 180 hp Austro-Daimler. The first completed aircraft of Aviatik (Ba 36) was delivered in September 1916 but only tested in Aspern on 10 February 1917 and revealed fatal structural problems: The wings collapsed in flight and the plane crasehd, killing the crew. They were solved by inscreasing the surface struts and fitting an additional fuselage strut. The first Lohner aircraft with this innovation and a 160 hp Austro-Daimler was the 19.25, prototype for the Ba. 119.

However as more accidents happened with this fighter aircraft, the War Ministry received instructions from the parliament to stop further work on the Knoller series in June 12, 1917. The Knoller C.II was a conventional reconnaissance biplane design, with staggered wings, pilot and observer seating in tandem in an open cockpit, but no defense MG. The upper wing was slightly less swept back and the fuselage was made of plywood with skinned fabric wings and the interplane struts were made of steel, placed in a warren truss configuration. Three batches of 25 planes were delivered respectively by Aviatik, Lohner, and WKF. The only surviving C.II is now on display at the National Technical Museum in Prague.
Crew: 2, pilot and observer
Dimensions: 8.54 x 10.37 x 3.02 m (28 ft x 34 ft x 9 ft 11 in), Wing area: 30 m2 (323 ft2)
Weight: Empty 695 kg (1,630 lb)
Engine: Austro-Daimler 185hp 6-cylinder 138 kW (185 hp).
Armament 2x Spandau 8mm MGs.

Knoller 70 (1918)

Knoller 70
Despite the cancellation of the program, the Knoller was still undergoing improvements. The model 70 single-seat biplane was started in late 1917 but was tested in 1918, followed quickly by an order for ten pre-series aircraft for additional evaluation. The Knoller 70.01 was the first of the only two prototypes completed, at Fliegerarsenal Fischamend. The wings were unstaggered with single bays with an inherent ability to "flex" on-the-fly with speed, reducing drag. Struts and bracing were both under and above the aircraft which fuselage had a large spinner added to the nose. The tail had a single vertical fin with mid-set horizontal planes while the undercarriage was a classic tail-dragger arrangement.

The plane was 7.98m (26.2 feet) wide for 6.37m (20.9 feet) long and 2.86m in height (9.4 feet). It was propelled by a Hiero 6-cylinder, water-cooled engine rated for 230 hp giving a top speed of 149 mph (239 kph) which is quite good. Th Knoller 70 was also armed by two 8mm Schwarzlose machine guns, synchronized and placed on the engine hood. The 70.01 first flew on November 23rd, 1917 but took some damaged and was repaired, ailerons being fitted at the upper wing members and it went into more tests in the spring of 1918, sadly undergoing a crash landing. The 70.02 ended testings in September 1918 but the next month where it was ready for orders, the armistice came out. Knoller 70 drawing
Profile of the Knoller 70.01 (from wingspalette.ru)
Dimensions: 6.35 x 8.00 x 2.85 m(20.83 x 26.25 ft x 9.35 ft)
Propulsion: Hiero 6-cylinder water-cooled 230 hp - Speed: 149 mph (240 kph; 130 kts)
Armament: 2 x 8mm Schwarzlose machine guns mounted over the nose and synchronized to fire through the spinning propeller blades

Src, Read More

https://knollerbikonstrukt.blogspot.fr/ (DE)
https://www.militaryfactory.com/aircraft/by-country.asp?Nation=Austria-Hungary https://ww1.habsburger.net/en/chapters/procurement-campaign-1915-16-and-knoller-programme
Did you known Karl Urban is an Hollywood actor but was also an Austro-Hungarian ww1 ace ?